Revert "merge revision(s) c8d162c889008028b148437d02f36f4edaa749fd: [Backport #19973]"

This reverts commit 24dd529750c08b5603fb418a4f34998b9bf6c8f9.

3 files changed, 5 insertions, 13 deletions

diff --git a/parse.y b/parse.y
index 3c7702db7d..d58fa6e0b7 100644
--- a/parse.y
+++ b/parse.y
@@ -12889,17 +12889,15 @@ remove_duplicate_keys(struct parser_params *p, NODE *hash)
     NODE *result = 0;
     NODE *last_expr = 0;
     rb_code_location_t loc = hash->nd_loc;
-    while (hash && hash->nd_next) {
+    while (hash && hash->nd_head && hash->nd_next) {
 	NODE *head = hash->nd_head;
 	NODE *value = hash->nd_next;
 	NODE *next = value->nd_next;
 	st_data_t key = (st_data_t)head;
 	st_data_t data;
 	value->nd_next = 0;
-        if (!head) {
-        }
-        else if (nd_type_p(head, NODE_LIT) &&
-	         st_delete(literal_keys, (key = (st_data_t)head->nd_lit, &key), &data)) {
+	if (nd_type_p(head, NODE_LIT) &&
+	    st_delete(literal_keys, (key = (st_data_t)head->nd_lit, &key), &data)) {
 	    NODE *dup_value = ((NODE *)data)->nd_next;
 	    rb_compile_warn(p->ruby_sourcefile, nd_line((NODE *)data),
 			    "key %+"PRIsVALUE" is duplicated and overwritten on line %d",
@@ -12912,7 +12910,7 @@ remove_duplicate_keys(struct parser_params *p, NODE *hash)
 	    }
 	}
 	st_insert(literal_keys, (st_data_t)key, (st_data_t)hash);
-	last_expr = !head || nd_type_p(head, NODE_LIT) ? value : head;
+	last_expr = nd_type_p(head, NODE_LIT) ? value : head;
 	hash = next;
     }
     st_foreach(literal_keys, append_literal_keys, (st_data_t)&result);
diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index f9b807d1e9..29de9b18c7 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -336,12 +336,6 @@ class TestSyntax < Test::Unit::TestCase
     assert_warn(/duplicated/) {r = eval("a.f(**{k: a.add(1), j: a.add(2), k: a.add(3), k: a.add(4)})")}
     assert_equal(4, r)
     assert_equal([1, 2, 3, 4], a)
-    a.clear
-    r = nil
-    z = {}
-    assert_warn(/duplicated/) {r = eval("a.f(k: a.add(1), **z, k: a.add(2))")}
-    assert_equal(2, r)
-    assert_equal([1, 2], a)
   end
 
   def test_keyword_empty_splat
diff --git a/version.h b/version.h
index a84b0012c8..d390ec031b 100644
--- a/version.h
+++ b/version.h
@@ -11,7 +11,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 3
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 159
+#define RUBY_PATCHLEVEL 158
 
 #include "ruby/version.h"
 #include "ruby/internal/abi.h"