gh-103763: Implement PEP 695 (#103764)

This implements PEP 695, Type Parameter Syntax. It adds support for:

- Generic functions (def func[T](): ...)
- Generic classes (class X[T](): ...)
- Type aliases (type X = ...)
- New scoping when the new syntax is used within a class body
- Compiler and interpreter changes to support the new syntax and scoping rules 

Co-authored-by: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Co-authored-by: Eric Traut <eric@traut.com>
Co-authored-by: Larry Hastings <larry@hastings.org>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

Doc/library/ast.rst

@@ -1724,6 +1724,7 @@ Function and class definitions
             body=[
                 FunctionDef(
                     name='f',
+                    typeparams=[],
                     args=arguments(
                         posonlyargs=[],
                         args=[
@@ -1847,6 +1848,7 @@ Function and class definitions
             body=[
                 ClassDef(
                     name='Foo',
+                    typeparams=[],
                     bases=[
                         Name(id='base1', ctx=Load()),
                         Name(id='base2', ctx=Load())],
@@ -1885,6 +1887,7 @@ Async and await
         body=[
             AsyncFunctionDef(
                 name='f',
+                typeparams=[],
                 args=arguments(
                     posonlyargs=[],
                     args=[],

Grammar/python.gram

@@ -112,6 +112,7 @@ simple_stmts[asdl_stmt_seq*]:
 # will throw a SyntaxError.
 simple_stmt[stmt_ty] (memo):
     | assignment
+    | &"type" type_alias
     | e=star_expressions { _PyAST_Expr(e, EXTRA) }
     | &'return' return_stmt
     | &('import' | 'from') import_stmt
@@ -252,8 +253,8 @@ class_def[stmt_ty]:
 
 class_def_raw[stmt_ty]:
     | invalid_class_def_raw
-    | 'class' a=NAME b=['(' z=[arguments] ')' { z }] ':' c=block {
+    | 'class' a=NAME t=[type_params] b=['(' z=[arguments] ')' { z }] ':' c=block {
-        _PyAST_ClassDef(a->v.Name.id,
+        _PyAST_ClassDef(a->v.Name.id, t,
                      (b) ? ((expr_ty) b)->v.Call.args : NULL,
                      (b) ? ((expr_ty) b)->v.Call.keywords : NULL,
                      c, NULL, EXTRA) }
@@ -267,16 +268,16 @@ function_def[stmt_ty]:
 
 function_def_raw[stmt_ty]:
     | invalid_def_raw
-    | 'def' n=NAME &&'(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block {
+    | 'def' n=NAME t=[type_params] &&'(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block {
-        _PyAST_FunctionDef(n->v.Name.id,
+        _PyAST_FunctionDef(n->v.Name.id, t,
                         (params) ? params : CHECK(arguments_ty, _PyPegen_empty_arguments(p)),
                         b, NULL, a, NEW_TYPE_COMMENT(p, tc), EXTRA) }
-    | ASYNC 'def' n=NAME &&'(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block {
+    | ASYNC 'def' n=NAME t=[type_params] &&'(' params=[params] ')' a=['->' z=expression { z }] &&':' tc=[func_type_comment] b=block {
         CHECK_VERSION(
             stmt_ty,
             5,
             "Async functions are",
-            _PyAST_AsyncFunctionDef(n->v.Name.id,
+            _PyAST_AsyncFunctionDef(n->v.Name.id, t,
                             (params) ? params : CHECK(arguments_ty, _PyPegen_empty_arguments(p)),
                             b, NULL, a, NEW_TYPE_COMMENT(p, tc), EXTRA)
         ) }
@@ -628,6 +629,39 @@ keyword_patterns[asdl_seq*]:
 keyword_pattern[KeyPatternPair*]:
     | arg=NAME '=' value=pattern { _PyPegen_key_pattern_pair(p, arg, value) }
 
+# Type statement
+# ---------------
+
+type_alias[stmt_ty]:
+    | "type" n=NAME t=[type_params] '=' b=expression {
+        CHECK_VERSION(stmt_ty, 12, "Type statement is",
+        _PyAST_TypeAlias(CHECK(expr_ty, _PyPegen_set_expr_context(p, n, Store)), t, b, EXTRA)) }
+
+# Type parameter declaration
+# --------------------------
+
+type_params[asdl_typeparam_seq*]: '[' t=type_param_seq  ']' {
+        CHECK_VERSION(asdl_typeparam_seq *, 12, "Type parameter lists are", t) }
+
+type_param_seq[asdl_typeparam_seq*]: a[asdl_typeparam_seq*]=','.type_param+ [','] { a }
+
+type_param[typeparam_ty] (memo):
+    | a=NAME b=[type_param_bound] { _PyAST_TypeVar(a->v.Name.id, b, EXTRA) }
+    | '*' a=NAME colon=":" e=expression {
+            RAISE_SYNTAX_ERROR_STARTING_FROM(colon, e->kind == Tuple_kind
+                ? "cannot use constraints with TypeVarTuple"
+                : "cannot use bound with TypeVarTuple")
+        }
+    | '*' a=NAME { _PyAST_TypeVarTuple(a->v.Name.id, EXTRA) }
+    | '**' a=NAME colon=":" e=expression {
+            RAISE_SYNTAX_ERROR_STARTING_FROM(colon, e->kind == Tuple_kind
+                ? "cannot use constraints with ParamSpec"
+                : "cannot use bound with ParamSpec")
+        }
+    | '**' a=NAME { _PyAST_ParamSpec(a->v.Name.id, EXTRA) }
+
+type_param_bound[expr_ty]: ":" e=expression { e }
+
 # EXPRESSIONS
 # -----------
 

Include/cpython/funcobject.h

@@ -41,6 +41,7 @@ typedef struct {
     PyObject *func_weakreflist; /* List of weak references */
     PyObject *func_module;      /* The __module__ attribute, can be anything */
     PyObject *func_annotations; /* Annotations, a dict or NULL */
+    PyObject *func_typeparams;  /* Tuple of active type variables or NULL */
     vectorcallfunc vectorcall;
     /* Version number for use by specializer.
      * Can set to non-zero when we want to specialize.

Include/internal/pycore_ast.h

@@ -51,6 +51,8 @@ typedef struct _pattern *pattern_ty;
 
 typedef struct _type_ignore *type_ignore_ty;
 
+typedef struct _typeparam *typeparam_ty;
+
 
 typedef struct {
     _ASDL_SEQ_HEAD
@@ -147,6 +149,13 @@ typedef struct {
 asdl_type_ignore_seq *_Py_asdl_type_ignore_seq_new(Py_ssize_t size, PyArena
                                                    *arena);
 
+typedef struct {
+    _ASDL_SEQ_HEAD
+    typeparam_ty typed_elements[1];
+} asdl_typeparam_seq;
+
+asdl_typeparam_seq *_Py_asdl_typeparam_seq_new(Py_ssize_t size, PyArena *arena);
+
 
 enum _mod_kind {Module_kind=1, Interactive_kind=2, Expression_kind=3,
                  FunctionType_kind=4};
@@ -176,17 +185,19 @@ struct _mod {
 
 enum _stmt_kind {FunctionDef_kind=1, AsyncFunctionDef_kind=2, ClassDef_kind=3,
                   Return_kind=4, Delete_kind=5, Assign_kind=6,
-                  AugAssign_kind=7, AnnAssign_kind=8, For_kind=9,
+                  TypeAlias_kind=7, AugAssign_kind=8, AnnAssign_kind=9,
-                  AsyncFor_kind=10, While_kind=11, If_kind=12, With_kind=13,
+                  For_kind=10, AsyncFor_kind=11, While_kind=12, If_kind=13,
-                  AsyncWith_kind=14, Match_kind=15, Raise_kind=16, Try_kind=17,
+                  With_kind=14, AsyncWith_kind=15, Match_kind=16,
-                  TryStar_kind=18, Assert_kind=19, Import_kind=20,
+                  Raise_kind=17, Try_kind=18, TryStar_kind=19, Assert_kind=20,
-                  ImportFrom_kind=21, Global_kind=22, Nonlocal_kind=23,
+                  Import_kind=21, ImportFrom_kind=22, Global_kind=23,
-                  Expr_kind=24, Pass_kind=25, Break_kind=26, Continue_kind=27};
+                  Nonlocal_kind=24, Expr_kind=25, Pass_kind=26, Break_kind=27,
+                  Continue_kind=28};
 struct _stmt {
     enum _stmt_kind kind;
     union {
         struct {
             identifier name;
+            asdl_typeparam_seq *typeparams;
             arguments_ty args;
             asdl_stmt_seq *body;
             asdl_expr_seq *decorator_list;
@@ -196,6 +207,7 @@ struct _stmt {
 
         struct {
             identifier name;
+            asdl_typeparam_seq *typeparams;
             arguments_ty args;
             asdl_stmt_seq *body;
             asdl_expr_seq *decorator_list;
@@ -205,6 +217,7 @@ struct _stmt {
 
         struct {
             identifier name;
+            asdl_typeparam_seq *typeparams;
             asdl_expr_seq *bases;
             asdl_keyword_seq *keywords;
             asdl_stmt_seq *body;
@@ -225,6 +238,12 @@ struct _stmt {
             string type_comment;
         } Assign;
 
+        struct {
+            expr_ty name;
+            asdl_typeparam_seq *typeparams;
+            expr_ty value;
+        } TypeAlias;
+
         struct {
             expr_ty target;
             operator_ty op;
@@ -630,6 +649,30 @@ struct _type_ignore {
     } v;
 };
 
+enum _typeparam_kind {TypeVar_kind=1, ParamSpec_kind=2, TypeVarTuple_kind=3};
+struct _typeparam {
+    enum _typeparam_kind kind;
+    union {
+        struct {
+            identifier name;
+            expr_ty bound;
+        } TypeVar;
+
+        struct {
+            identifier name;
+        } ParamSpec;
+
+        struct {
+            identifier name;
+        } TypeVarTuple;
+
+    } v;
+    int lineno;
+    int col_offset;
+    int end_lineno;
+    int end_col_offset;
+};
+
 
 // Note: these macros affect function definitions, not only call sites.
 mod_ty _PyAST_Module(asdl_stmt_seq * body, asdl_type_ignore_seq * type_ignores,
@@ -638,21 +681,22 @@ mod_ty _PyAST_Interactive(asdl_stmt_seq * body, PyArena *arena);
 mod_ty _PyAST_Expression(expr_ty body, PyArena *arena);
 mod_ty _PyAST_FunctionType(asdl_expr_seq * argtypes, expr_ty returns, PyArena
                            *arena);
-stmt_ty _PyAST_FunctionDef(identifier name, arguments_ty args, asdl_stmt_seq *
+stmt_ty _PyAST_FunctionDef(identifier name, asdl_typeparam_seq * typeparams,
-                           body, asdl_expr_seq * decorator_list, expr_ty
+                           arguments_ty args, asdl_stmt_seq * body,
-                           returns, string type_comment, int lineno, int
+                           asdl_expr_seq * decorator_list, expr_ty returns,
-                           col_offset, int end_lineno, int end_col_offset,
+                           string type_comment, int lineno, int col_offset, int
-                           PyArena *arena);
+                           end_lineno, int end_col_offset, PyArena *arena);
-stmt_ty _PyAST_AsyncFunctionDef(identifier name, arguments_ty args,
+stmt_ty _PyAST_AsyncFunctionDef(identifier name, asdl_typeparam_seq *
-                                asdl_stmt_seq * body, asdl_expr_seq *
+                                typeparams, arguments_ty args, asdl_stmt_seq *
-                                decorator_list, expr_ty returns, string
+                                body, asdl_expr_seq * decorator_list, expr_ty
-                                type_comment, int lineno, int col_offset, int
+                                returns, string type_comment, int lineno, int
-                                end_lineno, int end_col_offset, PyArena *arena);
+                                col_offset, int end_lineno, int end_col_offset,
-stmt_ty _PyAST_ClassDef(identifier name, asdl_expr_seq * bases,
+                                PyArena *arena);
-                        asdl_keyword_seq * keywords, asdl_stmt_seq * body,
+stmt_ty _PyAST_ClassDef(identifier name, asdl_typeparam_seq * typeparams,
-                        asdl_expr_seq * decorator_list, int lineno, int
+                        asdl_expr_seq * bases, asdl_keyword_seq * keywords,
-                        col_offset, int end_lineno, int end_col_offset, PyArena
+                        asdl_stmt_seq * body, asdl_expr_seq * decorator_list,
-                        *arena);
+                        int lineno, int col_offset, int end_lineno, int
+                        end_col_offset, PyArena *arena);
 stmt_ty _PyAST_Return(expr_ty value, int lineno, int col_offset, int
                       end_lineno, int end_col_offset, PyArena *arena);
 stmt_ty _PyAST_Delete(asdl_expr_seq * targets, int lineno, int col_offset, int
@@ -660,6 +704,9 @@ stmt_ty _PyAST_Delete(asdl_expr_seq * targets, int lineno, int col_offset, int
 stmt_ty _PyAST_Assign(asdl_expr_seq * targets, expr_ty value, string
                       type_comment, int lineno, int col_offset, int end_lineno,
                       int end_col_offset, PyArena *arena);
+stmt_ty _PyAST_TypeAlias(expr_ty name, asdl_typeparam_seq * typeparams, expr_ty
+                         value, int lineno, int col_offset, int end_lineno, int
+                         end_col_offset, PyArena *arena);
 stmt_ty _PyAST_AugAssign(expr_ty target, operator_ty op, expr_ty value, int
                          lineno, int col_offset, int end_lineno, int
                          end_col_offset, PyArena *arena);
@@ -844,6 +891,14 @@ pattern_ty _PyAST_MatchOr(asdl_pattern_seq * patterns, int lineno, int
                           col_offset, int end_lineno, int end_col_offset,
                           PyArena *arena);
 type_ignore_ty _PyAST_TypeIgnore(int lineno, string tag, PyArena *arena);
+typeparam_ty _PyAST_TypeVar(identifier name, expr_ty bound, int lineno, int
+                            col_offset, int end_lineno, int end_col_offset,
+                            PyArena *arena);
+typeparam_ty _PyAST_ParamSpec(identifier name, int lineno, int col_offset, int
+                              end_lineno, int end_col_offset, PyArena *arena);
+typeparam_ty _PyAST_TypeVarTuple(identifier name, int lineno, int col_offset,
+                                 int end_lineno, int end_col_offset, PyArena
+                                 *arena);
 
 
 PyObject* PyAST_mod2obj(mod_ty t);

Include/internal/pycore_ast_state.h

@@ -118,6 +118,7 @@ struct ast_state {
     PyObject *Not_type;
     PyObject *Or_singleton;
     PyObject *Or_type;
+    PyObject *ParamSpec_type;
     PyObject *Pass_type;
     PyObject *Pow_singleton;
     PyObject *Pow_type;
@@ -137,7 +138,10 @@ struct ast_state {
     PyObject *TryStar_type;
     PyObject *Try_type;
     PyObject *Tuple_type;
+    PyObject *TypeAlias_type;
     PyObject *TypeIgnore_type;
+    PyObject *TypeVarTuple_type;
+    PyObject *TypeVar_type;
     PyObject *UAdd_singleton;
     PyObject *UAdd_type;
     PyObject *USub_singleton;
@@ -166,6 +170,7 @@ struct ast_state {
     PyObject *bases;
     PyObject *body;
     PyObject *boolop_type;
+    PyObject *bound;
     PyObject *cases;
     PyObject *cause;
     PyObject *cls;
@@ -243,6 +248,8 @@ struct ast_state {
     PyObject *type_comment;
     PyObject *type_ignore_type;
     PyObject *type_ignores;
+    PyObject *typeparam_type;
+    PyObject *typeparams;
     PyObject *unaryop_type;
     PyObject *upper;
     PyObject *value;

Include/internal/pycore_function.h

@@ -17,6 +17,8 @@ struct _py_func_state {
 extern PyFunctionObject* _PyFunction_FromConstructor(PyFrameConstructor *constr);
 
 extern uint32_t _PyFunction_GetVersionForCurrentState(PyFunctionObject *func);
+extern PyObject *_Py_set_function_type_params(
+    PyThreadState* unused, PyObject *func, PyObject *type_params);
 
 #ifdef __cplusplus
 }

Include/internal/pycore_global_objects.h

@@ -68,6 +68,14 @@ struct _Py_interp_cached_objects {
     PyObject *type_slots_pname;
     pytype_slotdef *type_slots_ptrs[MAX_EQUIV];
 
+    /* TypeVar and related types */
+    PyTypeObject *generic_type;
+    PyTypeObject *typevar_type;
+    PyTypeObject *typevartuple_type;
+    PyTypeObject *paramspec_type;
+    PyTypeObject *paramspecargs_type;
+    PyTypeObject *paramspeckwargs_type;
+    PyTypeObject *typealias_type;
 };
 
 #define _Py_INTERP_STATIC_OBJECT(interp, NAME) \

Include/internal/pycore_global_objects_fini_generated.h

@@ -555,15 +555,19 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(dbl_close_br));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(dbl_open_br));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(dbl_percent));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(defaults));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(dot));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(dot_locals));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(empty));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(generic_base));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(json_decoder));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(kwdefaults));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(list_err));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(newline));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(open_br));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(percent));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(shim_name));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(type_params));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(utf_8));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(CANCELLED));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(FINISHED));
@@ -602,6 +606,8 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__class__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__class_getitem__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__classcell__));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__classdict__));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__classdictcell__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__complex__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__contains__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__copy__));
@@ -724,6 +730,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__subclasshook__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__truediv__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__trunc__));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__type_params__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__typing_is_unpacked_typevartuple__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__typing_prepare_subst__));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(__typing_subst__));
@@ -779,8 +786,11 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(after_in_child));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(after_in_parent));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(aggregate_class));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(alias));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(append));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(arg));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(argdefs));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(args));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(arguments));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(argv));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(as_integer_ratio));
@@ -795,6 +805,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(big));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(binary_form));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(block));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(bound));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(buffer));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(buffer_callback));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(buffer_size));
@@ -850,11 +861,13 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(compile_mode));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(consts));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(context));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(contravariant));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(cookie));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(copy));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(copyreg));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(coro));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(count));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(covariant));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(cwd));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(d));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(data));
@@ -964,6 +977,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(incoming));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(indexgroup));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(inf));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(infer_variance));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(inheritable));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(initial));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(initial_bytes));
@@ -1080,6 +1094,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(optimize));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(options));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(order));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(origin));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(out_fd));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(outgoing));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(overlapped));
@@ -1213,6 +1228,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(twice));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(txt));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(type));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(type_params));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(tz));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(tzname));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(uid));

Include/internal/pycore_global_strings.h

@@ -40,15 +40,19 @@ struct _Py_global_strings {
         STRUCT_FOR_STR(dbl_close_br, "}}")
         STRUCT_FOR_STR(dbl_open_br, "{{")
         STRUCT_FOR_STR(dbl_percent, "%%")
+        STRUCT_FOR_STR(defaults, ".defaults")
         STRUCT_FOR_STR(dot, ".")
         STRUCT_FOR_STR(dot_locals, ".<locals>")
         STRUCT_FOR_STR(empty, "")
+        STRUCT_FOR_STR(generic_base, ".generic_base")
         STRUCT_FOR_STR(json_decoder, "json.decoder")
+        STRUCT_FOR_STR(kwdefaults, ".kwdefaults")
         STRUCT_FOR_STR(list_err, "list index out of range")
         STRUCT_FOR_STR(newline, "\n")
         STRUCT_FOR_STR(open_br, "{")
         STRUCT_FOR_STR(percent, "%")
         STRUCT_FOR_STR(shim_name, "<shim>")
+        STRUCT_FOR_STR(type_params, ".type_params")
         STRUCT_FOR_STR(utf_8, "utf-8")
     } literals;
 
@@ -90,6 +94,8 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(__class__)
         STRUCT_FOR_ID(__class_getitem__)
         STRUCT_FOR_ID(__classcell__)
+        STRUCT_FOR_ID(__classdict__)
+        STRUCT_FOR_ID(__classdictcell__)
         STRUCT_FOR_ID(__complex__)
         STRUCT_FOR_ID(__contains__)
         STRUCT_FOR_ID(__copy__)
@@ -212,6 +218,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(__subclasshook__)
         STRUCT_FOR_ID(__truediv__)
         STRUCT_FOR_ID(__trunc__)
+        STRUCT_FOR_ID(__type_params__)
         STRUCT_FOR_ID(__typing_is_unpacked_typevartuple__)
         STRUCT_FOR_ID(__typing_prepare_subst__)
         STRUCT_FOR_ID(__typing_subst__)
@@ -267,8 +274,11 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(after_in_child)
         STRUCT_FOR_ID(after_in_parent)
         STRUCT_FOR_ID(aggregate_class)
+        STRUCT_FOR_ID(alias)
         STRUCT_FOR_ID(append)
+        STRUCT_FOR_ID(arg)
         STRUCT_FOR_ID(argdefs)
+        STRUCT_FOR_ID(args)
         STRUCT_FOR_ID(arguments)
         STRUCT_FOR_ID(argv)
         STRUCT_FOR_ID(as_integer_ratio)
@@ -283,6 +293,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(big)
         STRUCT_FOR_ID(binary_form)
         STRUCT_FOR_ID(block)
+        STRUCT_FOR_ID(bound)
         STRUCT_FOR_ID(buffer)
         STRUCT_FOR_ID(buffer_callback)
         STRUCT_FOR_ID(buffer_size)
@@ -338,11 +349,13 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(compile_mode)
         STRUCT_FOR_ID(consts)
         STRUCT_FOR_ID(context)
+        STRUCT_FOR_ID(contravariant)
         STRUCT_FOR_ID(cookie)
         STRUCT_FOR_ID(copy)
         STRUCT_FOR_ID(copyreg)
         STRUCT_FOR_ID(coro)
         STRUCT_FOR_ID(count)
+        STRUCT_FOR_ID(covariant)
         STRUCT_FOR_ID(cwd)
         STRUCT_FOR_ID(d)
         STRUCT_FOR_ID(data)
@@ -452,6 +465,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(incoming)
         STRUCT_FOR_ID(indexgroup)
         STRUCT_FOR_ID(inf)
+        STRUCT_FOR_ID(infer_variance)
         STRUCT_FOR_ID(inheritable)
         STRUCT_FOR_ID(initial)
         STRUCT_FOR_ID(initial_bytes)
@@ -568,6 +582,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(optimize)
         STRUCT_FOR_ID(options)
         STRUCT_FOR_ID(order)
+        STRUCT_FOR_ID(origin)
         STRUCT_FOR_ID(out_fd)
         STRUCT_FOR_ID(outgoing)
         STRUCT_FOR_ID(overlapped)
@@ -701,6 +716,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(twice)
         STRUCT_FOR_ID(txt)
         STRUCT_FOR_ID(type)
+        STRUCT_FOR_ID(type_params)
         STRUCT_FOR_ID(tz)
         STRUCT_FOR_ID(tzname)
         STRUCT_FOR_ID(uid)

Include/internal/pycore_intrinsics.h

@@ -8,15 +8,23 @@
 #define INTRINSIC_ASYNC_GEN_WRAP                 4
 #define INTRINSIC_UNARY_POSITIVE                 5
 #define INTRINSIC_LIST_TO_TUPLE                  6
+#define INTRINSIC_TYPEVAR                        7
+#define INTRINSIC_PARAMSPEC                      8
+#define INTRINSIC_TYPEVARTUPLE                   9
+#define INTRINSIC_SUBSCRIPT_GENERIC             10
+#define INTRINSIC_TYPEALIAS                     11
 
-#define MAX_INTRINSIC_1                          6
+#define MAX_INTRINSIC_1                         11
 
 
 /* Binary Functions: */
 #define INTRINSIC_2_INVALID                      0
 #define INTRINSIC_PREP_RERAISE_STAR              1
+#define INTRINSIC_TYPEVAR_WITH_BOUND             2
+#define INTRINSIC_TYPEVAR_WITH_CONSTRAINTS       3
+#define INTRINSIC_SET_FUNCTION_TYPE_PARAMS       4
 
-#define MAX_INTRINSIC_2                          1
+#define MAX_INTRINSIC_2                          4
 
 typedef PyObject *(*instrinsic_func1)(PyThreadState* tstate, PyObject *value);
 typedef PyObject *(*instrinsic_func2)(PyThreadState* tstate, PyObject *value1, PyObject *value2);

Include/internal/pycore_opcode.h

@@ -167,7 +167,6 @@ const uint8_t _PyOpcode_Deopt[256] = {
     [LOAD_ATTR_SLOT] = LOAD_ATTR,
     [LOAD_ATTR_WITH_HINT] = LOAD_ATTR,
     [LOAD_BUILD_CLASS] = LOAD_BUILD_CLASS,
-    [LOAD_CLASSDEREF] = LOAD_CLASSDEREF,
     [LOAD_CLOSURE] = LOAD_CLOSURE,
     [LOAD_CONST] = LOAD_CONST,
     [LOAD_CONST__LOAD_FAST] = LOAD_CONST,
@@ -177,9 +176,12 @@ const uint8_t _PyOpcode_Deopt[256] = {
     [LOAD_FAST_CHECK] = LOAD_FAST_CHECK,
     [LOAD_FAST__LOAD_CONST] = LOAD_FAST,
     [LOAD_FAST__LOAD_FAST] = LOAD_FAST,
+    [LOAD_FROM_DICT_OR_DEREF] = LOAD_FROM_DICT_OR_DEREF,
+    [LOAD_FROM_DICT_OR_GLOBALS] = LOAD_FROM_DICT_OR_GLOBALS,
     [LOAD_GLOBAL] = LOAD_GLOBAL,
     [LOAD_GLOBAL_BUILTIN] = LOAD_GLOBAL,
     [LOAD_GLOBAL_MODULE] = LOAD_GLOBAL,
+    [LOAD_LOCALS] = LOAD_LOCALS,
     [LOAD_NAME] = LOAD_NAME,
     [LOAD_SUPER_ATTR] = LOAD_SUPER_ATTR,
     [LOAD_SUPER_ATTR_ATTR] = LOAD_SUPER_ATTR,
@@ -329,8 +331,8 @@ static const char *const _PyOpcode_OpName[267] = {
     [LOAD_CONST__LOAD_FAST] = "LOAD_CONST__LOAD_FAST",
     [SETUP_ANNOTATIONS] = "SETUP_ANNOTATIONS",
     [LOAD_FAST__LOAD_CONST] = "LOAD_FAST__LOAD_CONST",
+    [LOAD_LOCALS] = "LOAD_LOCALS",
     [LOAD_FAST__LOAD_FAST] = "LOAD_FAST__LOAD_FAST",
-    [LOAD_GLOBAL_BUILTIN] = "LOAD_GLOBAL_BUILTIN",
     [POP_EXCEPT] = "POP_EXCEPT",
     [STORE_NAME] = "STORE_NAME",
     [DELETE_NAME] = "DELETE_NAME",
@@ -353,9 +355,9 @@ static const char *const _PyOpcode_OpName[267] = {
     [IMPORT_NAME] = "IMPORT_NAME",
     [IMPORT_FROM] = "IMPORT_FROM",
     [JUMP_FORWARD] = "JUMP_FORWARD",
+    [LOAD_GLOBAL_BUILTIN] = "LOAD_GLOBAL_BUILTIN",
     [LOAD_GLOBAL_MODULE] = "LOAD_GLOBAL_MODULE",
     [STORE_ATTR_INSTANCE_VALUE] = "STORE_ATTR_INSTANCE_VALUE",
-    [STORE_ATTR_SLOT] = "STORE_ATTR_SLOT",
     [POP_JUMP_IF_FALSE] = "POP_JUMP_IF_FALSE",
     [POP_JUMP_IF_TRUE] = "POP_JUMP_IF_TRUE",
     [LOAD_GLOBAL] = "LOAD_GLOBAL",
@@ -390,7 +392,7 @@ static const char *const _PyOpcode_OpName[267] = {
     [LIST_APPEND] = "LIST_APPEND",
     [SET_ADD] = "SET_ADD",
     [MAP_ADD] = "MAP_ADD",
-    [LOAD_CLASSDEREF] = "LOAD_CLASSDEREF",
+    [STORE_ATTR_SLOT] = "STORE_ATTR_SLOT",
     [COPY_FREE_VARS] = "COPY_FREE_VARS",
     [YIELD_VALUE] = "YIELD_VALUE",
     [RESUME] = "RESUME",
@@ -417,8 +419,8 @@ static const char *const _PyOpcode_OpName[267] = {
     [KW_NAMES] = "KW_NAMES",
     [CALL_INTRINSIC_1] = "CALL_INTRINSIC_1",
     [CALL_INTRINSIC_2] = "CALL_INTRINSIC_2",
-    [175] = "<175>",
+    [LOAD_FROM_DICT_OR_GLOBALS] = "LOAD_FROM_DICT_OR_GLOBALS",
-    [176] = "<176>",
+    [LOAD_FROM_DICT_OR_DEREF] = "LOAD_FROM_DICT_OR_DEREF",
     [177] = "<177>",
     [178] = "<178>",
     [179] = "<179>",
@@ -515,8 +517,6 @@ static const char *const _PyOpcode_OpName[267] = {
 #define EXTRA_CASES \
     case 169: \
     case 170: \
-    case 175: \
-    case 176: \
     case 177: \
     case 178: \
     case 179: \

Include/internal/pycore_runtime_init_generated.h

@@ -546,15 +546,19 @@ extern "C" {
     INIT_STR(dbl_close_br, "}}"), \
     INIT_STR(dbl_open_br, "{{"), \
     INIT_STR(dbl_percent, "%%"), \
+    INIT_STR(defaults, ".defaults"), \
     INIT_STR(dot, "."), \
     INIT_STR(dot_locals, ".<locals>"), \
     INIT_STR(empty, ""), \
+    INIT_STR(generic_base, ".generic_base"), \
     INIT_STR(json_decoder, "json.decoder"), \
+    INIT_STR(kwdefaults, ".kwdefaults"), \
     INIT_STR(list_err, "list index out of range"), \
     INIT_STR(newline, "\n"), \
     INIT_STR(open_br, "{"), \
     INIT_STR(percent, "%"), \
     INIT_STR(shim_name, "<shim>"), \
+    INIT_STR(type_params, ".type_params"), \
     INIT_STR(utf_8, "utf-8"), \
 }
 
@@ -596,6 +600,8 @@ extern "C" {
     INIT_ID(__class__), \
     INIT_ID(__class_getitem__), \
     INIT_ID(__classcell__), \
+    INIT_ID(__classdict__), \
+    INIT_ID(__classdictcell__), \
     INIT_ID(__complex__), \
     INIT_ID(__contains__), \
     INIT_ID(__copy__), \
@@ -718,6 +724,7 @@ extern "C" {
     INIT_ID(__subclasshook__), \
     INIT_ID(__truediv__), \
     INIT_ID(__trunc__), \
+    INIT_ID(__type_params__), \
     INIT_ID(__typing_is_unpacked_typevartuple__), \
     INIT_ID(__typing_prepare_subst__), \
     INIT_ID(__typing_subst__), \
@@ -773,8 +780,11 @@ extern "C" {
     INIT_ID(after_in_child), \
     INIT_ID(after_in_parent), \
     INIT_ID(aggregate_class), \
+    INIT_ID(alias), \
     INIT_ID(append), \
+    INIT_ID(arg), \
     INIT_ID(argdefs), \
+    INIT_ID(args), \
     INIT_ID(arguments), \
     INIT_ID(argv), \
     INIT_ID(as_integer_ratio), \
@@ -789,6 +799,7 @@ extern "C" {
     INIT_ID(big), \
     INIT_ID(binary_form), \
     INIT_ID(block), \
+    INIT_ID(bound), \
     INIT_ID(buffer), \
     INIT_ID(buffer_callback), \
     INIT_ID(buffer_size), \
@@ -844,11 +855,13 @@ extern "C" {
     INIT_ID(compile_mode), \
     INIT_ID(consts), \
     INIT_ID(context), \
+    INIT_ID(contravariant), \
     INIT_ID(cookie), \
     INIT_ID(copy), \
     INIT_ID(copyreg), \
     INIT_ID(coro), \
     INIT_ID(count), \
+    INIT_ID(covariant), \
     INIT_ID(cwd), \
     INIT_ID(d), \
     INIT_ID(data), \
@@ -958,6 +971,7 @@ extern "C" {
     INIT_ID(incoming), \
     INIT_ID(indexgroup), \
     INIT_ID(inf), \
+    INIT_ID(infer_variance), \
     INIT_ID(inheritable), \
     INIT_ID(initial), \
     INIT_ID(initial_bytes), \
@@ -1074,6 +1088,7 @@ extern "C" {
     INIT_ID(optimize), \
     INIT_ID(options), \
     INIT_ID(order), \
+    INIT_ID(origin), \
     INIT_ID(out_fd), \
     INIT_ID(outgoing), \
     INIT_ID(overlapped), \
@@ -1207,6 +1222,7 @@ extern "C" {
     INIT_ID(twice), \
     INIT_ID(txt), \
     INIT_ID(type), \
+    INIT_ID(type_params), \
     INIT_ID(tz), \
     INIT_ID(tzname), \
     INIT_ID(uid), \

