From 820c541671d9485144d81138bb029f2da8379edd Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Thu, 13 Mar 2025 15:17:26 +0900
Subject: [PATCH] [Bug #21026] no singleton method on pseudo variable literal

---
 parse.y                                      | 28 ++++++++++++--------
 prism/prism.c                                |  2 +-
 test/prism/fixtures/keyword_method_names.txt |  9 -------
 test/ruby/test_parse.rb                      |  6 +++++
 4 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/parse.y b/parse.y
index 8a775174fe..16f91a9483 100644
--- a/parse.y
+++ b/parse.y
@@ -2757,7 +2757,7 @@ rb_parser_ary_free(rb_parser_t *p, rb_parser_ary_t *ary)
 %token <num>  tREGEXP_END
 %token <num>  tDUMNY_END     "dummy end"
 
-%type <node> singleton strings string string1 xstring regexp
+%type <node> singleton singleton_expr strings string string1 xstring regexp
 %type <node> string_contents xstring_contents regexp_contents string_content
 %type <node> words symbols symbol_list qwords qsymbols word_list qword_list qsym_list word
 %type <node> literal numeric simple_numeric ssym dsym symbol cpath
@@ -6581,16 +6581,10 @@ opt_f_block_arg	: ',' f_block_arg
                 | none
                 ;
 
-singleton	: value_expr(var_ref)
-                | '('
+
+singleton	: value_expr(singleton_expr)
                     {
-                        SET_LEX_STATE(EXPR_BEG);
-                        p->ctxt.in_argdef = 0;
-                    }
-                  expr rparen
-                    {
-                        p->ctxt.in_argdef = 1;
-                        NODE *expr = last_expr_node($3);
+                        NODE *expr = last_expr_node($1);
                         switch (nd_type(expr)) {
                           case NODE_STR:
                           case NODE_DSTR:
@@ -6612,9 +6606,21 @@ singleton	: value_expr(var_ref)
                             yyerror1(&expr->nd_loc, "can't define singleton method for literals");
                             break;
                           default:
-                            value_expr($3);
                             break;
                         }
+                        $$ = $1;
+                    }
+                ;
+
+singleton_expr	: var_ref
+                | '('
+                    {
+                        SET_LEX_STATE(EXPR_BEG);
+                        p->ctxt.in_argdef = 0;
+                    }
+                  expr rparen
+                    {
+                        p->ctxt.in_argdef = 1;
                         $$ = $3;
                     /*% ripper: paren!($:3) %*/
                     }
diff --git a/prism/prism.c b/prism/prism.c
index c4cab8f00e..8597aa63fa 100644
--- a/prism/prism.c
+++ b/prism/prism.c
@@ -3874,7 +3874,7 @@ pm_def_node_create(
         end = end_keyword->end;
     }
 
-    if ((receiver != NULL) && PM_NODE_TYPE_P(receiver, PM_PARENTHESES_NODE)) {
+    if (receiver != NULL) {
         pm_def_node_receiver_check(parser, receiver);
     }
 
diff --git a/test/prism/fixtures/keyword_method_names.txt b/test/prism/fixtures/keyword_method_names.txt
index 9154469441..d3b6eac537 100644
--- a/test/prism/fixtures/keyword_method_names.txt
+++ b/test/prism/fixtures/keyword_method_names.txt
@@ -12,18 +12,9 @@ end
 def m(a, **nil)
 end
 
-def __ENCODING__.a
-end
-
 %{abc}
 
 %"abc"
 
-def __FILE__.a
-end
-
-def __LINE__.a
-end
-
 def nil::a
 end
diff --git a/test/ruby/test_parse.rb b/test/ruby/test_parse.rb
index 0c50793549..98e95b98af 100644
--- a/test/ruby/test_parse.rb
+++ b/test/ruby/test_parse.rb
@@ -475,6 +475,12 @@ class TestParse < Test::Unit::TestCase
     assert_parse_error(%q[def (:"#{42}").foo; end], msg)
     assert_parse_error(%q[def ([]).foo; end], msg)
     assert_parse_error(%q[def ([1]).foo; end], msg)
+    assert_parse_error(%q[def (__FILE__).foo; end], msg)
+    assert_parse_error(%q[def (__LINE__).foo; end], msg)
+    assert_parse_error(%q[def (__ENCODING__).foo; end], msg)
+    assert_parse_error(%q[def __FILE__.foo; end], msg)
+    assert_parse_error(%q[def __LINE__.foo; end], msg)
+    assert_parse_error(%q[def __ENCODING__.foo; end], msg)
   end
 
   def test_flip_flop