[Issue 11704] New: std.conv.to fails from string to std.typecons.Typedef

[d-bugmail at puremagic.com]

https://d.puremagic.com/issues/show_bug.cgi?id=11704

           Summary: std.conv.to fails from string to std.typecons.Typedef
           Product: D
           Version: D2
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Keywords: rejects-valid
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: nobody at puremagic.com
        ReportedBy: bearophile_hugs at eml.cc


--- Comment #0 from bearophile_hugs at eml.cc 2013-12-07 07:09:15 PST ---
void main() {
    import std.typecons: Typedef;
    import std.conv: to;
    alias T = Typedef!int;
    string x = "5";
    T y = to!T(x);
}



dmd 2.065alpha gives:

...\dmd2\src\phobos\std\conv.d(281): Error: template std.conv.toImpl does not
match any function template declaration. Candidates are:
...\dmd2\src\phobos\std\conv.d(346):        std.conv.toImpl(T, S)(S value) if
(isImplicitlyConvertible!(S, T) && !isEnumStrToStr!(S, T) && !isNullToStr!(S,
T))
...\dmd2\src\phobos\std\conv.d(458):        std.conv.toImpl(T, S)(ref S s) if
(isRawStaticArray!S)
...\dmd2\src\phobos\std\conv.d(474):        std.conv.toImpl(T, S)(S value) if
(!isImplicitlyConvertible!(S, T) && is(typeof(S.init.opCast!T()) : T) &&
!isExactSomeString!T)
...\dmd2\src\phobos\std\conv.d(506):        std.conv.toImpl(T, S)(S value) if
(!isImplicitlyConvertible!(S, T) && is(T == struct) && is(typeof(T(value))))
...\dmd2\src\phobos\std\conv.d(556):        std.conv.toImpl(T, S)(S value) if
(!isImplicitlyConvertible!(S, T) && is(T == class) && is(typeof(new T(value))))
...\dmd2\src\phobos\std\conv.d(281):        ... (16 more, -v to show) ...
...\dmd2\src\phobos\std\conv.d(281): Error: template std.conv.toImpl(T, S)(S
value) if (isImplicitlyConvertible!(S, T) && !isEnumStrToStr!(S, T) &&
!isNullToStr!(S, T)) cannot deduce template function from argument types
!(Typedef!(int, 0))(string)
temp.d(6): Error: template instance std.conv.to!(Typedef!(int, 0)).to!(string)
error instantiating


A workaround:

T y = T(to!int(x));

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