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

Ben <ben.james.jones@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Self struct definition      |Self referential struct
                   |causes stack overflow       |definition causes stack
                   |                            |overflow

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

--- Comment #1 from Ben <ben.james.jones@gmail.com> ---
Reduced test case:

import std.meta : AliasSeq;
import std.typecons : ReplaceTypeUnless;
import std.traits : isCopyable, isAssignable;

struct This; //defined in std.variant this way

struct SumType(TypeArgs)
{
  alias Types = AliasSeq!(ReplaceTypeUnless!(isSumType, This, typeof(this),
TypeArgs));
  union Storage
  {
    template memberName(T)
    {
      mixin("enum memberName = `values_", "`;");
    }

    static foreach (T; Types)
      mixin("T ", memberName!T, ";");
  }

  Storage storage;

  static foreach (T; Types) static if (isCopyable!T){}
  static foreach (T; Types) static if (isAssignable!T){}
}

enum isSumType(T) = is(Args);
struct B {
  SumType!(This)elems;
}

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

moonlightsentinel@disroot.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |moonlightsentinel@disroot.o
                   |                            |rg

--- Comment #2 from moonlightsentinel@disroot.org ---
Maybe related reduction from dustmite:

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

alias AliasSeq(TList...) = TList;

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


struct SumType
{
    alias Types = AliasSeq!(typeof(this));

    Types[0] t;

    alias cp = isCopyable!(Types[0]);
}

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

This also segfaults but prints

test.d(6): Error: struct test.SumType cannot have field t with same struct type

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

--- Comment #3 from Ben <ben.james.jones@gmail.com> ---
Not sure it's the same bug since mine triggers a stack overflow with no diagnostics.  Here's the dustmite script I used to reduce:

#!/bin/sh

# arguments to dmd
DMDARGS="test20719.d"

OUTPUT=$(lldb --batch -o "run $DMDARGS" -k 'bt 30' -k 'quit' -o 'quit' dmd
2>&1)
#echo $OUTPUT
echo "$OUTPUT" | egrep -q
"_D3dmd4func15FuncDeclaration14isTypeIsolatedMFCQBt5mtype4TypeZb"
exit $?

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

--- Comment #4 from moonlightsentinel@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.

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

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull

--- Comment #5 from Dlang Bot <dlang-bot@dlang.rocks> ---
@benjones created dlang/dmd pull request #11083 "fix issue 20719 by passing previously seen structs to isTypeIsolated …" fixing this issue:

- fix issue 20719 by passing previously seen structs to isTypeIsolated recursive calls

https://github.com/dlang/dmd/pull/11083

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

Dlang Bot <dlang-bot@dlang.rocks> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #6 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/dmd pull request #11083 "fix issue 20719 by passing previously seen structs to isTypeIsolated …" was merged into master:

- 9fa18aa20a9975b2c5673522a4761a564c8b067b by Ben Jones:
  fix issue 20719 by passing previously seen structs to isTypeIsolated
recursive calls

https://github.com/dlang/dmd/pull/11083

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