Include/internal/pycore_symtable.h

@@ -10,8 +10,17 @@ extern "C" {
 
 struct _mod;   // Type defined in pycore_ast.h
 
-typedef enum _block_type { FunctionBlock, ClassBlock, ModuleBlock, AnnotationBlock }
+typedef enum _block_type {
-    _Py_block_ty;
+    FunctionBlock, ClassBlock, ModuleBlock,
+    // Used for annotations if 'from __future__ import annotations' is active.
+    // Annotation blocks cannot bind names and are not evaluated.
+    AnnotationBlock,
+    // Used for generics and type aliases. These work mostly like functions
+    // (see PEP 695 for details). The three different blocks function identically;
+    // they are different enum entries only so that error messages can be more
+    // precise.
+    TypeVarBoundBlock, TypeAliasBlock, TypeParamBlock
+} _Py_block_ty;
 
 typedef enum _comprehension_type {
     NoComprehension = 0,
@@ -49,7 +58,7 @@ typedef struct _symtable_entry {
     PyObject *ste_varnames;  /* list of function parameters */
     PyObject *ste_children;  /* list of child blocks */
     PyObject *ste_directives;/* locations of global and nonlocal statements */
-    _Py_block_ty ste_type;   /* module, class, function or annotation */
+    _Py_block_ty ste_type;
     int ste_nested;      /* true if block is nested */
     unsigned ste_free : 1;        /* true if block has free variables */
     unsigned ste_child_free : 1;  /* true if a child block has free vars,
@@ -64,8 +73,12 @@ typedef struct _symtable_entry {
     unsigned ste_needs_class_closure : 1; /* for class scopes, true if a
                                              closure over __class__
                                              should be created */
+    unsigned ste_needs_classdict : 1; /* for class scopes, true if a closure
+                                         over the class dict should be created */
     unsigned ste_comp_inlined : 1; /* true if this comprehension is inlined */
     unsigned ste_comp_iter_target : 1; /* true if visiting comprehension target */
+    unsigned ste_can_see_class_scope : 1; /* true if this block can see names bound in an
+                                             enclosing class scope */
     int ste_comp_iter_expr; /* non-zero if visiting a comprehension range expression */
     int ste_lineno;          /* first line of block */
     int ste_col_offset;      /* offset of first line of block */
@@ -82,6 +95,7 @@ extern PyTypeObject PySTEntry_Type;
 
 extern long _PyST_GetSymbol(PySTEntryObject *, PyObject *);
 extern int _PyST_GetScope(PySTEntryObject *, PyObject *);
+extern int _PyST_IsFunctionLike(PySTEntryObject *);
 
 extern struct symtable* _PySymtable_Build(
     struct _mod *mod,
@@ -105,6 +119,7 @@ extern PyObject* _Py_Mangle(PyObject *p, PyObject *name);
 #define DEF_IMPORT 2<<6        /* assignment occurred via import */
 #define DEF_ANNOT 2<<7         /* this name is annotated */
 #define DEF_COMP_ITER 2<<8     /* this name is a comprehension iteration variable */
+#define DEF_TYPE_PARAM 2<<9    /* this name is a type parameter */
 
 #define DEF_BOUND (DEF_LOCAL | DEF_PARAM | DEF_IMPORT)
 

Include/internal/pycore_typevarobject.h

@@ -0,0 +1,22 @@
+#ifndef Py_INTERNAL_TYPEVAROBJECT_H
+#define Py_INTERNAL_TYPEVAROBJECT_H
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef Py_BUILD_CORE
+#  error "this header requires Py_BUILD_CORE define"
+#endif
+
+extern PyObject *_Py_make_typevar(PyObject *, PyObject *, PyObject *);
+extern PyObject *_Py_make_paramspec(PyThreadState *, PyObject *);
+extern PyObject *_Py_make_typevartuple(PyThreadState *, PyObject *);
+extern PyObject *_Py_make_typealias(PyThreadState *, PyObject *);
+extern PyObject *_Py_subscript_generic(PyThreadState *, PyObject *);
+extern int _Py_initialize_generic(PyInterpreterState *);
+extern void _Py_clear_generic_types(PyInterpreterState *);
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* !Py_INTERNAL_TYPEVAROBJECT_H */

Include/internal/pycore_unicodeobject_generated.h

@@ -123,6 +123,12 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(__classcell__);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(__classdict__);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(__classdictcell__);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(__complex__);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -489,6 +495,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(__trunc__);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(__type_params__);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(__typing_is_unpacked_typevartuple__);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -654,12 +663,21 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(aggregate_class);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(alias);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(append);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(arg);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(argdefs);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(args);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(arguments);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -702,6 +720,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(block);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(bound);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(buffer);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -867,6 +888,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(context);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(contravariant);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(cookie);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -882,6 +906,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(count);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(covariant);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(cwd);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1209,6 +1236,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(inf);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(infer_variance);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(inheritable);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1557,6 +1587,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(order);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(origin);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(out_fd);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
@@ -1956,6 +1989,9 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     string = &_Py_ID(type);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);
+    string = &_Py_ID(type_params);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    _PyUnicode_InternInPlace(interp, &string);
     string = &_Py_ID(tz);
     assert(_PyUnicode_CheckConsistency(string, 1));
     _PyUnicode_InternInPlace(interp, &string);

Include/opcode.h

@@ -45,6 +45,7 @@ extern "C" {
 #define RETURN_GENERATOR                        75
 #define RETURN_VALUE                            83
 #define SETUP_ANNOTATIONS                       85
+#define LOAD_LOCALS                             87
 #define POP_EXCEPT                              89
 #define HAVE_ARGUMENT                           90
 #define STORE_NAME                              90
@@ -102,7 +103,6 @@ extern "C" {
 #define LIST_APPEND                            145
 #define SET_ADD                                146
 #define MAP_ADD                                147
-#define LOAD_CLASSDEREF                        148
 #define COPY_FREE_VARS                         149
 #define YIELD_VALUE                            150
 #define RESUME                                 151
@@ -118,6 +118,8 @@ extern "C" {
 #define KW_NAMES                               172
 #define CALL_INTRINSIC_1                       173
 #define CALL_INTRINSIC_2                       174
+#define LOAD_FROM_DICT_OR_GLOBALS              175
+#define LOAD_FROM_DICT_OR_DEREF                176
 #define MIN_INSTRUMENTED_OPCODE                238
 #define INSTRUMENTED_POP_JUMP_IF_NONE          238
 #define INSTRUMENTED_POP_JUMP_IF_NOT_NONE      239
@@ -199,11 +201,11 @@ extern "C" {
 #define LOAD_ATTR_METHOD_WITH_VALUES            82
 #define LOAD_CONST__LOAD_FAST                   84
 #define LOAD_FAST__LOAD_CONST                   86
-#define LOAD_FAST__LOAD_FAST                    87
+#define LOAD_FAST__LOAD_FAST                    88
-#define LOAD_GLOBAL_BUILTIN                     88
+#define LOAD_GLOBAL_BUILTIN                    111
-#define LOAD_GLOBAL_MODULE                     111
+#define LOAD_GLOBAL_MODULE                     112
-#define STORE_ATTR_INSTANCE_VALUE              112
+#define STORE_ATTR_INSTANCE_VALUE              113
-#define STORE_ATTR_SLOT                        113
+#define STORE_ATTR_SLOT                        148
 #define STORE_ATTR_WITH_HINT                   153
 #define STORE_FAST__LOAD_FAST                  154
 #define STORE_FAST__STORE_FAST                 158

Lib/ast.py

@@ -1051,6 +1051,7 @@ class _Unparser(NodeVisitor):
             self.fill("@")
             self.traverse(deco)
         self.fill("class " + node.name)
+        self._typeparams_helper(node.typeparams)
         with self.delimit_if("(", ")", condition = node.bases or node.keywords):
             comma = False
             for e in node.bases:
@@ -1082,6 +1083,7 @@ class _Unparser(NodeVisitor):
             self.traverse(deco)
         def_str = fill_suffix + " " + node.name
         self.fill(def_str)
+        self._typeparams_helper(node.typeparams)
         with self.delimit("(", ")"):
             self.traverse(node.args)
         if node.returns:
@@ -1090,6 +1092,30 @@ class _Unparser(NodeVisitor):
         with self.block(extra=self.get_type_comment(node)):
             self._write_docstring_and_traverse_body(node)
 
+    def _typeparams_helper(self, typeparams):
+        if typeparams is not None and len(typeparams) > 0:
+            with self.delimit("[", "]"):
+                self.interleave(lambda: self.write(", "), self.traverse, typeparams)
+
+    def visit_TypeVar(self, node):
+        self.write(node.name)
+        if node.bound:
+            self.write(": ")
+            self.traverse(node.bound)
+
+    def visit_TypeVarTuple(self, node):
+        self.write("*" + node.name)
+
+    def visit_ParamSpec(self, node):
+        self.write("**" + node.name)
+
+    def visit_TypeAlias(self, node):
+        self.fill("type ")
+        self.traverse(node.name)
+        self._typeparams_helper(node.typeparams)
+        self.write(" = ")
+        self.traverse(node.value)
+
     def visit_For(self, node):
         self._for_helper("for ", node)
 

Lib/importlib/_bootstrap_external.py

@@ -444,6 +444,7 @@ _code_type = type(_write_atomic.__code__)
 #     Python 3.12b1 3528 (Add LOAD_SUPER_ATTR_METHOD specialization)
 #     Python 3.12b1 3529 (Inline list/dict/set comprehensions)
 #     Python 3.12b1 3530 (Shrink the LOAD_SUPER_ATTR caches)
+#     Python 3.12b1 3531 (Add PEP 695 changes)
 
 #     Python 3.13 will start with 3550
 
@@ -460,7 +461,7 @@ _code_type = type(_write_atomic.__code__)
 # Whenever MAGIC_NUMBER is changed, the ranges in the magic_values array
 # in PC/launcher.c must also be updated.
 
-MAGIC_NUMBER = (3530).to_bytes(2, 'little') + b'\r\n'
+MAGIC_NUMBER = (3531).to_bytes(2, 'little') + b'\r\n'
 
 _RAW_MAGIC_NUMBER = int.from_bytes(MAGIC_NUMBER, 'little')  # For import.c
 

Lib/keyword.py

@@ -56,7 +56,8 @@ kwlist = [
 softkwlist = [
     '_',
     'case',
-    'match'
+    'match',
+    'type'
 ]
 
 iskeyword = frozenset(kwlist).__contains__

Lib/opcode.py

@@ -131,6 +131,7 @@ def_op('RETURN_GENERATOR', 75)
 def_op('RETURN_VALUE', 83)
 
 def_op('SETUP_ANNOTATIONS', 85)
+def_op('LOAD_LOCALS', 87)
 
 def_op('POP_EXCEPT', 89)
 
@@ -206,7 +207,6 @@ EXTENDED_ARG = 144
 def_op('LIST_APPEND', 145)
 def_op('SET_ADD', 146)
 def_op('MAP_ADD', 147)
-def_op('LOAD_CLASSDEREF', 148)
 hasfree.append(148)
 def_op('COPY_FREE_VARS', 149)
 def_op('YIELD_VALUE', 150)
@@ -228,6 +228,10 @@ hasconst.append(172)
 def_op('CALL_INTRINSIC_1', 173)
 def_op('CALL_INTRINSIC_2', 174)
 
+name_op('LOAD_FROM_DICT_OR_GLOBALS', 175)
+def_op('LOAD_FROM_DICT_OR_DEREF', 176)
+hasfree.append(176)
+
 # Instrumented instructions
 MIN_INSTRUMENTED_OPCODE = 238
 
@@ -318,12 +322,20 @@ _intrinsic_1_descs = [
     "INTRINSIC_ASYNC_GEN_WRAP",
     "INTRINSIC_UNARY_POSITIVE",
     "INTRINSIC_LIST_TO_TUPLE",
+    "INTRINSIC_TYPEVAR",
+    "INTRINSIC_PARAMSPEC",
+    "INTRINSIC_TYPEVARTUPLE",
+    "INTRINSIC_SUBSCRIPT_GENERIC",
+    "INTRINSIC_TYPEALIAS",
 ]
 
 _intrinsic_2_descs = [
-    'INTRINSIC_2_INVALID',
+    "INTRINSIC_2_INVALID",
-    'INTRINSIC_PREP_RERAISE_STAR',
+    "INTRINSIC_PREP_RERAISE_STAR",
-    ]
+    "INTRINSIC_TYPEVAR_WITH_BOUND",
+    "INTRINSIC_TYPEVAR_WITH_CONSTRAINTS",
+    "INTRINSIC_SET_FUNCTION_TYPE_PARAMS",
+]
 
 _specializations = {
     "BINARY_OP": [

Lib/test/support/__init__.py

@@ -12,6 +12,7 @@ import re
 import stat
 import sys
 import sysconfig
+import textwrap
 import time
 import types
 import unittest
@@ -619,6 +620,14 @@ def sortdict(dict):
     withcommas = ", ".join(reprpairs)
     return "{%s}" % withcommas
 
+
+def run_code(code: str) -> dict[str, object]:
+    """Run a piece of code after dedenting it, and return its global namespace."""
+    ns = {}
+    exec(textwrap.dedent(code), ns)
+    return ns
+
+
 def check_syntax_error(testcase, statement, errtext='', *, lineno=None, offset=None):
     with testcase.assertRaisesRegex(SyntaxError, errtext) as cm:
         compile(statement, '<test string>', 'exec')

Lib/test/test_ast.py

@@ -181,7 +181,22 @@ exec_tests = [
     "def f(a=1, /, b=2, *, c): pass",
     "def f(a=1, /, b=2, *, c=4, **kwargs): pass",
     "def f(a=1, /, b=2, *, c, **kwargs): pass",
-
+    # Type aliases
+    "type X = int",
+    "type X[T] = int",
+    "type X[T, *Ts, **P] = (T, Ts, P)",
+    "type X[T: int, *Ts, **P] = (T, Ts, P)",
+    "type X[T: (int, str), *Ts, **P] = (T, Ts, P)",
+    # Generic classes
+    "class X[T]: pass",
+    "class X[T, *Ts, **P]: pass",
+    "class X[T: int, *Ts, **P]: pass",
+    "class X[T: (int, str), *Ts, **P]: pass",
+    # Generic functions
+    "def f[T](): pass",
+    "def f[T, *Ts, **P](): pass",
+    "def f[T: int, *Ts, **P](): pass",
+    "def f[T: (int, str), *Ts, **P](): pass",
 ]
 
 # These are compiled through "single"
@@ -262,7 +277,6 @@ eval_tests = [
   "()",
   # Combination
   "a.b.c.d(a.b[1:2])",
-
 ]
 
 # TODO: expr_context, slice, boolop, operator, unaryop, cmpop, comprehension
@@ -1013,6 +1027,18 @@ class AST_Tests(unittest.TestCase):
         with self.assertRaises(SyntaxError):
             ast.parse(code, feature_version=(3, 10))
 
+    def test_type_params_feature_version(self):
+        samples = [
+            "type X = int",
+            "class X[T]: pass",
+            "def f[T](): pass",
+        ]
+        for sample in samples:
+            with self.subTest(sample):
+                ast.parse(sample)
+                with self.assertRaises(SyntaxError):
+                    ast.parse(sample, feature_version=(3, 11))
+
     def test_invalid_major_feature_version(self):
         with self.assertRaises(ValueError):
             ast.parse('pass', feature_version=(2, 7))
@@ -1557,16 +1583,16 @@ class ASTValidatorTests(unittest.TestCase):
 
     def test_funcdef(self):
         a = ast.arguments([], [], None, [], [], None, [])
-        f = ast.FunctionDef("x", a, [], [], None)
+        f = ast.FunctionDef("x", [], a, [], [], None)
         self.stmt(f, "empty body on FunctionDef")
-        f = ast.FunctionDef("x", a, [ast.Pass()], [ast.Name("x", ast.Store())],
+        f = ast.FunctionDef("x", [], a, [ast.Pass()], [ast.Name("x", ast.Store())],
                             None)
         self.stmt(f, "must have Load context")
-        f = ast.FunctionDef("x", a, [ast.Pass()], [],
+        f = ast.FunctionDef("x", [], a, [ast.Pass()], [],
                             ast.Name("x", ast.Store()))
         self.stmt(f, "must have Load context")
         def fac(args):
-            return ast.FunctionDef("x", args, [ast.Pass()], [], None)
+            return ast.FunctionDef("x", [], args, [ast.Pass()], [], None)
         self._check_arguments(fac, self.stmt)
 
     def test_classdef(self):
@@ -1579,7 +1605,7 @@ class ASTValidatorTests(unittest.TestCase):
                 body = [ast.Pass()]
             if decorator_list is None:
                 decorator_list = []
-            return ast.ClassDef("myclass", bases, keywords,
+            return ast.ClassDef("myclass", [], bases, keywords,
                                 body, decorator_list)
         self.stmt(cls(bases=[ast.Name("x", ast.Store())]),
                   "must have Load context")
@@ -2869,23 +2895,23 @@ def main():
 exec_results = [
 ('Module', [('Expr', (1, 0, 1, 4), ('Constant', (1, 0, 1, 4), None, None))], []),
 ('Module', [('Expr', (1, 0, 1, 18), ('Constant', (1, 0, 1, 18), 'module docstring', None))], []),
-('Module', [('FunctionDef', (1, 0, 1, 13), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 9, 1, 13))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 13), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 9, 1, 13))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 29), 'f', ('arguments', [], [], None, [], [], None, []), [('Expr', (1, 9, 1, 29), ('Constant', (1, 9, 1, 29), 'function docstring', None))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 29), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Expr', (1, 9, 1, 29), ('Constant', (1, 9, 1, 29), 'function docstring', None))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 14), 'f', ('arguments', [], [('arg', (1, 6, 1, 7), 'a', None, None)], None, [], [], None, []), [('Pass', (1, 10, 1, 14))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 14), 'f', [], ('arguments', [], [('arg', (1, 6, 1, 7), 'a', None, None)], None, [], [], None, []), [('Pass', (1, 10, 1, 14))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 16), 'f', ('arguments', [], [('arg', (1, 6, 1, 7), 'a', None, None)], None, [], [], None, [('Constant', (1, 8, 1, 9), 0, None)]), [('Pass', (1, 12, 1, 16))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 16), 'f', [], ('arguments', [], [('arg', (1, 6, 1, 7), 'a', None, None)], None, [], [], None, [('Constant', (1, 8, 1, 9), 0, None)]), [('Pass', (1, 12, 1, 16))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 18), 'f', ('arguments', [], [], ('arg', (1, 7, 1, 11), 'args', None, None), [], [], None, []), [('Pass', (1, 14, 1, 18))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 18), 'f', [], ('arguments', [], [], ('arg', (1, 7, 1, 11), 'args', None, None), [], [], None, []), [('Pass', (1, 14, 1, 18))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 23), 'f', ('arguments', [], [], ('arg', (1, 7, 1, 16), 'args', ('Starred', (1, 13, 1, 16), ('Name', (1, 14, 1, 16), 'Ts', ('Load',)), ('Load',)), None), [], [], None, []), [('Pass', (1, 19, 1, 23))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 23), 'f', [], ('arguments', [], [], ('arg', (1, 7, 1, 16), 'args', ('Starred', (1, 13, 1, 16), ('Name', (1, 14, 1, 16), 'Ts', ('Load',)), ('Load',)), None), [], [], None, []), [('Pass', (1, 19, 1, 23))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 36), 'f', ('arguments', [], [], ('arg', (1, 7, 1, 29), 'args', ('Starred', (1, 13, 1, 29), ('Subscript', (1, 14, 1, 29), ('Name', (1, 14, 1, 19), 'tuple', ('Load',)), ('Tuple', (1, 20, 1, 28), [('Name', (1, 20, 1, 23), 'int', ('Load',)), ('Constant', (1, 25, 1, 28), Ellipsis, None)], ('Load',)), ('Load',)), ('Load',)), None), [], [], None, []), [('Pass', (1, 32, 1, 36))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 36), 'f', [], ('arguments', [], [], ('arg', (1, 7, 1, 29), 'args', ('Starred', (1, 13, 1, 29), ('Subscript', (1, 14, 1, 29), ('Name', (1, 14, 1, 19), 'tuple', ('Load',)), ('Tuple', (1, 20, 1, 28), [('Name', (1, 20, 1, 23), 'int', ('Load',)), ('Constant', (1, 25, 1, 28), Ellipsis, None)], ('Load',)), ('Load',)), ('Load',)), None), [], [], None, []), [('Pass', (1, 32, 1, 36))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 36), 'f', ('arguments', [], [], ('arg', (1, 7, 1, 29), 'args', ('Starred', (1, 13, 1, 29), ('Subscript', (1, 14, 1, 29), ('Name', (1, 14, 1, 19), 'tuple', ('Load',)), ('Tuple', (1, 20, 1, 28), [('Name', (1, 20, 1, 23), 'int', ('Load',)), ('Starred', (1, 25, 1, 28), ('Name', (1, 26, 1, 28), 'Ts', ('Load',)), ('Load',))], ('Load',)), ('Load',)), ('Load',)), None), [], [], None, []), [('Pass', (1, 32, 1, 36))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 36), 'f', [], ('arguments', [], [], ('arg', (1, 7, 1, 29), 'args', ('Starred', (1, 13, 1, 29), ('Subscript', (1, 14, 1, 29), ('Name', (1, 14, 1, 19), 'tuple', ('Load',)), ('Tuple', (1, 20, 1, 28), [('Name', (1, 20, 1, 23), 'int', ('Load',)), ('Starred', (1, 25, 1, 28), ('Name', (1, 26, 1, 28), 'Ts', ('Load',)), ('Load',))], ('Load',)), ('Load',)), ('Load',)), None), [], [], None, []), [('Pass', (1, 32, 1, 36))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 21), 'f', ('arguments', [], [], None, [], [], ('arg', (1, 8, 1, 14), 'kwargs', None, None), []), [('Pass', (1, 17, 1, 21))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 21), 'f', [], ('arguments', [], [], None, [], [], ('arg', (1, 8, 1, 14), 'kwargs', None, None), []), [('Pass', (1, 17, 1, 21))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 71), 'f', ('arguments', [], [('arg', (1, 6, 1, 7), 'a', None, None), ('arg', (1, 9, 1, 10), 'b', None, None), ('arg', (1, 14, 1, 15), 'c', None, None), ('arg', (1, 22, 1, 23), 'd', None, None), ('arg', (1, 28, 1, 29), 'e', None, None)], ('arg', (1, 35, 1, 39), 'args', None, None), [('arg', (1, 41, 1, 42), 'f', None, None)], [('Constant', (1, 43, 1, 45), 42, None)], ('arg', (1, 49, 1, 55), 'kwargs', None, None), [('Constant', (1, 11, 1, 12), 1, None), ('Constant', (1, 16, 1, 20), None, None), ('List', (1, 24, 1, 26), [], ('Load',)), ('Dict', (1, 30, 1, 32), [], [])]), [('Expr', (1, 58, 1, 71), ('Constant', (1, 58, 1, 71), 'doc for f()', None))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 71), 'f', [], ('arguments', [], [('arg', (1, 6, 1, 7), 'a', None, None), ('arg', (1, 9, 1, 10), 'b', None, None), ('arg', (1, 14, 1, 15), 'c', None, None), ('arg', (1, 22, 1, 23), 'd', None, None), ('arg', (1, 28, 1, 29), 'e', None, None)], ('arg', (1, 35, 1, 39), 'args', None, None), [('arg', (1, 41, 1, 42), 'f', None, None)], [('Constant', (1, 43, 1, 45), 42, None)], ('arg', (1, 49, 1, 55), 'kwargs', None, None), [('Constant', (1, 11, 1, 12), 1, None), ('Constant', (1, 16, 1, 20), None, None), ('List', (1, 24, 1, 26), [], ('Load',)), ('Dict', (1, 30, 1, 32), [], [])]), [('Expr', (1, 58, 1, 71), ('Constant', (1, 58, 1, 71), 'doc for f()', None))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 27), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 23, 1, 27))], [], ('Subscript', (1, 11, 1, 21), ('Name', (1, 11, 1, 16), 'tuple', ('Load',)), ('Tuple', (1, 17, 1, 20), [('Starred', (1, 17, 1, 20), ('Name', (1, 18, 1, 20), 'Ts', ('Load',)), ('Load',))], ('Load',)), ('Load',)), None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 27), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 23, 1, 27))], [], ('Subscript', (1, 11, 1, 21), ('Name', (1, 11, 1, 16), 'tuple', ('Load',)), ('Tuple', (1, 17, 1, 20), [('Starred', (1, 17, 1, 20), ('Name', (1, 18, 1, 20), 'Ts', ('Load',)), ('Load',))], ('Load',)), ('Load',)), None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 32), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 28, 1, 32))], [], ('Subscript', (1, 11, 1, 26), ('Name', (1, 11, 1, 16), 'tuple', ('Load',)), ('Tuple', (1, 17, 1, 25), [('Name', (1, 17, 1, 20), 'int', ('Load',)), ('Starred', (1, 22, 1, 25), ('Name', (1, 23, 1, 25), 'Ts', ('Load',)), ('Load',))], ('Load',)), ('Load',)), None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 32), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 28, 1, 32))], [], ('Subscript', (1, 11, 1, 26), ('Name', (1, 11, 1, 16), 'tuple', ('Load',)), ('Tuple', (1, 17, 1, 25), [('Name', (1, 17, 1, 20), 'int', ('Load',)), ('Starred', (1, 22, 1, 25), ('Name', (1, 23, 1, 25), 'Ts', ('Load',)), ('Load',))], ('Load',)), ('Load',)), None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 45), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 41, 1, 45))], [], ('Subscript', (1, 11, 1, 39), ('Name', (1, 11, 1, 16), 'tuple', ('Load',)), ('Tuple', (1, 17, 1, 38), [('Name', (1, 17, 1, 20), 'int', ('Load',)), ('Starred', (1, 22, 1, 38), ('Subscript', (1, 23, 1, 38), ('Name', (1, 23, 1, 28), 'tuple', ('Load',)), ('Tuple', (1, 29, 1, 37), [('Name', (1, 29, 1, 32), 'int', ('Load',)), ('Constant', (1, 34, 1, 37), Ellipsis, None)], ('Load',)), ('Load',)), ('Load',))], ('Load',)), ('Load',)), None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 45), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 41, 1, 45))], [], ('Subscript', (1, 11, 1, 39), ('Name', (1, 11, 1, 16), 'tuple', ('Load',)), ('Tuple', (1, 17, 1, 38), [('Name', (1, 17, 1, 20), 'int', ('Load',)), ('Starred', (1, 22, 1, 38), ('Subscript', (1, 23, 1, 38), ('Name', (1, 23, 1, 28), 'tuple', ('Load',)), ('Tuple', (1, 29, 1, 37), [('Name', (1, 29, 1, 32), 'int', ('Load',)), ('Constant', (1, 34, 1, 37), Ellipsis, None)], ('Load',)), ('Load',)), ('Load',))], ('Load',)), ('Load',)), None)], []),
-('Module', [('ClassDef', (1, 0, 1, 12), 'C', [], [], [('Pass', (1, 8, 1, 12))], [])], []),
+('Module', [('ClassDef', (1, 0, 1, 12), 'C', [], [], [], [('Pass', (1, 8, 1, 12))], [])], []),
-('Module', [('ClassDef', (1, 0, 1, 32), 'C', [], [], [('Expr', (1, 9, 1, 32), ('Constant', (1, 9, 1, 32), 'docstring for class C', None))], [])], []),
+('Module', [('ClassDef', (1, 0, 1, 32), 'C', [], [], [], [('Expr', (1, 9, 1, 32), ('Constant', (1, 9, 1, 32), 'docstring for class C', None))], [])], []),
-('Module', [('ClassDef', (1, 0, 1, 21), 'C', [('Name', (1, 8, 1, 14), 'object', ('Load',))], [], [('Pass', (1, 17, 1, 21))], [])], []),
+('Module', [('ClassDef', (1, 0, 1, 21), 'C', [], [('Name', (1, 8, 1, 14), 'object', ('Load',))], [], [('Pass', (1, 17, 1, 21))], [])], []),
-('Module', [('FunctionDef', (1, 0, 1, 16), 'f', ('arguments', [], [], None, [], [], None, []), [('Return', (1, 8, 1, 16), ('Constant', (1, 15, 1, 16), 1, None))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 16), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Return', (1, 8, 1, 16), ('Constant', (1, 15, 1, 16), 1, None))], [], None, None)], []),
 ('Module', [('Delete', (1, 0, 1, 5), [('Name', (1, 4, 1, 5), 'v', ('Del',))])], []),
 ('Module', [('Assign', (1, 0, 1, 5), [('Name', (1, 0, 1, 1), 'v', ('Store',))], ('Constant', (1, 4, 1, 5), 1, None), None)], []),
 ('Module', [('Assign', (1, 0, 1, 7), [('Tuple', (1, 0, 1, 3), [('Name', (1, 0, 1, 1), 'a', ('Store',)), ('Name', (1, 2, 1, 3), 'b', ('Store',))], ('Store',))], ('Name', (1, 6, 1, 7), 'c', ('Load',)), None)], []),
@@ -2922,28 +2948,41 @@ exec_results = [
 ('Module', [('Expr', (1, 0, 1, 20), ('DictComp', (1, 0, 1, 20), ('Name', (1, 1, 1, 2), 'a', ('Load',)), ('Name', (1, 5, 1, 6), 'b', ('Load',)), [('comprehension', ('Tuple', (1, 11, 1, 14), [('Name', (1, 11, 1, 12), 'v', ('Store',)), ('Name', (1, 13, 1, 14), 'w', ('Store',))], ('Store',)), ('Name', (1, 18, 1, 19), 'x', ('Load',)), [], 0)]))], []),
 ('Module', [('Expr', (1, 0, 1, 19), ('SetComp', (1, 0, 1, 19), ('Name', (1, 1, 1, 2), 'r', ('Load',)), [('comprehension', ('Name', (1, 7, 1, 8), 'l', ('Store',)), ('Name', (1, 12, 1, 13), 'x', ('Load',)), [('Name', (1, 17, 1, 18), 'g', ('Load',))], 0)]))], []),
 ('Module', [('Expr', (1, 0, 1, 16), ('SetComp', (1, 0, 1, 16), ('Name', (1, 1, 1, 2), 'r', ('Load',)), [('comprehension', ('Tuple', (1, 7, 1, 10), [('Name', (1, 7, 1, 8), 'l', ('Store',)), ('Name', (1, 9, 1, 10), 'm', ('Store',))], ('Store',)), ('Name', (1, 14, 1, 15), 'x', ('Load',)), [], 0)]))], []),
-('Module', [('AsyncFunctionDef', (1, 0, 3, 18), 'f', ('arguments', [], [], None, [], [], None, []), [('Expr', (2, 1, 2, 17), ('Constant', (2, 1, 2, 17), 'async function', None)), ('Expr', (3, 1, 3, 18), ('Await', (3, 1, 3, 18), ('Call', (3, 7, 3, 18), ('Name', (3, 7, 3, 16), 'something', ('Load',)), [], [])))], [], None, None)], []),
+('Module', [('AsyncFunctionDef', (1, 0, 3, 18), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Expr', (2, 1, 2, 17), ('Constant', (2, 1, 2, 17), 'async function', None)), ('Expr', (3, 1, 3, 18), ('Await', (3, 1, 3, 18), ('Call', (3, 7, 3, 18), ('Name', (3, 7, 3, 16), 'something', ('Load',)), [], [])))], [], None, None)], []),
-('Module', [('AsyncFunctionDef', (1, 0, 3, 8), 'f', ('arguments', [], [], None, [], [], None, []), [('AsyncFor', (2, 1, 3, 8), ('Name', (2, 11, 2, 12), 'e', ('Store',)), ('Name', (2, 16, 2, 17), 'i', ('Load',)), [('Expr', (2, 19, 2, 20), ('Constant', (2, 19, 2, 20), 1, None))], [('Expr', (3, 7, 3, 8), ('Constant', (3, 7, 3, 8), 2, None))], None)], [], None, None)], []),
+('Module', [('AsyncFunctionDef', (1, 0, 3, 8), 'f', [], ('arguments', [], [], None, [], [], None, []), [('AsyncFor', (2, 1, 3, 8), ('Name', (2, 11, 2, 12), 'e', ('Store',)), ('Name', (2, 16, 2, 17), 'i', ('Load',)), [('Expr', (2, 19, 2, 20), ('Constant', (2, 19, 2, 20), 1, None))], [('Expr', (3, 7, 3, 8), ('Constant', (3, 7, 3, 8), 2, None))], None)], [], None, None)], []),
-('Module', [('AsyncFunctionDef', (1, 0, 2, 21), 'f', ('arguments', [], [], None, [], [], None, []), [('AsyncWith', (2, 1, 2, 21), [('withitem', ('Name', (2, 12, 2, 13), 'a', ('Load',)), ('Name', (2, 17, 2, 18), 'b', ('Store',)))], [('Expr', (2, 20, 2, 21), ('Constant', (2, 20, 2, 21), 1, None))], None)], [], None, None)], []),
+('Module', [('AsyncFunctionDef', (1, 0, 2, 21), 'f', [], ('arguments', [], [], None, [], [], None, []), [('AsyncWith', (2, 1, 2, 21), [('withitem', ('Name', (2, 12, 2, 13), 'a', ('Load',)), ('Name', (2, 17, 2, 18), 'b', ('Store',)))], [('Expr', (2, 20, 2, 21), ('Constant', (2, 20, 2, 21), 1, None))], None)], [], None, None)], []),
 ('Module', [('Expr', (1, 0, 1, 14), ('Dict', (1, 0, 1, 14), [None, ('Constant', (1, 10, 1, 11), 2, None)], [('Dict', (1, 3, 1, 8), [('Constant', (1, 4, 1, 5), 1, None)], [('Constant', (1, 6, 1, 7), 2, None)]), ('Constant', (1, 12, 1, 13), 3, None)]))], []),
 ('Module', [('Expr', (1, 0, 1, 12), ('Set', (1, 0, 1, 12), [('Starred', (1, 1, 1, 8), ('Set', (1, 2, 1, 8), [('Constant', (1, 3, 1, 4), 1, None), ('Constant', (1, 6, 1, 7), 2, None)]), ('Load',)), ('Constant', (1, 10, 1, 11), 3, None)]))], []),
-('Module', [('AsyncFunctionDef', (1, 0, 2, 21), 'f', ('arguments', [], [], None, [], [], None, []), [('Expr', (2, 1, 2, 21), ('ListComp', (2, 1, 2, 21), ('Name', (2, 2, 2, 3), 'i', ('Load',)), [('comprehension', ('Name', (2, 14, 2, 15), 'b', ('Store',)), ('Name', (2, 19, 2, 20), 'c', ('Load',)), [], 1)]))], [], None, None)], []),
+('Module', [('AsyncFunctionDef', (1, 0, 2, 21), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Expr', (2, 1, 2, 21), ('ListComp', (2, 1, 2, 21), ('Name', (2, 2, 2, 3), 'i', ('Load',)), [('comprehension', ('Name', (2, 14, 2, 15), 'b', ('Store',)), ('Name', (2, 19, 2, 20), 'c', ('Load',)), [], 1)]))], [], None, None)], []),
-('Module', [('FunctionDef', (4, 0, 4, 13), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (4, 9, 4, 13))], [('Name', (1, 1, 1, 6), 'deco1', ('Load',)), ('Call', (2, 1, 2, 8), ('Name', (2, 1, 2, 6), 'deco2', ('Load',)), [], []), ('Call', (3, 1, 3, 9), ('Name', (3, 1, 3, 6), 'deco3', ('Load',)), [('Constant', (3, 7, 3, 8), 1, None)], [])], None, None)], []),
+('Module', [('FunctionDef', (4, 0, 4, 13), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (4, 9, 4, 13))], [('Name', (1, 1, 1, 6), 'deco1', ('Load',)), ('Call', (2, 1, 2, 8), ('Name', (2, 1, 2, 6), 'deco2', ('Load',)), [], []), ('Call', (3, 1, 3, 9), ('Name', (3, 1, 3, 6), 'deco3', ('Load',)), [('Constant', (3, 7, 3, 8), 1, None)], [])], None, None)], []),
-('Module', [('AsyncFunctionDef', (4, 0, 4, 19), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (4, 15, 4, 19))], [('Name', (1, 1, 1, 6), 'deco1', ('Load',)), ('Call', (2, 1, 2, 8), ('Name', (2, 1, 2, 6), 'deco2', ('Load',)), [], []), ('Call', (3, 1, 3, 9), ('Name', (3, 1, 3, 6), 'deco3', ('Load',)), [('Constant', (3, 7, 3, 8), 1, None)], [])], None, None)], []),
+('Module', [('AsyncFunctionDef', (4, 0, 4, 19), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (4, 15, 4, 19))], [('Name', (1, 1, 1, 6), 'deco1', ('Load',)), ('Call', (2, 1, 2, 8), ('Name', (2, 1, 2, 6), 'deco2', ('Load',)), [], []), ('Call', (3, 1, 3, 9), ('Name', (3, 1, 3, 6), 'deco3', ('Load',)), [('Constant', (3, 7, 3, 8), 1, None)], [])], None, None)], []),
-('Module', [('ClassDef', (4, 0, 4, 13), 'C', [], [], [('Pass', (4, 9, 4, 13))], [('Name', (1, 1, 1, 6), 'deco1', ('Load',)), ('Call', (2, 1, 2, 8), ('Name', (2, 1, 2, 6), 'deco2', ('Load',)), [], []), ('Call', (3, 1, 3, 9), ('Name', (3, 1, 3, 6), 'deco3', ('Load',)), [('Constant', (3, 7, 3, 8), 1, None)], [])])], []),
+('Module', [('ClassDef', (4, 0, 4, 13), 'C', [], [], [], [('Pass', (4, 9, 4, 13))], [('Name', (1, 1, 1, 6), 'deco1', ('Load',)), ('Call', (2, 1, 2, 8), ('Name', (2, 1, 2, 6), 'deco2', ('Load',)), [], []), ('Call', (3, 1, 3, 9), ('Name', (3, 1, 3, 6), 'deco3', ('Load',)), [('Constant', (3, 7, 3, 8), 1, None)], [])])], []),
-('Module', [('FunctionDef', (2, 0, 2, 13), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (2, 9, 2, 13))], [('Call', (1, 1, 1, 19), ('Name', (1, 1, 1, 5), 'deco', ('Load',)), [('GeneratorExp', (1, 5, 1, 19), ('Name', (1, 6, 1, 7), 'a', ('Load',)), [('comprehension', ('Name', (1, 12, 1, 13), 'a', ('Store',)), ('Name', (1, 17, 1, 18), 'b', ('Load',)), [], 0)])], [])], None, None)], []),
+('Module', [('FunctionDef', (2, 0, 2, 13), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (2, 9, 2, 13))], [('Call', (1, 1, 1, 19), ('Name', (1, 1, 1, 5), 'deco', ('Load',)), [('GeneratorExp', (1, 5, 1, 19), ('Name', (1, 6, 1, 7), 'a', ('Load',)), [('comprehension', ('Name', (1, 12, 1, 13), 'a', ('Store',)), ('Name', (1, 17, 1, 18), 'b', ('Load',)), [], 0)])], [])], None, None)], []),
-('Module', [('FunctionDef', (2, 0, 2, 13), 'f', ('arguments', [], [], None, [], [], None, []), [('Pass', (2, 9, 2, 13))], [('Attribute', (1, 1, 1, 6), ('Attribute', (1, 1, 1, 4), ('Name', (1, 1, 1, 2), 'a', ('Load',)), 'b', ('Load',)), 'c', ('Load',))], None, None)], []),
+('Module', [('FunctionDef', (2, 0, 2, 13), 'f', [], ('arguments', [], [], None, [], [], None, []), [('Pass', (2, 9, 2, 13))], [('Attribute', (1, 1, 1, 6), ('Attribute', (1, 1, 1, 4), ('Name', (1, 1, 1, 2), 'a', ('Load',)), 'b', ('Load',)), 'c', ('Load',))], None, None)], []),
 ('Module', [('Expr', (1, 0, 1, 8), ('NamedExpr', (1, 1, 1, 7), ('Name', (1, 1, 1, 2), 'a', ('Store',)), ('Constant', (1, 6, 1, 7), 1, None)))], []),
-('Module', [('FunctionDef', (1, 0, 1, 18), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [], None, [], [], None, []), [('Pass', (1, 14, 1, 18))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 18), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [], None, [], [], None, []), [('Pass', (1, 14, 1, 18))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 26), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 12, 1, 13), 'c', None, None), ('arg', (1, 15, 1, 16), 'd', None, None), ('arg', (1, 18, 1, 19), 'e', None, None)], None, [], [], None, []), [('Pass', (1, 22, 1, 26))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 26), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 12, 1, 13), 'c', None, None), ('arg', (1, 15, 1, 16), 'd', None, None), ('arg', (1, 18, 1, 19), 'e', None, None)], None, [], [], None, []), [('Pass', (1, 22, 1, 26))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 29), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 12, 1, 13), 'c', None, None)], None, [('arg', (1, 18, 1, 19), 'd', None, None), ('arg', (1, 21, 1, 22), 'e', None, None)], [None, None], None, []), [('Pass', (1, 25, 1, 29))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 29), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 12, 1, 13), 'c', None, None)], None, [('arg', (1, 18, 1, 19), 'd', None, None), ('arg', (1, 21, 1, 22), 'e', None, None)], [None, None], None, []), [('Pass', (1, 25, 1, 29))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 39), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 12, 1, 13), 'c', None, None)], None, [('arg', (1, 18, 1, 19), 'd', None, None), ('arg', (1, 21, 1, 22), 'e', None, None)], [None, None], ('arg', (1, 26, 1, 32), 'kwargs', None, None), []), [('Pass', (1, 35, 1, 39))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 39), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 12, 1, 13), 'c', None, None)], None, [('arg', (1, 18, 1, 19), 'd', None, None), ('arg', (1, 21, 1, 22), 'e', None, None)], [None, None], ('arg', (1, 26, 1, 32), 'kwargs', None, None), []), [('Pass', (1, 35, 1, 39))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 20), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [], None, [], [], None, [('Constant', (1, 8, 1, 9), 1, None)]), [('Pass', (1, 16, 1, 20))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 20), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [], None, [], [], None, [('Constant', (1, 8, 1, 9), 1, None)]), [('Pass', (1, 16, 1, 20))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 29), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None), ('arg', (1, 19, 1, 20), 'c', None, None)], None, [], [], None, [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None), ('Constant', (1, 21, 1, 22), 4, None)]), [('Pass', (1, 25, 1, 29))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 29), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None), ('arg', (1, 19, 1, 20), 'c', None, None)], None, [], [], None, [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None), ('Constant', (1, 21, 1, 22), 4, None)]), [('Pass', (1, 25, 1, 29))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 32), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [('Constant', (1, 24, 1, 25), 4, None)], None, [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 28, 1, 32))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 32), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [('Constant', (1, 24, 1, 25), 4, None)], None, [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 28, 1, 32))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 30), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [None], None, [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 26, 1, 30))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 30), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [None], None, [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 26, 1, 30))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 42), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [('Constant', (1, 24, 1, 25), 4, None)], ('arg', (1, 29, 1, 35), 'kwargs', None, None), [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 38, 1, 42))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 42), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [('Constant', (1, 24, 1, 25), 4, None)], ('arg', (1, 29, 1, 35), 'kwargs', None, None), [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 38, 1, 42))], [], None, None)], []),
-('Module', [('FunctionDef', (1, 0, 1, 40), 'f', ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [None], ('arg', (1, 27, 1, 33), 'kwargs', None, None), [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 36, 1, 40))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 40), 'f', [], ('arguments', [('arg', (1, 6, 1, 7), 'a', None, None)], [('arg', (1, 14, 1, 15), 'b', None, None)], None, [('arg', (1, 22, 1, 23), 'c', None, None)], [None], ('arg', (1, 27, 1, 33), 'kwargs', None, None), [('Constant', (1, 8, 1, 9), 1, None), ('Constant', (1, 16, 1, 17), 2, None)]), [('Pass', (1, 36, 1, 40))], [], None, None)], []),
+('Module', [('TypeAlias', (1, 0, 1, 12), ('Name', (1, 5, 1, 6), 'X', ('Store',)), [], ('Name', (1, 9, 1, 12), 'int', ('Load',)))], []),
+('Module', [('TypeAlias', (1, 0, 1, 15), ('Name', (1, 5, 1, 6), 'X', ('Store',)), [('TypeVar', (1, 7, 1, 8), 'T', None)], ('Name', (1, 12, 1, 15), 'int', ('Load',)))], []),
+('Module', [('TypeAlias', (1, 0, 1, 32), ('Name', (1, 5, 1, 6), 'X', ('Store',)), [('TypeVar', (1, 7, 1, 8), 'T', None), ('TypeVarTuple', (1, 10, 1, 13), 'Ts'), ('ParamSpec', (1, 15, 1, 18), 'P')], ('Tuple', (1, 22, 1, 32), [('Name', (1, 23, 1, 24), 'T', ('Load',)), ('Name', (1, 26, 1, 28), 'Ts', ('Load',)), ('Name', (1, 30, 1, 31), 'P', ('Load',))], ('Load',)))], []),
+('Module', [('TypeAlias', (1, 0, 1, 37), ('Name', (1, 5, 1, 6), 'X', ('Store',)), [('TypeVar', (1, 7, 1, 13), 'T', ('Name', (1, 10, 1, 13), 'int', ('Load',))), ('TypeVarTuple', (1, 15, 1, 18), 'Ts'), ('ParamSpec', (1, 20, 1, 23), 'P')], ('Tuple', (1, 27, 1, 37), [('Name', (1, 28, 1, 29), 'T', ('Load',)), ('Name', (1, 31, 1, 33), 'Ts', ('Load',)), ('Name', (1, 35, 1, 36), 'P', ('Load',))], ('Load',)))], []),
+('Module', [('TypeAlias', (1, 0, 1, 44), ('Name', (1, 5, 1, 6), 'X', ('Store',)), [('TypeVar', (1, 7, 1, 20), 'T', ('Tuple', (1, 10, 1, 20), [('Name', (1, 11, 1, 14), 'int', ('Load',)), ('Name', (1, 16, 1, 19), 'str', ('Load',))], ('Load',))), ('TypeVarTuple', (1, 22, 1, 25), 'Ts'), ('ParamSpec', (1, 27, 1, 30), 'P')], ('Tuple', (1, 34, 1, 44), [('Name', (1, 35, 1, 36), 'T', ('Load',)), ('Name', (1, 38, 1, 40), 'Ts', ('Load',)), ('Name', (1, 42, 1, 43), 'P', ('Load',))], ('Load',)))], []),
+('Module', [('ClassDef', (1, 0, 1, 16), 'X', [('TypeVar', (1, 8, 1, 9), 'T', None)], [], [], [('Pass', (1, 12, 1, 16))], [])], []),
+('Module', [('ClassDef', (1, 0, 1, 26), 'X', [('TypeVar', (1, 8, 1, 9), 'T', None), ('TypeVarTuple', (1, 11, 1, 14), 'Ts'), ('ParamSpec', (1, 16, 1, 19), 'P')], [], [], [('Pass', (1, 22, 1, 26))], [])], []),
+('Module', [('ClassDef', (1, 0, 1, 31), 'X', [('TypeVar', (1, 8, 1, 14), 'T', ('Name', (1, 11, 1, 14), 'int', ('Load',))), ('TypeVarTuple', (1, 16, 1, 19), 'Ts'), ('ParamSpec', (1, 21, 1, 24), 'P')], [], [], [('Pass', (1, 27, 1, 31))], [])], []),
+('Module', [('ClassDef', (1, 0, 1, 38), 'X', [('TypeVar', (1, 8, 1, 21), 'T', ('Tuple', (1, 11, 1, 21), [('Name', (1, 12, 1, 15), 'int', ('Load',)), ('Name', (1, 17, 1, 20), 'str', ('Load',))], ('Load',))), ('TypeVarTuple', (1, 23, 1, 26), 'Ts'), ('ParamSpec', (1, 28, 1, 31), 'P')], [], [], [('Pass', (1, 34, 1, 38))], [])], []),
+('Module', [('FunctionDef', (1, 0, 1, 16), 'f', [('TypeVar', (1, 6, 1, 7), 'T', None)], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 12, 1, 16))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 26), 'f', [('TypeVar', (1, 6, 1, 7), 'T', None), ('TypeVarTuple', (1, 9, 1, 12), 'Ts'), ('ParamSpec', (1, 14, 1, 17), 'P')], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 22, 1, 26))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 31), 'f', [('TypeVar', (1, 6, 1, 12), 'T', ('Name', (1, 9, 1, 12), 'int', ('Load',))), ('TypeVarTuple', (1, 14, 1, 17), 'Ts'), ('ParamSpec', (1, 19, 1, 22), 'P')], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 27, 1, 31))], [], None, None)], []),
+('Module', [('FunctionDef', (1, 0, 1, 38), 'f', [('TypeVar', (1, 6, 1, 19), 'T', ('Tuple', (1, 9, 1, 19), [('Name', (1, 10, 1, 13), 'int', ('Load',)), ('Name', (1, 15, 1, 18), 'str', ('Load',))], ('Load',))), ('TypeVarTuple', (1, 21, 1, 24), 'Ts'), ('ParamSpec', (1, 26, 1, 29), 'P')], ('arguments', [], [], None, [], [], None, []), [('Pass', (1, 34, 1, 38))], [], None, None)], []),
 ]
 single_results = [
 ('Interactive', [('Expr', (1, 0, 1, 3), ('BinOp', (1, 0, 1, 3), ('Constant', (1, 0, 1, 1), 1, None), ('Add',), ('Constant', (1, 2, 1, 3), 2, None)))]),

