Error: template cannot deduce function from argument types.

[anonymous via Digitalmars-d-learn]

On Sunday, 24 August 2014 at 02:53:41 UTC, Damian Day wrote:
> Hi, I've been trying to reduce a bug in the containers (8824).
>
> From the example below it seems the dup method is passing the 
> constructor
> an array of dchars and the template is failing.
>
> Is this a compiler bug, or ?
>
> import std.range, std.traits;
>
> struct Array2(T)
> {
>     private T[] _payload;
>
>     size_t insertAt(R)(size_t index, R rng)
>         if (isInputRange!R && 
> isImplicitlyConvertible!(ElementType!R, T))
>     {
>         return 0;
>     }
>
>     this(U)(U[] values...)
>         if (isImplicitlyConvertible!(U, T))
>     {
>         insertAt(0, values);
>     }
>
>     @property Array2 dup()
>     {
>         return Array2(_payload);
>     }
> }
>
> unittest
> {
>     Array2!int a; //passes
>     Array2!char a; //fails
> }

Not a compiler bug. char[] (and wchar[]) as ranges auto-decode to
dchars. I.e. ElementType!(char[]) is dchar. And dchar isn't
implicitly convertible to char. So the instantiation of insertAt
fails.