Bug?

[Jack Applegame]

On Monday, 11 May 2020 at 12:30:22 UTC, Adam D. Ruppe wrote:
> UFCS is only defined to work with global scope functions. A 
> restricted import (module : symbol, symbols) puts things in 
> local scope so ufcs doesn't apply.

But in this case the error should be displayed for lines 4 and 5, 
not 11.
Line 11 contains a call to a member function, not UFCS.

In addition, if you add the parentheses, then it works:
assert(rng.front() == '1');