Generic assumeUnique

[Per Nordlöw]

On Thursday, 5 May 2022 at 12:32:07 UTC, Dennis wrote:
> What non-array type do you want to use `assumeUnique` on and 
> why don't you `cast(immutable)`?

http://mir-algorithm.libmir.org/mir_string_map.html

I _can_ use `cast(immutable)` but that needs to be qualified as 
@trusted.

`StringMap` is implemented using three pointers fields and one 
length field and is a hybrid between a normal array and an 
associative array.