https://issues.dlang.org/show_bug.cgi?id=23101

--- Comment #1 from João Lourenço <jlourenco5691@gmail.com> ---
Because of this, when matching, `canMatch` will fail as it will test for a copy, and returning a reference of that value results in escaping it.

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https://issues.dlang.org/show_bug.cgi?id=23101

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

           What    |Removed                     |Added
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           Keywords|                            |pull

--- Comment #2 from Dlang Bot <dlang-bot@dlang.rocks> ---
@iK4tsu created dlang/phobos pull request #8457 "Issue 23101 - [std.sumtype] canMatch does not account ref " fixing this issue:

- fix(sumtype): template canMatch does not account for ref when matching

  The template `canMatch` does not account for `ref`.
  The template `valueTypes` stores all types of the member values and uses
SumTypes's `get` function, which returns a `ref`.
  However, ref does not persist and the type is not sent to `canMatch` as a
`ref`.
  Because of this, when matching, `canMatch` will fail as it will test for a
copy, and returning a reference of that value results in escaping it.

  Fix Issue 23101

  Signed-off-by: João Lourenço <jlourenco5691@gmail.com>

https://github.com/dlang/phobos/pull/8457

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https://issues.dlang.org/show_bug.cgi?id=23101

--- Comment #3 from João Lourenço <jlourenco5691@gmail.com> ---
Sorry, correction of the bug report example:
```
SumType!(int, string) st;
st.match!(
  function int*(string _) => assert(0),
  function int*(ref int i) => &i,
);
```

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https://issues.dlang.org/show_bug.cgi?id=23101

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

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

--- Comment #4 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/phobos pull request #8457 "Issue 23101 - [std.sumtype] canMatch does not account ref " was merged into master:

- 6069c449303e8571b7b73c4fe50fc3088832d5fe by João Lourenço:
  fix(sumtype): template canMatch does not account for ref when matching

  The template `canMatch` does not account for `ref`.
  The template `valueTypes` stores all types of the member values and uses
SumTypes's `get` function, which returns a `ref`.
  However, ref does not persist and the type is not sent to `canMatch` as a
`ref`.
  Because of this, when matching, `canMatch` will fail as it will test for a
copy, and returning a reference of that value results in escaping it.

  Fix Issue 23101

  Signed-off-by: João Lourenço <jlourenco5691@gmail.com>

https://github.com/dlang/phobos/pull/8457

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