isInputRange looks like this:

template isInputRange(R)
{
    enum bool isInputRange = is(typeof(
    (inout int = 0)
    {
        R r = R.init;     // can define a range object
        if (r.empty) {}   // can test for empty
        r.popFront;       // can invoke popFront()
        auto h = r.front; // can get the front of the range
    }));
}


If I change the `enum bool` line to `enum bool isInputRange = true && is(typeof(`, all is fine.
If instead I:

enum foo = true;
enum bool isInputRange = foo && is(typeof(

Then:

std/range/primitives.d(352): Error: static assert  "Cannot put a char[] into a Appender!string."
std/format.d(1877):        instantiated from here: put!(Appender!string, char[])
std/format.d(1784):        instantiated from here: formatUnsigned!(Appender!string, ulong, char)
std/format.d(1755):        instantiated from here: formatIntegral!(Appender!string, ulong, char)
std/format.d(3778):        ... (3 instantiations, -v to show) ...
std/typecons.d(421):        instantiated from here: format!(char, ulong, ulong)
std/encoding.d(3468):        instantiated from here: Tuple!(BOM, "schema", ubyte[], "sequence")


Surely they should be identical? Obviously I was trying to do something else with an enum, but this is the reduced sample.

Atila

On Wednesday, 22 March 2017 at 14:06:56 UTC, Atila Neves wrote:
> isInputRange looks like this:
>
> template isInputRange(R)
> {
>     enum bool isInputRange = is(typeof(
>     (inout int = 0)
>     {
>         R r = R.init;     // can define a range object
>         if (r.empty) {}   // can test for empty
>         r.popFront;       // can invoke popFront()
>         auto h = r.front; // can get the front of the range
>     }));
> }
>
> [...]

Got the same error when I changed it to:

enum isInputRange(R) = is(typeof({...}));

Which might explain why it's still inside an explicit template declaration. Or not, this whole thing is weird to me.

Atila