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digitalmars.D.bugs - [Issue 22209] New: NRVO variable detection ignoring `alias this`


          Issue ID: 22209
           Summary: NRVO variable detection ignoring `alias this`
                    conversion => segfaults
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: major
          Priority: P1
         Component: dmd
          Assignee: nobody puremagic.com
          Reporter: kinke gmx.net

This segfaults at runtime (for all versions currently on run.dlang.io):
struct U { size_t[4] a; }

struct S
    int x;
    U u;
    alias u this;

U foo()
    S s = S(42, U([1, 2, 3, 4]));
    return s;

void main()
    assert(foo().a[0] == 1);

It's apparently caused by the frontend wrongly marking `s` in `foo()` as the
NRVO variable (FuncDeclaration.nrvo_var), ignoring that it requires an implicit
conversion via `alias this` - return type and variable type clearly differ.

Aug 13 2021