Lib/test/test_keyword.py

@@ -39,7 +39,8 @@ class Test_iskeyword(unittest.TestCase):
         self.assertIn("async", keyword.kwlist)
         self.assertIn("await", keyword.kwlist)
 
-    def test_match_and_case_are_soft_keywords(self):
+    def test_soft_keywords(self):
+        self.assertIn("type", keyword.softkwlist)
         self.assertIn("match", keyword.softkwlist)
         self.assertIn("case", keyword.softkwlist)
         self.assertIn("_", keyword.softkwlist)

Lib/test/test_sys.py

@@ -1449,7 +1449,7 @@ class SizeofTest(unittest.TestCase):
         check(x, size('3Pi3c7P2ic??2P'))
         # function
         def func(): pass
-        check(func, size('14Pi'))
+        check(func, size('15Pi'))
         class c():
             @staticmethod
             def foo():

Lib/test/test_type_aliases.py

@@ -0,0 +1,204 @@
+import types
+import unittest
+from test.support import check_syntax_error, run_code
+
+from typing import Callable, TypeAliasType, TypeVar, get_args
+
+
+class TypeParamsInvalidTest(unittest.TestCase):
+    def test_name_collision_01(self):
+        check_syntax_error(self, """type TA1[A, **A] = None""", "duplicate type parameter 'A'")
+
+    def test_name_non_collision_02(self):
+        ns = run_code("""type TA1[A] = lambda A: A""")
+        self.assertIsInstance(ns["TA1"], TypeAliasType)
+        self.assertTrue(callable(ns["TA1"].__value__))
+        self.assertEqual("arg", ns["TA1"].__value__("arg"))
+
+    def test_name_non_collision_03(self):
+        ns = run_code("""
+            class Outer[A]:
+                type TA1[A] = None
+            """
+        )
+        outer_A, = ns["Outer"].__type_params__
+        inner_A, = ns["Outer"].TA1.__type_params__
+        self.assertIsNot(outer_A, inner_A)
+
+
+class TypeParamsAccessTest(unittest.TestCase):
+    def test_alias_access_01(self):
+        ns = run_code("type TA1[A, B] = dict[A, B]")
+        alias = ns["TA1"]
+        self.assertIsInstance(alias, TypeAliasType)
+        self.assertEqual(alias.__type_params__, get_args(alias.__value__))
+
+    def test_alias_access_02(self):
+        ns = run_code("""
+            type TA1[A, B] = TA1[A, B] | int
+            """
+        )
+        alias = ns["TA1"]
+        self.assertIsInstance(alias, TypeAliasType)
+        A, B = alias.__type_params__
+        self.assertEqual(alias.__value__, alias[A, B] | int)
+
+    def test_alias_access_03(self):
+        ns = run_code("""
+            class Outer[A]:
+                def inner[B](self):
+                    type TA1[C] = TA1[A, B] | int
+                    return TA1
+            """
+        )
+        cls = ns["Outer"]
+        A, = cls.__type_params__
+        B, = cls.inner.__type_params__
+        alias = cls.inner(None)
+        self.assertIsInstance(alias, TypeAliasType)
+        alias2 = cls.inner(None)
+        self.assertIsNot(alias, alias2)
+        self.assertEqual(len(alias.__type_params__), 1)
+
+        self.assertEqual(alias.__value__, alias[A, B] | int)
+
+
+class TypeParamsAliasValueTest(unittest.TestCase):
+    def test_alias_value_01(self):
+        type TA1 = int
+
+        self.assertIsInstance(TA1, TypeAliasType)
+        self.assertEqual(TA1.__value__, int)
+        self.assertEqual(TA1.__parameters__, ())
+        self.assertEqual(TA1.__type_params__, ())
+
+        type TA2 = TA1 | str
+
+        self.assertIsInstance(TA2, TypeAliasType)
+        a, b = TA2.__value__.__args__
+        self.assertEqual(a, TA1)
+        self.assertEqual(b, str)
+        self.assertEqual(TA2.__parameters__, ())
+        self.assertEqual(TA2.__type_params__, ())
+
+    def test_alias_value_02(self):
+        class Parent[A]:
+            type TA1[B] = dict[A, B]
+
+        self.assertIsInstance(Parent.TA1, TypeAliasType)
+        self.assertEqual(len(Parent.TA1.__parameters__), 1)
+        self.assertEqual(len(Parent.__parameters__), 1)
+        a, = Parent.__parameters__
+        b, = Parent.TA1.__parameters__
+        self.assertEqual(Parent.__type_params__, (a,))
+        self.assertEqual(Parent.TA1.__type_params__, (b,))
+        self.assertEqual(Parent.TA1.__value__, dict[a, b])
+
+    def test_alias_value_03(self):
+        def outer[A]():
+            type TA1[B] = dict[A, B]
+            return TA1
+
+        o = outer()
+        self.assertIsInstance(o, TypeAliasType)
+        self.assertEqual(len(o.__parameters__), 1)
+        self.assertEqual(len(outer.__type_params__), 1)
+        b = o.__parameters__[0]
+        self.assertEqual(o.__type_params__, (b,))
+
+    def test_alias_value_04(self):
+        def more_generic[T, *Ts, **P]():
+            type TA[T2, *Ts2, **P2] = tuple[Callable[P, tuple[T, *Ts]], Callable[P2, tuple[T2, *Ts2]]]
+            return TA
+
+        alias = more_generic()
+        self.assertIsInstance(alias, TypeAliasType)
+        T2, Ts2, P2 = alias.__type_params__
+        self.assertEqual(alias.__parameters__, (T2, *Ts2, P2))
+        T, Ts, P = more_generic.__type_params__
+        self.assertEqual(alias.__value__, tuple[Callable[P, tuple[T, *Ts]], Callable[P2, tuple[T2, *Ts2]]])
+
+    def test_subscripting(self):
+        type NonGeneric = int
+        type Generic[A] = dict[A, A]
+        type VeryGeneric[T, *Ts, **P] = Callable[P, tuple[T, *Ts]]
+
+        with self.assertRaises(TypeError):
+            NonGeneric[int]
+
+        specialized = Generic[int]
+        self.assertIsInstance(specialized, types.GenericAlias)
+        self.assertIs(specialized.__origin__, Generic)
+        self.assertEqual(specialized.__args__, (int,))
+
+        specialized2 = VeryGeneric[int, str, float, [bool, range]]
+        self.assertIsInstance(specialized2, types.GenericAlias)
+        self.assertIs(specialized2.__origin__, VeryGeneric)
+        self.assertEqual(specialized2.__args__, (int, str, float, [bool, range]))
+
+    def test_repr(self):
+        type Simple = int
+        self.assertEqual(repr(Simple), "Simple")
+
+    def test_recursive_repr(self):
+        type Recursive = Recursive
+        self.assertEqual(repr(Recursive), "Recursive")
+
+        type X = list[Y]
+        type Y = list[X]
+        self.assertEqual(repr(X), "X")
+
+
+class TypeAliasConstructorTest(unittest.TestCase):
+    def test_basic(self):
+        TA = TypeAliasType("TA", int)
+        self.assertEqual(TA.__name__, "TA")
+        self.assertIs(TA.__value__, int)
+        self.assertEqual(TA.__type_params__, ())
+
+    def test_generic(self):
+        T = TypeVar("T")
+        TA = TypeAliasType("TA", list[T], type_params=(T,))
+        self.assertEqual(TA.__name__, "TA")
+        self.assertEqual(TA.__value__, list[T])
+        self.assertEqual(TA.__type_params__, (T,))
+
+    def test_keywords(self):
+        TA = TypeAliasType(name="TA", value=int)
+        self.assertEqual(TA.__name__, "TA")
+        self.assertIs(TA.__value__, int)
+        self.assertEqual(TA.__type_params__, ())
+
+    def test_errors(self):
+        with self.assertRaises(TypeError):
+            TypeAliasType()
+        with self.assertRaises(TypeError):
+            TypeAliasType("TA")
+        with self.assertRaises(TypeError):
+            TypeAliasType("TA", list, ())
+        with self.assertRaises(TypeError):
+            TypeAliasType("TA", list, type_params=42)
+
+
+class TypeAliasTypeTest(unittest.TestCase):
+    def test_immutable(self):
+        with self.assertRaises(TypeError):
+            TypeAliasType.whatever = "not allowed"
+
+    def test_no_subclassing(self):
+        with self.assertRaisesRegex(TypeError, "not an acceptable base type"):
+            class MyAlias(TypeAliasType):
+                pass
+
+    def test_union(self):
+        type Alias1 = int
+        type Alias2 = str
+        union = Alias1 | Alias2
+        self.assertIsInstance(union, types.UnionType)
+        self.assertEqual(get_args(union), (Alias1, Alias2))
+        union2 = Alias1 | list[float]
+        self.assertIsInstance(union2, types.UnionType)
+        self.assertEqual(get_args(union2), (Alias1, list[float]))
+        union3 = list[range] | Alias1
+        self.assertIsInstance(union3, types.UnionType)
+        self.assertEqual(get_args(union3), (list[range], Alias1))

