forwardable.rb: backtrace

* lib/forwardable.rb (_delegator_method): leave the backtrace
  untouched during accessor.  forwardable.rb does not appear in
  the backtrace during delegated method because of tail-call
  optimization.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55372 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 5 deletions

diff --git a/test/test_forwardable.rb b/test/test_forwardable.rb
index b948fddac0..0d3fe19213 100644
--- a/test/test_forwardable.rb
+++ b/test/test_forwardable.rb
@@ -225,18 +225,21 @@ class TestForwardable < Test::Unit::TestCase
   class Foo
     extend Forwardable
 
+    attr_accessor :bar
     def_delegator :bar, :baz
     def_delegator :caller, :itself, :c
-
-    class Exception
-    end
   end
 
   def test_backtrace_adjustment
+    obj = Foo.new
+    def (obj.bar = Object.new).baz
+      foo
+    end
     e = assert_raise(NameError) {
-      Foo.new.baz
+      obj.baz
     }
-    assert_not_match(/\/forwardable\.rb/, e.backtrace[0])
+    assert_not_match(/\/forwardable\.rb/, e.backtrace[0],
+                     proc {RubyVM::InstructionSequence.of(obj.method(:baz)).disassemble})
     assert_equal(caller(0, 1)[0], Foo.new.c[0])
   end