The code


auto asStatic(T, size_t length)(T[length] arr)
{
    return arr;
}

@safe pure nothrow @nogc unittest
{
    auto x = [1, 2, 3].asStatic;
    static assert(is(typeof(x) == int[x.length]));
    static assert(is(typeof([1, 2, 3].asStatic) == int[x.length]));
}


now fails on Git master (after DIP-1000 has been merged) as


array_ex.d(55,6): Error: parameter arr is 'return' but function does not return any indirections
array_ex.d(63,23): Error: template instance array_ex.asStatic!(int, 3LU) error instantiating
array_ex.d(64,5): Error: static assert  (is(typeof(x) == int[x.length])) is false


I tried qualifying argument with `return ref` as described at

https://wiki.dlang.org/DIP25

but that fails because parameter must be allowed to be an r-value aswell.

Any clues?

On Sunday, 1 January 2017 at 17:41:46 UTC, Nordlöw wrote:
> The code
>
>
> auto asStatic(T, size_t length)(T[length] arr)
> {
>     return arr;
> }
>
> @safe pure nothrow @nogc unittest
> {
>     auto x = [1, 2, 3].asStatic;
>     static assert(is(typeof(x) == int[x.length]));
>     static assert(is(typeof([1, 2, 3].asStatic) == int[x.length]));
> }
>
>
> now fails on Git master (after DIP-1000 has been merged) as
>
>
> array_ex.d(55,6): Error: parameter arr is 'return' but function does not return any indirections
> array_ex.d(63,23): Error: template instance array_ex.asStatic!(int, 3LU) error instantiating
> array_ex.d(64,5): Error: static assert  (is(typeof(x) == int[x.length])) is false
>
>
> I tried qualifying argument with `return ref` as described at
>
> https://wiki.dlang.org/DIP25
>
> but that fails because parameter must be allowed to be an r-value aswell.
>
> Any clues?


Try:
 auto asStatic(T, size_t length)(scope T[length] arr)
 {
     return arr;
 }

On Sunday, 1 January 2017 at 18:00:54 UTC, Stefan Koch wrote:
> Try:
>  auto asStatic(T, size_t length)(scope T[length] arr)
>  {
>      return arr;
>  }

Fails as

array_ex.d(72,10): Error: parameter arr is 'return' but function does not return any indirections
array_ex.d(80,27): Error: template instance array_ex.asStatic!(int, 3LU) error instantiating
array_ex.d(81,9): Error: static assert  (is(typeof(x) == int[x.length])) is false

On Sunday, 1 January 2017 at 17:41:46 UTC, Nordlöw wrote:
> now fails on Git master (after DIP-1000 has been merged) as

When compiled with `-transition=safe`, that is.

On Sunday, 1 January 2017 at 18:00:54 UTC, Stefan Koch wrote:

> Try:
>  auto asStatic(T, size_t length)(scope T[length] arr)
>  {
>      return arr;
>  }

I've tried as many combinations of `return` and `scope` as I can think of such as

    T[length] asStatic(T, size_t length)(return scope T[length] arr)
    {
        return arr;
    }

but all complain about the same thing

Error: parameter arr is 'return' but function does not return any indirections

It seems like compiler incorrectly infers that `arr` must be `return` despite it doesn't have any indirections (because it's a static array).

Walter?

On Monday, 2 January 2017 at 14:38:53 UTC, Nordlöw wrote:
> I've tried as many combinations of `return` and `scope` as I can think of such as

Update:

Qualifying `asStatic` with `@safe pure nothrow @nogc` as

T[length] asStatic(T, size_t length)(T[length] arr)
    @safe pure nothrow @nogc
{
    return arr;
}

makes

@safe pure nothrow @nogc unittest
{
    auto x = [1, 2, 3].asStatic;
    static assert(is(typeof(x) == int[x.length]));
    static assert(is(typeof([1, 2, 3].asStatic) == int[x.length]));
}

compile. Also

T[length] asStatic(T, size_t length)(scope T[length] arr)
    @safe pure nothrow @nogc
{
    return arr;
}

works. Is with or without `scope` preferred here?

Seems to be some problem with template qualifier inference. Should I file a bug report?

On Monday, 2 January 2017 at 15:28:57 UTC, Nordlöw wrote:

> Should I file a bug report?

Yes please