https://issues.dlang.org/show_bug.cgi?id=20410

Simen Kjaeraas <simen.kjaras@gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |simen.kjaras@gmail.com

--- Comment #1 from Simen Kjaeraas <simen.kjaras@gmail.com> ---
This is only true where the base type of the enum fits one of the other patterns that ReplaceTypeUnless looks for, e.g. U[], U*, etc. - it will leave regular enums well enough alone, but string enums and the like will decay to their base types. Of course, there is a discussion to be had here - should the type change if I do this?

import std.typecons : ReplaceType;

enum Foo : string { bar = "baz" }

pragma(msg, ReplaceType!(char, int, Foo));

Currently, that'd be immutable(int)[], since Foo is a kind of
immutable(char)[], and I've asked to replace char with int.

While there are arguments to be had on both sides of this, I'd go with treating enums as opaque, since it's easier to forcibly decay them than filter them out beforehand.

Should be a simple two lines here: https://github.com/dlang/phobos/blob/58cb6963fbe54e7dc96ae8b48064e84f1eaf818a/std/typecons.d#L8748

        else static if (is(T[0] == enum))
            alias ReplaceTypeUnless = T;

test case:

@safe unittest
{
    enum Enum : string { foo = "Bar" }
    assert(is(ReplaceType!(char, int, Enum)[0] == Enum));
}

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https://issues.dlang.org/show_bug.cgi?id=20410

Paul Backus <snarwin+bugzilla@gmail.com> changed:

           What    |Removed                     |Added
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                 CC|                            |snarwin+bugzilla@gmail.com
          Component|phobos                      |dmd

--- Comment #2 from Paul Backus <snarwin+bugzilla@gmail.com> ---
Looks like a bug in the is expression. The "true" below ought to be "false":

enum Enum : string { foo = "bar" }

pragma(msg, is(Enum == string)); // false
pragma(msg, is(Enum == T[], T)); // true
pragma(msg, T); // immutable(char)

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https://issues.dlang.org/show_bug.cgi?id=20410

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
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           Keywords|                            |pull

--- Comment #3 from Dlang Bot <dlang-bot@dlang.rocks> ---
@pbackus updated dlang/dmd pull request #11235 "Fix 20410 - ReplaceTypeUnless replaces enums with their basetype" fixing this issue:

- Fix issue 20410 - ReplaceTypeUnless replaces enums with their basetype

  When matching an enum against a type specialization, a match obtained
  using the enum's base type is now correctly considered a match by
  implicit conversion rather than an exact match.

https://github.com/dlang/dmd/pull/11235

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https://issues.dlang.org/show_bug.cgi?id=20410

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/dmd pull request #11235 "Fix 20410 - ReplaceTypeUnless replaces enums with their basetype" was merged into master:

- 98259447cd40f28b539574dacd822a11aeb8167c by Paul Backus:
  Fix issue 20410 - ReplaceTypeUnless replaces enums with their basetype

  When matching an enum against a type specialization, a match obtained
  using the enum's base type is now correctly considered a match by
  implicit conversion rather than an exact match.

https://github.com/dlang/dmd/pull/11235

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