Fix error message for block/lambda with ... argument

Earlopain · kddnewton · commit 0aa236333176 · 2026-02-27T08:33:10.000-05:00
They currently complain that the parent method is not forwarding.
But the actual problem is that these types of arguments simply don't
accept `...`

Fixes [Bug #21927]
diff --git a/config.yml b/config.yml
@@ -17,6 +17,8 @@ errors:
   - ARGUMENT_FORWARDING_UNBOUND
   - ARGUMENT_NO_FORWARDING_AMPERSAND
   - ARGUMENT_NO_FORWARDING_ELLIPSES
+  - ARGUMENT_NO_FORWARDING_ELLIPSES_LAMBDA
+  - ARGUMENT_NO_FORWARDING_ELLIPSES_BLOCK
   - ARGUMENT_NO_FORWARDING_STAR
   - ARGUMENT_NO_FORWARDING_STAR_STAR
   - ARGUMENT_SPLAT_AFTER_ASSOC_SPLAT
diff --git a/src/prism.c b/src/prism.c
@@ -13957,6 +13957,7 @@ parse_parameters(
     bool allows_forwarding_parameters,
     bool accepts_blocks_in_defaults,
     bool in_block,
+    pm_diagnostic_id_t diag_id_forwarding,
     uint16_t depth
 ) {
     pm_do_loop_stack_push(parser, false);
@@ -14018,7 +14019,7 @@ parse_parameters(
             }
             case PM_TOKEN_UDOT_DOT_DOT: {
                 if (!allows_forwarding_parameters) {
-                    pm_parser_err_current(parser, PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES);
+                    pm_parser_err_current(parser, diag_id_forwarding);
                 }
 
                 bool succeeded = update_parameter_state(parser, &parser->current, &order);
@@ -14682,6 +14683,7 @@ parse_block_parameters(
             false,
             accepts_blocks_in_defaults,
             true,
+            is_lambda_literal ? PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES_LAMBDA : PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES_BLOCK,
             (uint16_t) (depth + 1)
         );
         if (!is_lambda_literal) {
@@ -18904,7 +18906,17 @@ parse_expression_prefix(pm_parser_t *parser, pm_binding_power_t binding_power, b
                     } else {
                         // https://bugs.ruby-lang.org/issues/19107
                         bool allow_trailing_comma = parser->version >= PM_OPTIONS_VERSION_CRUBY_4_1;
-                        params = parse_parameters(parser, PM_BINDING_POWER_DEFINED, true, allow_trailing_comma, true, true, false, (uint16_t) (depth + 1));
+                        params = parse_parameters(
+                            parser,
+                            PM_BINDING_POWER_DEFINED,
+                            true,
+                            allow_trailing_comma,
+                            true,
+                            true,
+                            false,
+                            PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES,
+                            (uint16_t) (depth + 1)
+                        );
                     }
 
                     lex_state_set(parser, PM_LEX_STATE_BEG);
@@ -18927,7 +18939,17 @@ parse_expression_prefix(pm_parser_t *parser, pm_binding_power_t binding_power, b
                         lex_state_set(parser, parser->lex_state | PM_LEX_STATE_LABEL);
                     }
 
-                    params = parse_parameters(parser, PM_BINDING_POWER_DEFINED, false, false, true, true, false, (uint16_t) (depth + 1));
+                    params = parse_parameters(
+                        parser,
+                        PM_BINDING_POWER_DEFINED,
+                        false,
+                        false,
+                        true,
+                        true,
+                        false,
+                        PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES,
+                        (uint16_t) (depth + 1)
+                    );
 
                     // Reject `def * = 1` and similar. We have to specifically check
                     // for them because they create ambiguity with optional arguments.
diff --git a/templates/src/diagnostic.c.erb b/templates/src/diagnostic.c.erb
@@ -102,6 +102,8 @@ static const pm_diagnostic_data_t diagnostic_messages[PM_DIAGNOSTIC_ID_MAX] = {
     [PM_ERR_ARGUMENT_FORWARDING_UNBOUND]        = { "unexpected `...` in an non-parenthesized call", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_ARGUMENT_NO_FORWARDING_AMPERSAND]   = { "unexpected `&`; no anonymous block parameter", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES]    = { "unexpected ... when the parent method is not forwarding", PM_ERROR_LEVEL_SYNTAX },
+    [PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES_LAMBDA] = { "unexpected ... in lambda argument", PM_ERROR_LEVEL_SYNTAX },
+    [PM_ERR_ARGUMENT_NO_FORWARDING_ELLIPSES_BLOCK]  = { "unexpected ... in block argument", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_ARGUMENT_NO_FORWARDING_STAR]        = { "unexpected `*`; no anonymous rest parameter", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_ARGUMENT_NO_FORWARDING_STAR_STAR]   = { "unexpected `**`; no anonymous keyword rest parameter", PM_ERROR_LEVEL_SYNTAX },
     [PM_ERR_ARGUMENT_SPLAT_AFTER_ASSOC_SPLAT]   = { "unexpected `*` splat argument after a `**` keyword splat argument", PM_ERROR_LEVEL_SYNTAX },
diff --git a/test/prism/errors/do_not_allow_forward_arguments_in_blocks.txt b/test/prism/errors/do_not_allow_forward_arguments_in_blocks.txt
@@ -1,3 +1,13 @@
 a {|...|}
-    ^~~ unexpected ... when the parent method is not forwarding
+    ^~~ unexpected ... in block argument
+
+def foo(...)
+  a {|...|}
+      ^~~ unexpected ... in block argument
+end
+
+def foo
+  a {|...|}
+      ^~~ unexpected ... in block argument
+end
 
diff --git a/test/prism/errors/do_not_allow_forward_arguments_in_lambda_literals.txt b/test/prism/errors/do_not_allow_forward_arguments_in_lambda_literals.txt
@@ -1,3 +1,13 @@
 ->(...) {}
-   ^~~ unexpected ... when the parent method is not forwarding
+   ^~~ unexpected ... in lambda argument
+
+def foo(...)
+  ->(...) {}
+     ^~~ unexpected ... in lambda argument
+end
+
+def foo
+  ->(...) {}
+     ^~~ unexpected ... in lambda argument
+end
 
