re PR c/31673 ("`for' loop initial declaration used outside C99 mode" is confusing)

2008-08-27  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>

	PR c/31673
	* c-decl.c (check_for_loop_decls): Improve error message. Give
	hint.
testsuite/
	* gcc.dg/c90-fordecl-1.c: Update.

From-SVN: r139681

gcc/ChangeLog

 2008-08-27  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
 
+	PR c/31673
+	* c-decl.c (check_for_loop_decls): Improve error message. Give
+	hint.
+
+2008-08-27  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
 	PR c/37186
 	* c-typeck.c (WARN_FOR_ASSIGNMENT): Add OPT parameter.
 	(convert_for_assignment): Pass corrent OPT_W* parameter to

gcc/c-decl.c

@@ -6796,13 +6796,19 @@ check_for_loop_decls (void)
   tree one_decl = NULL_TREE;
   int n_decls = 0;
 
-
   if (!flag_isoc99)
     {
+      static bool hint = true;
       /* If we get here, declarations have been used in a for loop without
 	 the C99 for loop scope.  This doesn't make much sense, so don't
 	 allow it.  */
-      error ("%<for%> loop initial declaration used outside C99 mode");
+      error ("%<for%> loop initial declarations are only allowed in C99 mode");
+      if (hint)
+	{
+	  inform (input_location, 
+		  "use option -std=c99 or -std=gnu99 to compile your code");
+	  hint = false;
+	}
       return NULL_TREE;
     }
   /* C99 subclause 6.8.5 paragraph 3:

gcc/testsuite/ChangeLog

 2008-08-27  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
 
+	PR c/31673
+	* gcc.dg/c90-fordecl-1.c: Update.
+
+2008-08-27  Manuel Lopez-Ibanez  <manu@gcc.gnu.org>
+
 	PR c/37186
 	* gcc.dg/pr37186.c: New.
 

gcc/testsuite/gcc.dg/c90-fordecl-1.c

@@ -9,5 +9,6 @@ foo (void)
   int j = 0;
   for (int i = 1; i <= 10; i++) /* { dg-bogus "warning" "warning in place of error" } */
     j += i;
-  /* { dg-error "parse|decl" "declaration in for loop" { target *-*-* } 10 } */
+  /* { dg-error "'for' loop initial declarations are only allowed in C99 mode" "declaration in for loop" { target *-*-* } 10 } */
+  /* { dg-message "note: use option -std=c99 or -std=gnu99 to compile your code" "note" { target *-*-* } 10 }} */
 }