[Issue 20719] Self referential struct definition causes stack overflow

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20719

--- Comment #4 from moonlightsentinel at disroot.org ---
Without error message:

================================

struct SumType
{
    alias Types = AliasSeq!(typeof(this));
    union Storage
    {
        Types[0] t;
    }

    Storage storage;

    static if (isCopyable!(Types[0])) {}
    static if (isAssignable!(Types[0])) {}
}

alias AliasSeq(TList...) = TList;

enum isAssignable(Rhs) = __traits(compiles, lvalueOf = rvalueOf!Rhs);

struct __InoutWorkaroundStruct {}

T rvalueOf(T)();

T lvalueOf()(__InoutWorkaroundStruct);

enum isCopyable(S) = { S foo; };

=====================================

Both original and reduction cause a segfault for me.

--