... I think that by the time we do the check, if old_decl is a
FUNCTION_DECL we can safely assume that new_decl is also a
FUNCTION_DECL, thus I can simplify the code. I'm finishing testing the
below variant.
Thanks
Paolo.
///////////////////////
Index: cp/decl.c
===================================================================
--- cp/decl.c (revision 197572)
+++ cp/decl.c (working copy)
@@ -1196,12 +1196,21 @@ validate_constexpr_redeclaration (tree old_decl, t
if (DECL_DECLARED_CONSTEXPR_P (old_decl)
== DECL_DECLARED_CONSTEXPR_P (new_decl))
return true;
- if (TREE_CODE (old_decl) == FUNCTION_DECL && DECL_BUILT_IN (old_decl))
+ if (TREE_CODE (old_decl) == FUNCTION_DECL)
{
- /* Hide a built-in declaration. */
- DECL_DECLARED_CONSTEXPR_P (old_decl)
- = DECL_DECLARED_CONSTEXPR_P (new_decl);
- return true;
+ if (DECL_BUILT_IN (old_decl))
+ {
+ /* Hide a built-in declaration. */
+ DECL_DECLARED_CONSTEXPR_P (old_decl)
+ = DECL_DECLARED_CONSTEXPR_P (new_decl);
+ return true;
+ }
+ /* 7.1.5 [dcl.constexpr]
+ Note: An explicit specialization can differ from the template
+ declaration with respect to the constexpr specifier. */
+ if (! DECL_TEMPLATE_SPECIALIZATION (old_decl)
+ && DECL_TEMPLATE_SPECIALIZATION (new_decl))
+ return true;
}
error ("redeclaration %qD differs in %<constexpr%>", new_decl);
error ("from previous declaration %q+D", old_decl);
Index: testsuite/g++.dg/cpp0x/constexpr-specialization.C
===================================================================
--- testsuite/g++.dg/cpp0x/constexpr-specialization.C (revision 0)
+++ testsuite/g++.dg/cpp0x/constexpr-specialization.C (working copy)
@@ -0,0 +1,12 @@
+// PR c++/56871
+// { dg-options "-std=c++11" }
+
+template<typename T> constexpr int foo(T);
+template<> int foo(int);
+template<> int foo(int); // { dg-error "previous" }
+template<> constexpr int foo(int); // { dg-error "redeclaration" }
+
+template<typename T> int bar(T);
+template<> constexpr int bar(int);
+template<> constexpr int bar(int); // { dg-error "previous" }
+template<> int bar(int); // { dg-error "redeclaration" }
