I'm not sure if it's the same as #15064 bug:

import std.array, std.range, std.algorithm;

  immutable static foo = ["a", "b", "c"];
  auto bar(R)(R r)
  {
      string s = r[1];
      return s;
  }
  immutable static res = foo.enumerate.map!bar().array;

std/typecons.d(526): Error: reinterpreting cast from inout(ulong)* to inout(Tuple!(ulong, immutable(string)))* is not supported in CTFE
bug.d(9):        called from here: r._Tuple_super()
std/algorithm/iteration.d(593):        called from here: bar(this._input.front())
std/array.d(105):        called from here: __r2091.front()
bug.d(15):        called from here: array(map(enumerate(foo, 0LU)))

---
Paolo

On Monday, 21 November 2016 at 13:22:57 UTC, Paolo Invernizzi wrote:
> I'm not sure if it's the same as #15064 bug:
>
> import std.array, std.range, std.algorithm;
>
>   immutable static foo = ["a", "b", "c"];
>   auto bar(R)(R r)
>   {
>       string s = r[1];
>       return s;
>   }
>   immutable static res = foo.enumerate.map!bar().array;
>
> std/typecons.d(526): Error: reinterpreting cast from inout(ulong)* to inout(Tuple!(ulong, immutable(string)))* is not supported in CTFE
> bug.d(9):        called from here: r._Tuple_super()
> std/algorithm/iteration.d(593):        called from here: bar(this._input.front())
> std/array.d(105):        called from here: __r2091.front()
> bug.d(15):        called from here: array(map(enumerate(foo, 0LU)))
>
> ---
> Paolo

Yes looks like it.
Adding a special case in phobos should solve the problem.