[Issue 13820] New: switch and case expressions should support alias this types

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=13820

          Issue ID: 13820
           Summary: switch and case expressions should support alias this
                    types
           Product: D
           Version: unspecified
          Hardware: x86_64
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: DMD
          Assignee: nobody at puremagic.com
          Reporter: code at dawg.eu

cat > enh.d << CODE
struct Foo
{
    int val;
    alias val this;
}

void main()
{
    auto foo = Foo(10);

    switch (foo)
    {
    case Foo(5):
        break;

    default:
        break;
    }
}
CODE

dmd -c enh
----
enh.d(11): Error: 'foo' must be of integral or string type, it is a Foo
enh.d(13): Error: case must be a string or an integral constant, not Foo(5)
----

The compiler should attempt to implicitly convert the expressions to an
integral or string type.

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