diff --git a/schala-lang/src/parsing/combinator.rs b/schala-lang/src/parsing/combinator.rs
index d9a2683..5e14998 100644
--- a/schala-lang/src/parsing/combinator.rs
+++ b/schala-lang/src/parsing/combinator.rs
@@ -293,32 +293,34 @@ fn func_signature(input: Span) -> ParseResult<Signature> {
         "func-signature",
         preceded(
             kw("fn"),
-            cut(verify(
-                alt((
-                    map(normal_fn, |(name, params, type_anno)| Signature {
-                        name: rc_string(name.fragment()),
-                        operator: false,
-                        params,
-                        type_anno,
-                    }),
-                    map(operator_fn, |(op, params, type_anno)| Signature {
-                        name: rc_string(op.sigil()),
-                        operator: true,
-                        params,
-                        type_anno,
-                    }),
-                )),
-                |sig| sig.params.len() < 256,
-            )),
+            cut(alt((
+                map(normal_fn, |(name, params, type_anno)| Signature {
+                    name: rc_string(name.fragment()),
+                    operator: false,
+                    params,
+                    type_anno,
+                }),
+                map(operator_fn, |(op, params, type_anno)| Signature {
+                    name: rc_string(op.sigil()),
+                    operator: true,
+                    params,
+                    type_anno,
+                }),
+            ))),
         ),
     )(input)
 }
 
 fn formal_params(input: Span) -> ParseResult<Vec<FormalParam>> {
-    delimited(tok(char('(')), separated_list0(tok(char(',')), formal_param), tok(char(')')))(input)
+    context(
+        "formal-params",
+        verify(
+            delimited(tok(char('(')), separated_list0(tok(char(',')), formal_param), tok(char(')'))),
+            |params: &Vec<_>| params.len() < 256,
+        ),
+    )(input)
 }
 
-//TODO support 256-limit
 fn formal_param(input: Span) -> ParseResult<FormalParam> {
     map(
         tuple((identifier, opt(type_anno), opt(preceded(tok(char('=')), expression)))),
diff --git a/schala-lang/src/parsing/test.rs b/schala-lang/src/parsing/test.rs
index 9d4e6cb..21079f3 100644
--- a/schala-lang/src/parsing/test.rs
+++ b/schala-lang/src/parsing/test.rs
@@ -886,6 +886,14 @@ fn max_function_params() {
     //TODO need to create a good, custom error message for this case
     //assert_fail!(&buf, "A function cannot have more than 255 arguments");
     assert_fail!(&buf);
+
+    let mut buf = r#"\("#.to_string();
+    for n in 0..255 {
+        write!(buf, "a{}, ", n).unwrap();
+    }
+    write!(buf, " a256").unwrap();
+    write!(buf, ") {{ return 10 }}").unwrap();
+    assert_fail!(&buf);
 }
 
 #[test]