Lib/test/test_type_params.py

@@ -0,0 +1,847 @@
+import asyncio
+import textwrap
+import types
+import unittest
+from test.support import requires_working_socket, check_syntax_error, run_code
+
+from typing import Generic, Sequence, TypeVar, TypeVarTuple, ParamSpec, get_args
+
+
+class TypeParamsInvalidTest(unittest.TestCase):
+    def test_name_collision_01(self):
+        check_syntax_error(self, """def func[**A, A](): ...""")
+
+    def test_name_non_collision_02(self):
+        ns = run_code("""def func[A](A): return A""")
+        func = ns["func"]
+        self.assertEqual(func(1), 1)
+        A, = func.__type_params__
+        self.assertEqual(A.__name__, "A")
+
+    def test_name_non_collision_03(self):
+        ns = run_code("""def func[A](*A): return A""")
+        func = ns["func"]
+        self.assertEqual(func(1), (1,))
+        A, = func.__type_params__
+        self.assertEqual(A.__name__, "A")
+
+    def test_name_non_collision_04(self):
+        # Mangled names should not cause a conflict.
+        ns = run_code("""
+            class ClassA:
+                def func[__A](self, __A): return __A
+            """
+        )
+        cls = ns["ClassA"]
+        self.assertEqual(cls().func(1), 1)
+        A, = cls.func.__type_params__
+        self.assertEqual(A.__name__, "__A")
+
+    def test_name_non_collision_05(self):
+        ns = run_code("""
+            class ClassA:
+                def func[_ClassA__A](self, __A): return __A
+            """
+        )
+        cls = ns["ClassA"]
+        self.assertEqual(cls().func(1), 1)
+        A, = cls.func.__type_params__
+        self.assertEqual(A.__name__, "_ClassA__A")
+
+    def test_name_non_collision_06(self):
+        ns = run_code("""
+            class ClassA[X]:
+                def func(self, X): return X
+            """
+        )
+        cls = ns["ClassA"]
+        self.assertEqual(cls().func(1), 1)
+        X, = cls.__type_params__
+        self.assertEqual(X.__name__, "X")
+
+    def test_name_non_collision_07(self):
+        ns = run_code("""
+            class ClassA[X]:
+                def func(self):
+                    X = 1
+                    return X
+            """
+        )
+        cls = ns["ClassA"]
+        self.assertEqual(cls().func(), 1)
+        X, = cls.__type_params__
+        self.assertEqual(X.__name__, "X")
+
+    def test_name_non_collision_08(self):
+        ns = run_code("""
+            class ClassA[X]:
+                def func(self):
+                    return [X for X in [1, 2]]
+            """
+        )
+        cls = ns["ClassA"]
+        self.assertEqual(cls().func(), [1, 2])
+        X, = cls.__type_params__
+        self.assertEqual(X.__name__, "X")
+
+    def test_name_non_collision_9(self):
+        ns = run_code("""
+            class ClassA[X]:
+                def func[X](self):
+                    ...
+            """
+        )
+        cls = ns["ClassA"]
+        outer_X, = cls.__type_params__
+        inner_X, = cls.func.__type_params__
+        self.assertEqual(outer_X.__name__, "X")
+        self.assertEqual(inner_X.__name__, "X")
+        self.assertIsNot(outer_X, inner_X)
+
+    def test_name_non_collision_10(self):
+        ns = run_code("""
+            class ClassA[X]:
+                X: int
+            """
+        )
+        cls = ns["ClassA"]
+        X, = cls.__type_params__
+        self.assertEqual(X.__name__, "X")
+        self.assertIs(cls.__annotations__["X"], int)
+
+    def test_name_non_collision_13(self):
+        ns = run_code("""
+            X = 1
+            def outer():
+                def inner[X]():
+                    global X
+                    X = 2
+                return inner
+            """
+        )
+        self.assertEqual(ns["X"], 1)
+        outer = ns["outer"]
+        outer()()
+        self.assertEqual(ns["X"], 2)
+
+    def test_disallowed_expressions(self):
+        check_syntax_error(self, "type X = (yield)")
+        check_syntax_error(self, "type X = (yield from x)")
+        check_syntax_error(self, "type X = (await 42)")
+        check_syntax_error(self, "async def f(): type X = (yield)")
+        check_syntax_error(self, "type X = (y := 3)")
+        check_syntax_error(self, "class X[T: (yield)]: pass")
+        check_syntax_error(self, "class X[T: (yield from x)]: pass")
+        check_syntax_error(self, "class X[T: (await 42)]: pass")
+        check_syntax_error(self, "class X[T: (y := 3)]: pass")
+        check_syntax_error(self, "class X[T](y := Sequence[T]): pass")
+        check_syntax_error(self, "def f[T](y: (x := Sequence[T])): pass")
+
+
+class TypeParamsNonlocalTest(unittest.TestCase):
+    def test_nonlocal_disallowed_01(self):
+        code = """
+            def outer():
+                X = 1
+                def inner[X]():
+                    nonlocal X
+                return X
+            """
+        check_syntax_error(self, code)
+
+    def test_nonlocal_disallowed_02(self):
+        code = """
+            def outer2[T]():
+                def inner1():
+                    nonlocal T
+        """
+        check_syntax_error(self, textwrap.dedent(code))
+
+    def test_nonlocal_disallowed_03(self):
+        code = """
+            class Cls[T]:
+                nonlocal T
+        """
+        check_syntax_error(self, textwrap.dedent(code))
+
+    def test_nonlocal_allowed(self):
+        code = """
+            def func[T]():
+                T = "func"
+                def inner():
+                    nonlocal T
+                    T = "inner"
+                inner()
+                assert T == "inner"
+        """
+        ns = run_code(code)
+        func = ns["func"]
+        T, = func.__type_params__
+        self.assertEqual(T.__name__, "T")
+
+
+class TypeParamsAccessTest(unittest.TestCase):
+    def test_class_access_01(self):
+        ns = run_code("""
+            class ClassA[A, B](dict[A, B]):
+                ...
+            """
+        )
+        cls = ns["ClassA"]
+        A, B = cls.__type_params__
+        self.assertEqual(types.get_original_bases(cls), (dict[A, B], Generic[A, B]))
+
+    def test_class_access_02(self):
+        ns = run_code("""
+            class MyMeta[A, B](type): ...
+            class ClassA[A, B](metaclass=MyMeta[A, B]):
+                ...
+            """
+        )
+        meta = ns["MyMeta"]
+        cls = ns["ClassA"]
+        A1, B1 = meta.__type_params__
+        A2, B2 = cls.__type_params__
+        self.assertIsNot(A1, A2)
+        self.assertIsNot(B1, B2)
+        self.assertIs(type(cls), meta)
+
+    def test_class_access_03(self):
+        code = """
+            def my_decorator(a):
+                ...
+            @my_decorator(A)
+            class ClassA[A, B]():
+                ...
+            """
+
+        with self.assertRaisesRegex(NameError, "name 'A' is not defined"):
+            run_code(code)
+
+    def test_function_access_01(self):
+        ns = run_code("""
+            def func[A, B](a: dict[A, B]):
+                ...
+            """
+        )
+        func = ns["func"]
+        A, B = func.__type_params__
+        self.assertEqual(func.__annotations__["a"], dict[A, B])
+
+    def test_function_access_02(self):
+        code = """
+            def func[A](a = list[A]()):
+                ...
+            """
+
+        with self.assertRaisesRegex(NameError, "name 'A' is not defined"):
+            run_code(code)
+
+    def test_function_access_03(self):
+        code = """
+            def my_decorator(a):
+                ...
+            @my_decorator(A)
+            def func[A]():
+                ...
+            """
+
+        with self.assertRaisesRegex(NameError, "name 'A' is not defined"):
+            run_code(code)
+
+    def test_method_access_01(self):
+        ns = run_code("""
+            class ClassA:
+                x = int
+                def func[T](self, a: x, b: T):
+                    ...
+            """
+        )
+        cls = ns["ClassA"]
+        self.assertIs(cls.func.__annotations__["a"], int)
+        T, = cls.func.__type_params__
+        self.assertIs(cls.func.__annotations__["b"], T)
+
+    def test_nested_access_01(self):
+        ns = run_code("""
+            class ClassA[A]:
+                def funcB[B](self):
+                    class ClassC[C]:
+                        def funcD[D](self):
+                            return lambda: (A, B, C, D)
+                    return ClassC
+            """
+        )
+        cls = ns["ClassA"]
+        A, = cls.__type_params__
+        B, = cls.funcB.__type_params__
+        classC = cls().funcB()
+        C, = classC.__type_params__
+        D, = classC.funcD.__type_params__
+        self.assertEqual(classC().funcD()(), (A, B, C, D))
+
+    def test_out_of_scope_01(self):
+        code = """
+            class ClassA[T]: ...
+            x = T
+            """
+
+        with self.assertRaisesRegex(NameError, "name 'T' is not defined"):
+            run_code(code)
+
+    def test_out_of_scope_02(self):
+        code = """
+            class ClassA[A]:
+                def funcB[B](self): ...
+
+                x = B
+            """
+
+        with self.assertRaisesRegex(NameError, "name 'B' is not defined"):
+            run_code(code)
+
+    def test_class_scope_interaction_01(self):
+        ns = run_code("""
+            class C:
+                x = 1
+                def method[T](self, arg: x): pass
+        """)
+        cls = ns["C"]
+        self.assertEqual(cls.method.__annotations__["arg"], 1)
+
+    def test_class_scope_interaction_02(self):
+        ns = run_code("""
+            class C:
+                class Base: pass
+                class Child[T](Base): pass
+        """)
+        cls = ns["C"]
+        self.assertEqual(cls.Child.__bases__, (cls.Base, Generic))
+        T, = cls.Child.__type_params__
+        self.assertEqual(types.get_original_bases(cls.Child), (cls.Base, Generic[T]))
+
+    def test_class_deref(self):
+        ns = run_code("""
+            class C[T]:
+                T = "class"
+                type Alias = T
+        """)
+        cls = ns["C"]
+        self.assertEqual(cls.Alias.__value__, "class")
+
+    def test_shadowing_nonlocal(self):
+        ns = run_code("""
+            def outer[T]():
+                T = "outer"
+                def inner():
+                    nonlocal T
+                    T = "inner"
+                    return T
+                return lambda: T, inner
+        """)
+        outer = ns["outer"]
+        T, = outer.__type_params__
+        self.assertEqual(T.__name__, "T")
+        getter, inner = outer()
+        self.assertEqual(getter(), "outer")
+        self.assertEqual(inner(), "inner")
+        self.assertEqual(getter(), "inner")
+
+    def test_reference_previous_typevar(self):
+        def func[S, T: Sequence[S]]():
+            pass
+
+        S, T = func.__type_params__
+        self.assertEqual(T.__bound__, Sequence[S])
+
+    def test_super(self):
+        class Base:
+            def meth(self):
+                return "base"
+
+        class Child(Base):
+            # Having int in the annotation ensures the class gets cells for both
+            # __class__ and __classdict__
+            def meth[T](self, arg: int) -> T:
+                return super().meth() + "child"
+
+        c = Child()
+        self.assertEqual(c.meth(1), "basechild")
+
+    def test_type_alias_containing_lambda(self):
+        type Alias[T] = lambda: T
+        T, = Alias.__type_params__
+        self.assertIs(Alias.__value__(), T)
+
+    def test_class_base_containing_lambda(self):
+        # Test that scopes nested inside hidden functions work correctly
+        outer_var = "outer"
+        class Base[T]: ...
+        class Child[T](Base[lambda: (int, outer_var, T)]): ...
+        base, _ = types.get_original_bases(Child)
+        func, = get_args(base)
+        T, = Child.__type_params__
+        self.assertEqual(func(), (int, "outer", T))
+
+    def test_comprehension_01(self):
+        type Alias[T: ([T for T in (T, [1])[1]], T)] = [T for T in T.__name__]
+        self.assertEqual(Alias.__value__, ["T"])
+        T, = Alias.__type_params__
+        self.assertEqual(T.__constraints__, ([1], T))
+
+    def test_comprehension_02(self):
+        type Alias[T: [lambda: T for T in (T, [1])[1]]] = [lambda: T for T in T.__name__]
+        func, = Alias.__value__
+        self.assertEqual(func(), "T")
+        T, = Alias.__type_params__
+        func, = T.__bound__
+        self.assertEqual(func(), 1)
+
+
+def global_generic_func[T]():
+    pass
+
+class GlobalGenericClass[T]:
+    pass
+
+
+class TypeParamsLazyEvaluationTest(unittest.TestCase):
+    def test_qualname(self):
+        class Foo[T]:
+            pass
+
+        def func[T]():
+            pass
+
+        self.assertEqual(Foo.__qualname__, "TypeParamsLazyEvaluationTest.test_qualname.<locals>.Foo")
+        self.assertEqual(func.__qualname__, "TypeParamsLazyEvaluationTest.test_qualname.<locals>.func")
+        self.assertEqual(global_generic_func.__qualname__, "global_generic_func")
+        self.assertEqual(GlobalGenericClass.__qualname__, "GlobalGenericClass")
+
+    def test_recursive_class(self):
+        class Foo[T: Foo, U: (Foo, Foo)]:
+            pass
+
+        type_params = Foo.__type_params__
+        self.assertEqual(len(type_params), 2)
+        self.assertEqual(type_params[0].__name__, "T")
+        self.assertEqual(type_params[0].__bound__, Foo)
+        self.assertEqual(type_params[0].__constraints__, None)
+
+        self.assertEqual(type_params[1].__name__, "U")
+        self.assertEqual(type_params[1].__bound__, None)
+        self.assertEqual(type_params[1].__constraints__, (Foo, Foo))
+
+    def test_evaluation_error(self):
+        class Foo[T: Undefined, U: (Undefined,)]:
+            pass
+
+        type_params = Foo.__type_params__
+        with self.assertRaises(NameError):
+            type_params[0].__bound__
+        self.assertEqual(type_params[0].__constraints__, None)
+        self.assertEqual(type_params[1].__bound__, None)
+        with self.assertRaises(NameError):
+            type_params[1].__constraints__
+
+        Undefined = "defined"
+        self.assertEqual(type_params[0].__bound__, "defined")
+        self.assertEqual(type_params[0].__constraints__, None)
+
+        self.assertEqual(type_params[1].__bound__, None)
+        self.assertEqual(type_params[1].__constraints__, ("defined",))
+
+
+class TypeParamsClassScopeTest(unittest.TestCase):
+    def test_alias(self):
+        class X:
+            T = int
+            type U = T
+        self.assertIs(X.U.__value__, int)
+
+        ns = run_code("""
+            glb = "global"
+            class X:
+                cls = "class"
+                type U = (glb, cls)
+        """)
+        cls = ns["X"]
+        self.assertEqual(cls.U.__value__, ("global", "class"))
+
+    def test_bound(self):
+        class X:
+            T = int
+            def foo[U: T](self): ...
+        self.assertIs(X.foo.__type_params__[0].__bound__, int)
+
+        ns = run_code("""
+            glb = "global"
+            class X:
+                cls = "class"
+                def foo[T: glb, U: cls](self): ...
+        """)
+        cls = ns["X"]
+        T, U = cls.foo.__type_params__
+        self.assertEqual(T.__bound__, "global")
+        self.assertEqual(U.__bound__, "class")
+
+    def test_modified_later(self):
+        class X:
+            T = int
+            def foo[U: T](self): ...
+            type Alias = T
+        X.T = float
+        self.assertIs(X.foo.__type_params__[0].__bound__, float)
+        self.assertIs(X.Alias.__value__, float)
+
+    def test_binding_uses_global(self):
+        ns = run_code("""
+            x = "global"
+            def outer():
+                x = "nonlocal"
+                class Cls:
+                    type Alias = x
+                    val = Alias.__value__
+                    def meth[T: x](self, arg: x): ...
+                    bound = meth.__type_params__[0].__bound__
+                    annotation = meth.__annotations__["arg"]
+                    x = "class"
+                return Cls
+        """)
+        cls = ns["outer"]()
+        self.assertEqual(cls.val, "global")
+        self.assertEqual(cls.bound, "global")
+        self.assertEqual(cls.annotation, "global")
+
+    def test_no_binding_uses_nonlocal(self):
+        ns = run_code("""
+            x = "global"
+            def outer():
+                x = "nonlocal"
+                class Cls:
+                    type Alias = x
+                    val = Alias.__value__
+                    def meth[T: x](self, arg: x): ...
+                    bound = meth.__type_params__[0].__bound__
+                return Cls
+        """)
+        cls = ns["outer"]()
+        self.assertEqual(cls.val, "nonlocal")
+        self.assertEqual(cls.bound, "nonlocal")
+        self.assertEqual(cls.meth.__annotations__["arg"], "nonlocal")
+
+    def test_explicit_global(self):
+        ns = run_code("""
+            x = "global"
+            def outer():
+                x = "nonlocal"
+                class Cls:
+                    global x
+                    type Alias = x
+                Cls.x = "class"
+                return Cls
+        """)
+        cls = ns["outer"]()
+        self.assertEqual(cls.Alias.__value__, "global")
+
+    def test_explicit_global_with_no_static_bound(self):
+        ns = run_code("""
+            def outer():
+                class Cls:
+                    global x
+                    type Alias = x
+                Cls.x = "class"
+                return Cls
+        """)
+        ns["x"] = "global"
+        cls = ns["outer"]()
+        self.assertEqual(cls.Alias.__value__, "global")
+
+    def test_explicit_global_with_assignment(self):
+        ns = run_code("""
+            x = "global"
+            def outer():
+                x = "nonlocal"
+                class Cls:
+                    global x
+                    type Alias = x
+                    x = "global from class"
+                Cls.x = "class"
+                return Cls
+        """)
+        cls = ns["outer"]()
+        self.assertEqual(cls.Alias.__value__, "global from class")
+
+    def test_explicit_nonlocal(self):
+        ns = run_code("""
+            x = "global"
+            def outer():
+                x = "nonlocal"
+                class Cls:
+                    nonlocal x
+                    type Alias = x
+                    x = "class"
+                return Cls
+        """)
+        cls = ns["outer"]()
+        self.assertEqual(cls.Alias.__value__, "class")
+
+
+class TypeParamsManglingTest(unittest.TestCase):
+    def test_mangling(self):
+        class Foo[__T]:
+            param = __T
+            def meth[__U](self, arg: __T, arg2: __U):
+                return (__T, __U)
+            type Alias[__V] = (__T, __V)
+
+        T = Foo.__type_params__[0]
+        self.assertEqual(T.__name__, "__T")
+        U = Foo.meth.__type_params__[0]
+        self.assertEqual(U.__name__, "__U")
+        V = Foo.Alias.__type_params__[0]
+        self.assertEqual(V.__name__, "__V")
+
+        anno = Foo.meth.__annotations__
+        self.assertIs(anno["arg"], T)
+        self.assertIs(anno["arg2"], U)
+        self.assertEqual(Foo().meth(1, 2), (T, U))
+
+        self.assertEqual(Foo.Alias.__value__, (T, V))
+
+
+class TypeParamsComplexCallsTest(unittest.TestCase):
+    def test_defaults(self):
+        # Generic functions with both defaults and kwdefaults trigger a specific code path
+        # in the compiler.
+        def func[T](a: T = "a", *, b: T = "b"):
+            return (a, b)
+
+        T, = func.__type_params__
+        self.assertIs(func.__annotations__["a"], T)
+        self.assertIs(func.__annotations__["b"], T)
+        self.assertEqual(func(), ("a", "b"))
+        self.assertEqual(func(1), (1, "b"))
+        self.assertEqual(func(b=2), ("a", 2))
+
+    def test_complex_base(self):
+        class Base:
+            def __init_subclass__(cls, **kwargs) -> None:
+                cls.kwargs = kwargs
+
+        kwargs = {"c": 3}
+        # Base classes with **kwargs trigger a different code path in the compiler.
+        class C[T](Base, a=1, b=2, **kwargs):
+            pass
+
+        T, = C.__type_params__
+        self.assertEqual(T.__name__, "T")
+        self.assertEqual(C.kwargs, {"a": 1, "b": 2, "c": 3})
+
+        bases = (Base,)
+        class C2[T](*bases, **kwargs):
+            pass
+
+        T, = C2.__type_params__
+        self.assertEqual(T.__name__, "T")
+        self.assertEqual(C2.kwargs, {"c": 3})
+
+
+class TypeParamsTraditionalTypeVarsTest(unittest.TestCase):
+    def test_traditional_01(self):
+        code = """
+            from typing import Generic
+            class ClassA[T](Generic[T]): ...
+        """
+
+        with self.assertRaisesRegex(TypeError, r"Cannot inherit from Generic\[...\] multiple times."):
+            run_code(code)
+
+    def test_traditional_02(self):
+        from typing import TypeVar
+        S = TypeVar("S")
+        with self.assertRaises(TypeError):
+            class ClassA[T](dict[T, S]): ...
+
+    def test_traditional_03(self):
+        # This does not generate a runtime error, but it should be
+        # flagged as an error by type checkers.
+        from typing import TypeVar
+        S = TypeVar("S")
+        def func[T](a: T, b: S) -> T | S:
+            return a
+
+
+class TypeParamsTypeVarTest(unittest.TestCase):
+    def test_typevar_01(self):
+        def func1[A: str, B: str | int, C: (int, str)]():
+            return (A, B, C)
+
+        a, b, c = func1()
+
+        self.assertIsInstance(a, TypeVar)
+        self.assertEqual(a.__bound__, str)
+        self.assertTrue(a.__infer_variance__)
+        self.assertFalse(a.__covariant__)
+        self.assertFalse(a.__contravariant__)
+
+        self.assertIsInstance(b, TypeVar)
+        self.assertEqual(b.__bound__, str | int)
+        self.assertTrue(b.__infer_variance__)
+        self.assertFalse(b.__covariant__)
+        self.assertFalse(b.__contravariant__)
+
+        self.assertIsInstance(c, TypeVar)
+        self.assertEqual(c.__bound__, None)
+        self.assertEqual(c.__constraints__, (int, str))
+        self.assertTrue(c.__infer_variance__)
+        self.assertFalse(c.__covariant__)
+        self.assertFalse(c.__contravariant__)
+
+    def test_typevar_generator(self):
+        def get_generator[A]():
+            def generator1[C]():
+                yield C
+
+            def generator2[B]():
+                yield A
+                yield B
+                yield from generator1()
+            return generator2
+
+        gen = get_generator()
+
+        a, b, c = [x for x in gen()]
+
+        self.assertIsInstance(a, TypeVar)
+        self.assertEqual(a.__name__, "A")
+        self.assertIsInstance(b, TypeVar)
+        self.assertEqual(b.__name__, "B")
+        self.assertIsInstance(c, TypeVar)
+        self.assertEqual(c.__name__, "C")
+
+    @requires_working_socket()
+    def test_typevar_coroutine(self):
+        def get_coroutine[A]():
+            async def coroutine[B]():
+                return (A, B)
+            return coroutine
+
+        co = get_coroutine()
+
+        self.addCleanup(asyncio.set_event_loop_policy, None)
+        a, b = asyncio.run(co())
+
+        self.assertIsInstance(a, TypeVar)
+        self.assertEqual(a.__name__, "A")
+        self.assertIsInstance(b, TypeVar)
+        self.assertEqual(b.__name__, "B")
+
+
+class TypeParamsTypeVarTupleTest(unittest.TestCase):
+    def test_typevartuple_01(self):
+        code = """def func1[*A: str](): pass"""
+        check_syntax_error(self, code, "cannot use bound with TypeVarTuple")
+        code = """def func1[*A: (int, str)](): pass"""
+        check_syntax_error(self, code, "cannot use constraints with TypeVarTuple")
+        code = """class X[*A: str]: pass"""
+        check_syntax_error(self, code, "cannot use bound with TypeVarTuple")
+        code = """class X[*A: (int, str)]: pass"""
+        check_syntax_error(self, code, "cannot use constraints with TypeVarTuple")
+        code = """type X[*A: str] = int"""
+        check_syntax_error(self, code, "cannot use bound with TypeVarTuple")
+        code = """type X[*A: (int, str)] = int"""
+        check_syntax_error(self, code, "cannot use constraints with TypeVarTuple")
+
+    def test_typevartuple_02(self):
+        def func1[*A]():
+            return A
+
+        a = func1()
+        self.assertIsInstance(a, TypeVarTuple)
+
+
+class TypeParamsTypeVarParamSpecTest(unittest.TestCase):
+    def test_paramspec_01(self):
+        code = """def func1[**A: str](): pass"""
+        check_syntax_error(self, code, "cannot use bound with ParamSpec")
+        code = """def func1[**A: (int, str)](): pass"""
+        check_syntax_error(self, code, "cannot use constraints with ParamSpec")
+        code = """class X[**A: str]: pass"""
+        check_syntax_error(self, code, "cannot use bound with ParamSpec")
+        code = """class X[**A: (int, str)]: pass"""
+        check_syntax_error(self, code, "cannot use constraints with ParamSpec")
+        code = """type X[**A: str] = int"""
+        check_syntax_error(self, code, "cannot use bound with ParamSpec")
+        code = """type X[**A: (int, str)] = int"""
+        check_syntax_error(self, code, "cannot use constraints with ParamSpec")
+
+    def test_paramspec_02(self):
+        def func1[**A]():
+            return A
+
+        a = func1()
+        self.assertIsInstance(a, ParamSpec)
+        self.assertTrue(a.__infer_variance__)
+        self.assertFalse(a.__covariant__)
+        self.assertFalse(a.__contravariant__)
+
+
+class TypeParamsTypeParamsDunder(unittest.TestCase):
+    def test_typeparams_dunder_class_01(self):
+        class Outer[A, B]:
+            class Inner[C, D]:
+                @staticmethod
+                def get_typeparams():
+                    return A, B, C, D
+
+        a, b, c, d = Outer.Inner.get_typeparams()
+        self.assertEqual(Outer.__type_params__, (a, b))
+        self.assertEqual(Outer.Inner.__type_params__, (c, d))
+
+        self.assertEqual(Outer.__parameters__, (a, b))
+        self.assertEqual(Outer.Inner.__parameters__, (c, d))
+
+    def test_typeparams_dunder_class_02(self):
+        class ClassA:
+            pass
+
+        self.assertEqual(ClassA.__type_params__, ())
+
+    def test_typeparams_dunder_class_03(self):
+        code = """
+            class ClassA[A]():
+                pass
+            ClassA.__type_params__ = ()
+        """
+
+        with self.assertRaisesRegex(AttributeError, "attribute '__type_params__' of 'type' objects is not writable"):
+            run_code(code)
+
+    def test_typeparams_dunder_function_01(self):
+        def outer[A, B]():
+            def inner[C, D]():
+                return A, B, C, D
+
+            return inner
+
+        inner = outer()
+        a, b, c, d = inner()
+        self.assertEqual(outer.__type_params__, (a, b))
+        self.assertEqual(inner.__type_params__, (c, d))
+
+    def test_typeparams_dunder_function_02(self):
+        def func1():
+            pass
+
+        self.assertEqual(func1.__type_params__, ())
+
+    def test_typeparams_dunder_function_03(self):
+        code = """
+            def func[A]():
+                pass
+            func.__type_params__ = ()
+        """
+
+        with self.assertRaisesRegex(AttributeError, "attribute '__type_params__' of 'function' objects is not writable"):
+            run_code(code)

Lib/test/test_typing.py

@@ -48,11 +48,8 @@ from test import mod_generics_cache
 from test import _typed_dict_helper
 
 
-py_typing = import_helper.import_fresh_module('typing', blocked=['_typing'])
-c_typing = import_helper.import_fresh_module('typing', fresh=['_typing'])
-
-
 CANNOT_SUBCLASS_TYPE = 'Cannot subclass special typing classes'
+NOT_A_BASE_TYPE = "type 'typing.%s' is not an acceptable base type"
 CANNOT_SUBCLASS_INSTANCE = 'Cannot subclass an instance of %s'
 
 
@@ -430,7 +427,7 @@ class TypeVarTests(BaseTestCase):
         self.assertNotEqual(TypeVar('T', int, str), TypeVar('T', int, str))
 
     def test_cannot_subclass(self):
-        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
+        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'TypeVar'):
             class V(TypeVar): pass
         T = TypeVar("T")
         with self.assertRaisesRegex(TypeError,
@@ -446,6 +443,9 @@ class TypeVarTests(BaseTestCase):
             TypeVar('X', bound=Union)
         with self.assertRaises(TypeError):
             TypeVar('X', str, float, bound=Employee)
+        with self.assertRaisesRegex(TypeError,
+                                    r"Bound must be a type\. Got \(1, 2\)\."):
+            TypeVar('X', bound=(1, 2))
 
     def test_missing__name__(self):
         # See bpo-39942
@@ -1161,7 +1161,7 @@ class TypeVarTupleTests(BaseTestCase):
         self.assertEndsWith(repr(K[float, str]), 'A[float, str, typing.Unpack[typing.Tuple[str, ...]]]')
 
     def test_cannot_subclass(self):
-        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
+        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'TypeVarTuple'):
             class C(TypeVarTuple): pass
         Ts = TypeVarTuple('Ts')
         with self.assertRaisesRegex(TypeError,
@@ -6444,34 +6444,27 @@ class TypeTests(BaseTestCase):
 class TestModules(TestCase):
     func_names = ['_idfunc']
 
-    def test_py_functions(self):
-        for fname in self.func_names:
-            self.assertEqual(getattr(py_typing, fname).__module__, 'typing')
-
-    @skipUnless(c_typing, 'requires _typing')
     def test_c_functions(self):
         for fname in self.func_names:
-            self.assertEqual(getattr(c_typing, fname).__module__, '_typing')
+            self.assertEqual(getattr(typing, fname).__module__, '_typing')
 
 
-class NewTypeTests:
+class NewTypeTests(BaseTestCase):
     def cleanup(self):
-        for f in self.module._cleanups:
+        for f in typing._cleanups:
             f()
 
     @classmethod
     def setUpClass(cls):
-        sys.modules['typing'] = cls.module
         global UserId
-        UserId = cls.module.NewType('UserId', int)
+        UserId = typing.NewType('UserId', int)
-        cls.UserName = cls.module.NewType(cls.__qualname__ + '.UserName', str)
+        cls.UserName = typing.NewType(cls.__qualname__ + '.UserName', str)
 
     @classmethod
     def tearDownClass(cls):
         global UserId
         del UserId
         del cls.UserName
-        sys.modules['typing'] = typing
 
     def tearDown(self):
         self.cleanup()
@@ -6491,11 +6484,11 @@ class NewTypeTests:
     def test_or(self):
         for cls in (int, self.UserName):
             with self.subTest(cls=cls):
-                self.assertEqual(UserId | cls, self.module.Union[UserId, cls])
+                self.assertEqual(UserId | cls, typing.Union[UserId, cls])
-                self.assertEqual(cls | UserId, self.module.Union[cls, UserId])
+                self.assertEqual(cls | UserId, typing.Union[cls, UserId])
 
-                self.assertEqual(self.module.get_args(UserId | cls), (UserId, cls))
+                self.assertEqual(typing.get_args(UserId | cls), (UserId, cls))
-                self.assertEqual(self.module.get_args(cls | UserId), (cls, UserId))
+                self.assertEqual(typing.get_args(cls | UserId), (cls, UserId))
 
     def test_special_attrs(self):
         self.assertEqual(UserId.__name__, 'UserId')
@@ -6516,7 +6509,7 @@ class NewTypeTests:
                          f'{__name__}.{self.__class__.__qualname__}.UserName')
 
     def test_pickle(self):
-        UserAge = self.module.NewType('UserAge', float)
+        UserAge = typing.NewType('UserAge', float)
         for proto in range(pickle.HIGHEST_PROTOCOL + 1):
             with self.subTest(proto=proto):
                 pickled = pickle.dumps(UserId, proto)
@@ -6548,15 +6541,6 @@ class NewTypeTests:
                 ...
 
 
-class NewTypePythonTests(NewTypeTests, BaseTestCase):
-    module = py_typing
-
-
-@skipUnless(c_typing, 'requires _typing')
-class NewTypeCTests(NewTypeTests, BaseTestCase):
-    module = c_typing
-
-
 class NamedTupleTests(BaseTestCase):
     class NestedEmployee(NamedTuple):
         name: str
@@ -8170,11 +8154,11 @@ class ParamSpecTests(BaseTestCase):
         self.assertEqual(C2[Concatenate[T, P2]].__parameters__, (T, P2))
 
     def test_cannot_subclass(self):
-        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
+        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'ParamSpec'):
             class C(ParamSpec): pass
-        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
+        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'ParamSpecArgs'):
             class C(ParamSpecArgs): pass
-        with self.assertRaisesRegex(TypeError, CANNOT_SUBCLASS_TYPE):
+        with self.assertRaisesRegex(TypeError, NOT_A_BASE_TYPE % 'ParamSpecKwargs'):
             class C(ParamSpecKwargs): pass
         P = ParamSpec('P')
         with self.assertRaisesRegex(TypeError,

Lib/typing.py

@@ -23,6 +23,7 @@ from abc import abstractmethod, ABCMeta
 import collections
 from collections import defaultdict
 import collections.abc
+import copyreg
 import contextlib
 import functools
 import operator
@@ -32,12 +33,16 @@ import types
 import warnings
 from types import WrapperDescriptorType, MethodWrapperType, MethodDescriptorType, GenericAlias
 
-
+from _typing import (
-try:
+    _idfunc,
-    from _typing import _idfunc
+    TypeVar,
-except ImportError:
+    ParamSpec,
-    def _idfunc(_, x):
+    TypeVarTuple,
-        return x
+    ParamSpecArgs,
+    ParamSpecKwargs,
+    TypeAliasType,
+    Generic,
+)
 
 # Please keep __all__ alphabetized within each category.
 __all__ = [
@@ -149,6 +154,7 @@ __all__ = [
     'TYPE_CHECKING',
     'TypeAlias',
     'TypeGuard',
+    'TypeAliasType',
     'Unpack',
 ]
 
@@ -695,6 +701,15 @@ def Union(self, parameters):
         return _UnionGenericAlias(self, parameters, name="Optional")
     return _UnionGenericAlias(self, parameters)
 
+def _make_union(left, right):
+    """Used from the C implementation of TypeVar.
+
+    TypeVar.__or__ calls this instead of returning types.UnionType
+    because we want to allow unions between TypeVars and strings
+    (forward references.)
+    """
+    return Union[left, right]
+
 @_SpecialForm
 def Optional(self, parameters):
     """Optional type.
@@ -926,333 +941,162 @@ class _PickleUsingNameMixin:
         return self.__name__
 
 
-class _BoundVarianceMixin:
+def _typevar_subst(self, arg):
-    """Mixin giving __init__ bound and variance arguments.
+    msg = "Parameters to generic types must be types."
+    arg = _type_check(arg, msg, is_argument=True)
+    if ((isinstance(arg, _GenericAlias) and arg.__origin__ is Unpack) or
+        (isinstance(arg, GenericAlias) and getattr(arg, '__unpacked__', False))):
+        raise TypeError(f"{arg} is not valid as type argument")
+    return arg
 
-    This is used by TypeVar and ParamSpec, which both employ the notions of
+
-    a type 'bound' (restricting type arguments to be a subtype of some
+def _typevartuple_prepare_subst(self, alias, args):
-    specified type) and type 'variance' (determining subtype relations between
+    params = alias.__parameters__
-    generic types).
+    typevartuple_index = params.index(self)
+    for param in params[typevartuple_index + 1:]:
+        if isinstance(param, TypeVarTuple):
+            raise TypeError(f"More than one TypeVarTuple parameter in {alias}")
+
+    alen = len(args)
+    plen = len(params)
+    left = typevartuple_index
+    right = plen - typevartuple_index - 1
+    var_tuple_index = None
+    fillarg = None
+    for k, arg in enumerate(args):
+        if not isinstance(arg, type):
+            subargs = getattr(arg, '__typing_unpacked_tuple_args__', None)
+            if subargs and len(subargs) == 2 and subargs[-1] is ...:
+                if var_tuple_index is not None:
+                    raise TypeError("More than one unpacked arbitrary-length tuple argument")
+                var_tuple_index = k
+                fillarg = subargs[0]
+    if var_tuple_index is not None:
+        left = min(left, var_tuple_index)
+        right = min(right, alen - var_tuple_index - 1)
+    elif left + right > alen:
+        raise TypeError(f"Too few arguments for {alias};"
+                        f" actual {alen}, expected at least {plen-1}")
+
+    return (
+        *args[:left],
+        *([fillarg]*(typevartuple_index - left)),
+        tuple(args[left: alen - right]),
+        *([fillarg]*(plen - right - left - typevartuple_index - 1)),
+        *args[alen - right:],
+    )
+
+
+def _paramspec_subst(self, arg):
+    if isinstance(arg, (list, tuple)):
+        arg = tuple(_type_check(a, "Expected a type.") for a in arg)
+    elif not _is_param_expr(arg):
+        raise TypeError(f"Expected a list of types, an ellipsis, "
+                        f"ParamSpec, or Concatenate. Got {arg}")
+    return arg
+
+
+def _paramspec_prepare_subst(self, alias, args):
+    params = alias.__parameters__
+    i = params.index(self)
+    if i >= len(args):
+        raise TypeError(f"Too few arguments for {alias}")
+    # Special case where Z[[int, str, bool]] == Z[int, str, bool] in PEP 612.
+    if len(params) == 1 and not _is_param_expr(args[0]):
+        assert i == 0
+        args = (args,)
+    # Convert lists to tuples to help other libraries cache the results.
+    elif isinstance(args[i], list):
+        args = (*args[:i], tuple(args[i]), *args[i+1:])
+    return args
+
+
+@_tp_cache
+def _generic_class_getitem(cls, params):
+    """Parameterizes a generic class.
+
+    At least, parameterizing a generic class is the *main* thing this method
+    does. For example, for some generic class `Foo`, this is called when we
+    do `Foo[int]` - there, with `cls=Foo` and `params=int`.
+
+    However, note that this method is also called when defining generic
+    classes in the first place with `class Foo(Generic[T]): ...`.
     """
-    def __init__(self, bound, covariant, contravariant):
+    if not isinstance(params, tuple):
-        """Used to setup TypeVars and ParamSpec's bound, covariant and
+        params = (params,)
-        contravariant attributes.
-        """
-        if covariant and contravariant:
-            raise ValueError("Bivariant types are not supported.")
-        self.__covariant__ = bool(covariant)
-        self.__contravariant__ = bool(contravariant)
-        if bound:
-            self.__bound__ = _type_check(bound, "Bound must be a type.")
-        else:
-            self.__bound__ = None
 
-    def __or__(self, right):
+    params = tuple(_type_convert(p) for p in params)
-        return Union[self, right]
+    is_generic_or_protocol = cls in (Generic, Protocol)
 
-    def __ror__(self, left):
+    if is_generic_or_protocol:
-        return Union[left, self]
+        # Generic and Protocol can only be subscripted with unique type variables.
+        if not params:
+            raise TypeError(
+                f"Parameter list to {cls.__qualname__}[...] cannot be empty"
+            )
+        if not all(_is_typevar_like(p) for p in params):
+            raise TypeError(
+                f"Parameters to {cls.__name__}[...] must all be type variables "
+                f"or parameter specification variables.")
+        if len(set(params)) != len(params):
+            raise TypeError(
+                f"Parameters to {cls.__name__}[...] must all be unique")
+    else:
+        # Subscripting a regular Generic subclass.
+        for param in cls.__parameters__:
+            prepare = getattr(param, '__typing_prepare_subst__', None)
+            if prepare is not None:
+                params = prepare(cls, params)
+        _check_generic(cls, params, len(cls.__parameters__))
 
-    def __repr__(self):
+        new_args = []
-        if self.__covariant__:
+        for param, new_arg in zip(cls.__parameters__, params):
-            prefix = '+'
-        elif self.__contravariant__:
-            prefix = '-'
-        else:
-            prefix = '~'
-        return prefix + self.__name__
-
-    def __mro_entries__(self, bases):
-        raise TypeError(f"Cannot subclass an instance of {type(self).__name__}")
-
-
-class TypeVar(_Final, _Immutable, _BoundVarianceMixin, _PickleUsingNameMixin,
-              _root=True):
-    """Type variable.
-
-    Usage::
-
-      T = TypeVar('T')  # Can be anything
-      A = TypeVar('A', str, bytes)  # Must be str or bytes
-
-    Type variables exist primarily for the benefit of static type
-    checkers.  They serve as the parameters for generic types as well
-    as for generic function definitions.  See class Generic for more
-    information on generic types.  Generic functions work as follows:
-
-      def repeat(x: T, n: int) -> List[T]:
-          '''Return a list containing n references to x.'''
-          return [x]*n
-
-      def longest(x: A, y: A) -> A:
-          '''Return the longest of two strings.'''
-          return x if len(x) >= len(y) else y
-
-    The latter example's signature is essentially the overloading
-    of (str, str) -> str and (bytes, bytes) -> bytes.  Also note
-    that if the arguments are instances of some subclass of str,
-    the return type is still plain str.
-
-    At runtime, isinstance(x, T) and issubclass(C, T) will raise TypeError.
-
-    Type variables defined with covariant=True or contravariant=True
-    can be used to declare covariant or contravariant generic types.
-    See PEP 484 for more details. By default generic types are invariant
-    in all type variables.
-
-    Type variables can be introspected. e.g.:
-
-      T.__name__ == 'T'
-      T.__constraints__ == ()
-      T.__covariant__ == False
-      T.__contravariant__ = False
-      A.__constraints__ == (str, bytes)
-
-    Note that only type variables defined in global scope can be pickled.
-    """
-
-    def __init__(self, name, *constraints, bound=None,
-                 covariant=False, contravariant=False):
-        self.__name__ = name
-        super().__init__(bound, covariant, contravariant)
-        if constraints and bound is not None:
-            raise TypeError("Constraints cannot be combined with bound=...")
-        if constraints and len(constraints) == 1:
-            raise TypeError("A single constraint is not allowed")
-        msg = "TypeVar(name, constraint, ...): constraints must be types."
-        self.__constraints__ = tuple(_type_check(t, msg) for t in constraints)
-        def_mod = _caller()
-        if def_mod != 'typing':
-            self.__module__ = def_mod
-
-    def __typing_subst__(self, arg):
-        msg = "Parameters to generic types must be types."
-        arg = _type_check(arg, msg, is_argument=True)
-        if ((isinstance(arg, _GenericAlias) and arg.__origin__ is Unpack) or
-            (isinstance(arg, GenericAlias) and getattr(arg, '__unpacked__', False))):
-            raise TypeError(f"{arg} is not valid as type argument")
-        return arg
-
-
-class TypeVarTuple(_Final, _Immutable, _PickleUsingNameMixin, _root=True):
-    """Type variable tuple.
-
-    Usage:
-
-      Ts = TypeVarTuple('Ts')  # Can be given any name
-
-    Just as a TypeVar (type variable) is a placeholder for a single type,
-    a TypeVarTuple is a placeholder for an *arbitrary* number of types. For
-    example, if we define a generic class using a TypeVarTuple:
-
-      class C(Generic[*Ts]): ...
-
-    Then we can parameterize that class with an arbitrary number of type
-    arguments:
-
-      C[int]       # Fine
-      C[int, str]  # Also fine
-      C[()]        # Even this is fine
-
-    For more details, see PEP 646.
-
-    Note that only TypeVarTuples defined in global scope can be pickled.
-    """
-
-    def __init__(self, name):
-        self.__name__ = name
-
-        # Used for pickling.
-        def_mod = _caller()
-        if def_mod != 'typing':
-            self.__module__ = def_mod
-
-    def __iter__(self):
-        yield Unpack[self]
-
-    def __repr__(self):
-        return self.__name__
-
-    def __typing_subst__(self, arg):
-        raise TypeError("Substitution of bare TypeVarTuple is not supported")
-
-    def __typing_prepare_subst__(self, alias, args):
-        params = alias.__parameters__
-        typevartuple_index = params.index(self)
-        for param in params[typevartuple_index + 1:]:
             if isinstance(param, TypeVarTuple):
-                raise TypeError(f"More than one TypeVarTuple parameter in {alias}")
+                new_args.extend(new_arg)
+            else:
+                new_args.append(new_arg)
+        params = tuple(new_args)
 
