From 27ddb6e99848c397a415b785315896ab50308076 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Fri, 20 Dec 2019 01:01:17 +0900
Subject: Warn also numbered parameter like parameters

[Feature #16433]
---
 parse.y                            | 14 ++++++++++----
 test/ripper/test_scanner_events.rb |  2 +-
 test/ruby/test_syntax.rb           |  2 ++
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/parse.y b/parse.y
index 7de84ee700..33c1c89c3d 100644
--- a/parse.y
+++ b/parse.y
@@ -11829,19 +11829,25 @@ node_newnode_with_locals(struct parser_params *p, enum node_type type, VALUE a1,
 
 #endif
 
+static void
+numparam_name(struct parser_params *p, ID id)
+{
+    if (!NUMPARAM_ID_P(id)) return;
+    rb_warn1("`_%d' is used as numbered parameter",
+	     WARN_I(NUMPARAM_ID_TO_IDX(id)));
+}
+
 static void
 arg_var(struct parser_params *p, ID id)
 {
+    numparam_name(p, id);
     vtable_add(p->lvtbl->args, id);
 }
 
 static void
 local_var(struct parser_params *p, ID id)
 {
-    if (NUMPARAM_ID_P(id)) {
-	rb_warn1("`_%d' is used as numbered parameter",
-		 WARN_I(NUMPARAM_ID_TO_IDX(id)));
-    }
+    numparam_name(p, id);
     vtable_add(p->lvtbl->vars, id);
     if (p->lvtbl->used) {
 	vtable_add(p->lvtbl->used, (ID)p->ruby_sourceline);
diff --git a/test/ripper/test_scanner_events.rb b/test/ripper/test_scanner_events.rb
index ffe2ea1e37..cef584c157 100644
--- a/test/ripper/test_scanner_events.rb
+++ b/test/ripper/test_scanner_events.rb
@@ -31,7 +31,7 @@ class TestRipper::ScannerEvents < Test::Unit::TestCase
         alias compile_error on_error
       end
     end
-    lexer.lex.select {|_1,type,_2| type == sym }.map {|_1,_2,tok| tok }
+    lexer.lex.select {|_,type,_| type == sym }.map {|_,_,tok| tok }
   end
 
   def test_tokenize
diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index 286beb7074..b292b24894 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -1439,6 +1439,8 @@ eom
     assert_syntax_error('proc {_1; _1 = nil}', /Can't assign to numbered parameter _1/)
     assert_warn(/`_1' is used as numbered parameter/) {eval('proc {_1 = nil}')}
     assert_warn(/`_2' is used as numbered parameter/) {eval('_2=1')}
+    assert_warn(/`_3' is used as numbered parameter/) {eval('proc {|_3|}')}
+    assert_warn(/`_4' is used as numbered parameter/) {instance_eval('def x(_4) end')}
     assert_raise_with_message(NameError, /undefined local variable or method `_1'/) {
       eval('_1')
     }
-- 
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