Today I learned [0] that opDollar must be explicitly implemented
and might not be available by some ranges. Likewise slicing. If
you think it further, there are lots of functions in Phobos (I'm
currently looking into std.algorithm.searching) which use more
features than they check capabilities for. Ranges which satisfy
isRandomAccessRange do not automatically satisfy hasSlicing.
Can we provide opSlice and opDollar implicitly for random access
ranges?
Alternatively, we should comb through Phobos to fix the
capability checks and write unittests with minimalistic ranges.
I already filed issue 16073 [1], but then realized it does not go
far enough.
Also, std.range.primitives should have a predicate for opDollar
similar to hasSlicing.
[0] https://github.com/dlang/phobos/pull/4362#discussion_r64576690
[1] https://issues.dlang.org/show_bug.cgi?id=16073