-        alen = len(args)
+    return _GenericAlias(cls, params)
-        plen = len(params)
-        left = typevartuple_index
-        right = plen - typevartuple_index - 1
-        var_tuple_index = None
-        fillarg = None
-        for k, arg in enumerate(args):
-            if not isinstance(arg, type):
-                subargs = getattr(arg, '__typing_unpacked_tuple_args__', None)
-                if subargs and len(subargs) == 2 and subargs[-1] is ...:
-                    if var_tuple_index is not None:
-                        raise TypeError("More than one unpacked arbitrary-length tuple argument")
-                    var_tuple_index = k
-                    fillarg = subargs[0]
-        if var_tuple_index is not None:
-            left = min(left, var_tuple_index)
-            right = min(right, alen - var_tuple_index - 1)
-        elif left + right > alen:
-            raise TypeError(f"Too few arguments for {alias};"
-                            f" actual {alen}, expected at least {plen-1}")
-
-        return (
-            *args[:left],
-            *([fillarg]*(typevartuple_index - left)),
-            tuple(args[left: alen - right]),
-            *([fillarg]*(plen - right - left - typevartuple_index - 1)),
-            *args[alen - right:],
-        )
-
-    def __mro_entries__(self, bases):
-        raise TypeError(f"Cannot subclass an instance of {type(self).__name__}")
 
 
-class ParamSpecArgs(_Final, _Immutable, _root=True):
+def _generic_init_subclass(cls, *args, **kwargs):
-    """The args for a ParamSpec object.
+    super(Generic, cls).__init_subclass__(*args, **kwargs)
+    tvars = []
+    if '__orig_bases__' in cls.__dict__:
+        error = Generic in cls.__orig_bases__
+    else:
+        error = (Generic in cls.__bases__ and
+                    cls.__name__ != 'Protocol' and
+                    type(cls) != _TypedDictMeta)
+    if error:
+        raise TypeError("Cannot inherit from plain Generic")
+    if '__orig_bases__' in cls.__dict__:
+        tvars = _collect_parameters(cls.__orig_bases__)
+        # Look for Generic[T1, ..., Tn].
+        # If found, tvars must be a subset of it.
+        # If not found, tvars is it.
+        # Also check for and reject plain Generic,
+        # and reject multiple Generic[...].
+        gvars = None
+        for base in cls.__orig_bases__:
+            if (isinstance(base, _GenericAlias) and
+                    base.__origin__ is Generic):
+                if gvars is not None:
+                    raise TypeError(
+                        "Cannot inherit from Generic[...] multiple times.")
+                gvars = base.__parameters__
+        if gvars is not None:
+            tvarset = set(tvars)
+            gvarset = set(gvars)
+            if not tvarset <= gvarset:
+                s_vars = ', '.join(str(t) for t in tvars if t not in gvarset)
+                s_args = ', '.join(str(g) for g in gvars)
+                raise TypeError(f"Some type variables ({s_vars}) are"
+                                f" not listed in Generic[{s_args}]")
+            tvars = gvars
+    cls.__parameters__ = tuple(tvars)
 
-    Given a ParamSpec object P, P.args is an instance of ParamSpecArgs.
-
-    ParamSpecArgs objects have a reference back to their ParamSpec:
-
-       P.args.__origin__ is P
-
-    This type is meant for runtime introspection and has no special meaning to
-    static type checkers.
-    """
-    def __init__(self, origin):
-        self.__origin__ = origin
-
-    def __repr__(self):
-        return f"{self.__origin__.__name__}.args"
-
-    def __eq__(self, other):
-        if not isinstance(other, ParamSpecArgs):
-            return NotImplemented
-        return self.__origin__ == other.__origin__
-
-    def __mro_entries__(self, bases):
-        raise TypeError(f"Cannot subclass an instance of {type(self).__name__}")
-
-
-class ParamSpecKwargs(_Final, _Immutable, _root=True):
-    """The kwargs for a ParamSpec object.
-
-    Given a ParamSpec object P, P.kwargs is an instance of ParamSpecKwargs.
-
-    ParamSpecKwargs objects have a reference back to their ParamSpec:
-
-       P.kwargs.__origin__ is P
-
-    This type is meant for runtime introspection and has no special meaning to
-    static type checkers.
-    """
-    def __init__(self, origin):
-        self.__origin__ = origin
-
-    def __repr__(self):
-        return f"{self.__origin__.__name__}.kwargs"
-
-    def __eq__(self, other):
-        if not isinstance(other, ParamSpecKwargs):
-            return NotImplemented
-        return self.__origin__ == other.__origin__
-
-    def __mro_entries__(self, bases):
-        raise TypeError(f"Cannot subclass an instance of {type(self).__name__}")
-
-
-class ParamSpec(_Final, _Immutable, _BoundVarianceMixin, _PickleUsingNameMixin,
-                _root=True):
-    """Parameter specification variable.
-
-    Usage::
-
-       P = ParamSpec('P')
-
-    Parameter specification variables exist primarily for the benefit of static
-    type checkers.  They are used to forward the parameter types of one
-    callable to another callable, a pattern commonly found in higher order
-    functions and decorators.  They are only valid when used in ``Concatenate``,
-    or as the first argument to ``Callable``, or as parameters for user-defined
-    Generics.  See class Generic for more information on generic types.  An
-    example for annotating a decorator::
-
-       T = TypeVar('T')
-       P = ParamSpec('P')
-
-       def add_logging(f: Callable[P, T]) -> Callable[P, T]:
-           '''A type-safe decorator to add logging to a function.'''
-           def inner(*args: P.args, **kwargs: P.kwargs) -> T:
-               logging.info(f'{f.__name__} was called')
-               return f(*args, **kwargs)
-           return inner
-
-       @add_logging
-       def add_two(x: float, y: float) -> float:
-           '''Add two numbers together.'''
-           return x + y
-
-    Parameter specification variables defined with covariant=True or
-    contravariant=True can be used to declare covariant or contravariant
-    generic types.  These keyword arguments are valid, but their actual semantics
-    are yet to be decided.  See PEP 612 for details.
-
-    Parameter specification variables can be introspected. e.g.:
-
-       P.__name__ == 'P'
-       P.__bound__ == None
-       P.__covariant__ == False
-       P.__contravariant__ == False
-
-    Note that only parameter specification variables defined in global scope can
-    be pickled.
-    """
-
-    @property
-    def args(self):
-        return ParamSpecArgs(self)
-
-    @property
-    def kwargs(self):
-        return ParamSpecKwargs(self)
-
-    def __init__(self, name, *, bound=None, covariant=False, contravariant=False):
-        self.__name__ = name
-        super().__init__(bound, covariant, contravariant)
-        def_mod = _caller()
-        if def_mod != 'typing':
-            self.__module__ = def_mod
-
-    def __typing_subst__(self, arg):
-        if isinstance(arg, (list, tuple)):
-            arg = tuple(_type_check(a, "Expected a type.") for a in arg)
-        elif not _is_param_expr(arg):
-            raise TypeError(f"Expected a list of types, an ellipsis, "
-                            f"ParamSpec, or Concatenate. Got {arg}")
-        return arg
-
-    def __typing_prepare_subst__(self, alias, args):
-        params = alias.__parameters__
-        i = params.index(self)
-        if i >= len(args):
-            raise TypeError(f"Too few arguments for {alias}")
-        # Special case where Z[[int, str, bool]] == Z[int, str, bool] in PEP 612.
-        if len(params) == 1 and not _is_param_expr(args[0]):
-            assert i == 0
-            args = (args,)
-        # Convert lists to tuples to help other libraries cache the results.
-        elif isinstance(args[i], list):
-            args = (*args[:i], tuple(args[i]), *args[i+1:])
-        return args
 
 def _is_dunder(attr):
     return attr.startswith('__') and attr.endswith('__')
@@ -1812,113 +1656,6 @@ class _UnpackGenericAlias(_GenericAlias, _root=True):
         return isinstance(self.__args__[0], TypeVarTuple)
 
 
-class Generic:
-    """Abstract base class for generic types.
-
-    A generic type is typically declared by inheriting from
-    this class parameterized with one or more type variables.
-    For example, a generic mapping type might be defined as::
-
-      class Mapping(Generic[KT, VT]):
-          def __getitem__(self, key: KT) -> VT:
-              ...
-          # Etc.
-
-    This class can then be used as follows::
-
-      def lookup_name(mapping: Mapping[KT, VT], key: KT, default: VT) -> VT:
-          try:
-              return mapping[key]
-          except KeyError:
-              return default
-    """
-    __slots__ = ()
-    _is_protocol = False
-
-    @_tp_cache
-    def __class_getitem__(cls, params):
-        """Parameterizes a generic class.
-
-        At least, parameterizing a generic class is the *main* thing this method
-        does. For example, for some generic class `Foo`, this is called when we
-        do `Foo[int]` - there, with `cls=Foo` and `params=int`.
-
-        However, note that this method is also called when defining generic
-        classes in the first place with `class Foo(Generic[T]): ...`.
-        """
-        if not isinstance(params, tuple):
-            params = (params,)
-
-        params = tuple(_type_convert(p) for p in params)
-        if cls in (Generic, Protocol):
-            # Generic and Protocol can only be subscripted with unique type variables.
-            if not params:
-                raise TypeError(
-                    f"Parameter list to {cls.__qualname__}[...] cannot be empty"
-                )
-            if not all(_is_typevar_like(p) for p in params):
-                raise TypeError(
-                    f"Parameters to {cls.__name__}[...] must all be type variables "
-                    f"or parameter specification variables.")
-            if len(set(params)) != len(params):
-                raise TypeError(
-                    f"Parameters to {cls.__name__}[...] must all be unique")
-        else:
-            # Subscripting a regular Generic subclass.
-            for param in cls.__parameters__:
-                prepare = getattr(param, '__typing_prepare_subst__', None)
-                if prepare is not None:
-                    params = prepare(cls, params)
-            _check_generic(cls, params, len(cls.__parameters__))
-
-            new_args = []
-            for param, new_arg in zip(cls.__parameters__, params):
-                if isinstance(param, TypeVarTuple):
-                    new_args.extend(new_arg)
-                else:
-                    new_args.append(new_arg)
-            params = tuple(new_args)
-
-        return _GenericAlias(cls, params)
-
-    def __init_subclass__(cls, *args, **kwargs):
-        super().__init_subclass__(*args, **kwargs)
-        tvars = []
-        if '__orig_bases__' in cls.__dict__:
-            error = Generic in cls.__orig_bases__
-        else:
-            error = (Generic in cls.__bases__ and
-                        cls.__name__ != 'Protocol' and
-                        type(cls) != _TypedDictMeta)
-        if error:
-            raise TypeError("Cannot inherit from plain Generic")
-        if '__orig_bases__' in cls.__dict__:
-            tvars = _collect_parameters(cls.__orig_bases__)
-            # Look for Generic[T1, ..., Tn].
-            # If found, tvars must be a subset of it.
-            # If not found, tvars is it.
-            # Also check for and reject plain Generic,
-            # and reject multiple Generic[...].
-            gvars = None
-            for base in cls.__orig_bases__:
-                if (isinstance(base, _GenericAlias) and
-                        base.__origin__ is Generic):
-                    if gvars is not None:
-                        raise TypeError(
-                            "Cannot inherit from Generic[...] multiple times.")
-                    gvars = base.__parameters__
-            if gvars is not None:
-                tvarset = set(tvars)
-                gvarset = set(gvars)
-                if not tvarset <= gvarset:
-                    s_vars = ', '.join(str(t) for t in tvars if t not in gvarset)
-                    s_args = ', '.join(str(g) for g in gvars)
-                    raise TypeError(f"Some type variables ({s_vars}) are"
-                                    f" not listed in Generic[{s_args}]")
-                tvars = gvars
-        cls.__parameters__ = tuple(tvars)
-
-
 class _TypingEllipsis:
     """Internal placeholder for ... (ellipsis)."""
 
@@ -2024,6 +1761,18 @@ def _lazy_load_getattr_static():
 
 _cleanups.append(_lazy_load_getattr_static.cache_clear)
 
+def _pickle_psargs(psargs):
+    return ParamSpecArgs, (psargs.__origin__,)
+
+copyreg.pickle(ParamSpecArgs, _pickle_psargs)
+
+def _pickle_pskwargs(pskwargs):
+    return ParamSpecKwargs, (pskwargs.__origin__,)
+
+copyreg.pickle(ParamSpecKwargs, _pickle_pskwargs)
+
+del _pickle_psargs, _pickle_pskwargs
+
 
 class _ProtocolMeta(ABCMeta):
     # This metaclass is really unfortunate and exists only because of
@@ -2943,7 +2692,7 @@ class NamedTupleMeta(type):
                                module=ns['__module__'])
         nm_tpl.__bases__ = bases
         if Generic in bases:
-            class_getitem = Generic.__class_getitem__.__func__
+            class_getitem = _generic_class_getitem
             nm_tpl.__class_getitem__ = classmethod(class_getitem)
         # update from user namespace without overriding special namedtuple attributes
         for key in ns:

Makefile.pre.in

@@ -479,6 +479,7 @@ OBJECT_OBJS=	\
 		Objects/structseq.o \
 		Objects/tupleobject.o \
 		Objects/typeobject.o \
+		Objects/typevarobject.o \
 		Objects/unicodeobject.o \
 		Objects/unicodectype.o \
 		Objects/unionobject.o \
@@ -1767,6 +1768,7 @@ PYTHON_HEADERS= \
 		$(srcdir)/Include/internal/pycore_tracemalloc.h \
 		$(srcdir)/Include/internal/pycore_tuple.h \
 		$(srcdir)/Include/internal/pycore_typeobject.h \
+		$(srcdir)/Include/internal/pycore_typevarobject.h \
 		$(srcdir)/Include/internal/pycore_ucnhash.h \
 		$(srcdir)/Include/internal/pycore_unionobject.h \
 		$(srcdir)/Include/internal/pycore_unicodeobject.h \

Misc/NEWS.d/next/Core and Builtins/2023-04-25-08-43-11.gh-issue-103763.ZLBZk1.rst

@@ -0,0 +1,23 @@
+Implement :pep:`695`, adding syntactic support for generic classes, generic
+functions, and type aliases.
+
+A new ``type X = ...`` syntax is added for type aliases, which resolves at
+runtime to an instance of the new class ``typing.TypeAliasType``.
+The value is lazily evaluated and is accessible through the ``.__value__``
+attribute. This is implemented as a new AST node ``ast.TypeAlias``.
+
+New syntax (``class X[T]: ...``, ``def func[T](): ...``) is added for defining
+generic functions and classes. This is implemented as a new
+``typeparams`` attribute on the AST nodes for classes and functions.
+This node holds instances of the new AST classes ``ast.TypeVar``,
+``ast.ParamSpec``, and ``ast.TypeVarTuple``.
+
+``typing.TypeVar``, ``typing.ParamSpec``, ``typing.ParamSpecArgs``,
+``typing.ParamSpecKwargs``, ``typing.TypeVarTuple``, and
+``typing.Generic`` are now implemented in C rather than Python.
+
+There are new bytecode instructions ``LOAD_LOCALS``,
+``LOAD_CLASSDICT_OR_GLOBAL``, and ``LOAD_CLASSDICT_OR_DEREF``
+to support correct resolution of names in class namespaces.
+
+Patch by Eric Traut, Larry Hastings, and Jelle Zijlstra.

Modules/Setup.bootstrap.in

@@ -21,6 +21,7 @@ itertools itertoolsmodule.c
 _sre _sre/sre.c
 _thread _threadmodule.c
 time timemodule.c
+_typing _typingmodule.c
 _weakref _weakref.c
 
 # commonly used core modules

Modules/Setup.stdlib.in

@@ -41,7 +41,6 @@
 @MODULE__QUEUE_TRUE@_queue _queuemodule.c
 @MODULE__RANDOM_TRUE@_random _randommodule.c
 @MODULE__STRUCT_TRUE@_struct _struct.c
-@MODULE__TYPING_TRUE@_typing _typingmodule.c
 @MODULE__XXSUBINTERPRETERS_TRUE@_xxsubinterpreters _xxsubinterpretersmodule.c
 @MODULE__XXINTERPCHANNELS_TRUE@_xxinterpchannels _xxinterpchannelsmodule.c
 @MODULE__ZONEINFO_TRUE@_zoneinfo _zoneinfo.c

Modules/_typingmodule.c

@@ -1,6 +1,11 @@
 /* typing accelerator C extension: _typing module. */
 
+#ifndef Py_BUILD_CORE
+#define Py_BUILD_CORE
+#endif
+
 #include "Python.h"
+#include "internal/pycore_interp.h"
 #include "clinic/_typingmodule.c.h"
 
 /*[clinic input]
@@ -35,7 +40,30 @@ static PyMethodDef typing_methods[] = {
 PyDoc_STRVAR(typing_doc,
 "Accelerators for the typing module.\n");
 
+static int
+_typing_exec(PyObject *m)
+{
+    PyInterpreterState *interp = PyInterpreterState_Get();
+
+#define EXPORT_TYPE(name, typename) \
+    if (PyModule_AddObjectRef(m, name, \
+                              (PyObject *)interp->cached_objects.typename) < 0) { \
+        return -1; \
+    }
+
+    EXPORT_TYPE("TypeVar", typevar_type);
+    EXPORT_TYPE("TypeVarTuple", typevartuple_type);
+    EXPORT_TYPE("ParamSpec", paramspec_type);
+    EXPORT_TYPE("ParamSpecArgs", paramspecargs_type);
+    EXPORT_TYPE("ParamSpecKwargs", paramspeckwargs_type);
+    EXPORT_TYPE("TypeAliasType", typealias_type);
+    EXPORT_TYPE("Generic", generic_type);
+#undef EXPORT_TYPE
+    return 0;
+}
+
 static struct PyModuleDef_Slot _typingmodule_slots[] = {
+    {Py_mod_exec, _typing_exec},
     {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
     {0, NULL}
 };

Objects/clinic/typevarobject.c.h

@@ -0,0 +1,786 @@
+/*[clinic input]
+preserve
+[clinic start generated code]*/
+
+#if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+#  include "pycore_gc.h"            // PyGC_Head
+#  include "pycore_runtime.h"       // _Py_ID()
+#endif
+
+
+PyDoc_STRVAR(typevar_new__doc__,
+"typevar(name, *constraints, *, bound=None, covariant=False,\n"
+"        contravariant=False, infer_variance=False)\n"
+"--\n"
+"\n"
+"Create a TypeVar.");
+
+static PyObject *
+typevar_new_impl(PyTypeObject *type, PyObject *name, PyObject *constraints,
+                 PyObject *bound, int covariant, int contravariant,
+                 int infer_variance);
+
+static PyObject *
+typevar_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 5
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(name), &_Py_ID(bound), &_Py_ID(covariant), &_Py_ID(contravariant), &_Py_ID(infer_variance), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"name", "bound", "covariant", "contravariant", "infer_variance", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "typevar",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[6];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = Py_MIN(nargs, 1) + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
+    PyObject *name;
+    PyObject *constraints = NULL;
+    PyObject *bound = Py_None;
+    int covariant = 0;
+    int contravariant = 0;
+    int infer_variance = 0;
+
+    fastargs = _PyArg_UnpackKeywordsWithVararg(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, 1, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(fastargs[0])) {
+        _PyArg_BadArgument("typevar", "argument 'name'", "str", fastargs[0]);
+        goto exit;
+    }
+    name = fastargs[0];
+    constraints = fastargs[1];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (fastargs[2]) {
+        bound = fastargs[2];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[3]) {
+        covariant = PyObject_IsTrue(fastargs[3]);
+        if (covariant < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[4]) {
+        contravariant = PyObject_IsTrue(fastargs[4]);
+        if (contravariant < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    infer_variance = PyObject_IsTrue(fastargs[5]);
+    if (infer_variance < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
+    return_value = typevar_new_impl(type, name, constraints, bound, covariant, contravariant, infer_variance);
+
+exit:
+    Py_XDECREF(constraints);
+    return return_value;
+}
+
+PyDoc_STRVAR(typevar_typing_subst__doc__,
+"__typing_subst__($self, /, arg)\n"
+"--\n"
+"\n");
+
+#define TYPEVAR_TYPING_SUBST_METHODDEF    \
+    {"__typing_subst__", _PyCFunction_CAST(typevar_typing_subst), METH_FASTCALL|METH_KEYWORDS, typevar_typing_subst__doc__},
+
+static PyObject *
+typevar_typing_subst_impl(typevarobject *self, PyObject *arg);
+
+static PyObject *
+typevar_typing_subst(typevarobject *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(arg), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"arg", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "__typing_subst__",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject *arg;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    arg = args[0];
+    return_value = typevar_typing_subst_impl(self, arg);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(typevar_reduce__doc__,
+"__reduce__($self, /)\n"
+"--\n"
+"\n");
+
+#define TYPEVAR_REDUCE_METHODDEF    \
+    {"__reduce__", (PyCFunction)typevar_reduce, METH_NOARGS, typevar_reduce__doc__},
+
+static PyObject *
+typevar_reduce_impl(typevarobject *self);
+
+static PyObject *
+typevar_reduce(typevarobject *self, PyObject *Py_UNUSED(ignored))
+{
+    return typevar_reduce_impl(self);
+}
+
+PyDoc_STRVAR(paramspecargs_new__doc__,
+"paramspecargs(origin)\n"
+"--\n"
+"\n"
+"Create a ParamSpecArgs object.");
+
+static PyObject *
+paramspecargs_new_impl(PyTypeObject *type, PyObject *origin);
+
+static PyObject *
+paramspecargs_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(origin), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"origin", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "paramspecargs",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    PyObject *origin;
+
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    origin = fastargs[0];
+    return_value = paramspecargs_new_impl(type, origin);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(paramspeckwargs_new__doc__,
+"paramspeckwargs(origin)\n"
+"--\n"
+"\n"
+"Create a ParamSpecKwargs object.");
+
+static PyObject *
+paramspeckwargs_new_impl(PyTypeObject *type, PyObject *origin);
+
+static PyObject *
+paramspeckwargs_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(origin), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"origin", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "paramspeckwargs",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    PyObject *origin;
+
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    origin = fastargs[0];
+    return_value = paramspeckwargs_new_impl(type, origin);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(paramspec_new__doc__,
+"paramspec(name, *, bound=None, covariant=False, contravariant=False,\n"
+"          infer_variance=False)\n"
+"--\n"
+"\n"
+"Create a ParamSpec object.");
+
+static PyObject *
+paramspec_new_impl(PyTypeObject *type, PyObject *name, PyObject *bound,
+                   int covariant, int contravariant, int infer_variance);
+
+static PyObject *
+paramspec_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 5
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(name), &_Py_ID(bound), &_Py_ID(covariant), &_Py_ID(contravariant), &_Py_ID(infer_variance), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"name", "bound", "covariant", "contravariant", "infer_variance", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "paramspec",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[5];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
+    PyObject *name;
+    PyObject *bound = Py_None;
+    int covariant = 0;
+    int contravariant = 0;
+    int infer_variance = 0;
+
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(fastargs[0])) {
+        _PyArg_BadArgument("paramspec", "argument 'name'", "str", fastargs[0]);
+        goto exit;
+    }
+    name = fastargs[0];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    if (fastargs[1]) {
+        bound = fastargs[1];
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[2]) {
+        covariant = PyObject_IsTrue(fastargs[2]);
+        if (covariant < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[3]) {
+        contravariant = PyObject_IsTrue(fastargs[3]);
+        if (contravariant < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    infer_variance = PyObject_IsTrue(fastargs[4]);
+    if (infer_variance < 0) {
+        goto exit;
+    }
+skip_optional_kwonly:
+    return_value = paramspec_new_impl(type, name, bound, covariant, contravariant, infer_variance);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(paramspec_typing_subst__doc__,
+"__typing_subst__($self, /, arg)\n"
+"--\n"
+"\n");
+
+#define PARAMSPEC_TYPING_SUBST_METHODDEF    \
+    {"__typing_subst__", _PyCFunction_CAST(paramspec_typing_subst), METH_FASTCALL|METH_KEYWORDS, paramspec_typing_subst__doc__},
+
+static PyObject *
+paramspec_typing_subst_impl(paramspecobject *self, PyObject *arg);
+
+static PyObject *
+paramspec_typing_subst(paramspecobject *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(arg), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"arg", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "__typing_subst__",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject *arg;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    arg = args[0];
+    return_value = paramspec_typing_subst_impl(self, arg);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(paramspec_typing_prepare_subst__doc__,
+"__typing_prepare_subst__($self, /, alias, args)\n"
+"--\n"
+"\n");
+
+#define PARAMSPEC_TYPING_PREPARE_SUBST_METHODDEF    \
+    {"__typing_prepare_subst__", _PyCFunction_CAST(paramspec_typing_prepare_subst), METH_FASTCALL|METH_KEYWORDS, paramspec_typing_prepare_subst__doc__},
+
+static PyObject *
+paramspec_typing_prepare_subst_impl(paramspecobject *self, PyObject *alias,
+                                    PyObject *args);
+
+static PyObject *
+paramspec_typing_prepare_subst(paramspecobject *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 2
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(alias), &_Py_ID(args), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"alias", "args", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "__typing_prepare_subst__",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[2];
+    PyObject *alias;
+    PyObject *__clinic_args;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    alias = args[0];
+    __clinic_args = args[1];
+    return_value = paramspec_typing_prepare_subst_impl(self, alias, __clinic_args);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(paramspec_reduce__doc__,
+"__reduce__($self, /)\n"
+"--\n"
+"\n");
+
+#define PARAMSPEC_REDUCE_METHODDEF    \
+    {"__reduce__", (PyCFunction)paramspec_reduce, METH_NOARGS, paramspec_reduce__doc__},
+
+static PyObject *
+paramspec_reduce_impl(paramspecobject *self);
+
+static PyObject *
+paramspec_reduce(paramspecobject *self, PyObject *Py_UNUSED(ignored))
+{
+    return paramspec_reduce_impl(self);
+}
+
+PyDoc_STRVAR(typevartuple__doc__,
+"typevartuple(name)\n"
+"--\n"
+"\n"
+"Create a new TypeVarTuple with the given name.");
+
+static PyObject *
+typevartuple_impl(PyTypeObject *type, PyObject *name);
+
+static PyObject *
+typevartuple(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(name), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"name", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "typevartuple",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    PyObject *name;
+
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 1, 1, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(fastargs[0])) {
+        _PyArg_BadArgument("typevartuple", "argument 'name'", "str", fastargs[0]);
+        goto exit;
+    }
+    name = fastargs[0];
+    return_value = typevartuple_impl(type, name);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(typevartuple_typing_subst__doc__,
+"__typing_subst__($self, /, arg)\n"
+"--\n"
+"\n");
+
+#define TYPEVARTUPLE_TYPING_SUBST_METHODDEF    \
+    {"__typing_subst__", _PyCFunction_CAST(typevartuple_typing_subst), METH_FASTCALL|METH_KEYWORDS, typevartuple_typing_subst__doc__},
+
+static PyObject *
+typevartuple_typing_subst_impl(typevartupleobject *self, PyObject *arg);
+
+static PyObject *
+typevartuple_typing_subst(typevartupleobject *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 1
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(arg), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"arg", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "__typing_subst__",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[1];
+    PyObject *arg;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    arg = args[0];
+    return_value = typevartuple_typing_subst_impl(self, arg);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(typevartuple_typing_prepare_subst__doc__,
+"__typing_prepare_subst__($self, /, alias, args)\n"
+"--\n"
+"\n");
+
+#define TYPEVARTUPLE_TYPING_PREPARE_SUBST_METHODDEF    \
+    {"__typing_prepare_subst__", _PyCFunction_CAST(typevartuple_typing_prepare_subst), METH_FASTCALL|METH_KEYWORDS, typevartuple_typing_prepare_subst__doc__},
+
+static PyObject *
+typevartuple_typing_prepare_subst_impl(typevartupleobject *self,
+                                       PyObject *alias, PyObject *args);
+
+static PyObject *
+typevartuple_typing_prepare_subst(typevartupleobject *self, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 2
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(alias), &_Py_ID(args), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"alias", "args", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "__typing_prepare_subst__",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[2];
+    PyObject *alias;
+    PyObject *__clinic_args;
+
+    args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 2, 2, 0, argsbuf);
+    if (!args) {
+        goto exit;
+    }
+    alias = args[0];
+    __clinic_args = args[1];
+    return_value = typevartuple_typing_prepare_subst_impl(self, alias, __clinic_args);
+
+exit:
+    return return_value;
+}
+
+PyDoc_STRVAR(typevartuple_reduce__doc__,
+"__reduce__($self, /)\n"
+"--\n"
+"\n");
+
+#define TYPEVARTUPLE_REDUCE_METHODDEF    \
+    {"__reduce__", (PyCFunction)typevartuple_reduce, METH_NOARGS, typevartuple_reduce__doc__},
+
+static PyObject *
+typevartuple_reduce_impl(typevartupleobject *self);
+
+static PyObject *
+typevartuple_reduce(typevartupleobject *self, PyObject *Py_UNUSED(ignored))
+{
+    return typevartuple_reduce_impl(self);
+}
+
+PyDoc_STRVAR(typealias_reduce__doc__,
+"__reduce__($self, /)\n"
+"--\n"
+"\n");
+
+#define TYPEALIAS_REDUCE_METHODDEF    \
+    {"__reduce__", (PyCFunction)typealias_reduce, METH_NOARGS, typealias_reduce__doc__},
+
+static PyObject *
+typealias_reduce_impl(typealiasobject *self);
+
+static PyObject *
+typealias_reduce(typealiasobject *self, PyObject *Py_UNUSED(ignored))
+{
+    return typealias_reduce_impl(self);
+}
+
+PyDoc_STRVAR(typealias_new__doc__,
+"typealias(name, value, *, type_params=<unrepresentable>)\n"
+"--\n"
+"\n"
+"Create a TypeAliasType.");
+
+static PyObject *
+typealias_new_impl(PyTypeObject *type, PyObject *name, PyObject *value,
+                   PyObject *type_params);
+
+static PyObject *
+typealias_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
+{
+    PyObject *return_value = NULL;
+    #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
+
+    #define NUM_KEYWORDS 3
+    static struct {
+        PyGC_Head _this_is_not_used;
+        PyObject_VAR_HEAD
+        PyObject *ob_item[NUM_KEYWORDS];
+    } _kwtuple = {
+        .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
+        .ob_item = { &_Py_ID(name), &_Py_ID(value), &_Py_ID(type_params), },
+    };
+    #undef NUM_KEYWORDS
+    #define KWTUPLE (&_kwtuple.ob_base.ob_base)
+
+    #else  // !Py_BUILD_CORE
+    #  define KWTUPLE NULL
+    #endif  // !Py_BUILD_CORE
+
+    static const char * const _keywords[] = {"name", "value", "type_params", NULL};
+    static _PyArg_Parser _parser = {
+        .keywords = _keywords,
+        .fname = "typealias",
+        .kwtuple = KWTUPLE,
+    };
+    #undef KWTUPLE
+    PyObject *argsbuf[3];
+    PyObject * const *fastargs;
+    Py_ssize_t nargs = PyTuple_GET_SIZE(args);
+    Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 2;
+    PyObject *name;
+    PyObject *value;
+    PyObject *type_params = NULL;
+
+    fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser, 2, 2, 0, argsbuf);
+    if (!fastargs) {
+        goto exit;
+    }
+    if (!PyUnicode_Check(fastargs[0])) {
+        _PyArg_BadArgument("typealias", "argument 'name'", "str", fastargs[0]);
+        goto exit;
+    }
+    name = fastargs[0];
+    value = fastargs[1];
+    if (!noptargs) {
+        goto skip_optional_kwonly;
+    }
+    type_params = fastargs[2];
+skip_optional_kwonly:
+    return_value = typealias_new_impl(type, name, value, type_params);
+
+exit:
+    return return_value;
+}
+/*[clinic end generated code: output=807bcd30ebd10ac3 input=a9049054013a1b77]*/

Objects/funcobject.c

@@ -127,6 +127,7 @@ _PyFunction_FromConstructor(PyFrameConstructor *constr)
         PyErr_Clear();
     }
     op->func_annotations = NULL;
+    op->func_typeparams = NULL;
     op->vectorcall = _PyFunction_Vectorcall;
     op->func_version = 0;
     _PyObject_GC_TRACK(op);
@@ -202,6 +203,7 @@ PyFunction_NewWithQualName(PyObject *code, PyObject *globals, PyObject *qualname
     op->func_weakreflist = NULL;
     op->func_module = module;
     op->func_annotations = NULL;
+    op->func_typeparams = NULL;
     op->vectorcall = _PyFunction_Vectorcall;
     op->func_version = 0;
     _PyObject_GC_TRACK(op);
@@ -652,6 +654,28 @@ func_set_annotations(PyFunctionObject *op, PyObject *value, void *Py_UNUSED(igno
     return 0;
 }
 
