diff --git a/ChangeLog b/ChangeLog
index 4351f38ae3..d3b7aff6a1 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Nov 25 00:54:15 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* parse.y (kwd_append): fix segv after invalid keyword argument,
+	  preceding keyword list is NULL when syntax error is there.
+	  [ruby-core:71356] [Bug #11663]
+
 Wed Nov 25 00:47:07 2015  SHIBATA Hiroshi  <hsbt@ruby-lang.org>
 
 	* lib/ipaddr.rb, test/test_ipaddr.rb: Reject invalid address contained
diff --git a/parse.y b/parse.y
index 4df09c9411..9df51a19b9 100644
--- a/parse.y
+++ b/parse.y
@@ -456,6 +456,8 @@ static NODE *new_attr_op_assign_gen(struct parser_params *parser, NODE *lhs, ID
 static NODE *new_const_op_assign_gen(struct parser_params *parser, NODE *lhs, ID op, NODE *rhs);
 #define new_const_op_assign(lhs, op, rhs) new_const_op_assign_gen(parser, (lhs), (op), (rhs))
 
+static NODE *kwd_append(NODE*, NODE*);
+
 static NODE *new_hash_gen(struct parser_params *parser, NODE *hash);
 #define new_hash(hash) new_hash_gen(parser, (hash))
 
@@ -4786,13 +4788,7 @@ f_block_kwarg	: f_block_kw
 		| f_block_kwarg ',' f_block_kw
 		    {
 		    /*%%%*/
-			NODE *kws = $1;
-
-			while (kws->nd_next) {
-			    kws = kws->nd_next;
-			}
-			kws->nd_next = $3;
-			$$ = $1;
+			$$ = kwd_append($1, $3);
 		    /*%
 			$$ = rb_ary_push($1, $3);
 		    %*/
@@ -4811,13 +4807,7 @@ f_kwarg		: f_kw
 		| f_kwarg ',' f_kw
 		    {
 		    /*%%%*/
-			NODE *kws = $1;
-
-			while (kws->nd_next) {
-			    kws = kws->nd_next;
-			}
-			kws->nd_next = $3;
-			$$ = $1;
+			$$ = kwd_append($1, $3);
 		    /*%
 			$$ = rb_ary_push($1, $3);
 		    %*/
@@ -6790,6 +6780,9 @@ formal_argument_gen(struct parser_params *parser, ID lhs)
       case ID_CLASS:
 	yyerror("formal argument cannot be a class variable");
 	return 0;
+      default:
+	yyerror("formal argument must be local variable");
+	return 0;
 #else
       default:
 	lhs = dispatch1(param_error, lhs);
@@ -8957,6 +8950,19 @@ gettable_gen(struct parser_params *parser, ID id)
     compile_error(PARSER_ARG "identifier %"PRIsVALUE" is not valid to get", rb_id2str(id));
     return 0;
 }
+
+static NODE *
+kwd_append(NODE *kwlist, NODE *kw)
+{
+    if (kwlist) {
+	NODE *kws = kwlist;
+	while (kws->nd_next) {
+	    kws = kws->nd_next;
+	}
+	kws->nd_next = kw;
+    }
+    return kwlist;
+}
 #else  /* !RIPPER */
 static int
 id_is_var_gen(struct parser_params *parser, ID id)
diff --git a/test/ruby/test_syntax.rb b/test/ruby/test_syntax.rb
index e4a623208a..cc5ed5f35a 100644
--- a/test/ruby/test_syntax.rb
+++ b/test/ruby/test_syntax.rb
@@ -184,6 +184,16 @@ class TestSyntax < Test::Unit::TestCase
     end
   end
 
+  def test_keyword_invalid_name
+    bug11663 = '[ruby-core:71356] [Bug #11663]'
+
+    o = Object.new
+    assert_syntax_error('def o.foo(arg1?:) end', /arg1\?/, bug11663)
+    assert_syntax_error('def o.foo(arg1?:, arg2:) end', /arg1\?/, bug11663)
+    assert_syntax_error('proc {|arg1?:|}', /arg1\?/, bug11663)
+    assert_syntax_error('proc {|arg1?:, arg2:|}', /arg1\?/, bug11663)
+  end
+
   def test_optional_self_reference
     bug9593 = '[ruby-core:61299] [Bug #9593]'
     o = Object.new
diff --git a/version.h b/version.h
index cb08b547b2..a9f37bbc27 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.2.4"
 #define RUBY_RELEASE_DATE "2015-11-25"
-#define RUBY_PATCHLEVEL 198
+#define RUBY_PATCHLEVEL 199
 
 #define RUBY_RELEASE_YEAR 2015
 #define RUBY_RELEASE_MONTH 11