Hello.

I am using dmd 2.094.1 on linux for compiling a piece code I found on the github. Unfortunately linker can't link it as it can't find opCall symbol instantiation demangled as:

pure nothrow @nogc @safe bool app.IsEqual!(char).IsEqual.opCall(in char, in char)

Do you have any ideas on:

1. Why compiler searches for such function attributes - pure nothrow @nogc @safe, as I don't specify them. Is this a bug or feature?)

2. What changes are needed to compile this rather simple example.


Please, help me!


Reference to my piece of code in app.d:

struct IsEqual(T)
{
    static bool opCall( in T p1, in T p2 )
    {
        return p1 == p2;
    }
}


size_t find(T, Pred = IsEqual!(T))
    (in T[] haystack, in T needle, Pred pred = Pred.init)
{
    foreach ( pos, cur; haystack )
    {
        if( pred( cur, needle ) )
            return pos;
    }
    return haystack.length;
}


int main(string[] args)
{
    auto pos = find("abc" , 'b');
    assert(pos == 1);

    return 0;
}


Linker error message:

Linking...
/usr/bin/ld: .dub/build/application-debug-linux.posix-x86_64-dmd_2094-BD99179F1B52B13DDA1C2B0172F5081E/app.bin.o: in function `_D3app__T4findTaTSQq__T7IsEqualTaZQlZQBcFNaNbNiNfIAaIaQBlZm':
source/app.d:15: undefined reference to `_D3app__T7IsEqualTaZQl6opCallFNaNbNiNfIaIaZb'
collect2: error: ld returned 1 exit status


ddemangle output on these symbols:

_D3app__T7IsEqualTaZQl6opCallFNaNbNiNfIaIaZb
pure nothrow @nogc @safe bool app.IsEqual!(char).IsEqual.opCall(in char, in char)

_D3app__T4findTaTSQq__T7IsEqualTaZQlZQBcFNaNbNiNfIAaIaQBlZm
pure nothrow @nogc @safe ulong app.find!(char, app.IsEqual!(char).IsEqual).find(in char[], in char, app.IsEqual!(char).IsEqual)


Thanks you!

On 3/11/21 8:41 AM, Iliya wrote:

> I am using dmd 2.094.1 on linux

Your program links fine for me with 2.094.2 on Linux.

Ali

On Thursday, 11 March 2021 at 17:25:35 UTC, Ali Çehreli wrote:
> On 3/11/21 8:41 AM, Iliya wrote:
>
> > I am using dmd 2.094.1 on linux
>
> Your program links fine for me with 2.094.2 on Linux.
>
> Ali

Thank you, Ali!

I also played with it on playground. Seems that it is a bug.
The compilation results:

Up to      2.093.1: Success and no output
Since      2.094.1: Failure with output:
-----
onlineapp.o: In function `_D9onlineapp__T4findTaTSQw__T7IsEqualTaZQlZQBcFNaNbNiNfIAaIaQBlZm':
/sandbox/onlineapp.d:15: undefined reference to `_D9onlineapp__T7IsEqualTaZQl6opCallFNaNbNiNfIaIaZb'
collect2: error: ld returned 1 exit status
Error: linker exited with status 1
-----

Try it with:

-allinst

It may just be deciding a template instance isn't required.

On Thursday, 11 March 2021 at 17:41:27 UTC, rikki cattermole wrote:
> Try it with:
>
> -allinst
>
> It may just be deciding a template instance isn't required.

Good workaround for such kind of bugs! )

Up to      2.063  : Failure with output: Error: unrecognized switch '-allinst'
Since      2.064  : Success and no output

On Thursday, 11 March 2021 at 17:41:27 UTC, rikki cattermole wrote:
> Try it with:
>
> -allinst
>
> It may just be deciding a template instance isn't required.

The error message could maybe be changed to include this? "Try -allinst bla bla"