[Issue 20649] New: _d_arraysetlengthT crashes when std.traits.ReturnType is used with auto function

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20649

          Issue ID: 20649
           Summary: _d_arraysetlengthT crashes when std.traits.ReturnType
                    is used with auto function
           Product: D
           Version: D2
          Hardware: x86
                OS: Windows
            Status: NEW
          Severity: normal
          Priority: P1
         Component: druntime
          Assignee: nobody at puremagic.com
          Reporter: menodinulla at gmail.com

The following code causes `object.Error@(0): Access Violation` at `ss.length =
1` on Windows 64bit.

--- app.d
import std.traits;

struct S { int i; }

auto f()
{
    S[] ss;
    ss.length = 1;
}

alias a = ReturnType!f;

void main()
{
    f();
}
---

Tested on the following versions.

- dmd-2.090.0
- dmd-2.091.0-rc.1

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