Handle IDENTIFIER at parse_bare_function_type(

gcc/rust/ChangeLog:

	* parse/rust-parse-impl.h: new error

Signed-off-by: Lúcio Boari Fleury <lucboari@gmail.com>

Author: lucbf

gcc/rust/parse/rust-parse-impl.h

@@ -9670,6 +9670,17 @@ Parser<ManagedTokenSource>::parse_bare_function_type (
   if (!skip_token (FN_KW))
     return nullptr;
 
+  auto t = lexer.peek_token ();
+  if (t->get_id () == IDENTIFIER)
+    {
+      Error error (t->get_locus (),
+		   "unexpected token %qs - expected bare function",
+		   t->get_token_description ());
+      add_error (std::move (error));
+
+      return nullptr;
+    }
+
   if (!skip_token (LEFT_PAREN))
     return nullptr;
 
@@ -9678,7 +9689,7 @@ Parser<ManagedTokenSource>::parse_bare_function_type (
   bool is_variadic = false;
   AST::AttrVec variadic_attrs;
 
-  const_TokenPtr t = lexer.peek_token ();
+  t = lexer.peek_token ();
   while (t->get_id () != RIGHT_PAREN)
     {
       AST::AttrVec temp_attrs = parse_outer_attributes ();