• d-bugmail puremagic.com (40/40) Oct 03 2022 https://issues.dlang.org/show_bug.cgi?id=23384

d-bugmail puremagic.com writes:

https://issues.dlang.org/show_bug.cgi?id=23384

          Issue ID: 23384
           Summary: Suggest calling matching base class method when hidden
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: nick geany.org

struct A {}
struct B {}

class Base
{
    void fun(A a) {}
}

class Derived : Base
{
    void fun(B b) {}
}

void main()
{
    Derived d;
    d.fun(A());
}

The above code (rightly IMO) produces this error:
overloadhiding.d(18): Error: function `overloadhiding.Derived.fun(B b)` is not
callable using argument types `(A)`
overloadhiding.d(18):        cannot pass argument `A()` of type `A` to
parameter `B b`

This sometimes gets reported as a suspected compiler bug, e.g. bug 23377
(closed as WONTFIX) or on the forum.

After the error message for Derived.fun(A), the compiler should add an
informational message when the base class has a match, explaining that match is
hidden. That would help the user know the workaround and also make it clear the
error is by design. (I had a look but I'm not sure how to implement it).

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