compiler: Don't allow multiple function declarations.

    
    Fixes golang/go#11573.
    
    Reviewed-on: https://go-review.googlesource.com/12508

From-SVN: r226529

gcc/go/gofrontend/MERGE

@@ -1,4 +1,4 @@
-2b1a79c6395991fc4e60e20312ff44065fdb816b
+7a6089333f4ab10449f9140c4639cfe741abcb25
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/gogo.cc

@@ -7408,16 +7408,10 @@ Bindings::new_definition(Named_object* old_object, Named_object* new_object)
 
     case Named_object::NAMED_OBJECT_FUNC_DECLARATION:
       {
-	Function_type* old_type = old_object->func_declaration_value()->type();
-	if (new_object->is_function_declaration())
-	  {
-	    Function_type* new_type =
-	      new_object->func_declaration_value()->type();
-	    if (old_type->is_valid_redeclaration(new_type, &reason))
-	      return old_object;
-	  }
 	if (new_object->is_function())
 	  {
+            Function_type* old_type =
+                old_object->func_declaration_value()->type();
 	    Function_type* new_type = new_object->func_value()->type();
 	    if (old_type->is_valid_redeclaration(new_type, &reason))
 	      {

gcc/go/gofrontend/parse.cc

@@ -2231,9 +2231,11 @@ Parse::function_decl(bool saw_nointerface)
   std::string extern_name = this->lex_->extern_name();
   const Token* token = this->advance_token();
 
+  bool expected_receiver = false;
   Typed_identifier* rec = NULL;
   if (token->is_op(OPERATOR_LPAREN))
     {
+      expected_receiver = true;
       rec = this->receiver();
       token = this->peek_token();
     }
@@ -2304,7 +2306,8 @@ Parse::function_decl(bool saw_nointerface)
     {
       if (named_object == NULL && !Gogo::is_sink_name(name))
 	{
-	  if (fntype == NULL)
+	  if (fntype == NULL
+              || (expected_receiver && rec == NULL))
 	    this->gogo_->add_erroneous_name(name);
 	  else
 	    {