+static PyObject *
+func_get_type_params(PyFunctionObject *op, void *Py_UNUSED(ignored))
+{
+    if (op->func_typeparams == NULL) {
+        return PyTuple_New(0);
+    }
+
+    assert(PyTuple_Check(op->func_typeparams));
+    return Py_NewRef(op->func_typeparams);
+}
+
+PyObject *
+_Py_set_function_type_params(PyThreadState *Py_UNUSED(ignored), PyObject *func,
+                             PyObject *type_params)
+{
+    assert(PyFunction_Check(func));
+    assert(PyTuple_Check(type_params));
+    PyFunctionObject *f = (PyFunctionObject *)func;
+    Py_XSETREF(f->func_typeparams, Py_NewRef(type_params));
+    return Py_NewRef(func);
+}
+
 static PyGetSetDef func_getsetlist[] = {
     {"__code__", (getter)func_get_code, (setter)func_set_code},
     {"__defaults__", (getter)func_get_defaults,
@@ -663,6 +687,7 @@ static PyGetSetDef func_getsetlist[] = {
     {"__dict__", PyObject_GenericGetDict, PyObject_GenericSetDict},
     {"__name__", (getter)func_get_name, (setter)func_set_name},
     {"__qualname__", (getter)func_get_qualname, (setter)func_set_qualname},
+    {"__type_params__", (getter)func_get_type_params, NULL},
     {NULL} /* Sentinel */
 };
 
@@ -783,6 +808,7 @@ func_clear(PyFunctionObject *op)
     Py_CLEAR(op->func_dict);
     Py_CLEAR(op->func_closure);
     Py_CLEAR(op->func_annotations);
+    Py_CLEAR(op->func_typeparams);
     // Don't Py_CLEAR(op->func_code), since code is always required
     // to be non-NULL. Similarly, name and qualname shouldn't be NULL.
     // However, name and qualname could be str subclasses, so they
@@ -837,6 +863,7 @@ func_traverse(PyFunctionObject *f, visitproc visit, void *arg)
     Py_VISIT(f->func_dict);
     Py_VISIT(f->func_closure);
     Py_VISIT(f->func_annotations);
+    Py_VISIT(f->func_typeparams);
     Py_VISIT(f->func_qualname);
     return 0;
 }

Objects/object.c

@@ -14,6 +14,7 @@
 #include "pycore_pymem.h"         // _PyMem_IsPtrFreed()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
 #include "pycore_symtable.h"      // PySTEntry_Type
+#include "pycore_typevarobject.h" // _PyTypeVar_Type etc., _Py_initialize_generic
 #include "pycore_typeobject.h"    // _PyBufferWrapper_Type
 #include "pycore_unionobject.h"   // _PyUnion_Type
 #include "pycore_interpreteridobject.h"  // _PyInterpreterID_Type
@@ -2139,6 +2140,11 @@ _PyTypes_InitTypes(PyInterpreterState *interp)
         }
     }
 
+    // Must be after static types are initialized
+    if (_Py_initialize_generic(interp) < 0) {
+        return _PyStatus_ERR("Can't initialize generic types");
+    }
+
     return _PyStatus_OK();
 }
 

Objects/typeobject.c

@@ -1460,6 +1460,18 @@ type_get_annotations(PyTypeObject *type, void *context)
     return annotations;
 }
 
+static PyObject *
+type_get_type_params(PyTypeObject *type, void *context)
+{
+    PyObject *params = PyDict_GetItem(lookup_tp_dict(type), &_Py_ID(__type_params__));
+
+    if (params) {
+        return Py_NewRef(params);
+    }
+
+    return PyTuple_New(0);
+}
+
 static int
 type_set_annotations(PyTypeObject *type, PyObject *value, void *context)
 {
@@ -1536,6 +1548,7 @@ static PyGetSetDef type_getsets[] = {
     {"__doc__", (getter)type_get_doc, (setter)type_set_doc, NULL},
     {"__text_signature__", (getter)type_get_text_signature, NULL, NULL},
     {"__annotations__", (getter)type_get_annotations, (setter)type_set_annotations, NULL},
+    {"__type_params__", (getter)type_get_type_params, NULL, NULL},
     {0}
 };
 
@@ -3130,11 +3143,12 @@ type_new_copy_slots(type_new_ctx *ctx, PyObject *dict)
             goto error;
         }
         if (r > 0) {
-            /* CPython inserts __qualname__ and __classcell__ (when needed)
+            /* CPython inserts these names (when needed)
                into the namespace when creating a class.  They will be deleted
                below so won't act as class variables. */
             if (!_PyUnicode_Equal(slot, &_Py_ID(__qualname__)) &&
-                !_PyUnicode_Equal(slot, &_Py_ID(__classcell__)))
+                !_PyUnicode_Equal(slot, &_Py_ID(__classcell__)) &&
+                !_PyUnicode_Equal(slot, &_Py_ID(__classdictcell__)))
             {
                 PyErr_Format(PyExc_ValueError,
                              "%R in __slots__ conflicts with class variable",
@@ -3585,6 +3599,32 @@ type_new_set_classcell(PyTypeObject *type)
     return 0;
 }
 
+static int
+type_new_set_classdictcell(PyTypeObject *type)
+{
+    PyObject *dict = lookup_tp_dict(type);
+    PyObject *cell = PyDict_GetItemWithError(dict, &_Py_ID(__classdictcell__));
+    if (cell == NULL) {
+        if (PyErr_Occurred()) {
+            return -1;
+        }
+        return 0;
+    }
+
+    /* At least one method requires a reference to the dict of its defining class */
+    if (!PyCell_Check(cell)) {
+        PyErr_Format(PyExc_TypeError,
+                     "__classdictcell__ must be a nonlocal cell, not %.200R",
+                     Py_TYPE(cell));
+        return -1;
+    }
+
+    (void)PyCell_Set(cell, (PyObject *)dict);
+    if (PyDict_DelItem(dict, &_Py_ID(__classdictcell__)) < 0) {
+        return -1;
+    }
+    return 0;
+}
 
 static int
 type_new_set_attrs(const type_new_ctx *ctx, PyTypeObject *type)
@@ -3629,6 +3669,9 @@ type_new_set_attrs(const type_new_ctx *ctx, PyTypeObject *type)
     if (type_new_set_classcell(type) < 0) {
         return -1;
     }
+    if (type_new_set_classdictcell(type) < 0) {
+        return -1;
+    }
     return 0;
 }
 

Objects/unionobject.c

@@ -147,10 +147,14 @@ get_types(PyObject **obj, Py_ssize_t *size)
 static int
 is_unionable(PyObject *obj)
 {
-    return (obj == Py_None ||
+    if (obj == Py_None ||
         PyType_Check(obj) ||
         _PyGenericAlias_Check(obj) ||
-        _PyUnion_Check(obj));
+        _PyUnion_Check(obj)) {
+        return 1;
+    }
+    PyInterpreterState *interp = PyInterpreterState_Get();
+    return Py_IS_TYPE(obj, interp->cached_objects.typealias_type);
 }
 
 PyObject *

PCbuild/_freeze_module.vcxproj

@@ -159,6 +159,7 @@
     <ClCompile Include="..\Objects\structseq.c" />
     <ClCompile Include="..\Objects\tupleobject.c" />
     <ClCompile Include="..\Objects\typeobject.c" />
+    <ClCompile Include="..\Objects\typevarobject.c" />
     <ClCompile Include="..\Objects\unicodectype.c" />
     <ClCompile Include="..\Objects\unicodeobject.c" />
     <ClCompile Include="..\Objects\unionobject.c" />

PCbuild/pythoncore.vcxproj

@@ -269,6 +269,7 @@
     <ClInclude Include="..\Include\internal\pycore_tracemalloc.h" />
     <ClInclude Include="..\Include\internal\pycore_tuple.h" />
     <ClInclude Include="..\Include\internal\pycore_typeobject.h" />
+    <ClInclude Include="..\Include\internal\pycore_typevarobject.h" />
     <ClInclude Include="..\Include\internal\pycore_ucnhash.h" />
     <ClInclude Include="..\Include\internal\pycore_unionobject.h" />
     <ClInclude Include="..\Include\internal\pycore_unicodeobject.h" />
@@ -481,6 +482,7 @@
     <ClCompile Include="..\Objects\structseq.c" />
     <ClCompile Include="..\Objects\tupleobject.c" />
     <ClCompile Include="..\Objects\typeobject.c" />
+    <ClCompile Include="..\Objects\typevarobject.c" />
     <ClCompile Include="..\Objects\unicodectype.c" />
     <ClCompile Include="..\Objects\unicodeobject.c" />
     <ClCompile Include="..\Objects\unionobject.c" />

PCbuild/pythoncore.vcxproj.filters

@@ -705,6 +705,9 @@
     <ClInclude Include="..\Include\internal\pycore_typeobject.h">
       <Filter>Include\internal</Filter>
     </ClInclude>
+    <ClInclude Include="..\Include\internal\pycore_typevarobject.h">
+      <Filter>Include\internal</Filter>
+    </ClInclude>
     <ClInclude Include="..\Include\internal\pycore_ucnhash.h">
       <Filter>Include\internal</Filter>
     </ClInclude>
@@ -1364,6 +1367,9 @@
     <ClCompile Include="..\Objects\genericaliasobject.c">
       <Filter>Objects</Filter>
     </ClCompile>
+    <ClCompile Include="..\Objects\typevarobject.c">
+      <Filter>Objects</Filter>
+    </ClCompile>
     <ClCompile Include="..\Objects\unionobject.c">
       <Filter>Objects</Filter>
     </ClCompile>

Parser/Python.asdl

@@ -8,14 +8,15 @@ module Python
         | Expression(expr body)
         | FunctionType(expr* argtypes, expr returns)
 
-    stmt = FunctionDef(identifier name, arguments args,
+    stmt = FunctionDef(identifier name, typeparam* typeparams, arguments args,
                        stmt* body, expr* decorator_list, expr? returns,
                        string? type_comment)
-          | AsyncFunctionDef(identifier name, arguments args,
+          | AsyncFunctionDef(identifier name, typeparam* typeparams, arguments args,
                              stmt* body, expr* decorator_list, expr? returns,
                              string? type_comment)
 
           | ClassDef(identifier name,
+             typeparam* typeparams,
              expr* bases,
              keyword* keywords,
              stmt* body,
@@ -24,6 +25,7 @@ module Python
 
           | Delete(expr* targets)
           | Assign(expr* targets, expr value, string? type_comment)
+          | TypeAlias(expr name, typeparam* typeparams, expr value)
           | AugAssign(expr target, operator op, expr value)
           -- 'simple' indicates that we annotate simple name without parens
           | AnnAssign(expr target, expr annotation, expr? value, int simple)
@@ -142,4 +144,9 @@ module Python
              attributes (int lineno, int col_offset, int end_lineno, int end_col_offset)
 
     type_ignore = TypeIgnore(int lineno, string tag)
+
+    typeparam = TypeVar(identifier name, expr? bound)
+            | ParamSpec(identifier name)
+            | TypeVarTuple(identifier name)
+             attributes (int lineno, int col_offset, int? end_lineno, int? end_col_offset)
 }

Parser/action_helpers.c

@@ -752,7 +752,8 @@ _PyPegen_function_def_decorators(Parser *p, asdl_expr_seq *decorators, stmt_ty f
     assert(function_def != NULL);
     if (function_def->kind == AsyncFunctionDef_kind) {
         return _PyAST_AsyncFunctionDef(
-            function_def->v.FunctionDef.name, function_def->v.FunctionDef.args,
+            function_def->v.FunctionDef.name, function_def->v.FunctionDef.typeparams,
+            function_def->v.FunctionDef.args,
             function_def->v.FunctionDef.body, decorators, function_def->v.FunctionDef.returns,
             function_def->v.FunctionDef.type_comment, function_def->lineno,
             function_def->col_offset, function_def->end_lineno, function_def->end_col_offset,
@@ -760,7 +761,8 @@ _PyPegen_function_def_decorators(Parser *p, asdl_expr_seq *decorators, stmt_ty f
     }
 
     return _PyAST_FunctionDef(
-        function_def->v.FunctionDef.name, function_def->v.FunctionDef.args,
+        function_def->v.FunctionDef.name, function_def->v.FunctionDef.typeparams,
+        function_def->v.FunctionDef.args,
         function_def->v.FunctionDef.body, decorators,
         function_def->v.FunctionDef.returns,
         function_def->v.FunctionDef.type_comment, function_def->lineno,
@@ -774,8 +776,9 @@ _PyPegen_class_def_decorators(Parser *p, asdl_expr_seq *decorators, stmt_ty clas
 {
     assert(class_def != NULL);
     return _PyAST_ClassDef(
-        class_def->v.ClassDef.name, class_def->v.ClassDef.bases,
+        class_def->v.ClassDef.name, class_def->v.ClassDef.typeparams,
-        class_def->v.ClassDef.keywords, class_def->v.ClassDef.body, decorators,
+        class_def->v.ClassDef.bases, class_def->v.ClassDef.keywords,
+        class_def->v.ClassDef.body, decorators,
         class_def->lineno, class_def->col_offset, class_def->end_lineno,
         class_def->end_col_offset, p->arena);
 }

Python/ast.c

@@ -17,10 +17,12 @@ struct validator {
 static int validate_stmts(struct validator *, asdl_stmt_seq *);
 static int validate_exprs(struct validator *, asdl_expr_seq *, expr_context_ty, int);
 static int validate_patterns(struct validator *, asdl_pattern_seq *, int);
+static int validate_typeparams(struct validator *, asdl_typeparam_seq *);
 static int _validate_nonempty_seq(asdl_seq *, const char *, const char *);
 static int validate_stmt(struct validator *, stmt_ty);
 static int validate_expr(struct validator *, expr_ty, expr_context_ty);
 static int validate_pattern(struct validator *, pattern_ty, int);
+static int validate_typeparam(struct validator *, typeparam_ty);
 
 #define VALIDATE_POSITIONS(node) \
     if (node->lineno > node->end_lineno) { \
@@ -726,6 +728,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
     switch (stmt->kind) {
     case FunctionDef_kind:
         ret = validate_body(state, stmt->v.FunctionDef.body, "FunctionDef") &&
+            validate_typeparams(state, stmt->v.FunctionDef.typeparams) &&
             validate_arguments(state, stmt->v.FunctionDef.args) &&
             validate_exprs(state, stmt->v.FunctionDef.decorator_list, Load, 0) &&
             (!stmt->v.FunctionDef.returns ||
@@ -733,6 +736,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
         break;
     case ClassDef_kind:
         ret = validate_body(state, stmt->v.ClassDef.body, "ClassDef") &&
+            validate_typeparams(state, stmt->v.ClassDef.typeparams) &&
             validate_exprs(state, stmt->v.ClassDef.bases, Load, 0) &&
             validate_keywords(state, stmt->v.ClassDef.keywords) &&
             validate_exprs(state, stmt->v.ClassDef.decorator_list, Load, 0);
@@ -763,6 +767,11 @@ validate_stmt(struct validator *state, stmt_ty stmt)
                 validate_expr(state, stmt->v.AnnAssign.value, Load)) &&
                validate_expr(state, stmt->v.AnnAssign.annotation, Load);
         break;
+    case TypeAlias_kind:
+        ret = validate_expr(state, stmt->v.TypeAlias.name, Store) &&
+            validate_typeparams(state, stmt->v.TypeAlias.typeparams) &&
+            validate_expr(state, stmt->v.TypeAlias.value, Load);
+        break;
     case For_kind:
         ret = validate_expr(state, stmt->v.For.target, Store) &&
             validate_expr(state, stmt->v.For.iter, Load) &&
@@ -910,6 +919,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
         break;
     case AsyncFunctionDef_kind:
         ret = validate_body(state, stmt->v.AsyncFunctionDef.body, "AsyncFunctionDef") &&
+            validate_typeparams(state, stmt->v.AsyncFunctionDef.typeparams) &&
             validate_arguments(state, stmt->v.AsyncFunctionDef.args) &&
             validate_exprs(state, stmt->v.AsyncFunctionDef.decorator_list, Load, 0) &&
             (!stmt->v.AsyncFunctionDef.returns ||
@@ -982,6 +992,41 @@ validate_patterns(struct validator *state, asdl_pattern_seq *patterns, int star_
     return 1;
 }
 
+static int
+validate_typeparam(struct validator *state, typeparam_ty tp)
+{
+    VALIDATE_POSITIONS(tp);
+    int ret = -1;
+    switch (tp->kind) {
+        case TypeVar_kind:
+            ret = validate_name(tp->v.TypeVar.name) &&
+                (!tp->v.TypeVar.bound ||
+                 validate_expr(state, tp->v.TypeVar.bound, Load));
+            break;
+        case ParamSpec_kind:
+            ret = validate_name(tp->v.ParamSpec.name);
+            break;
+        case TypeVarTuple_kind:
+            ret = validate_name(tp->v.TypeVarTuple.name);
+            break;
+    }
+    return ret;
+}
+
+static int
+validate_typeparams(struct validator *state, asdl_typeparam_seq *tps)
+{
+    Py_ssize_t i;
+    for (i = 0; i < asdl_seq_LEN(tps); i++) {
+        typeparam_ty tp = asdl_seq_GET(tps, i);
+        if (tp) {
+            if (!validate_typeparam(state, tp))
+                return 0;
+        }
+    }
+    return 1;
+}
+
 
 /* See comments in symtable.c. */
 #define COMPILER_STACK_FRAME_SCALE 3

Python/ast_opt.c

@@ -642,6 +642,7 @@ static int astfold_withitem(withitem_ty node_, PyArena *ctx_, _PyASTOptimizeStat
 static int astfold_excepthandler(excepthandler_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
 static int astfold_match_case(match_case_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
 static int astfold_pattern(pattern_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
+static int astfold_typeparam(typeparam_ty node_, PyArena *ctx_, _PyASTOptimizeState *state);
 
 #define CALL(FUNC, TYPE, ARG) \
     if (!FUNC((ARG), ctx_, state)) \
@@ -880,6 +881,7 @@ astfold_stmt(stmt_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
     }
     switch (node_->kind) {
     case FunctionDef_kind:
+        CALL_SEQ(astfold_typeparam, typeparam, node_->v.FunctionDef.typeparams);
         CALL(astfold_arguments, arguments_ty, node_->v.FunctionDef.args);
         CALL(astfold_body, asdl_seq, node_->v.FunctionDef.body);
         CALL_SEQ(astfold_expr, expr, node_->v.FunctionDef.decorator_list);
@@ -888,6 +890,7 @@ astfold_stmt(stmt_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
         }
         break;
     case AsyncFunctionDef_kind:
+        CALL_SEQ(astfold_typeparam, typeparam, node_->v.AsyncFunctionDef.typeparams);
         CALL(astfold_arguments, arguments_ty, node_->v.AsyncFunctionDef.args);
         CALL(astfold_body, asdl_seq, node_->v.AsyncFunctionDef.body);
         CALL_SEQ(astfold_expr, expr, node_->v.AsyncFunctionDef.decorator_list);
@@ -896,6 +899,7 @@ astfold_stmt(stmt_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
         }
         break;
     case ClassDef_kind:
+        CALL_SEQ(astfold_typeparam, typeparam, node_->v.ClassDef.typeparams);
         CALL_SEQ(astfold_expr, expr, node_->v.ClassDef.bases);
         CALL_SEQ(astfold_keyword, keyword, node_->v.ClassDef.keywords);
         CALL(astfold_body, asdl_seq, node_->v.ClassDef.body);
@@ -922,6 +926,11 @@ astfold_stmt(stmt_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
         }
         CALL_OPT(astfold_expr, expr_ty, node_->v.AnnAssign.value);
         break;
+    case TypeAlias_kind:
+        CALL(astfold_expr, expr_ty, node_->v.TypeAlias.name);
+        CALL_SEQ(astfold_typeparam, typeparam, node_->v.TypeAlias.typeparams);
+        CALL(astfold_expr, expr_ty, node_->v.TypeAlias.value);
+        break;
     case For_kind:
         CALL(astfold_expr, expr_ty, node_->v.For.target);
         CALL(astfold_expr, expr_ty, node_->v.For.iter);
@@ -1074,6 +1083,21 @@ astfold_match_case(match_case_ty node_, PyArena *ctx_, _PyASTOptimizeState *stat
     return 1;
 }
 
+static int
+astfold_typeparam(typeparam_ty node_, PyArena *ctx_, _PyASTOptimizeState *state)
+{
+    switch (node_->kind) {
+        case TypeVar_kind:
+            CALL_OPT(astfold_expr, expr_ty, node_->v.TypeVar.bound);
+            break;
+        case ParamSpec_kind:
+            break;
+        case TypeVarTuple_kind:
+            break;
+    }
+    return 1;
+}
+
 #undef CALL
 #undef CALL_OPT
 #undef CALL_SEQ

Python/bytecodes.c

@@ -56,7 +56,7 @@ static PyObject *value, *value1, *value2, *left, *right, *res, *sum, *prod, *sub
 static PyObject *container, *start, *stop, *v, *lhs, *rhs, *res2;
 static PyObject *list, *tuple, *dict, *owner, *set, *str, *tup, *map, *keys;
 static PyObject *exit_func, *lasti, *val, *retval, *obj, *iter;
-static PyObject *aiter, *awaitable, *iterable, *w, *exc_value, *bc;
+static PyObject *aiter, *awaitable, *iterable, *w, *exc_value, *bc, *locals;
 static PyObject *orig, *excs, *update, *b, *fromlist, *level, *from;
 static PyObject **pieces, **values;
 static size_t jump;
@@ -125,6 +125,7 @@ dummy_func(
     PyObject *subject;
     PyObject *top;
     PyObject *type;
+    PyObject *typevars;
     int values_or_none;
 
     switch (opcode) {
@@ -1002,6 +1003,7 @@ dummy_func(
             }
         }
 
+
         inst(STORE_NAME, (v -- )) {
             PyObject *name = GETITEM(frame->f_code->co_names, oparg);
             PyObject *ns = LOCALS();
@@ -1158,31 +1160,41 @@ dummy_func(
             }
         }
 
-        inst(LOAD_NAME, ( -- v)) {
+        op(_LOAD_LOCALS, ( -- locals)) {
-            PyObject *name = GETITEM(frame->f_code->co_names, oparg);
+            locals = LOCALS();
-            PyObject *locals = LOCALS();
             if (locals == NULL) {
-                _PyErr_Format(tstate, PyExc_SystemError,
+                _PyErr_SetString(tstate, PyExc_SystemError,
-                              "no locals when loading %R", name);
+                                 "no locals found");
-                goto error;
+                ERROR_IF(true, error);
             }
-            if (PyDict_CheckExact(locals)) {
+            Py_INCREF(locals);
-                v = PyDict_GetItemWithError(locals, name);
+        }
+
+        macro(LOAD_LOCALS) = _LOAD_LOCALS;
+
+        op(_LOAD_FROM_DICT_OR_GLOBALS, (mod_or_class_dict -- v)) {
+            PyObject *name = GETITEM(frame->f_code->co_names, oparg);
+            if (PyDict_CheckExact(mod_or_class_dict)) {
+                v = PyDict_GetItemWithError(mod_or_class_dict, name);
                 if (v != NULL) {
                     Py_INCREF(v);
                 }
                 else if (_PyErr_Occurred(tstate)) {
+                    Py_DECREF(mod_or_class_dict);
                     goto error;
                 }
             }
             else {
-                v = PyObject_GetItem(locals, name);
+                v = PyObject_GetItem(mod_or_class_dict, name);
                 if (v == NULL) {
-                    if (!_PyErr_ExceptionMatches(tstate, PyExc_KeyError))
+                    if (!_PyErr_ExceptionMatches(tstate, PyExc_KeyError)) {
+                        Py_DECREF(mod_or_class_dict);
                         goto error;
+                    }
                     _PyErr_Clear(tstate);
                 }
             }
+            Py_DECREF(mod_or_class_dict);
             if (v == NULL) {
                 v = PyDict_GetItemWithError(GLOBALS(), name);
                 if (v != NULL) {
@@ -1219,6 +1231,10 @@ dummy_func(
             }
         }
 
+        macro(LOAD_NAME) = _LOAD_LOCALS + _LOAD_FROM_DICT_OR_GLOBALS;
+
+        macro(LOAD_FROM_DICT_OR_GLOBALS) = _LOAD_FROM_DICT_OR_GLOBALS;
+
         family(load_global, INLINE_CACHE_ENTRIES_LOAD_GLOBAL) = {
             LOAD_GLOBAL,
             LOAD_GLOBAL_MODULE,
@@ -1339,29 +1355,32 @@ dummy_func(
             Py_DECREF(oldobj);
         }
 
-        inst(LOAD_CLASSDEREF, ( -- value)) {
+        inst(LOAD_FROM_DICT_OR_DEREF, (class_dict -- value)) {
-            PyObject *name, *locals = LOCALS();
+            PyObject *name;
-            assert(locals);
+            assert(class_dict);
             assert(oparg >= 0 && oparg < frame->f_code->co_nlocalsplus);
             name = PyTuple_GET_ITEM(frame->f_code->co_localsplusnames, oparg);
-            if (PyDict_CheckExact(locals)) {
+            if (PyDict_CheckExact(class_dict)) {
-                value = PyDict_GetItemWithError(locals, name);
+                value = PyDict_GetItemWithError(class_dict, name);
                 if (value != NULL) {
                     Py_INCREF(value);
                 }
                 else if (_PyErr_Occurred(tstate)) {
+                    Py_DECREF(class_dict);
                     goto error;
                 }
             }
             else {
-                value = PyObject_GetItem(locals, name);
+                value = PyObject_GetItem(class_dict, name);
                 if (value == NULL) {
                     if (!_PyErr_ExceptionMatches(tstate, PyExc_KeyError)) {
+                        Py_DECREF(class_dict);
                         goto error;
                     }
                     _PyErr_Clear(tstate);
                 }
             }
+            Py_DECREF(class_dict);
             if (!value) {
                 PyObject *cell = GETLOCAL(oparg);
                 value = PyCell_GET(cell);

Python/compile.c

@@ -147,6 +147,7 @@ enum {
     COMPILER_SCOPE_ASYNC_FUNCTION,
     COMPILER_SCOPE_LAMBDA,
     COMPILER_SCOPE_COMPREHENSION,
+    COMPILER_SCOPE_TYPEPARAMS,
 };
 
 
@@ -231,6 +232,7 @@ instr_sequence_next_inst(instr_sequence *seq) {
                                           &seq->s_allocated,
                                           INITIAL_INSTR_SEQUENCE_SIZE,
                                           sizeof(instruction)));
+    assert(seq->s_allocated >= 0);
     assert(seq->s_used < seq->s_allocated);
     return seq->s_used++;
 }
@@ -714,6 +716,19 @@ compiler_set_qualname(struct compiler *c)
         capsule = PyList_GET_ITEM(c->c_stack, stack_size - 1);
         parent = (struct compiler_unit *)PyCapsule_GetPointer(capsule, CAPSULE_NAME);
         assert(parent);
+        if (parent->u_scope_type == COMPILER_SCOPE_TYPEPARAMS) {
+            /* The parent is a type parameter scope, so we need to
+               look at the grandparent. */
+            if (stack_size == 2) {
+                // If we're immediately within the module, we can skip
+                // the rest and just set the qualname to be the same as name.
+                u->u_metadata.u_qualname = Py_NewRef(u->u_metadata.u_name);
+                return SUCCESS;
+            }
+            capsule = PyList_GET_ITEM(c->c_stack, stack_size - 2);
+            parent = (struct compiler_unit *)PyCapsule_GetPointer(capsule, CAPSULE_NAME);
+            assert(parent);
+        }
 
         if (u->u_scope_type == COMPILER_SCOPE_FUNCTION
             || u->u_scope_type == COMPILER_SCOPE_ASYNC_FUNCTION
@@ -1114,16 +1129,18 @@ codegen_addop_j(instr_sequence *seq, location loc,
     return instr_sequence_addop(seq, opcode, target.id, loc);
 }
 
-#define ADDOP(C, LOC, OP) \
+#define RETURN_IF_ERROR_IN_SCOPE(C, CALL) { \
-    RETURN_IF_ERROR(codegen_addop_noarg(INSTR_SEQUENCE(C), (OP), (LOC)))
+    if ((CALL) < 0) { \
-
+        compiler_exit_scope((C)); \
-#define ADDOP_IN_SCOPE(C, LOC, OP) { \
-    if (codegen_addop_noarg(INSTR_SEQUENCE(C), (OP), (LOC)) < 0) { \
-        compiler_exit_scope(C); \
         return ERROR; \
     } \
 }
 
+#define ADDOP(C, LOC, OP) \
+    RETURN_IF_ERROR(codegen_addop_noarg(INSTR_SEQUENCE(C), (OP), (LOC)))
+
+#define ADDOP_IN_SCOPE(C, LOC, OP) RETURN_IF_ERROR_IN_SCOPE((C), codegen_addop_noarg(INSTR_SEQUENCE(C), (OP), (LOC)))
+
 #define ADDOP_LOAD_CONST(C, LOC, O) \
     RETURN_IF_ERROR(compiler_addop_load_const((C)->c_const_cache, (C)->u, (LOC), (O)))
 
@@ -1183,12 +1200,8 @@ codegen_addop_j(instr_sequence *seq, location loc,
 #define VISIT(C, TYPE, V) \
     RETURN_IF_ERROR(compiler_visit_ ## TYPE((C), (V)));
 
-#define VISIT_IN_SCOPE(C, TYPE, V) {\
+#define VISIT_IN_SCOPE(C, TYPE, V) \
-    if (compiler_visit_ ## TYPE((C), (V)) < 0) { \
+    RETURN_IF_ERROR_IN_SCOPE((C), compiler_visit_ ## TYPE((C), (V)))
-        compiler_exit_scope(C); \
-        return ERROR; \
-    } \
-}
 
 #define VISIT_SEQ(C, TYPE, SEQ) { \
     int _i; \
@@ -1252,6 +1265,16 @@ compiler_enter_scope(struct compiler *c, identifier name,
             return ERROR;
         }
     }
+    if (u->u_ste->ste_needs_classdict) {
+        /* Cook up an implicit __classdict__ cell. */
+        Py_ssize_t res;
+        assert(u->u_scope_type == COMPILER_SCOPE_CLASS);
+        res = dict_add_o(u->u_metadata.u_cellvars, &_Py_ID(__classdict__));
+        if (res < 0) {
+            compiler_unit_free(u);
+            return ERROR;
+        }
+    }
 
     u->u_metadata.u_freevars = dictbytype(u->u_ste->ste_symbols, FREE, DEF_FREE_CLASS,
                                PyDict_GET_SIZE(u->u_metadata.u_cellvars));
@@ -1718,8 +1741,10 @@ get_ref_type(struct compiler *c, PyObject *name)
 {
     int scope;
     if (c->u->u_scope_type == COMPILER_SCOPE_CLASS &&
-        _PyUnicode_EqualToASCIIString(name, "__class__"))
+        (_PyUnicode_EqualToASCIIString(name, "__class__") ||
+         _PyUnicode_EqualToASCIIString(name, "__classdict__"))) {
         return CELL;
+    }
     scope = _PyST_GetScope(c->u->u_ste, name);
     if (scope == 0) {
         PyErr_Format(PyExc_SystemError,
@@ -2085,26 +2110,81 @@ wrap_in_stopiteration_handler(struct compiler *c)
 }
 
 static int
-compiler_function(struct compiler *c, stmt_ty s, int is_async)
+compiler_type_params(struct compiler *c, asdl_typeparam_seq *typeparams)
+{
+    if (!typeparams) {
+        return SUCCESS;
+    }
+    Py_ssize_t n = asdl_seq_LEN(typeparams);
+
+    for (Py_ssize_t i = 0; i < n; i++) {
+        typeparam_ty typeparam = asdl_seq_GET(typeparams, i);
+        location loc = LOC(typeparam);
+        switch(typeparam->kind) {
+        case TypeVar_kind:
+            ADDOP_LOAD_CONST(c, loc, typeparam->v.TypeVar.name);
+            if (typeparam->v.TypeVar.bound) {
+                expr_ty bound = typeparam->v.TypeVar.bound;
+                if (compiler_enter_scope(c, typeparam->v.TypeVar.name, COMPILER_SCOPE_TYPEPARAMS,
+                                        (void *)typeparam, bound->lineno) == -1) {
+                    return ERROR;
+                }
+                VISIT_IN_SCOPE(c, expr, bound);
+                ADDOP_IN_SCOPE(c, loc, RETURN_VALUE);
+                PyCodeObject *co = optimize_and_assemble(c, 1);
+                compiler_exit_scope(c);
+                if (co == NULL) {
+                    return ERROR;
+                }
+                if (compiler_make_closure(c, loc, co, 0) < 0) {
+                    Py_DECREF(co);
+                    return ERROR;
+                }
+                Py_DECREF(co);
+
+                int intrinsic = bound->kind == Tuple_kind
+                    ? INTRINSIC_TYPEVAR_WITH_CONSTRAINTS
+                    : INTRINSIC_TYPEVAR_WITH_BOUND;
+                ADDOP_I(c, loc, CALL_INTRINSIC_2, intrinsic);
+            }
+            else {
+                ADDOP_I(c, loc, CALL_INTRINSIC_1, INTRINSIC_TYPEVAR);
+            }
+            ADDOP_I(c, loc, COPY, 1);
+            RETURN_IF_ERROR(compiler_nameop(c, loc, typeparam->v.TypeVar.name, Store));
+            break;
+        case TypeVarTuple_kind:
+            ADDOP_LOAD_CONST(c, loc, typeparam->v.TypeVarTuple.name);
+            ADDOP_I(c, loc, CALL_INTRINSIC_1, INTRINSIC_TYPEVARTUPLE);
+            ADDOP_I(c, loc, COPY, 1);
+            RETURN_IF_ERROR(compiler_nameop(c, loc, typeparam->v.TypeVarTuple.name, Store));
+            break;
+        case ParamSpec_kind:
+            ADDOP_LOAD_CONST(c, loc, typeparam->v.ParamSpec.name);
+            ADDOP_I(c, loc, CALL_INTRINSIC_1, INTRINSIC_PARAMSPEC);
+            ADDOP_I(c, loc, COPY, 1);
+            RETURN_IF_ERROR(compiler_nameop(c, loc, typeparam->v.ParamSpec.name, Store));
+            break;
+        }
+    }
+    ADDOP_I(c, LOC(asdl_seq_GET(typeparams, 0)), BUILD_TUPLE, n);
+    return SUCCESS;
+}
+
+static int
+compiler_function_body(struct compiler *c, stmt_ty s, int is_async, Py_ssize_t funcflags,
+                       int firstlineno)
 {
-    PyCodeObject *co;
     PyObject *docstring = NULL;
     arguments_ty args;
-    expr_ty returns;
     identifier name;
-    asdl_expr_seq* decos;
     asdl_stmt_seq *body;
-    Py_ssize_t i, funcflags;
-    int annotations;
     int scope_type;
-    int firstlineno;
 
     if (is_async) {
         assert(s->kind == AsyncFunctionDef_kind);
 
         args = s->v.AsyncFunctionDef.args;
-        returns = s->v.AsyncFunctionDef.returns;
-        decos = s->v.AsyncFunctionDef.decorator_list;
         name = s->v.AsyncFunctionDef.name;
         body = s->v.AsyncFunctionDef.body;
 
