Fix PR c/91815

Message ID 5321767.8bt0uQpQXk@polaris
State New
Headers show
  • Fix PR c/91815
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Commit Message

Eric Botcazou Sept. 20, 2019, 9:11 a.m.
This gets rid of a bogus error issued by the C compiler on a type definition 
at file scope when there is a preceding external declaration in a local scope 
for the same symbol (but the error is still issued if the preceding external 
declaration is also at file scope).

Bootstrapped/regtested on x86-64/Linux, approved by Joseph in the audit trail 
and applied on the mainline.

2019-09-20  Eric Botcazou  <>

	PR c/91815
	* c-decl.c (pushdecl): In C detect duplicate declarations across scopes
	of identifiers in the external scope only for variables and functions.

2019-09-20  Eric Botcazou  <>

	* gcc.dg/typedef-var-1.c: New test.
	* gcc.dg/typedef-var-2.c: Likewise.

Eric Botcazou


Index: c-decl.c
--- c-decl.c	(revision 275988)
+++ c-decl.c	(working copy)
@@ -3130,8 +3130,11 @@  pushdecl (tree x)
      detecting duplicate declarations of the same object, no matter
      what scope they are in; this is what we do here.  (C99 6.2.7p2:
      All declarations that refer to the same object or function shall
-     have compatible type; otherwise, the behavior is undefined.)  */
-  if (DECL_EXTERNAL (x) || scope == file_scope)
+     have compatible type; otherwise, the behavior is undefined.)
+     However, in Objective-C, we also want to detect declarations
+     conflicting with those of the basic types.  */
+  if ((DECL_EXTERNAL (x) || scope == file_scope)
+      && (VAR_OR_FUNCTION_DECL_P (x) || c_dialect_objc ()))
       tree type = TREE_TYPE (x);
       tree vistype = NULL_TREE;