Patch #1531113: Fix augmented assignment with yield expressions.

Also fix a SystemError when trying to assign to yield expressions.

Lib/test/test_generators.py

@@ -1497,22 +1497,55 @@ And a more sane, but still weird usage:
 <type 'generator'>
 
 
+A yield expression with augmented assignment.
+
+>>> def coroutine(seq):
+...     count = 0
+...     while count < 200:
+...         count += yield
+...         seq.append(count)
+>>> seq = []
+>>> c = coroutine(seq)
+>>> c.next()
+>>> print seq
+[]
+>>> c.send(10)
+>>> print seq
+[10]
+>>> c.send(10)
+>>> print seq
+[10, 20]
+>>> c.send(10)
+>>> print seq
+[10, 20, 30]
+
+
 Check some syntax errors for yield expressions:
 
 >>> f=lambda: (yield 1),(yield 2)
 Traceback (most recent call last):
   ...
-SyntaxError: 'yield' outside function (<doctest test.test_generators.__test__.coroutine[10]>, line 1)
+SyntaxError: 'yield' outside function (<doctest test.test_generators.__test__.coroutine[21]>, line 1)
 
 >>> def f(): return lambda x=(yield): 1
 Traceback (most recent call last):
   ...
-SyntaxError: 'return' with argument inside generator (<doctest test.test_generators.__test__.coroutine[11]>, line 1)
+SyntaxError: 'return' with argument inside generator (<doctest test.test_generators.__test__.coroutine[22]>, line 1)
 
 >>> def f(): x = yield = y
 Traceback (most recent call last):
   ...
-SyntaxError: assignment to yield expression not possible (<doctest test.test_generators.__test__.coroutine[12]>, line 1)
+SyntaxError: assignment to yield expression not possible (<doctest test.test_generators.__test__.coroutine[23]>, line 1)
+
+>>> def f(): (yield bar) = y
+Traceback (most recent call last):
+  ...
+SyntaxError: can't assign to yield expression (<doctest test.test_generators.__test__.coroutine[24]>, line 1)
+
+>>> def f(): (yield bar) += y
+Traceback (most recent call last):
+  ...
+SyntaxError: augmented assignment to yield expression not possible (<doctest test.test_generators.__test__.coroutine[25]>, line 1)
 
 
 Now check some throw() conditions:

Misc/ACKS

@@ -624,6 +624,7 @@ Laurence Tratt
 John Tromp
 Jason Trowbridge
 Anthony Tuininga
+Christopher Tur Lesniewski-Laas
 Stephen Turner
 Bill Tutt
 Doobee R. Tzeck

Misc/NEWS

@@ -12,6 +12,9 @@ What's New in Python 2.5 beta 3?
 Core and builtins
 -----------------
 
+- Patch #1531113: Fix augmented assignment with yield expressions.
+  Also fix a SystemError when trying to assign to yield expressions.
+
 - Bug #1529871: The speed enhancement patch #921466 broke Python's compliance
   with PEP 302.  This was fixed by adding an ``imp.NullImporter`` type that is
   used in ``sys.path_importer_cache`` to cache non-directory paths and avoid

Python/ast.c

@@ -387,6 +387,9 @@ set_context(expr_ty e, expr_context_ty ctx, const node *n)
         case GeneratorExp_kind:
             expr_name = "generator expression";
             break;
+        case Yield_kind:
+            expr_name = "yield expression";
+            break;
         case ListComp_kind:
             expr_name = "list comprehension";
             break;
@@ -1928,12 +1931,7 @@ ast_for_expr_stmt(struct compiling *c, const node *n)
         operator_ty newoperator;
 	node *ch = CHILD(n, 0);
 
-	if (TYPE(ch) == testlist)
-	    expr1 = ast_for_testlist(c, ch);
-	else
-	    expr1 = Yield(ast_for_expr(c, CHILD(ch, 0)), LINENO(ch), n->n_col_offset,
-                          c->c_arena);
-
+	expr1 = ast_for_testlist(c, ch);
         if (!expr1)
             return NULL;
         /* TODO(nas): Remove duplicated error checks (set_context does it) */
@@ -1942,6 +1940,10 @@ ast_for_expr_stmt(struct compiling *c, const node *n)
                 ast_error(ch, "augmented assignment to generator "
                           "expression not possible");
                 return NULL;
+            case Yield_kind:
+                ast_error(ch, "augmented assignment to yield "
+                          "expression not possible");
+                return NULL;
             case Name_kind: {
                 const char *var_name = PyString_AS_STRING(expr1->v.Name.id);
                 if (var_name[0] == 'N' && !strcmp(var_name, "None")) {
@@ -1964,7 +1966,7 @@ ast_for_expr_stmt(struct compiling *c, const node *n)
 	if (TYPE(ch) == testlist)
 	    expr2 = ast_for_testlist(c, ch);
 	else
-	    expr2 = Yield(ast_for_expr(c, ch), LINENO(ch), ch->n_col_offset, c->c_arena);
+	    expr2 = ast_for_expr(c, ch);
         if (!expr2)
             return NULL;
 

Python/import.c

@@ -60,10 +60,11 @@ extern time_t PyOS_GetLastModificationTime(char *, FILE *);
        Python 2.5a0: 62081 (ast-branch)
        Python 2.5a0: 62091 (with)
        Python 2.5a0: 62092 (changed WITH_CLEANUP opcode)
-       Python 2.5c1: 62101 (fix wrong code: for x, in ...)
+       Python 2.5b3: 62101 (fix wrong code: for x, in ...)
+       Python 2.5b3: 62111 (fix wrong code: x += yield)
 .
 */
-#define MAGIC (62101 | ((long)'\r'<<16) | ((long)'\n'<<24))
+#define MAGIC (62111 | ((long)'\r'<<16) | ((long)'\n'<<24))
 
 /* Magic word as global; note that _PyImport_Init() can change the
    value of this global to accommodate for alterations of how the