@@ -2113,33 +2193,12 @@ compiler_function(struct compiler *c, stmt_ty s, int is_async)
         assert(s->kind == FunctionDef_kind);
 
         args = s->v.FunctionDef.args;
-        returns = s->v.FunctionDef.returns;
-        decos = s->v.FunctionDef.decorator_list;
         name = s->v.FunctionDef.name;
         body = s->v.FunctionDef.body;
 
         scope_type = COMPILER_SCOPE_FUNCTION;
     }
 
-    RETURN_IF_ERROR(compiler_check_debug_args(c, args));
-    RETURN_IF_ERROR(compiler_decorators(c, decos));
-
-    firstlineno = s->lineno;
-    if (asdl_seq_LEN(decos)) {
-        firstlineno = ((expr_ty)asdl_seq_GET(decos, 0))->lineno;
-    }
-
-    location loc = LOC(s);
-    funcflags = compiler_default_arguments(c, loc, args);
-    if (funcflags == -1) {
-        return ERROR;
-    }
-    annotations = compiler_visit_annotations(c, loc, args, returns);
-    RETURN_IF_ERROR(annotations);
-    if (annotations > 0) {
-        funcflags |= 0x04;
-    }
-
     RETURN_IF_ERROR(
         compiler_enter_scope(c, name, scope_type, (void *)s, firstlineno));
 
@@ -2155,7 +2214,7 @@ compiler_function(struct compiler *c, stmt_ty s, int is_async)
     c->u->u_metadata.u_argcount = asdl_seq_LEN(args->args);
     c->u->u_metadata.u_posonlyargcount = asdl_seq_LEN(args->posonlyargs);
     c->u->u_metadata.u_kwonlyargcount = asdl_seq_LEN(args->kwonlyargs);
-    for (i = docstring ? 1 : 0; i < asdl_seq_LEN(body); i++) {
+    for (Py_ssize_t i = docstring ? 1 : 0; i < asdl_seq_LEN(body); i++) {
         VISIT_IN_SCOPE(c, stmt, (stmt_ty)asdl_seq_GET(body, i));
     }
     if (c->u->u_ste->ste_coroutine || c->u->u_ste->ste_generator) {
@@ -2164,29 +2223,52 @@ compiler_function(struct compiler *c, stmt_ty s, int is_async)
             return ERROR;
         }
     }
-    co = optimize_and_assemble(c, 1);
+    PyCodeObject *co = optimize_and_assemble(c, 1);
     compiler_exit_scope(c);
     if (co == NULL) {
         Py_XDECREF(co);
         return ERROR;
     }
+    location loc = LOC(s);
     if (compiler_make_closure(c, loc, co, funcflags) < 0) {
         Py_DECREF(co);
         return ERROR;
     }
     Py_DECREF(co);
-
+    return SUCCESS;
-    RETURN_IF_ERROR(compiler_apply_decorators(c, decos));
-    return compiler_nameop(c, loc, name, Store);
 }
 
 static int
-compiler_class(struct compiler *c, stmt_ty s)
+compiler_function(struct compiler *c, stmt_ty s, int is_async)
 {
-    PyCodeObject *co;
+    arguments_ty args;
-    int i, firstlineno;
+    expr_ty returns;
-    asdl_expr_seq *decos = s->v.ClassDef.decorator_list;
+    identifier name;
+    asdl_expr_seq *decos;
+    asdl_typeparam_seq *typeparams;
+    Py_ssize_t funcflags;
+    int annotations;
+    int firstlineno;
 
+    if (is_async) {
+        assert(s->kind == AsyncFunctionDef_kind);
+
+        args = s->v.AsyncFunctionDef.args;
+        returns = s->v.AsyncFunctionDef.returns;
+        decos = s->v.AsyncFunctionDef.decorator_list;
+        name = s->v.AsyncFunctionDef.name;
+        typeparams = s->v.AsyncFunctionDef.typeparams;
+    } else {
+        assert(s->kind == FunctionDef_kind);
+
+        args = s->v.FunctionDef.args;
+        returns = s->v.FunctionDef.returns;
+        decos = s->v.FunctionDef.decorator_list;
+        name = s->v.FunctionDef.name;
+        typeparams = s->v.FunctionDef.typeparams;
+    }
+
+    RETURN_IF_ERROR(compiler_check_debug_args(c, args));
     RETURN_IF_ERROR(compiler_decorators(c, decos));
 
     firstlineno = s->lineno;
@@ -2194,6 +2276,108 @@ compiler_class(struct compiler *c, stmt_ty s)
         firstlineno = ((expr_ty)asdl_seq_GET(decos, 0))->lineno;
     }
 
+    location loc = LOC(s);
+
+    int is_generic = asdl_seq_LEN(typeparams) > 0;
+
+    if (is_generic) {
+        // Used by the CALL to the type parameters function.
+        ADDOP(c, loc, PUSH_NULL);
+    }
+
+    funcflags = compiler_default_arguments(c, loc, args);
+    if (funcflags == -1) {
+        return ERROR;
+    }
+
+    int num_typeparam_args = 0;
+
+    if (is_generic) {
+        if (funcflags & 0x01) {
+            num_typeparam_args += 1;
+        }
+        if (funcflags & 0x02) {
+            num_typeparam_args += 1;
+        }
+        if (num_typeparam_args == 2) {
+            ADDOP_I(c, loc, SWAP, 2);
+        }
+        PyObject *typeparams_name = PyUnicode_FromFormat("<generic parameters of %U>", name);
+        if (!typeparams_name) {
+            return ERROR;
+        }
+        if (compiler_enter_scope(c, typeparams_name, COMPILER_SCOPE_TYPEPARAMS,
+                                 (void *)typeparams, firstlineno) == -1) {
+            Py_DECREF(typeparams_name);
+            return ERROR;
+        }
+        Py_DECREF(typeparams_name);
+        RETURN_IF_ERROR_IN_SCOPE(c, compiler_type_params(c, typeparams));
+        if ((funcflags & 0x01) || (funcflags & 0x02)) {
+            RETURN_IF_ERROR_IN_SCOPE(c, codegen_addop_i(INSTR_SEQUENCE(c), LOAD_FAST, 0, loc));
+        }
+        if ((funcflags & 0x01) && (funcflags & 0x02)) {
+            RETURN_IF_ERROR_IN_SCOPE(c, codegen_addop_i(INSTR_SEQUENCE(c), LOAD_FAST, 1, loc));
+        }
+    }
+
+    annotations = compiler_visit_annotations(c, loc, args, returns);
+    if (annotations < 0) {
+        if (is_generic) {
+            compiler_exit_scope(c);
+        }
+        return ERROR;
+    }
+    if (annotations > 0) {
+        funcflags |= 0x04;
+    }
+
+    if (compiler_function_body(c, s, is_async, funcflags, firstlineno) < 0) {
+        if (is_generic) {
+            compiler_exit_scope(c);
+        }
+        return ERROR;
+    }
+
+    if (is_generic) {
+        RETURN_IF_ERROR_IN_SCOPE(c, codegen_addop_i(
+            INSTR_SEQUENCE(c), SWAP, 2, loc));
+        RETURN_IF_ERROR_IN_SCOPE(c, codegen_addop_i(
+            INSTR_SEQUENCE(c), CALL_INTRINSIC_2, INTRINSIC_SET_FUNCTION_TYPE_PARAMS, loc));
+
+        c->u->u_metadata.u_argcount = num_typeparam_args;
+        PyCodeObject *co = optimize_and_assemble(c, 0);
+        compiler_exit_scope(c);
+        if (co == NULL) {
+            return ERROR;
+        }
+        if (compiler_make_closure(c, loc, co, 0) < 0) {
+            Py_DECREF(co);
+            return ERROR;
+        }
+        Py_DECREF(co);
+        if (num_typeparam_args > 0) {
+            ADDOP_I(c, loc, SWAP, num_typeparam_args + 1);
+        }
+        ADDOP_I(c, loc, CALL, num_typeparam_args);
+    }
+
+    RETURN_IF_ERROR(compiler_apply_decorators(c, decos));
+    return compiler_nameop(c, loc, name, Store);
+}
+
+static int
+compiler_set_type_params_in_class(struct compiler *c, location loc)
+{
+    _Py_DECLARE_STR(type_params, ".type_params");
+    RETURN_IF_ERROR(compiler_nameop(c, loc, &_Py_STR(type_params), Load));
+    RETURN_IF_ERROR(compiler_nameop(c, loc, &_Py_ID(__type_params__), Store));
+    return 1;
+}
+
+static int
+compiler_class_body(struct compiler *c, stmt_ty s, int firstlineno)
+{
     /* ultimately generate code for:
          <name> = __build_class__(<func>, <name>, *<bases>, **<keywords>)
        where:
@@ -2204,68 +2388,100 @@ compiler_class(struct compiler *c, stmt_ty s)
          <keywords> is the keyword arguments and **kwds argument
        This borrows from compiler_call.
     */
+
     /* 1. compile the class body into a code object */
     RETURN_IF_ERROR(
         compiler_enter_scope(c, s->v.ClassDef.name,
                              COMPILER_SCOPE_CLASS, (void *)s, firstlineno));
 
-    /* this block represents what we do in the new scope */
+    location loc = LOCATION(firstlineno, firstlineno, 0, 0);
-    {
+    /* use the class name for name mangling */
-        location loc = LOCATION(firstlineno, firstlineno, 0, 0);
+    Py_XSETREF(c->u->u_private, Py_NewRef(s->v.ClassDef.name));
-        /* use the class name for name mangling */
+    /* load (global) __name__ ... */
-        Py_XSETREF(c->u->u_private, Py_NewRef(s->v.ClassDef.name));
+    if (compiler_nameop(c, loc, &_Py_ID(__name__), Load) < 0) {
-        /* load (global) __name__ ... */
+        compiler_exit_scope(c);
-        if (compiler_nameop(c, loc, &_Py_ID(__name__), Load) < 0) {
+        return ERROR;
-            compiler_exit_scope(c);
-            return ERROR;
-        }
-        /* ... and store it as __module__ */
-        if (compiler_nameop(c, loc, &_Py_ID(__module__), Store) < 0) {
-            compiler_exit_scope(c);
-            return ERROR;
-        }
-        assert(c->u->u_metadata.u_qualname);
-        ADDOP_LOAD_CONST(c, loc, c->u->u_metadata.u_qualname);
-        if (compiler_nameop(c, loc, &_Py_ID(__qualname__), Store) < 0) {
-            compiler_exit_scope(c);
-            return ERROR;
-        }
-        /* compile the body proper */
-        if (compiler_body(c, loc, s->v.ClassDef.body) < 0) {
-            compiler_exit_scope(c);
-            return ERROR;
-        }
-        /* The following code is artificial */
-        /* Return __classcell__ if it is referenced, otherwise return None */
-        if (c->u->u_ste->ste_needs_class_closure) {
-            /* Store __classcell__ into class namespace & return it */
-            i = compiler_lookup_arg(c->u->u_metadata.u_cellvars, &_Py_ID(__class__));
-            if (i < 0) {
-                compiler_exit_scope(c);
-                return ERROR;
-            }
-            ADDOP_I(c, NO_LOCATION, LOAD_CLOSURE, i);
-            ADDOP_I(c, NO_LOCATION, COPY, 1);
-            if (compiler_nameop(c, NO_LOCATION, &_Py_ID(__classcell__), Store) < 0) {
-                compiler_exit_scope(c);
-                return ERROR;
-            }
-        }
-        else {
-            /* No methods referenced __class__, so just return None */
-            ADDOP_LOAD_CONST(c, NO_LOCATION, Py_None);
-        }
-        ADDOP_IN_SCOPE(c, NO_LOCATION, RETURN_VALUE);
-        /* create the code object */
-        co = optimize_and_assemble(c, 1);
     }
+    /* ... and store it as __module__ */
+    if (compiler_nameop(c, loc, &_Py_ID(__module__), Store) < 0) {
+        compiler_exit_scope(c);
+        return ERROR;
+    }
+    assert(c->u->u_metadata.u_qualname);
+    ADDOP_LOAD_CONST(c, loc, c->u->u_metadata.u_qualname);
+    if (compiler_nameop(c, loc, &_Py_ID(__qualname__), Store) < 0) {
+        compiler_exit_scope(c);
+        return ERROR;
+    }
+    asdl_typeparam_seq *typeparams = s->v.ClassDef.typeparams;
+    if (asdl_seq_LEN(typeparams) > 0) {
+        if (!compiler_set_type_params_in_class(c, loc)) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+    }
+    if (c->u->u_ste->ste_needs_classdict) {
+        ADDOP(c, loc, LOAD_LOCALS);
+
+        // We can't use compiler_nameop here because we need to generate a
+        // STORE_DEREF in a class namespace, and compiler_nameop() won't do
+        // that by default.
+        PyObject *cellvars = c->u->u_metadata.u_cellvars;
+        if (compiler_addop_o(c->u, loc, STORE_DEREF, cellvars,
+                             &_Py_ID(__classdict__)) < 0) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+    }
+    /* compile the body proper */
+    if (compiler_body(c, loc, s->v.ClassDef.body) < 0) {
+        compiler_exit_scope(c);
+        return ERROR;
+    }
+    /* The following code is artificial */
+    /* Set __classdictcell__ if necessary */
+    if (c->u->u_ste->ste_needs_classdict) {
+        /* Store __classdictcell__ into class namespace */
+        int i = compiler_lookup_arg(c->u->u_metadata.u_cellvars, &_Py_ID(__classdict__));
+        if (i < 0) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+        ADDOP_I(c, NO_LOCATION, LOAD_CLOSURE, i);
+        if (compiler_nameop(c, NO_LOCATION, &_Py_ID(__classdictcell__), Store) < 0) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+    }
+    /* Return __classcell__ if it is referenced, otherwise return None */
+    if (c->u->u_ste->ste_needs_class_closure) {
+        /* Store __classcell__ into class namespace & return it */
+        int i = compiler_lookup_arg(c->u->u_metadata.u_cellvars, &_Py_ID(__class__));
+        if (i < 0) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+        ADDOP_I(c, NO_LOCATION, LOAD_CLOSURE, i);
+        ADDOP_I(c, NO_LOCATION, COPY, 1);
+        if (compiler_nameop(c, NO_LOCATION, &_Py_ID(__classcell__), Store) < 0) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+    }
+    else {
+        /* No methods referenced __class__, so just return None */
+        ADDOP_LOAD_CONST(c, NO_LOCATION, Py_None);
+    }
+    ADDOP_IN_SCOPE(c, NO_LOCATION, RETURN_VALUE);
+    /* create the code object */
+    PyCodeObject *co = optimize_and_assemble(c, 1);
+
     /* leave the new scope */
     compiler_exit_scope(c);
     if (co == NULL) {
         return ERROR;
     }
 
-    location loc = LOC(s);
     /* 2. load the 'build_class' function */
     ADDOP(c, loc, PUSH_NULL);
     ADDOP(c, loc, LOAD_BUILD_CLASS);
@@ -2280,10 +2496,100 @@ compiler_class(struct compiler *c, stmt_ty s)
     /* 4. load class name */
     ADDOP_LOAD_CONST(c, loc, s->v.ClassDef.name);
 
-    /* 5. generate the rest of the code for the call */
+    return SUCCESS;
-    RETURN_IF_ERROR(compiler_call_helper(c, loc, 2,
+}
-                                         s->v.ClassDef.bases,
+
-                                         s->v.ClassDef.keywords));
+static int
+compiler_class(struct compiler *c, stmt_ty s)
+{
+    asdl_expr_seq *decos = s->v.ClassDef.decorator_list;
+
+    RETURN_IF_ERROR(compiler_decorators(c, decos));
+
+    int firstlineno = s->lineno;
+    if (asdl_seq_LEN(decos)) {
+        firstlineno = ((expr_ty)asdl_seq_GET(decos, 0))->lineno;
+    }
+    location loc = LOC(s);
+
+    asdl_typeparam_seq *typeparams = s->v.ClassDef.typeparams;
+    int is_generic = asdl_seq_LEN(typeparams) > 0;
+    if (is_generic) {
+        Py_XSETREF(c->u->u_private, Py_NewRef(s->v.ClassDef.name));
+        ADDOP(c, loc, PUSH_NULL);
+        PyObject *typeparams_name = PyUnicode_FromFormat("<generic parameters of %U>",
+                                                         s->v.ClassDef.name);
+        if (!typeparams_name) {
+            return ERROR;
+        }
+        if (compiler_enter_scope(c, typeparams_name, COMPILER_SCOPE_TYPEPARAMS,
+                                 (void *)typeparams, firstlineno) == -1) {
+            Py_DECREF(typeparams_name);
+            return ERROR;
+        }
+        Py_DECREF(typeparams_name);
+        RETURN_IF_ERROR_IN_SCOPE(c, compiler_type_params(c, typeparams));
+        _Py_DECLARE_STR(type_params, ".type_params");
+        RETURN_IF_ERROR_IN_SCOPE(c, compiler_nameop(c, loc, &_Py_STR(type_params), Store));
+    }
+
+    if (compiler_class_body(c, s, firstlineno) < 0) {
+        if (is_generic) {
+            compiler_exit_scope(c);
+        }
+        return ERROR;
+    }
+
+    /* generate the rest of the code for the call */
+
+    if (is_generic) {
+        _Py_DECLARE_STR(type_params, ".type_params");
+        _Py_DECLARE_STR(generic_base, ".generic_base");
+        RETURN_IF_ERROR_IN_SCOPE(c, compiler_nameop(c, loc, &_Py_STR(type_params), Load));
+        RETURN_IF_ERROR_IN_SCOPE(
+            c, codegen_addop_i(INSTR_SEQUENCE(c), CALL_INTRINSIC_1, INTRINSIC_SUBSCRIPT_GENERIC, loc)
+        )
+        RETURN_IF_ERROR_IN_SCOPE(c, compiler_nameop(c, loc, &_Py_STR(generic_base), Store));
+
+        Py_ssize_t original_len = asdl_seq_LEN(s->v.ClassDef.bases);
+        asdl_expr_seq *bases = _Py_asdl_expr_seq_new(
+            original_len + 1, c->c_arena);
+        if (bases == NULL) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+        for (Py_ssize_t i = 0; i < original_len; i++) {
+            asdl_seq_SET(bases, i, asdl_seq_GET(s->v.ClassDef.bases, i));
+        }
+        expr_ty name_node = _PyAST_Name(
+            &_Py_STR(generic_base), Load,
+            loc.lineno, loc.col_offset, loc.end_lineno, loc.end_col_offset, c->c_arena
+        );
+        if (name_node == NULL) {
+            compiler_exit_scope(c);
+            return ERROR;
+        }
+        asdl_seq_SET(bases, original_len, name_node);
+        RETURN_IF_ERROR_IN_SCOPE(c, compiler_call_helper(c, loc, 2,
+                                                         bases,
+                                                         s->v.ClassDef.keywords));
+
+        PyCodeObject *co = optimize_and_assemble(c, 0);
+        compiler_exit_scope(c);
+        if (co == NULL) {
+            return ERROR;
+        }
+        if (compiler_make_closure(c, loc, co, 0) < 0) {
+            Py_DECREF(co);
+            return ERROR;
+        }
+        Py_DECREF(co);
+        ADDOP_I(c, loc, CALL, 0);
+    } else {
+        RETURN_IF_ERROR(compiler_call_helper(c, loc, 2,
+                                            s->v.ClassDef.bases,
+                                            s->v.ClassDef.keywords));
+    }
 
     /* 6. apply decorators */
     RETURN_IF_ERROR(compiler_apply_decorators(c, decos));
@@ -2293,6 +2599,87 @@ compiler_class(struct compiler *c, stmt_ty s)
     return SUCCESS;
 }
 
+static int
+compiler_typealias_body(struct compiler *c, stmt_ty s)
+{
+    location loc = LOC(s);
+    PyObject *name = s->v.TypeAlias.name->v.Name.id;
+    RETURN_IF_ERROR(
+        compiler_enter_scope(c, name, COMPILER_SCOPE_FUNCTION, s, loc.lineno));
+    /* Make None the first constant, so the evaluate function can't have a
+        docstring. */
+    RETURN_IF_ERROR(compiler_add_const(c->c_const_cache, c->u, Py_None));
+    VISIT_IN_SCOPE(c, expr, s->v.TypeAlias.value);
+    ADDOP_IN_SCOPE(c, loc, RETURN_VALUE);
+    PyCodeObject *co = optimize_and_assemble(c, 0);
+    compiler_exit_scope(c);
+    if (co == NULL) {
+        return ERROR;
+    }
+    if (compiler_make_closure(c, loc, co, 0) < 0) {
+        Py_DECREF(co);
+        return ERROR;
+    }
+    Py_DECREF(co);
+    ADDOP_I(c, loc, BUILD_TUPLE, 3);
+    ADDOP_I(c, loc, CALL_INTRINSIC_1, INTRINSIC_TYPEALIAS);
+    return SUCCESS;
+}
+
+static int
+compiler_typealias(struct compiler *c, stmt_ty s)
+{
+    location loc = LOC(s);
+    asdl_typeparam_seq *typeparams = s->v.TypeAlias.typeparams;
+    int is_generic = asdl_seq_LEN(typeparams) > 0;
+    PyObject *name = s->v.TypeAlias.name->v.Name.id;
+    if (is_generic) {
+        ADDOP(c, loc, PUSH_NULL);
+        PyObject *typeparams_name = PyUnicode_FromFormat("<generic parameters of %U>",
+                                                         name);
+        if (!typeparams_name) {
+            return ERROR;
+        }
+        if (compiler_enter_scope(c, typeparams_name, COMPILER_SCOPE_TYPEPARAMS,
+                                 (void *)typeparams, loc.lineno) == -1) {
+            Py_DECREF(typeparams_name);
+            return ERROR;
+        }
+        Py_DECREF(typeparams_name);
+        RETURN_IF_ERROR_IN_SCOPE(
+            c, compiler_addop_load_const(c->c_const_cache, c->u, loc, name)
+        );
+        RETURN_IF_ERROR_IN_SCOPE(c, compiler_type_params(c, typeparams));
+    }
+    else {
+        ADDOP_LOAD_CONST(c, loc, name);
+        ADDOP_LOAD_CONST(c, loc, Py_None);
+    }
+
+    if (compiler_typealias_body(c, s) < 0) {
+        if (is_generic) {
+            compiler_exit_scope(c);
+        }
+        return ERROR;
+    }
+
+    if (is_generic) {
+        PyCodeObject *co = optimize_and_assemble(c, 0);
+        compiler_exit_scope(c);
+        if (co == NULL) {
+            return ERROR;
+        }
+        if (compiler_make_closure(c, loc, co, 0) < 0) {
+            Py_DECREF(co);
+            return ERROR;
+        }
+        Py_DECREF(co);
+        ADDOP_I(c, loc, CALL, 0);
+    }
+    RETURN_IF_ERROR(compiler_nameop(c, loc, name, Store));
+    return SUCCESS;
+}
+
 /* Return false if the expression is a constant value except named singletons.
    Return true otherwise. */
 static bool
@@ -2705,7 +3092,7 @@ compiler_return(struct compiler *c, stmt_ty s)
     location loc = LOC(s);
     int preserve_tos = ((s->v.Return.value != NULL) &&
                         (s->v.Return.value->kind != Constant_kind));
-    if (c->u->u_ste->ste_type != FunctionBlock) {
+    if (!_PyST_IsFunctionLike(c->u->u_ste)) {
         return compiler_error(c, loc, "'return' outside function");
     }
     if (s->v.Return.value != NULL &&
@@ -3519,6 +3906,8 @@ compiler_visit_stmt(struct compiler *c, stmt_ty s)
         return compiler_function(c, s, 0);
     case ClassDef_kind:
         return compiler_class(c, s);
+    case TypeAlias_kind:
+        return compiler_typealias(c, s);
     case Return_kind:
         return compiler_return(c, s);
     case Delete_kind:
@@ -3725,12 +4114,12 @@ compiler_nameop(struct compiler *c, location loc,
         optype = OP_DEREF;
         break;
     case LOCAL:
-        if (c->u->u_ste->ste_type == FunctionBlock ||
+        if (_PyST_IsFunctionLike(c->u->u_ste) ||
                 (PyDict_GetItem(c->u->u_metadata.u_fasthidden, mangled) == Py_True))
             optype = OP_FAST;
         break;
     case GLOBAL_IMPLICIT:
-        if (c->u->u_ste->ste_type == FunctionBlock)
+        if (_PyST_IsFunctionLike(c->u->u_ste))
             optype = OP_GLOBAL;
         break;
     case GLOBAL_EXPLICIT:
@@ -3748,7 +4137,24 @@ compiler_nameop(struct compiler *c, location loc,
     case OP_DEREF:
         switch (ctx) {
         case Load:
-            op = (c->u->u_ste->ste_type == ClassBlock) ? LOAD_CLASSDEREF : LOAD_DEREF;
+            if (c->u->u_ste->ste_type == ClassBlock) {
+                op = LOAD_FROM_DICT_OR_DEREF;
+                // First load the locals
+                if (codegen_addop_noarg(INSTR_SEQUENCE(c), LOAD_LOCALS, loc) < 0) {
+                    return ERROR;
+                }
+            }
+            else if (c->u->u_ste->ste_can_see_class_scope) {
+                op = LOAD_FROM_DICT_OR_DEREF;
+                // First load the classdict
+                if (compiler_addop_o(c->u, loc, LOAD_DEREF,
+                                     c->u->u_metadata.u_freevars, &_Py_ID(__classdict__)) < 0) {
+                    return ERROR;
+                }
+            }
+            else {
+                op = LOAD_DEREF;
+            }
             break;
         case Store: op = STORE_DEREF; break;
         case Del: op = DELETE_DEREF; break;
@@ -3764,7 +4170,18 @@ compiler_nameop(struct compiler *c, location loc,
         return SUCCESS;
     case OP_GLOBAL:
         switch (ctx) {
-        case Load: op = LOAD_GLOBAL; break;
+        case Load:
+            if (c->u->u_ste->ste_can_see_class_scope && scope == GLOBAL_IMPLICIT) {
+                op = LOAD_FROM_DICT_OR_GLOBALS;
+                // First load the classdict
+                if (compiler_addop_o(c->u, loc, LOAD_DEREF,
+                                     c->u->u_metadata.u_freevars, &_Py_ID(__classdict__)) < 0) {
+                    return ERROR;
+                }
+            } else {
+                op = LOAD_GLOBAL;
+            }
+            break;
         case Store: op = STORE_GLOBAL; break;
         case Del: op = DELETE_GLOBAL; break;
         }
@@ -5008,7 +5425,7 @@ push_inlined_comprehension_state(struct compiler *c, location loc,
         // assignment expression to a nonlocal in the comprehension, these don't
         // need handling here since they shouldn't be isolated
         if (symbol & DEF_LOCAL && !(symbol & DEF_NONLOCAL)) {
-            if (c->u->u_ste->ste_type != FunctionBlock) {
+            if (!_PyST_IsFunctionLike(c->u->u_ste)) {
                 // non-function scope: override this name to use fast locals
                 PyObject *orig = PyDict_GetItem(c->u->u_metadata.u_fasthidden, k);
                 if (orig != Py_True) {
@@ -5604,7 +6021,7 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
     case DictComp_kind:
         return compiler_dictcomp(c, e);
     case Yield_kind:
-        if (c->u->u_ste->ste_type != FunctionBlock) {
+        if (!_PyST_IsFunctionLike(c->u->u_ste)) {
             return compiler_error(c, loc, "'yield' outside function");
         }
         if (e->v.Yield.value) {
@@ -5616,7 +6033,7 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
         ADDOP_YIELD(c, loc);
         break;
     case YieldFrom_kind:
-        if (c->u->u_ste->ste_type != FunctionBlock) {
+        if (!_PyST_IsFunctionLike(c->u->u_ste)) {
             return compiler_error(c, loc, "'yield' outside function");
         }
         if (c->u->u_scope_type == COMPILER_SCOPE_ASYNC_FUNCTION) {
@@ -5629,7 +6046,7 @@ compiler_visit_expr1(struct compiler *c, expr_ty e)
         break;
     case Await_kind:
         if (!IS_TOP_LEVEL_AWAIT(c)){
-            if (c->u->u_ste->ste_type != FunctionBlock){
+            if (!_PyST_IsFunctionLike(c->u->u_ste)) {
                 return compiler_error(c, loc, "'await' outside function");
             }
 
@@ -6916,7 +7333,7 @@ compute_code_flags(struct compiler *c)
 {
     PySTEntryObject *ste = c->u->u_ste;
     int flags = 0;
-    if (ste->ste_type == FunctionBlock) {
+    if (_PyST_IsFunctionLike(c->u->u_ste)) {
         flags |= CO_NEWLOCALS | CO_OPTIMIZED;
         if (ste->ste_nested)
             flags |= CO_NESTED;
@@ -7114,7 +7531,7 @@ fix_cell_offsets(_PyCompile_CodeUnitMetadata *umd, basicblock *entryblock, int *
                 case LOAD_DEREF:
                 case STORE_DEREF:
                 case DELETE_DEREF:
-                case LOAD_CLASSDEREF:
+                case LOAD_FROM_DICT_OR_DEREF:
                     assert(oldoffset >= 0);
                     assert(oldoffset < noffsets);
                     assert(fixedmap[oldoffset] >= 0);

Python/intrinsics.c

@@ -3,10 +3,12 @@
 
 #include "Python.h"
 #include "pycore_frame.h"
+#include "pycore_function.h"
 #include "pycore_runtime.h"
 #include "pycore_global_objects.h"
 #include "pycore_intrinsics.h"
 #include "pycore_pyerrors.h"
+#include "pycore_typevarobject.h"
 
 
 /******** Unary functions ********/
@@ -199,6 +201,13 @@ list_to_tuple(PyThreadState* unused, PyObject *v)
     return _PyTuple_FromArray(((PyListObject *)v)->ob_item, Py_SIZE(v));
 }
 
+static PyObject *
+make_typevar(PyThreadState* Py_UNUSED(ignored), PyObject *v)
+{
+    assert(PyUnicode_Check(v));
+    return _Py_make_typevar(v, NULL, NULL);
+}
+
 const instrinsic_func1
 _PyIntrinsics_UnaryFunctions[] = {
     [0] = no_intrinsic,
@@ -208,6 +217,11 @@ _PyIntrinsics_UnaryFunctions[] = {
     [INTRINSIC_ASYNC_GEN_WRAP] = _PyAsyncGenValueWrapperNew,
     [INTRINSIC_UNARY_POSITIVE] = unary_pos,
     [INTRINSIC_LIST_TO_TUPLE] = list_to_tuple,
+    [INTRINSIC_TYPEVAR] = make_typevar,
+    [INTRINSIC_PARAMSPEC] = _Py_make_paramspec,
+    [INTRINSIC_TYPEVARTUPLE] = _Py_make_typevartuple,
+    [INTRINSIC_SUBSCRIPT_GENERIC] = _Py_subscript_generic,
+    [INTRINSIC_TYPEALIAS] = _Py_make_typealias,
 };
 
 
@@ -221,8 +235,26 @@ prep_reraise_star(PyThreadState* unused, PyObject *orig, PyObject *excs)
     return _PyExc_PrepReraiseStar(orig, excs);
 }
 
+static PyObject *
+make_typevar_with_bound(PyThreadState* Py_UNUSED(ignored), PyObject *name,
+                        PyObject *evaluate_bound)
+{
+    assert(PyUnicode_Check(name));
+    return _Py_make_typevar(name, evaluate_bound, NULL);
+}
+
+static PyObject *
+make_typevar_with_constraints(PyThreadState* Py_UNUSED(ignored), PyObject *name,
+                              PyObject *evaluate_constraints)
+{
+    assert(PyUnicode_Check(name));
+    return _Py_make_typevar(name, NULL, evaluate_constraints);
+}
+
 const instrinsic_func2
 _PyIntrinsics_BinaryFunctions[] = {
     [INTRINSIC_PREP_RERAISE_STAR] = prep_reraise_star,
+    [INTRINSIC_TYPEVAR_WITH_BOUND] = make_typevar_with_bound,
+    [INTRINSIC_TYPEVAR_WITH_CONSTRAINTS] = make_typevar_with_constraints,
+    [INTRINSIC_SET_FUNCTION_TYPE_PARAMS] = _Py_set_function_type_params,
 };
-

