https://issues.dlang.org/show_bug.cgi?id=20848

Victor Porton <porton@narod.ru> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Bug in Nullable?            |Bug in Nullable

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https://issues.dlang.org/show_bug.cgi?id=20848

--- Comment #1 from Victor Porton <porton@narod.ru> ---
A simpler test case:

///////////////////////////////
import std.typecons;

struct MoFile {
    immutable(void)[] data;
}

Nullable!MoFile mo;
///////////////////////////////

$ dmd test.d
/snap/dmd/102/bin/../import/phobos/std/format.d(3217): Error: static assert:
"immutable(void)[] must be an InputRange"
/snap/dmd/102/bin/../import/phobos/std/format.d(1875):        instantiated from
here: formatValueImpl!(Appender!string, immutable(void)[], char)
/snap/dmd/102/bin/../import/phobos/std/format.d(3749):        instantiated from
here: formatValue!(Appender!string, immutable(void)[], char)
/snap/dmd/102/bin/../import/phobos/std/format.d(4451):        instantiated from
here: formatElement!(Appender!string, immutable(void)[], char)
/snap/dmd/102/bin/../import/phobos/std/format.d(1875):        ... (2
instantiations, -v to show) ...
/snap/dmd/102/bin/../import/phobos/std/typecons.d(2791):        instantiated
from here: toString!(Appender!string)
test.d(7):        instantiated from here: Nullable!(MoFile)

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https://issues.dlang.org/show_bug.cgi?id=20848

--- Comment #2 from Victor Porton <porton@narod.ru> ---
The error is here (format.d from phobos):

private void formatValueImpl(Writer, T, Char)(auto ref Writer w, T obj, scope
const ref FormatSpec!Char f)
if (is(DynamicArrayTypeOf!T) && !is(StringTypeOf!T) && !is(T == enum) &&
!hasToString!(T, Char))
{
    static if (is(const(ArrayTypeOf!T) == const(void[])))
    {
        formatValueImpl(w, cast(const ubyte[]) obj, f);
    }
    else static if (!isInputRange!T)
    {
        alias U = Unqual!(ArrayTypeOf!T);
        static assert(isInputRange!U, U.stringof ~ " must be an InputRange");
        U val = obj;
        formatValueImpl(w, val, f);
    }
    else
    {
        formatRange(w, obj, f);
    }
}

In the above code the type immutable(void)[] is forgotten to be considered.
Somebody, please fix it.

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https://issues.dlang.org/show_bug.cgi?id=20848

Victor Porton <porton@narod.ru> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|Bug in Nullable             |Bug in formatValueImpl

--

https://issues.dlang.org/show_bug.cgi?id=20848

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

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

--- Comment #3 from Dlang Bot <dlang-bot@dlang.rocks> ---
@quickfur created dlang/phobos pull request #7556 "Fix issue 20848: format should work with immutable(void)[]" fixing this issue:

- Fix issue 20848: format should work with immutable(void)[]

  The bug is that if `T == immutable(void)[]`, then `const(T)` does not
  collapse to `const(void[])`, but is actually `const(immutable(void)[])`.
  So a strict type equality check will fail.

  However, `const(T)` *is* implicitly convertible to `const(void[])`,
  which serves our purpose just as well. So just use that check instead.

https://github.com/dlang/phobos/pull/7556

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https://issues.dlang.org/show_bug.cgi?id=20848

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

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

--- Comment #4 from Dlang Bot <dlang-bot@dlang.rocks> ---
dlang/phobos pull request #7556 "Fix issue 20848: format should work with immutable(void)[]" was merged into master:

- 7cc61dda2ce197c44fbb6d505f31d81e654f5054 by H. S. Teoh:
  Fix issue 20848: format should work with immutable(void)[]

  The bug is that if `T == immutable(void)[]`, then `const(T)` does not
  collapse to `const(void[])`, but is actually `const(immutable(void)[])`.
  So a strict type equality check will fail.

  However, `const(T)` *is* implicitly convertible to `const(void[])`,
  which serves our purpose just as well. So just use that check instead.

https://github.com/dlang/phobos/pull/7556

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