vm.c: precedence of duplicated keys

* vm.c (kwmerge_i): override existing keys by new keys.
  [ruby-core:65368] [Bug #10315]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47878 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,4 +1,7 @@
-Sat Oct 11 13:46:53 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Sat Oct 11 13:46:58 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* vm.c (kwmerge_i): override existing keys by new keys.
+	  [ruby-core:65368] [Bug #10315]
 
 	* parse.y (assocs): concatenate splatted literal hashes.  the
 	  former key has precedence even if duplicated literal keys

test/ruby/test_syntax.rb

@@ -109,12 +109,12 @@ class TestSyntax < Test::Unit::TestCase
     def o.kw(k1: 1, k2: 2) [k1, k2] end
     h = {k1: 11, k2: 12}
     assert_equal([11, 12], o.kw(**h))
-    assert_equal([11, 22], o.kw(k2: 22, **h))
+    assert_equal([11, 12], o.kw(k2: 22, **h))
-    assert_equal([11, 12], o.kw(**h, **{k2: 22}))
+    assert_equal([11, 22], o.kw(**h, **{k2: 22}))
-    assert_equal([11, 22], o.kw(**{k2: 22}, **h))
+    assert_equal([11, 12], o.kw(**{k2: 22}, **h))
 
     bug10315 = '[ruby-core:65368] [Bug #10315]'
-    assert_equal([22, 2], o.kw(**{k1: 22}, **{k1: 23}), bug10315)
+    assert_equal([23, 2], o.kw(**{k1: 22}, **{k1: 23}), bug10315)
 
     h = {k3: 31}
     assert_raise(ArgumentError) {o.kw(**h)}

vm.c

@@ -2342,21 +2342,11 @@ m_core_hash_merge_ptr(int argc, VALUE *argv, VALUE recv)
     return hash;
 }
 
-static int
-kwmerge_ii(st_data_t *key, st_data_t *value, st_data_t arg, int existing)
-{
-    if (existing) return ST_STOP;
-    *value = arg;
-    return ST_CONTINUE;
-}
-
 static int
 kwmerge_i(VALUE key, VALUE value, VALUE hash)
 {
     if (!SYMBOL_P(key)) Check_Type(key, T_SYMBOL);
-    if (st_update(RHASH_TBL_RAW(hash), key, kwmerge_ii, (st_data_t)value) == 0) { /* !existing */
+    rb_hash_aset(hash, key, value);
-	RB_OBJ_WRITTEN(hash, Qundef, value);
-    }
     return ST_CONTINUE;
 }