schveiguy/io

Sockets can't be moved

schveiguy opened this issue · 3 comments

schveiguy commented

With dmd 2.083.0, I can't move a Socket using std.algorithm.move. I think this is a compiler bug, but I'm not sure why this fails.

I can call Socket.move no problem, but I can't call std.algorithm.move(Socket).

I can easily duplicate the problem in a small test case with:

import std.algorithm : move;

struct S
{
    int x;
    S foo() return nothrow @nogc pure { return S(x); }
    this(this) @disable;
}

void main()
{
    S s(2);
    auto s2 = s.foo; // ok
    auto s3 = move(s); // errors
}

Here are the errors (I removed some trivial path info):

std/algorithm/mutation.d(1232): Error: struct `testmove.S` is not copyable because it is annotated with @disable
std/algorithm/mutation.d(1225): Error: template instance `std.algorithm.mutation.moveImpl!(S)` error instantiating
std/algorithm/mutation.d(1183):        instantiated from here: trustedMoveImpl!(S)

The really odd thing is that the a member function MUST BE THERE, and it MUST have return attribute on it.

I will file an equivalent bug in bugzilla with this test case.

schveiguy commented

Update: it has nothing to do with std.algorithm.move, it's a compiler bug.

Reduced test case:

struct S
{ 
    int x;
    S foo() return { return S(x); }
    this(this) @disable;
}

auto bar()
{
    S s;
    return s; // Error: S is not copyable
}

Without the foo member, it works.

MartinNowak commented

Should be fixed with the upcoming v2.084.0-beta.1.