DR 1207 PR c++/49589

	DR 1207
	PR c++/49589
	* mangle.c (write_expression): Handle 'this'.
	* parser.c (cp_parser_postfix_dot_deref_expression): Allow
	incomplete *this.
	* semantics.c (potential_constant_expression_1): Check that
	DECL_CONTEXT is set on 'this'.

From-SVN: r175835

gcc/cp/ChangeLog

 2011-07-04  Jason Merrill  <jason@redhat.com>
 
+	DR 1207
+	PR c++/49589
+	* mangle.c (write_expression): Handle 'this'.
+	* parser.c (cp_parser_postfix_dot_deref_expression): Allow
+	incomplete *this.
+	* semantics.c (potential_constant_expression_1): Check that
+	DECL_CONTEXT is set on 'this'.
+
 	* error.c (dump_template_bindings): Don't print typenames
 	for a partial instantiation.
 	(dump_function_decl): If we aren't printing function arguments,

gcc/cp/mangle.c

@@ -2495,6 +2495,11 @@ write_expression (tree expr)
   else if (TREE_CODE_CLASS (code) == tcc_constant
 	   || (abi_version_at_least (2) && code == CONST_DECL))
     write_template_arg_literal (expr);
+  else if (code == PARM_DECL && DECL_ARTIFICIAL (expr))
+    {
+      gcc_assert (!strcmp ("this", IDENTIFIER_POINTER (DECL_NAME (expr))));
+      write_string ("fpT");
+    }
   else if (code == PARM_DECL)
     {
       /* A function parameter used in a late-specified return type.  */

gcc/cp/parser.c

@@ -5281,7 +5281,11 @@ cp_parser_postfix_dot_deref_expression (cp_parser *parser,
 		    postfix_expression);
 	  scope = NULL_TREE;
 	}
-      else
+      /* Unlike the object expression in other contexts, *this is not
+	 required to be of complete type for purposes of class member
+	 access (5.2.5) outside the member function body.  */
+      else if (scope != current_class_ref
+	       && !(processing_template_decl && scope == current_class_type))
 	scope = complete_type_or_else (scope, NULL_TREE);
       /* Let the name lookup machinery know that we are processing a
 	 class member access expression.  */

gcc/cp/semantics.c

@@ -7791,7 +7791,8 @@ potential_constant_expression_1 (tree t, bool want_rval, tsubst_flags_t flags)
         STRIP_NOPS (x);
         if (is_this_parameter (x))
 	  {
-	    if (DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)) && want_rval)
+	    if (want_rval && DECL_CONTEXT (x)
+		&& DECL_CONSTRUCTOR_P (DECL_CONTEXT (x)))
 	      {
 		if (flags & tf_error)
 		  sorry ("use of the value of the object being constructed "

gcc/testsuite/ChangeLog

 2011-07-04  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/abi/mangle48.C: New.
+
 	* g++.dg/cpp0x/diag1.C: New.
 
 	* g++.dg/diagnostic/aka1.C: New.

gcc/testsuite/g++.dg/abi/mangle48.C

+// Testcase for 'this' mangling
+// { dg-options -std=c++0x }
+
+struct B
+{
+  template <class U> U f();
+};
+
+struct A
+{
+  B b;
+  // { dg-final { scan-assembler "_ZN1A1fIiEEDTcldtdtdefpT1b1fIT_EEEv" } }
+  template <class U> auto f() -> decltype (b.f<U>());
+  // { dg-final { scan-assembler "_ZN1A1gIiEEDTcldtptfpT1b1fIT_EEEv" } }
+  template <class U> auto g() -> decltype (this->b.f<U>());
+};
+
+int main()
+{
+  A a;
+  a.f<int>();
+  a.g<int>();
+}