Python/opcode_metadata.h

@@ -161,8 +161,12 @@ _PyOpcode_num_popped(int opcode, int oparg, bool jump) {
             return 1;
         case DELETE_GLOBAL:
             return 0;
-        case LOAD_NAME:
+        case LOAD_LOCALS:
             return 0;
+        case LOAD_NAME:
+            return 0+1;
+        case LOAD_FROM_DICT_OR_GLOBALS:
+            return 1;
         case LOAD_GLOBAL:
             return 0;
         case LOAD_GLOBAL_MODULE:
@@ -175,8 +179,8 @@ _PyOpcode_num_popped(int opcode, int oparg, bool jump) {
             return 0;
         case DELETE_DEREF:
             return 0;
-        case LOAD_CLASSDEREF:
+        case LOAD_FROM_DICT_OR_DEREF:
-            return 0;
+            return 1;
         case LOAD_DEREF:
             return 0;
         case STORE_DEREF:
@@ -551,7 +555,11 @@ _PyOpcode_num_pushed(int opcode, int oparg, bool jump) {
             return 0;
         case DELETE_GLOBAL:
             return 0;
+        case LOAD_LOCALS:
+            return 1;
         case LOAD_NAME:
+            return 1+1;
+        case LOAD_FROM_DICT_OR_GLOBALS:
             return 1;
         case LOAD_GLOBAL:
             return ((oparg & 1) ? 1 : 0) + 1;
@@ -565,7 +573,7 @@ _PyOpcode_num_pushed(int opcode, int oparg, bool jump) {
             return 0;
         case DELETE_DEREF:
             return 0;
-        case LOAD_CLASSDEREF:
+        case LOAD_FROM_DICT_OR_DEREF:
             return 1;
         case LOAD_DEREF:
             return 1;
@@ -869,14 +877,16 @@ const struct opcode_metadata _PyOpcode_opcode_metadata[256] = {
     [DELETE_ATTR] = { true, INSTR_FMT_IB },
     [STORE_GLOBAL] = { true, INSTR_FMT_IB },
     [DELETE_GLOBAL] = { true, INSTR_FMT_IB },
+    [LOAD_LOCALS] = { true, INSTR_FMT_IB },
     [LOAD_NAME] = { true, INSTR_FMT_IB },
+    [LOAD_FROM_DICT_OR_GLOBALS] = { true, INSTR_FMT_IB },
     [LOAD_GLOBAL] = { true, INSTR_FMT_IBC000 },
     [LOAD_GLOBAL_MODULE] = { true, INSTR_FMT_IBC000 },
     [LOAD_GLOBAL_BUILTIN] = { true, INSTR_FMT_IBC000 },
     [DELETE_FAST] = { true, INSTR_FMT_IB },
     [MAKE_CELL] = { true, INSTR_FMT_IB },
     [DELETE_DEREF] = { true, INSTR_FMT_IB },
-    [LOAD_CLASSDEREF] = { true, INSTR_FMT_IB },
+    [LOAD_FROM_DICT_OR_DEREF] = { true, INSTR_FMT_IB },
     [LOAD_DEREF] = { true, INSTR_FMT_IB },
     [STORE_DEREF] = { true, INSTR_FMT_IB },
     [COPY_FREE_VARS] = { true, INSTR_FMT_IB },

Python/opcode_targets.h

@@ -86,8 +86,8 @@ static void *opcode_targets[256] = {
     &&TARGET_LOAD_CONST__LOAD_FAST,
     &&TARGET_SETUP_ANNOTATIONS,
     &&TARGET_LOAD_FAST__LOAD_CONST,
+    &&TARGET_LOAD_LOCALS,
     &&TARGET_LOAD_FAST__LOAD_FAST,
-    &&TARGET_LOAD_GLOBAL_BUILTIN,
     &&TARGET_POP_EXCEPT,
     &&TARGET_STORE_NAME,
     &&TARGET_DELETE_NAME,
@@ -110,9 +110,9 @@ static void *opcode_targets[256] = {
     &&TARGET_IMPORT_NAME,
     &&TARGET_IMPORT_FROM,
     &&TARGET_JUMP_FORWARD,
+    &&TARGET_LOAD_GLOBAL_BUILTIN,
     &&TARGET_LOAD_GLOBAL_MODULE,
     &&TARGET_STORE_ATTR_INSTANCE_VALUE,
-    &&TARGET_STORE_ATTR_SLOT,
     &&TARGET_POP_JUMP_IF_FALSE,
     &&TARGET_POP_JUMP_IF_TRUE,
     &&TARGET_LOAD_GLOBAL,
@@ -147,7 +147,7 @@ static void *opcode_targets[256] = {
     &&TARGET_LIST_APPEND,
     &&TARGET_SET_ADD,
     &&TARGET_MAP_ADD,
-    &&TARGET_LOAD_CLASSDEREF,
+    &&TARGET_STORE_ATTR_SLOT,
     &&TARGET_COPY_FREE_VARS,
     &&TARGET_YIELD_VALUE,
     &&TARGET_RESUME,
@@ -174,8 +174,8 @@ static void *opcode_targets[256] = {
     &&TARGET_KW_NAMES,
     &&TARGET_CALL_INTRINSIC_1,
     &&TARGET_CALL_INTRINSIC_2,
-    &&_unknown_opcode,
+    &&TARGET_LOAD_FROM_DICT_OR_GLOBALS,
-    &&_unknown_opcode,
+    &&TARGET_LOAD_FROM_DICT_OR_DEREF,
     &&_unknown_opcode,
     &&_unknown_opcode,
     &&_unknown_opcode,

Python/pylifecycle.c

@@ -26,6 +26,7 @@
 #include "pycore_sysmodule.h"     // _PySys_ClearAuditHooks()
 #include "pycore_traceback.h"     // _Py_DumpTracebackThreads()
 #include "pycore_typeobject.h"    // _PyTypes_InitTypes()
+#include "pycore_typevarobject.h" // _Py_clear_generic_types()
 #include "pycore_unicodeobject.h" // _PyUnicode_InitTypes()
 #include "opcode.h"
 
@@ -1698,6 +1699,7 @@ finalize_interp_clear(PyThreadState *tstate)
     int is_main_interp = _Py_IsMainInterpreter(tstate->interp);
 
     _PyExc_ClearExceptionGroupType(tstate->interp);
+    _Py_clear_generic_types(tstate->interp);
 
     /* Clear interpreter state and all thread states */
     _PyInterpreterState_Clear(tstate);

Python/symtable.c

@@ -47,6 +47,18 @@
 #define ANNOTATION_NOT_ALLOWED \
 "'%s' can not be used within an annotation"
 
+#define TYPEVAR_BOUND_NOT_ALLOWED \
+"'%s' can not be used within a TypeVar bound"
+
+#define TYPEALIAS_NOT_ALLOWED \
+"'%s' can not be used within a type alias"
+
+#define TYPEPARAM_NOT_ALLOWED \
+"'%s' can not be used within the definition of a generic"
+
+#define DUPLICATE_TYPE_PARAM \
+"duplicate type parameter '%U'"
+
 
 #define LOCATION(x) \
  (x)->lineno, (x)->col_offset, (x)->end_lineno, (x)->end_col_offset
@@ -95,7 +107,7 @@ ste_new(struct symtable *st, identifier name, _Py_block_ty block,
 
     if (st->st_cur != NULL &&
         (st->st_cur->ste_nested ||
-         st->st_cur->ste_type == FunctionBlock))
+         _PyST_IsFunctionLike(st->st_cur)))
         ste->ste_nested = 1;
     ste->ste_child_free = 0;
     ste->ste_generator = 0;
@@ -105,7 +117,9 @@ ste_new(struct symtable *st, identifier name, _Py_block_ty block,
     ste->ste_needs_class_closure = 0;
     ste->ste_comp_inlined = 0;
     ste->ste_comp_iter_target = 0;
+    ste->ste_can_see_class_scope = 0;
     ste->ste_comp_iter_expr = 0;
+    ste->ste_needs_classdict = 0;
 
     ste->ste_symbols = PyDict_New();
     ste->ste_varnames = PyList_New(0);
@@ -208,6 +222,7 @@ static int symtable_enter_block(struct symtable *st, identifier name,
 static int symtable_exit_block(struct symtable *st);
 static int symtable_visit_stmt(struct symtable *st, stmt_ty s);
 static int symtable_visit_expr(struct symtable *st, expr_ty s);
+static int symtable_visit_typeparam(struct symtable *st, typeparam_ty s);
 static int symtable_visit_genexp(struct symtable *st, expr_ty s);
 static int symtable_visit_listcomp(struct symtable *st, expr_ty s);
 static int symtable_visit_setcomp(struct symtable *st, expr_ty s);
@@ -403,6 +418,15 @@ _PyST_GetScope(PySTEntryObject *ste, PyObject *name)
     return (symbol >> SCOPE_OFFSET) & SCOPE_MASK;
 }
 
+int
+_PyST_IsFunctionLike(PySTEntryObject *ste)
+{
+    return ste->ste_type == FunctionBlock
+        || ste->ste_type == TypeVarBoundBlock
+        || ste->ste_type == TypeAliasBlock
+        || ste->ste_type == TypeParamBlock;
+}
+
 static int
 error_at_directive(PySTEntryObject *ste, PyObject *name)
 {
@@ -495,7 +519,7 @@ error_at_directive(PySTEntryObject *ste, PyObject *name)
 static int
 analyze_name(PySTEntryObject *ste, PyObject *scopes, PyObject *name, long flags,
              PyObject *bound, PyObject *local, PyObject *free,
-             PyObject *global)
+             PyObject *global, PyObject *typeparams, PySTEntryObject *class_entry)
 {
     if (flags & DEF_GLOBAL) {
         if (flags & DEF_NONLOCAL) {
@@ -524,6 +548,12 @@ analyze_name(PySTEntryObject *ste, PyObject *scopes, PyObject *name, long flags,
 
             return error_at_directive(ste, name);
         }
+        if (PySet_Contains(typeparams, name)) {
+            PyErr_Format(PyExc_SyntaxError,
+                         "nonlocal binding not allowed for type parameter '%U'",
+                         name);
+            return error_at_directive(ste, name);
+        }
         SET_SCOPE(scopes, name, FREE);
         ste->ste_free = 1;
         return PySet_Add(free, name) >= 0;
@@ -534,8 +564,34 @@ analyze_name(PySTEntryObject *ste, PyObject *scopes, PyObject *name, long flags,
             return 0;
         if (PySet_Discard(global, name) < 0)
             return 0;
+        if (flags & DEF_TYPE_PARAM) {
+            if (PySet_Add(typeparams, name) < 0)
+                return 0;
+        }
+        else {
+            if (PySet_Discard(typeparams, name) < 0)
+                return 0;
+        }
         return 1;
     }
+    // If we were passed class_entry (i.e., we're in an ste_can_see_class_scope scope)
+    // and the bound name is in that set, then the name is potentially bound both by
+    // the immediately enclosing class namespace, and also by an outer function namespace.
+    // In that case, we want the runtime name resolution to look at only the class
+    // namespace and the globals (not the namespace providing the bound).
+    // Similarly, if the name is explicitly global in the class namespace (through the
+    // global statement), we want to also treat it as a global in this scope.
+    if (class_entry != NULL) {
+        long class_flags = _PyST_GetSymbol(class_entry, name);
+        if (class_flags & DEF_GLOBAL) {
+            SET_SCOPE(scopes, name, GLOBAL_EXPLICIT);
+            return 1;
+        }
+        else if (class_flags & DEF_BOUND && !(class_flags & DEF_NONLOCAL)) {
+            SET_SCOPE(scopes, name, GLOBAL_IMPLICIT);
+            return 1;
+        }
+    }
     /* If an enclosing block has a binding for this name, it
        is a free variable rather than a global variable.
        Note that having a non-NULL bound implies that the block
@@ -611,7 +667,7 @@ inline_comprehension(PySTEntryObject *ste, PySTEntryObject *comp,
             if (PyLong_AsLong(existing) & DEF_BOUND) {
                 // cell vars in comprehension that are locals in outer scope
                 // must be promoted to cell so u_cellvars isn't wrong
-                if (scope == CELL && ste->ste_type == FunctionBlock) {
+                if (scope == CELL && _PyST_IsFunctionLike(ste)) {
                     if (PySet_Add(promote_to_cell, k) < 0) {
                         return 0;
                     }
@@ -682,6 +738,11 @@ drop_class_free(PySTEntryObject *ste, PyObject *free)
         return 0;
     if (res)
         ste->ste_needs_class_closure = 1;
+    res = PySet_Discard(free, &_Py_ID(__classdict__));
+    if (res < 0)
+        return 0;
+    if (res)
+        ste->ste_needs_classdict = 1;
     return 1;
 }
 
@@ -799,11 +860,13 @@ error:
 
 static int
 analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
-                    PyObject *global, PyObject **child_free);
+                    PyObject *global, PyObject *typeparams,
+                    PySTEntryObject *class_entry, PyObject **child_free);
 
 static int
 analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
-              PyObject *global)
+              PyObject *global, PyObject *typeparams,
+              PySTEntryObject *class_entry)
 {
     PyObject *name, *v, *local = NULL, *scopes = NULL, *newbound = NULL;
     PyObject *newglobal = NULL, *newfree = NULL, *promote_to_cell = NULL;
@@ -865,14 +928,14 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
     while (PyDict_Next(ste->ste_symbols, &pos, &name, &v)) {
         long flags = PyLong_AS_LONG(v);
         if (!analyze_name(ste, scopes, name, flags,
-                          bound, local, free, global))
+                          bound, local, free, global, typeparams, class_entry))
             goto error;
     }
 
     /* Populate global and bound sets to be passed to children. */
     if (ste->ste_type != ClassBlock) {
         /* Add function locals to bound set */
-        if (ste->ste_type == FunctionBlock) {
+        if (_PyST_IsFunctionLike(ste)) {
             temp = PyNumber_InPlaceOr(newbound, local);
             if (!temp)
                 goto error;
@@ -892,9 +955,11 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
         Py_DECREF(temp);
     }
     else {
-        /* Special-case __class__ */
+        /* Special-case __class__ and __classdict__ */
         if (PySet_Add(newbound, &_Py_ID(__class__)) < 0)
             goto error;
+        if (PySet_Add(newbound, &_Py_ID(__classdict__)) < 0)
+            goto error;
     }
 
     /* Recursively call analyze_child_block() on each child block.
@@ -910,13 +975,23 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
         assert(c && PySTEntry_Check(c));
         entry = (PySTEntryObject*)c;
 
+        PySTEntryObject *new_class_entry = NULL;
+        if (entry->ste_can_see_class_scope) {
+            if (ste->ste_type == ClassBlock) {
+                new_class_entry = ste;
+            }
+            else if (class_entry) {
+                new_class_entry = class_entry;
+            }
+        }
+
         // we inline all non-generator-expression comprehensions
         int inline_comp =
             entry->ste_comprehension &&
             !entry->ste_generator;
 
         if (!analyze_child_block(entry, newbound, newfree, newglobal,
-                                 &child_free))
+                                 typeparams, new_class_entry, &child_free))
         {
             goto error;
         }
@@ -952,7 +1027,7 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
     }
 
     /* Check if any local variables must be converted to cell variables */
-    if (ste->ste_type == FunctionBlock && !analyze_cells(scopes, newfree, promote_to_cell))
+    if (_PyST_IsFunctionLike(ste) && !analyze_cells(scopes, newfree, promote_to_cell))
         goto error;
     else if (ste->ste_type == ClassBlock && !drop_class_free(ste, newfree))
         goto error;
@@ -980,9 +1055,11 @@ analyze_block(PySTEntryObject *ste, PyObject *bound, PyObject *free,
 
 static int
 analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
-                    PyObject *global, PyObject** child_free)
+                    PyObject *global, PyObject *typeparams,
+                    PySTEntryObject *class_entry, PyObject** child_free)
 {
     PyObject *temp_bound = NULL, *temp_global = NULL, *temp_free = NULL;
+    PyObject *temp_typeparams = NULL;
 
     /* Copy the bound/global/free sets.
 
@@ -1000,24 +1077,30 @@ analyze_child_block(PySTEntryObject *entry, PyObject *bound, PyObject *free,
     temp_global = PySet_New(global);
     if (!temp_global)
         goto error;
+    temp_typeparams = PySet_New(typeparams);
+    if (!temp_typeparams)
+        goto error;
 
-    if (!analyze_block(entry, temp_bound, temp_free, temp_global))
+    if (!analyze_block(entry, temp_bound, temp_free, temp_global,
+                       temp_typeparams, class_entry))
         goto error;
     *child_free = temp_free;
     Py_DECREF(temp_bound);
     Py_DECREF(temp_global);
+    Py_DECREF(temp_typeparams);
     return 1;
  error:
     Py_XDECREF(temp_bound);
     Py_XDECREF(temp_free);
     Py_XDECREF(temp_global);
+    Py_XDECREF(temp_typeparams);
     return 0;
 }
 
 static int
 symtable_analyze(struct symtable *st)
 {
-    PyObject *free, *global;
+    PyObject *free, *global, *typeparams;
     int r;
 
     free = PySet_New(NULL);
@@ -1028,9 +1111,16 @@ symtable_analyze(struct symtable *st)
         Py_DECREF(free);
         return 0;
     }
-    r = analyze_block(st->st_top, NULL, free, global);
+    typeparams = PySet_New(NULL);
+    if (!typeparams) {
+        Py_DECREF(free);
+        Py_DECREF(global);
+        return 0;
+    }
+    r = analyze_block(st->st_top, NULL, free, global, typeparams, NULL);
     Py_DECREF(free);
     Py_DECREF(global);
+    Py_DECREF(typeparams);
     return r;
 }
 
@@ -1133,6 +1223,13 @@ symtable_add_def_helper(struct symtable *st, PyObject *name, int flag, struct _s
                                              end_lineno, end_col_offset + 1);
             goto error;
         }
+        if ((flag & DEF_TYPE_PARAM) && (val & DEF_TYPE_PARAM)) {
+            PyErr_Format(PyExc_SyntaxError, DUPLICATE_TYPE_PARAM, name);
+            PyErr_RangedSyntaxLocationObject(st->st_filename,
+                                             lineno, col_offset + 1,
+                                             end_lineno, end_col_offset + 1);
+            goto error;
+        }
         val |= flag;
     }
     else if (PyErr_Occurred()) {
@@ -1204,6 +1301,65 @@ symtable_add_def(struct symtable *st, PyObject *name, int flag,
                         lineno, col_offset, end_lineno, end_col_offset);
 }
 
+static int
+symtable_enter_typeparam_block(struct symtable *st, identifier name,
+                               void *ast, int has_defaults, int has_kwdefaults,
+                               enum _stmt_kind kind,
+                               int lineno, int col_offset,
+                               int end_lineno, int end_col_offset)
+{
+    _Py_block_ty current_type = st->st_cur->ste_type;
+    if(!symtable_enter_block(st, name, TypeParamBlock, ast, lineno,
+                             col_offset, end_lineno, end_col_offset)) {
+        return 0;
+    }
+    if (current_type == ClassBlock) {
+        st->st_cur->ste_can_see_class_scope = 1;
+        if (!symtable_add_def(st, &_Py_ID(__classdict__), USE, lineno, col_offset, end_lineno, end_col_offset)) {
+            return 0;
+        }
+    }
+    if (kind == ClassDef_kind) {
+        _Py_DECLARE_STR(type_params, ".type_params");
+        // It gets "set" when we create the type params tuple and
+        // "used" when we build up the bases.
+        if (!symtable_add_def(st, &_Py_STR(type_params), DEF_LOCAL,
+                              lineno, col_offset, end_lineno, end_col_offset)) {
+            return 0;
+        }
+        if (!symtable_add_def(st, &_Py_STR(type_params), USE,
+                              lineno, col_offset, end_lineno, end_col_offset)) {
+            return 0;
+        }
+        st->st_private = name;
+        // This is used for setting the generic base
+        _Py_DECLARE_STR(generic_base, ".generic_base");
+        if (!symtable_add_def(st, &_Py_STR(generic_base), DEF_LOCAL,
+                              lineno, col_offset, end_lineno, end_col_offset)) {
+            return 0;
+        }
+        if (!symtable_add_def(st, &_Py_STR(generic_base), USE,
+                              lineno, col_offset, end_lineno, end_col_offset)) {
+            return 0;
+        }
+    }
+    if (has_defaults) {
+        _Py_DECLARE_STR(defaults, ".defaults");
+        if (!symtable_add_def(st, &_Py_STR(defaults), DEF_PARAM,
+                              lineno, col_offset, end_lineno, end_col_offset)) {
+            return 0;
+        }
+    }
+    if (has_kwdefaults) {
+        _Py_DECLARE_STR(kwdefaults, ".kwdefaults");
+        if (!symtable_add_def(st, &_Py_STR(kwdefaults), DEF_PARAM,
+                              lineno, col_offset, end_lineno, end_col_offset)) {
+            return 0;
+        }
+    }
+    return 1;
+}
+
 /* VISIT, VISIT_SEQ and VIST_SEQ_TAIL take an ASDL type as their second argument.
    They use the ASDL name to synthesize the name of the C type and the visit
    function.
@@ -1275,6 +1431,17 @@ symtable_record_directive(struct symtable *st, identifier name, int lineno,
     return res == 0;
 }
 
+static int
+has_kwonlydefaults(asdl_arg_seq *kwonlyargs, asdl_expr_seq *kw_defaults)
+{
+    for (int i = 0; i < asdl_seq_LEN(kwonlyargs); i++) {
+        expr_ty default_ = asdl_seq_GET(kw_defaults, i);
+        if (default_) {
+            return 1;
+        }
+    }
+    return 0;
+}
 
 static int
 symtable_visit_stmt(struct symtable *st, stmt_ty s)
@@ -1292,11 +1459,24 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
             VISIT_SEQ(st, expr, s->v.FunctionDef.args->defaults);
         if (s->v.FunctionDef.args->kw_defaults)
             VISIT_SEQ_WITH_NULL(st, expr, s->v.FunctionDef.args->kw_defaults);
+        if (s->v.FunctionDef.decorator_list)
+            VISIT_SEQ(st, expr, s->v.FunctionDef.decorator_list);
+        if (asdl_seq_LEN(s->v.FunctionDef.typeparams) > 0) {
+            if (!symtable_enter_typeparam_block(
+                    st, s->v.FunctionDef.name,
+                    (void *)s->v.FunctionDef.typeparams,
+                    s->v.FunctionDef.args->defaults != NULL,
+                    has_kwonlydefaults(s->v.FunctionDef.args->kwonlyargs,
+                                       s->v.FunctionDef.args->kw_defaults),
+                    s->kind,
+                    LOCATION(s))) {
+                VISIT_QUIT(st, 0);
+            }
+            VISIT_SEQ(st, typeparam, s->v.FunctionDef.typeparams);
+        }
         if (!symtable_visit_annotations(st, s, s->v.FunctionDef.args,
                                         s->v.FunctionDef.returns))
             VISIT_QUIT(st, 0);
-        if (s->v.FunctionDef.decorator_list)
-            VISIT_SEQ(st, expr, s->v.FunctionDef.decorator_list);
         if (!symtable_enter_block(st, s->v.FunctionDef.name,
                                   FunctionBlock, (void *)s,
                                   LOCATION(s)))
@@ -1305,25 +1485,85 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
         VISIT_SEQ(st, stmt, s->v.FunctionDef.body);
         if (!symtable_exit_block(st))
             VISIT_QUIT(st, 0);
+        if (asdl_seq_LEN(s->v.FunctionDef.typeparams) > 0) {
+            if (!symtable_exit_block(st))
+                VISIT_QUIT(st, 0);
+        }
         break;
     case ClassDef_kind: {
         PyObject *tmp;
         if (!symtable_add_def(st, s->v.ClassDef.name, DEF_LOCAL, LOCATION(s)))
             VISIT_QUIT(st, 0);
-        VISIT_SEQ(st, expr, s->v.ClassDef.bases);
-        VISIT_SEQ(st, keyword, s->v.ClassDef.keywords);
         if (s->v.ClassDef.decorator_list)
             VISIT_SEQ(st, expr, s->v.ClassDef.decorator_list);
+        if (asdl_seq_LEN(s->v.ClassDef.typeparams) > 0) {
+            if (!symtable_enter_typeparam_block(st, s->v.ClassDef.name,
+                                                (void *)s->v.ClassDef.typeparams,
+                                                false, false, s->kind,
+                                                LOCATION(s))) {
+                VISIT_QUIT(st, 0);
+            }
+            VISIT_SEQ(st, typeparam, s->v.ClassDef.typeparams);
+        }
+        VISIT_SEQ(st, expr, s->v.ClassDef.bases);
+        VISIT_SEQ(st, keyword, s->v.ClassDef.keywords);
         if (!symtable_enter_block(st, s->v.ClassDef.name, ClassBlock,
                                   (void *)s, s->lineno, s->col_offset,
                                   s->end_lineno, s->end_col_offset))
             VISIT_QUIT(st, 0);
         tmp = st->st_private;
         st->st_private = s->v.ClassDef.name;
+        if (asdl_seq_LEN(s->v.ClassDef.typeparams) > 0) {
+            if (!symtable_add_def(st, &_Py_ID(__type_params__),
+                                  DEF_LOCAL, LOCATION(s))) {
+                VISIT_QUIT(st, 0);
+            }
+            _Py_DECLARE_STR(type_params, ".type_params");
+            if (!symtable_add_def(st, &_Py_STR(type_params),
+                                  USE, LOCATION(s))) {
+                VISIT_QUIT(st, 0);
+            }
+        }
         VISIT_SEQ(st, stmt, s->v.ClassDef.body);
         st->st_private = tmp;
         if (!symtable_exit_block(st))
             VISIT_QUIT(st, 0);
+        if (asdl_seq_LEN(s->v.ClassDef.typeparams) > 0) {
+            if (!symtable_exit_block(st))
+                VISIT_QUIT(st, 0);
+        }
+        break;
+    }
+    case TypeAlias_kind: {
+        VISIT(st, expr, s->v.TypeAlias.name);
+        assert(s->v.TypeAlias.name->kind == Name_kind);
+        PyObject *name = s->v.TypeAlias.name->v.Name.id;
+        int is_in_class = st->st_cur->ste_type == ClassBlock;
+        int is_generic = asdl_seq_LEN(s->v.TypeAlias.typeparams) > 0;
+        if (is_generic) {
+            if (!symtable_enter_typeparam_block(
+                    st, name,
+                    (void *)s->v.TypeAlias.typeparams,
+                    false, false, s->kind,
+                    LOCATION(s))) {
+                VISIT_QUIT(st, 0);
+            }
+            VISIT_SEQ(st, typeparam, s->v.TypeAlias.typeparams);
+        }
+        if (!symtable_enter_block(st, name, TypeAliasBlock,
+                                  (void *)s, LOCATION(s)))
+            VISIT_QUIT(st, 0);
+        st->st_cur->ste_can_see_class_scope = is_in_class;
+        if (is_in_class && !symtable_add_def(st, &_Py_ID(__classdict__), USE, LOCATION(s->v.TypeAlias.value))) {
+            VISIT_QUIT(st, 0);
+        }
+        VISIT(st, expr, s->v.TypeAlias.value);
+        if (!symtable_exit_block(st))
+            VISIT_QUIT(st, 0);
+        if (is_generic) {
+            if (!symtable_exit_block(st))
+                VISIT_QUIT(st, 0);
+        }
         break;
     }
     case Return_kind:
@@ -1532,11 +1772,24 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
         if (s->v.AsyncFunctionDef.args->kw_defaults)
             VISIT_SEQ_WITH_NULL(st, expr,
                                 s->v.AsyncFunctionDef.args->kw_defaults);
+        if (s->v.AsyncFunctionDef.decorator_list)
+            VISIT_SEQ(st, expr, s->v.AsyncFunctionDef.decorator_list);
+        if (asdl_seq_LEN(s->v.AsyncFunctionDef.typeparams) > 0) {
+            if (!symtable_enter_typeparam_block(
+                    st, s->v.AsyncFunctionDef.name,
+                    (void *)s->v.AsyncFunctionDef.typeparams,
+                    s->v.AsyncFunctionDef.args->defaults != NULL,
+                    has_kwonlydefaults(s->v.AsyncFunctionDef.args->kwonlyargs,
+                                       s->v.AsyncFunctionDef.args->kw_defaults),
+                    s->kind,
+                    LOCATION(s))) {
+                VISIT_QUIT(st, 0);
+            }
+            VISIT_SEQ(st, typeparam, s->v.AsyncFunctionDef.typeparams);
+        }
         if (!symtable_visit_annotations(st, s, s->v.AsyncFunctionDef.args,
                                         s->v.AsyncFunctionDef.returns))
             VISIT_QUIT(st, 0);
-        if (s->v.AsyncFunctionDef.decorator_list)
-            VISIT_SEQ(st, expr, s->v.AsyncFunctionDef.decorator_list);
         if (!symtable_enter_block(st, s->v.AsyncFunctionDef.name,
                                   FunctionBlock, (void *)s,
                                   s->lineno, s->col_offset,
@@ -1547,6 +1800,10 @@ symtable_visit_stmt(struct symtable *st, stmt_ty s)
         VISIT_SEQ(st, stmt, s->v.AsyncFunctionDef.body);
         if (!symtable_exit_block(st))
             VISIT_QUIT(st, 0);
+        if (asdl_seq_LEN(s->v.AsyncFunctionDef.typeparams) > 0) {
+            if (!symtable_exit_block(st))
+                VISIT_QUIT(st, 0);
+        }
         break;
     case AsyncWith_kind:
         VISIT_SEQ(st, withitem, s->v.AsyncWith.items);
@@ -1598,7 +1855,7 @@ symtable_extend_namedexpr_scope(struct symtable *st, expr_ty e)
         }
 
         /* If we find a FunctionBlock entry, add as GLOBAL/LOCAL or NONLOCAL/LOCAL */
-        if (ste->ste_type == FunctionBlock) {
+        if (_PyST_IsFunctionLike(ste)) {
             long target_in_scope = _PyST_GetSymbol(ste, target_name);
             if (target_in_scope & DEF_GLOBAL) {
                 if (!symtable_add_def(st, target_name, DEF_GLOBAL, LOCATION(e)))
@@ -1633,7 +1890,7 @@ symtable_extend_namedexpr_scope(struct symtable *st, expr_ty e)
         }
     }
 
-    /* We should always find either a FunctionBlock, ModuleBlock or ClassBlock
+    /* We should always find either a function-like block, ModuleBlock or ClassBlock
        and should never fall to this case
     */
     Py_UNREACHABLE();
@@ -1806,7 +2063,7 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
             VISIT_QUIT(st, 0);
         /* Special-case super: it counts as a use of __class__ */
         if (e->v.Name.ctx == Load &&
-            st->st_cur->ste_type == FunctionBlock &&
+            _PyST_IsFunctionLike(st->st_cur) &&
             _PyUnicode_EqualToASCIIString(e->v.Name.id, "super")) {
             if (!symtable_add_def(st, &_Py_ID(__class__), USE, LOCATION(e)))
                 VISIT_QUIT(st, 0);
@@ -1823,6 +2080,45 @@ symtable_visit_expr(struct symtable *st, expr_ty e)
     VISIT_QUIT(st, 1);
 }
 
+static int
+symtable_visit_typeparam(struct symtable *st, typeparam_ty tp)
+{
+    if (++st->recursion_depth > st->recursion_limit) {
+        PyErr_SetString(PyExc_RecursionError,
+                        "maximum recursion depth exceeded during compilation");
+        VISIT_QUIT(st, 0);
+    }
+    switch(tp->kind) {
+    case TypeVar_kind:
+        if (!symtable_add_def(st, tp->v.TypeVar.name, DEF_TYPE_PARAM | DEF_LOCAL, LOCATION(tp)))
+            VISIT_QUIT(st, 0);
+        if (tp->v.TypeVar.bound) {
+            int is_in_class = st->st_cur->ste_can_see_class_scope;
+            if (!symtable_enter_block(st, tp->v.TypeVar.name,
+                                      TypeVarBoundBlock, (void *)tp,
+                                      LOCATION(tp)))
+                VISIT_QUIT(st, 0);
+            st->st_cur->ste_can_see_class_scope = is_in_class;
+            if (is_in_class && !symtable_add_def(st, &_Py_ID(__classdict__), USE, LOCATION(tp->v.TypeVar.bound))) {
+                VISIT_QUIT(st, 0);
+            }
+            VISIT(st, expr, tp->v.TypeVar.bound);
+            if (!symtable_exit_block(st))
+                VISIT_QUIT(st, 0);
+        }
+        break;
+    case TypeVarTuple_kind:
+        if (!symtable_add_def(st, tp->v.TypeVarTuple.name, DEF_TYPE_PARAM | DEF_LOCAL, LOCATION(tp)))
+            VISIT_QUIT(st, 0);
+        break;
+    case ParamSpec_kind:
+        if (!symtable_add_def(st, tp->v.ParamSpec.name, DEF_TYPE_PARAM | DEF_LOCAL, LOCATION(tp)))
+            VISIT_QUIT(st, 0);
+        break;
+    }
+    VISIT_QUIT(st, 1);
+}
+
 static int
 symtable_visit_pattern(struct symtable *st, pattern_ty p)
 {
@@ -2194,11 +2490,18 @@ symtable_visit_dictcomp(struct symtable *st, expr_ty e)
 static int
 symtable_raise_if_annotation_block(struct symtable *st, const char *name, expr_ty e)
 {
-    if (st->st_cur->ste_type != AnnotationBlock) {
+    enum _block_type type = st->st_cur->ste_type;
+    if (type == AnnotationBlock)
+        PyErr_Format(PyExc_SyntaxError, ANNOTATION_NOT_ALLOWED, name);
+    else if (type == TypeVarBoundBlock)
+        PyErr_Format(PyExc_SyntaxError, TYPEVAR_BOUND_NOT_ALLOWED, name);
+    else if (type == TypeAliasBlock)
+        PyErr_Format(PyExc_SyntaxError, TYPEALIAS_NOT_ALLOWED, name);
+    else if (type == TypeParamBlock)
+        PyErr_Format(PyExc_SyntaxError, TYPEPARAM_NOT_ALLOWED, name);
+    else
         return 1;
-    }
 
-    PyErr_Format(PyExc_SyntaxError, ANNOTATION_NOT_ALLOWED, name);
     PyErr_RangedSyntaxLocationObject(st->st_filename,
                                      e->lineno,
                                      e->col_offset + 1,