diff --git a/schala-lang/src/parsing/combinator.rs b/schala-lang/src/parsing/combinator.rs
index ebe36ab..1d1643b 100644
--- a/schala-lang/src/parsing/combinator.rs
+++ b/schala-lang/src/parsing/combinator.rs
@@ -501,7 +501,15 @@ fn extended_expr_part(input: Span) -> ParseResult<ExtendedPart> {
     }
 
     fn call_part(input: Span) -> ParseResult<Vec<InvocationArgument>> {
-        delimited(tok(char('(')), separated_list0(tok(char(',')), invocation_argument), tok(char(')')))(input)
+        context(
+            "call-part",
+            //TODO generalize this `not`
+            delimited(
+                tok(char('(')),
+                separated_list0(tok(char(',')), preceded(not(tok(char(')'))), invocation_argument)),
+                tok(char(')')),
+            ),
+        )(input)
     }
 
     fn access_part(input: Span) -> ParseResult<&str> {
@@ -517,14 +525,16 @@ fn extended_expr_part(input: Span) -> ParseResult<ExtendedPart> {
 
 //TODO this shouldn't be an expression b/c type annotations disallowed here
 fn invocation_argument(input: Span) -> ParseResult<InvocationArgument> {
-    alt((
-        map(tok(char('_')), |_| InvocationArgument::Ignored),
-        map(tuple((identifier, tok(char('=')), expression)), |(name, _, expr)| InvocationArgument::Keyword {
-            name: rc_string(name.fragment()),
-            expr,
-        }),
-        map(expression, InvocationArgument::Positional),
-    ))(input)
+    context(
+        "invocation-argument",
+        cut(alt((
+            map(tok(char('_')), |_| InvocationArgument::Ignored),
+            map(tuple((identifier, tok(char('=')), expression)), |(name, _, expr)| {
+                InvocationArgument::Keyword { name: rc_string(name.fragment()), expr }
+            }),
+            map(expression, InvocationArgument::Positional),
+        ))),
+    )(input)
 }
 
 fn primary_expr(allow_struct: bool) -> impl FnMut(Span) -> ParseResult<ExpressionKind> {
diff --git a/schala-lang/src/parsing/test.rs b/schala-lang/src/parsing/test.rs
index fc10b70..14d8d88 100644
--- a/schala-lang/src/parsing/test.rs
+++ b/schala-lang/src/parsing/test.rs
@@ -125,6 +125,7 @@ macro_rules! assert_fail_comb {
     ($input:expr, $failure:expr) => {
         let mut parser = Parser::new();
         let err = parser.parse_comb($input).unwrap_err();
+        println!("assert_fail: {}", err.msg);
         assert_eq!(err.msg, $failure);
     };
 }
@@ -822,7 +823,8 @@ fn functions() {
             ]
         })
     );
-    assert_fail!("a(b,,c)","error at 1:5: expected one of \"(\", \".\", \"0b\", \"0x\", \"[\", \"\\\"\", \"_\", \"false\", \"for\", \"if\", \"true\", \"while\", ['+' | '-' | '!'], ['0' ..= '9'], ['a' ..= 'z' | 'A' ..= 'Z' | '_'], r#\"\\\"#");
+    let err_msg = "0: at line 1, in Alpha:\na(b,,c)\n    ^\n\n1: at line 1, in Alt:\na(b,,c)\n    ^\n\n2: at line 1, in tok:\na(b,,c)\n    ^\n\n3: at line 1, in identifier-expr:\na(b,,c)\n    ^\n\n4: at line 1, in Alt:\na(b,,c)\n    ^\n\n5: at line 1, in primary-expr:\na(b,,c)\n    ^\n\n6: at line 1, in extended-expr:\na(b,,c)\n    ^\n\n7: at line 1, in prefix-expr:\na(b,,c)\n    ^\n\n8: at line 1, in expression-kind:\na(b,,c)\n    ^\n\n9: at line 1, in Alt:\na(b,,c)\n    ^\n\n10: at line 1, in invocation-argument:\na(b,,c)\n    ^\n\n11: at line 1, in call-part:\na(b,,c)\n ^\n\n12: at line 1, in extended-expr:\na(b,,c)\n^\n\n13: at line 1, in prefix-expr:\na(b,,c)\n^\n\n14: at line 1, in expression-kind:\na(b,,c)\n^\n\n15: at line 1, in Parsing-statement:\na(b,,c)\n^\n\n16: at line 1, in AST:\na(b,,c)\n^\n\n";
+    assert_fail_comb!("a(b,,c)", err_msg);
 
     assert_ast!(
         "fn a(b, c: Int): Int",