re PR c++/39164 ([C++0x] defaulted dtor redefinition not caught)

	PR c++/39164
	* decl.c (grokfndecl): Diagnose redefinition of defaulted fn.

From-SVN: r179634

gcc/cp/ChangeLog

+2011-10-06  Jason Merrill  <jason@redhat.com>
+
+	PR c++/39164
+	* decl.c (grokfndecl): Diagnose redefinition of defaulted fn.
+
 2011-10-02  Jason Merrill  <jason@redhat.com>
 
 	* pt.c (tsubst_pack_expansion): Re-use ARGUMENT_PACK_SELECTs.

gcc/cp/decl.c

@@ -7418,6 +7418,12 @@ grokfndecl (tree ctype,
 	      error ("definition of implicitly-declared %qD", old_decl);
 	      return NULL_TREE;
 	    }
+	  else if (DECL_DEFAULTED_FN (old_decl))
+	    {
+	      error ("definition of explicitly-defaulted %q+D", decl);
+	      error ("%q+#D explicitly defaulted here", old_decl);
+	      return NULL_TREE;
+	    }
 
 	  /* Since we've smashed OLD_DECL to its
 	     DECL_TEMPLATE_RESULT, we must do the same to DECL.  */

gcc/testsuite/ChangeLog

+2011-10-06  Jason Merrill  <jason@redhat.com>
+
+	PR c++/39164
+	* g++.dg/cpp0x/default31.C: New.
+
 2011-10-06  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/50596

gcc/testsuite/g++.dg/cpp0x/defaulted31.C

+// PR c++/39164
+// { dg-options -std=c++0x }
+
+struct A
+{
+  A() { }			// { dg-error "defined" }
+  ~A() = default;		// { dg-error "defaulted" }
+};
+
+A::A() = default;		// { dg-error "redefinition" }
+A::~A() noexcept (true) { }	// { dg-error "defaulted" }
+
+int main()
+{
+  A a;
+}