[Issue 15408] S.init for struct containing member field with array literal initializer fails @nogc

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=15408

Steven Schveighoffer <schveiguy at gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |spec, wrong-code
                 CC|                            |schveiguy at gmail.com
                 OS|Mac OS X                    |All
           Severity|normal                      |major

--- Comment #1 from Steven Schveighoffer <schveiguy at gmail.com> ---
This reduces in AST to:

```d
S s = S([42]);
```

Which is why it always allocates.

This also defies the spec, which states:

> .init produces a constant expression that is the default initializer.

This is not a constant expression.

This also leads to such puzzles as `assert(S.init !is S.init)`

Also note that:

```d
S s;
```

Does *not* produce an allocation.

S.init should not allocate. Neither should S()

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