[PATCH] c++ parser: fix-it hints for wrong usage of 'friend' and 'auto'

[Volker Reichelt]

Hi,

the following patch adds fix-it hints to the C++ parser for two wrongly
used keywords detected in cp_parser_decl_specifier_seq.

Bootstrapped and regtested on x86_64-pc-linux-gnu.

OK for trunk?

Regards,
Volker


2017-04-29  Volker Reichelt  <v.reichelt@netcologne.de>

	* parser.c (cp_parser_decl_specifier_seq): Add fix-it hints for
	friend outside class and obsolete auto as storage-class-specifier.

Index: gcc/cp/parser.c
===================================================================
--- gcc/cp/parser.c	2017-04-28
+++ gcc/cp/parser.c	2017-04-28
@@ -13213,7 +13213,9 @@
 	case RID_FRIEND:
 	  if (!at_class_scope_p ())
 	    {
-	      error_at (token->location, "%<friend%> used outside of class");
+	      gcc_rich_location richloc (token->location);
+	      richloc.add_fixit_remove ();
+	      error_at_rich_loc (&richloc, "%<friend%> used outside of class");
 	      cp_lexer_purge_token (parser->lexer);
 	    }
 	  else
@@ -13277,8 +13279,11 @@
 
               /* Complain about `auto' as a storage specifier, if
                  we're complaining about C++0x compatibility.  */
-              warning_at (token->location, OPT_Wc__11_compat, "%<auto%>"
-			  " changes meaning in C++11; please remove it");
+	      gcc_rich_location richloc (token->location);
+	      richloc.add_fixit_remove ();
+	      warning_at_rich_loc (&richloc, OPT_Wc__11_compat,
+				   "%<auto%> changes meaning in C++11; "
+				   "please remove it");
 
               /* Set the storage class anyway.  */
               cp_parser_set_storage_class (parser, decl_specs, RID_AUTO,
===================================================================

2017-04-29  Volker Reichelt  <v.reichelt@netcologne.de>

	* g++.dg/diagnostic/friend1.C: New test.
	* g++.dg/cpp0x/auto1.C: Add check for fix-it hint.

Index: gcc/testsuite/g++.dg/diagnostic/friend1.C
===================================================================
--- gcc/testsuite/g++.dg/diagnostic/friend1.C	2017-04-29
+++ gcc/testsuite/g++.dg/diagnostic/friend1.C	2017-04-29
@@ -0,0 +1,8 @@
+// { dg-options "-fdiagnostics-show-caret" }
+
+friend void foo();  /* { dg-error "used outside of class" }
+  { dg-begin-multiline-output "" }
+ friend void foo();
+ ^~~~~~
+ ------
+  { dg-end-multiline-output "" } */
Index: gcc/testsuite/g++.dg/cpp0x/auto1.C
===================================================================
--- gcc/testsuite/g++.dg/cpp0x/auto1.C	(revision 247406)
+++ gcc/testsuite/g++.dg/cpp0x/auto1.C	(working copy)
@@ -1,9 +1,14 @@
 // { dg-do compile { target c++11 } }
-// { dg-options "-std=c++98 -Wc++11-compat" }
+// { dg-options "-std=c++98 -Wc++11-compat -fdiagnostics-show-caret" }
 
 // Test warning for use of auto in C++98 mode with C++11
 // compatibility warnings
 void f()
 {
-  auto int x = 5; // { dg-warning "changes meaning" }
+  auto int x = 5; /* { dg-warning "changes meaning" }
+  { dg-begin-multiline-output "" }
+   auto int x = 5;
+   ^~~~
+   ----
+  { dg-end-multiline-output "" } */
 }
===================================================================