Re: [PATCH] c++, v3: Fix range for error recovery [PR122465]

[Jason Merrill]

On 11/29/25 10:16 PM, Jakub Jelinek wrote:

On Sat, Nov 29, 2025 at 09:54:50PM +0530, Jason Merrill wrote:

+    error_out:
+      if (maybe_range_for_decl && *maybe_range_for_decl == NULL_TREE)
+       *maybe_range_for_decl = error_mark_node;
         goto done;

Instead of putting error_out: here...

@@ -17347,6 +17347,8 @@ cp_parser_simple_declaration (cp_parser*
         if (comma_loc != UNKNOWN_LOCATION)
        error_at (comma_loc,
                  "multiple declarations in range-based %<for%> loop");

...how about putting it here?

Like this?

Will test tonight.

OK.

2025-11-29  Jakub Jelinek  <ja...@redhat.com>

        PR c++/122465
        * parser.cc (cp_parser_simple_declaration): Adjust function comment.
        Set *maybe_range_for_decl to error_mark_node instead of keeping it
        NULL_TREE in error cases or when followed by CPP_COLON.

        * g++.dg/cpp0x/pr122465.C: New test.

--- gcc/cp/parser.cc.jj 2025-11-24 09:02:57.276720338 +0100
+++ gcc/cp/parser.cc    2025-11-29 17:41:35.368721400 +0100
@@ -17100,8 +17100,9 @@ cp_parser_block_declaration (cp_parser *

If MAYBE_RANGE_FOR_DECL is not NULL, the pointed tree will be set to the

     parsed declaration if it is an uninitialized single declarator not followed
-   by a `;', or to error_mark_node otherwise. Either way, the trailing `;',
-   if present, will not be consumed.  */
+   by a `;', or to NULL_TREE when not followed by `:' or to error_mark_node
+   otherwise.  Either way, the trailing `;', if present, will not be
+   consumed.  */

static void

  cp_parser_simple_declaration (cp_parser* parser,
@@ -17153,7 +17154,7 @@ cp_parser_simple_declaration (cp_parser*
        && !decl_specifiers.any_specifiers_p)
      {
        cp_parser_error (parser, "expected declaration");
-      goto done;
+      goto error_out;
      }

/* If the next two tokens are both identifiers, the code is

@@ -17169,7 +17170,7 @@ cp_parser_simple_declaration (cp_parser*
         looking at a declaration.  */
        cp_parser_commit_to_tentative_parse (parser);
        /* Give up.  */
-      goto done;
+      goto error_out;
      }

cp_parser_maybe_commit_to_declaration (parser, &decl_specifiers);

@@ -17194,11 +17195,7 @@ cp_parser_simple_declaration (cp_parser*
        if (token->type == CPP_SEMICOLON)
          goto finish;
        else if (maybe_range_for_decl)
-         {
-           if (*maybe_range_for_decl == NULL_TREE)
-             *maybe_range_for_decl = error_mark_node;
-           goto finish;
-         }
+         goto finish;
        /* Anything else is an error.  */
        else
          {
@@ -17277,7 +17274,7 @@ cp_parser_simple_declaration (cp_parser*
         statement is treated as a declaration-statement until proven
         otherwise.)  */
        if (cp_parser_error_occurred (parser))
-       goto done;
+       goto error_out;

if (auto_specifier_p && cxx_dialect >= cxx14)

        {
@@ -17415,6 +17412,9 @@ cp_parser_simple_declaration (cp_parser*
        if (comma_loc != UNKNOWN_LOCATION)
        error_at (comma_loc,
                  "multiple declarations in range-based %<for%> loop");
+    error_out:
+      if (maybe_range_for_decl && *maybe_range_for_decl == NULL_TREE)
+       *maybe_range_for_decl = error_mark_node;
      }

done:

--- gcc/testsuite/g++.dg/cpp0x/pr122465.C.jj    2025-11-29 17:39:37.187641552 
+0100
+++ gcc/testsuite/g++.dg/cpp0x/pr122465.C       2025-11-29 17:39:37.187641552 
+0100
@@ -0,0 +1,10 @@
+// PR c++/122465
+// { dg-do compile { target c++11 } }
+
+void
+foo ()
+{
+  int x = 0;
+  for (const T i = { i } : x)  // { dg-error "'T' does not name a type" }
+    ;
+}


        Jakub