https://issues.dlang.org/show_bug.cgi?id=5730

Kenji Hara <k.hara.pg@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Hardware|Other                       |All
                 OS|Linux                       |All

--- Comment #5 from Kenji Hara <k.hara.pg@gmail.com> ---
(In reply to Max Samukha from comment #2)
> No, no. The bug is not about the impossibility to build a closure. It is about __traits(compiles) not handling the compilation error properly. It should suppress the error and evaluate to false.

Today, a delegate literal in __traits(compiles) does not make the outer function closure, because the delegate is just a thing only in compile time.

I'd provide better example code:

struct S
{
    ~this() {}
}

void main()
{
    enum r = __traits(compiles, {
        auto madeClosure()
        {
            S s;
            auto dg = { auto s1 = s; };
            return dg;
        }
    });
    static assert(!r);  // line 1
}

The madeClosure function will be made a closure, because the dg that refers local variable s will escape from that. Then the "has scoped destruction..." error needs to be captured by the __traits(compile) and r should be false.

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https://issues.dlang.org/show_bug.cgi?id=5730

RazvanN <razvan.nitu1305@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|REOPENED                    |RESOLVED
                 CC|                            |razvan.nitu1305@gmail.com
         Resolution|---                         |FIXED

--- Comment #6 from RazvanN <razvan.nitu1305@gmail.com> ---
Today this code compiles succesfully and prints "destructor":

struct S
{
    ~this()
    {
        import std.stdio;
        writeln("destructor");
    }
}

void main()
{
    S s;
    enum error = __traits(compiles, { auto s1 = s; });
    //static assert(!error); // line 1
}

It seems that the compiler is able to allocate the closure and also track it with the gc.

Closing as fixed.

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https://issues.dlang.org/show_bug.cgi?id=5730

Iain Buclaw <ibuclaw@gdcproject.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
                 CC|                            |ibuclaw@gdcproject.org
         Resolution|FIXED                       |---

--- Comment #7 from Iain Buclaw <ibuclaw@gdcproject.org> ---
Related test still fails though.

struct S10666
{
    int val;
    ~this() {}
}


void foo10666(S10666 s1)
{
    // Error: s1 has scoped destruction, cannot build closure.
    auto f1 = (){ return () => s1.val; }();

    enum r1 = __traits(compiles, {
        auto f1 = (){ return () => s1.val; }();
    });
    static assert(!r1); // Error: static assert:  `!r1` is false
}

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https://issues.dlang.org/show_bug.cgi?id=5730

Iain Buclaw <ibuclaw@gdcproject.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P2                          |P3

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