• d-bugmail puremagic.com (50/50) Mar 02 2020 https://issues.dlang.org/show_bug.cgi?id=20625

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=20625

          Issue ID: 20625
           Summary: Function literal diagnostic is not on par with other
                    messages
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Keywords: diagnostic
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: pro.mathias.lang gmail.com

The following code:
```
void main()
{
    // No argument
    (x, y, z) { return 42; }();

    // Too many args, non-variadic
    (x, y, z) { return 42; }(42, "Hello", 42, 42);
    // Too many args, non-variadic, default param
    (x, y, string z = "Hello") { return x; }(42, 42, "Nope", "Noooope");
    // Too few args, non-variadic
    (x, y, string z = "Hello") { return x; }(42);
    // Too few args, non-variadic, default param
    (x, y, z) { return x; }(42);

    // Too few args, variadic
    (x, y, ...) { return x; }(42);
    // Too few args, variadic, default param
    (x, y, string z = "Hey", ...) { return x; }(42);
}
```

Outputs the following:
```
diag1111.d(4): Error: function literal __lambda1(x, y, z) is not callable using
argument types ()

diag1111.d(7): Error: cannot infer function literal type
diag1111.d(9): Error: cannot infer function literal type
diag1111.d(11): Error: cannot infer function literal type
diag1111.d(13): Error: cannot infer function literal type
diag1111.d(16): Error: cannot infer function literal type
diag1111.d(18): Error: cannot infer function literal type
```

You can see that the first error message, with no argument, is pretty good,
while the other error messages are much poorer.

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