From e8896a31d48e5797df3878696dcb50aed85b87c2 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Wed, 13 Sep 2023 21:55:12 +0900
Subject: [PATCH] [Bug #19877] Literals cannot have singleton methods even in
 blocks

---
 parse.y                 | 15 +++++++++++++--
 test/ruby/test_parse.rb | 25 ++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/parse.y b/parse.y
index d48d74db0f..e675793271 100644
--- a/parse.y
+++ b/parse.y
@@ -917,6 +917,15 @@ set_embraced_location(NODE *node, const rb_code_location_t *beg, const rb_code_l
     nd_set_line(node, beg->end_pos.lineno);
 }
 
+static NODE *
+last_expr_node(NODE *expr)
+{
+    if (nd_type_p(expr, NODE_BLOCK)) {
+        expr = expr->nd_end->nd_head;
+    }
+    return expr;
+}
+
 #define yyparse ruby_yyparse
 
 static NODE* cond(struct parser_params *p, NODE *node, const YYLTYPE *loc);
@@ -6050,16 +6059,18 @@ singleton	: var_ref
                 | '(' {SET_LEX_STATE(EXPR_BEG);} expr rparen
                     {
                     /*%%%*/
-                        switch (nd_type($3)) {
+                        NODE *expr = last_expr_node($3);
+                        switch (nd_type(expr)) {
                           case NODE_STR:
                           case NODE_DSTR:
                           case NODE_XSTR:
                           case NODE_DXSTR:
                           case NODE_DREGX:
                           case NODE_LIT:
+                          case NODE_DSYM:
                           case NODE_LIST:
                           case NODE_ZLIST:
-                            yyerror1(&@3, "can't define singleton method for literals");
+                            yyerror1(&expr->nd_loc, "can't define singleton method for literals");
                             break;
                           default:
                             value_expr($3);
diff --git a/test/ruby/test_parse.rb b/test/ruby/test_parse.rb
index 957a37eb81..5209a4839f 100644
--- a/test/ruby/test_parse.rb
+++ b/test/ruby/test_parse.rb
@@ -453,11 +453,16 @@ class TestParse < Test::Unit::TestCase
   end
 
   def test_define_singleton_error
-    assert_syntax_error("#{<<~"begin;"}\n#{<<~'end;'}", /singleton method for literals/) do
-      begin;
-        def ("foo").foo; end
-      end;
-    end
+    msg = /singleton method for literals/
+    assert_parse_error(%q[def ("foo").foo; end], msg)
+    assert_parse_error(%q[def (1).foo; end], msg)
+    assert_parse_error(%q[def ((1;1)).foo; end], msg)
+    assert_parse_error(%q[def ((;1)).foo; end], msg)
+    assert_parse_error(%q[def ((1+1;1)).foo; end], msg)
+    assert_parse_error(%q[def ((%s();1)).foo; end], msg)
+    assert_parse_error(%q[def ((%w();1)).foo; end], msg)
+    assert_parse_error(%q[def ("#{42}").foo; end], msg)
+    assert_parse_error(%q[def (:"#{42}").foo; end], msg)
   end
 
   def test_op_asgn1_with_block
@@ -1453,4 +1458,14 @@ x = __ENCODING__
     assert_warning(/past scope/) {catch {|tag| eval("BEGIN{throw tag}; tap {a = 1}; a")}}
   end
 =end
+
+  def assert_parse(code)
+    assert_kind_of(RubyVM::AbstractSyntaxTree::Node, RubyVM::AbstractSyntaxTree.parse(code))
+  end
+
+  def assert_parse_error(code, message)
+    assert_raise_with_message(SyntaxError, message) do
+      RubyVM::AbstractSyntaxTree.parse(code)
+    end
+  end
 end