record_type_one_positional_no_trailing_comma

A record type with exactly one positional field requires a trailing comma.

The analyzer produces this diagnostic when a record type annotation with a single positional field doesn't have a trailing comma after the field.

In some locations a record type with a single positional field could also be a parenthesized expression. A trailing comma is required to disambiguate these two valid interpretations.

The following code produces this diagnostic because the record type has one positional field, but doesn't have a trailing comma:

void f((int) r) {}

Add a trailing comma:

void f((int,) r) {}