Bug #1333982: string/number constants were inappropriately stored

in the byte code and co_consts even if they were not used, ie
immediately popped off the stack.

Lib/test/test_code.py

@@ -61,6 +61,23 @@ nlocals: 1
 flags: 67
 consts: ('None',)
 
+>>> def optimize_away():
+...     'doc string'
+...     'not a docstring'
+...     53
+...     53L
+
+>>> dump(optimize_away.func_code)
+name: optimize_away
+argcount: 0
+names: ()
+varnames: ()
+cellvars: ()
+freevars: ()
+nlocals: 0
+flags: 67
+consts: ("'doc string'", 'None')
+
 """
 
 def consts(t):

Misc/NEWS

@@ -17,6 +17,10 @@ Core and builtins
   magic number.  This means that .pyc files generated before 2.5c1
   will be regenerated.
 
+- Bug #1333982: string/number constants were inappropriately stored
+  in the byte code and co_consts even if they were not used, ie
+  immediately popped off the stack.
+
 
 Library
 -------

Python/compile.c

@@ -2745,11 +2745,13 @@ compiler_visit_stmt(struct compiler *c, stmt_ty s)
 	case Global_kind:
 		break;
 	case Expr_kind:
-		VISIT(c, expr, s->v.Expr.value);
 		if (c->c_interactive && c->c_nestlevel <= 1) {
+			VISIT(c, expr, s->v.Expr.value);
 			ADDOP(c, PRINT_EXPR);
 		}
-		else {
+		else if (s->v.Expr.value->kind != Str_kind &&
+			 s->v.Expr.value->kind != Num_kind) {
+			VISIT(c, expr, s->v.Expr.value);
 			ADDOP(c, POP_TOP);
 		}
 		break;