ZJIT: Reject direct send for hash passed as positional arg to keyword-only method

Author: ykawabata17

zjit/src/codegen_tests.rs

@@ -821,6 +821,38 @@ fn test_send_kwarg_optional_static_with_side_exit() {
     "), @"[10, 2, 10]");
 }
 
+#[test]
+fn test_send_hash_to_kwarg_only_method() {
+    assert_snapshot!(inspect(r#"
+        def callee(a:) = a
+
+        def entry
+          callee({a: 1})
+        rescue ArgumentError
+          "ArgumentError"
+        end
+
+        entry
+        entry
+    "#), @r#""ArgumentError""#);
+}
+
+#[test]
+fn test_send_hash_to_optional_kwarg_only_method() {
+    assert_snapshot!(inspect(r#"
+        def callee(a: nil) = a
+
+        def entry
+          callee({a: 1})
+        rescue ArgumentError
+          "ArgumentError"
+        end
+
+        entry
+        entry
+    "#), @r#""ArgumentError""#);
+}
+
 #[test]
 fn test_send_all_arg_types() {
     assert_snapshot!(inspect("

zjit/src/hir.rs

@@ -1933,6 +1933,15 @@ fn can_direct_send(function: &mut Function, block: BlockId, iseq: *const rb_iseq
         return false;
     }
 
+    // Caller passing a hash as a positional arg but callee expects keyword-only args will
+    // raise ArgumentError at runtime. Fall back to VM dispatch to handle this correctly.
+    if kwarg.is_null() && !keyword.is_null() {
+        if lead_num == 0 && opt_num == 0 && caller_positional > 0 {
+            function.set_dynamic_send_reason(send_insn, ArgcParamMismatch);
+            return false;
+        }
+    }
+
     can_send
 }