wrong isInputRange design

[rumbu via Digitalmars-d]

On Sunday, 4 December 2016 at 05:31:59 UTC, lobo wrote:
>
> This works for me when specialising for input ranges, strings 
> and arrays.
>
> auto f(T)(T val)
>     if(isInputRange!T && !isSomeString!T && !isArray!T) {}
>
> auto f(T)(T val)
>     if(isSomeString!T) {}
>
> auto f(T)(T val)
>     if(isArray!T && !isSomeString!T)
>
> bye,
> lobo

Yes, this is the same workaround I found, but that does not solve 
the fact that the following code does not compile:

import std.range.primitives : isInputRange;
void f(T)(T val) if (isInputRange!T)
{
   while (!val.empty) { auto c = val.front; val.popFront(); }
}

string s = "some string";
f(s);

Of course, the previous code will compile if we change the 
imports:
import std.range.primitives: isInputRange, front, popFront, empty;

But that just prove the bad design of isInputRange which cannot 
be used all alone without the rest of array UFCSs imported.