hash.c: support key swapping in Hash#transform_keys!

* hash.c (rb_hash_transform_keys_bang): support key swapping in
  Hash#transform_keys!
  [Bug #14380] [ruby-core:84951]

* test/ruby/test_hash.rb (test_transform_keys_bang):
  add assertions for this change

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@62042 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 8 insertions, 0 deletions

diff --git a/test/ruby/test_hash.rb b/test/ruby/test_hash.rb
index 313c2fd9de..55e46584b4 100644
--- a/test/ruby/test_hash.rb
+++ b/test/ruby/test_hash.rb
@@ -1576,6 +1576,14 @@ class TestHash < Test::Unit::TestCase
 
     x.transform_keys!.with_index {|k, i| "#{k}.#{i}" }
     assert_equal(%w(a!.0 b!.1 c!.2), x.keys)
+
+    x = @cls[1 => :a, -1 => :b]
+    x.transform_keys! {|k| -k }
+    assert_equal([-1, :a, 1, :b], x.flatten)
+
+    x = @cls[true => :a, false => :b]
+    x.transform_keys! {|k| !k }
+    assert_equal([false, :a, true, :b], x.flatten)
   end
 
   def test_transform_values