[Issue 23682] New: dip1000 problem with return by ref

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23682

          Issue ID: 23682
           Summary: dip1000 problem with return by ref
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: dmd
          Assignee: nobody at puremagic.com
          Reporter: bugzilla at digitalmars.com

For:
---
alias VErr = char*;

@safe:

ref char* front_p(return scope char** p) { return *p; }

__gshared char* g;

void main()
{
    char* _errors;
    g = front_p(&_errors); // Error: address of variable `_errors` assigned to
`g` with longer lifetime
}
---

The error is incorrect. The return value is indirected before assignment to
`g`, so the address of `_errors` isn't being assigned to `g`, what `_errors` is
pointing to is assigned to `g`.

This can be seen by commenting out `@safe:`, compiling it, and looking at the
assembler.

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