https://issues.dlang.org/show_bug.cgi?id=20149
--- Comment #2 from Mike Franklin <slavo5...@yahoo.com> --- Interestingly removing the `inout` attribution on `opSlice` causes the compiler to emit an error at the return statement in `fun`. I think the error should instead be emitted at the return statement of `opSlice`, but at least it doesn't compile. --