[ruby/yarp] Reject invalid call-operator-write

https://github.com/ruby/yarp/commit/d3a852dac2

1 files changed, 8 insertions, 1 deletions

diff --git a/test/yarp/errors_test.rb b/test/yarp/errors_test.rb
index 1285ba75cd..09abe3ee79 100644
--- a/test/yarp/errors_test.rb
+++ b/test/yarp/errors_test.rb
@@ -1137,13 +1137,20 @@ module YARP
       assert_errors expected, "def foo(a = 1,b,*c);end", [["Unexpected parameter `*`", 16..17]]
     end
 
-    def test_invalid_operator_write
+    def test_invalid_operator_write_fcall
       source = "foo! += 1"
       assert_errors expression(source), source, [
         ["Unexpected write target", 0..4]
       ]
     end
 
+    def test_invalid_operator_write_dot
+      source = "foo.+= 1"
+      assert_errors expression(source), source, [
+        ["Unexpected write target", 5..6]
+      ]
+    end
+
     def test_unterminated_global_variable
       assert_errors expression("$"), "$", [
         ["Invalid global variable", 0..1]