merge revision(s) 3ddf6ad4d2f6dae4caa00b8c407768c7062099a0: [Backport #18629]

	Private local variables should shadow outer variables [Bug #18629]

	---
	 parse.y                 | 3 ++-
	 test/ruby/test_parse.rb | 4 ++++
	 2 files changed, 6 insertions(+), 1 deletion(-)

3 files changed, 7 insertions, 2 deletions

diff --git a/parse.y b/parse.y
index e3e680414a..27890ff4e8 100644
--- a/parse.y
+++ b/parse.y
@@ -10984,9 +10984,9 @@ is_private_local_id(ID name)
 static int
 shadowing_lvar_0(struct parser_params *p, ID name)
 {
-    if (is_private_local_id(name)) return 1;
     if (dyna_in_block(p)) {
 	if (dvar_curr(p, name)) {
+	    if (is_private_local_id(name)) return 1;
 	    yyerror0("duplicated argument name");
 	}
 	else if (dvar_defined(p, name) || local_id(p, name)) {
@@ -10999,6 +10999,7 @@ shadowing_lvar_0(struct parser_params *p, ID name)
     }
     else {
 	if (local_id(p, name)) {
+	    if (is_private_local_id(name)) return 1;
 	    yyerror0("duplicated argument name");
 	}
     }
diff --git a/test/ruby/test_parse.rb b/test/ruby/test_parse.rb
index d697a29c1c..2841e20f6d 100644
--- a/test/ruby/test_parse.rb
+++ b/test/ruby/test_parse.rb
@@ -930,6 +930,10 @@ x = __ENCODING__
     assert_no_warning(/shadowing outer local variable/) {eval("a=1; tap {|a|}")}
   end
 
+  def test_shadowing_private_local_variable
+    assert_equal 1, eval("_ = 1; [[2]].each{ |(_)| }; _")
+  end
+
   def test_unused_variable
     o = Object.new
     assert_warning(/assigned but unused variable/) {o.instance_eval("def foo; a=1; nil; end")}
diff --git a/version.h b/version.h
index 9807ae4d8c..14ec0eea35 100644
--- a/version.h
+++ b/version.h
@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 4
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 190
+#define RUBY_PATCHLEVEL 191
 
 #define RUBY_RELEASE_YEAR 2023
 #define RUBY_RELEASE_MONTH 2