Re: template/generic instantiation of `map` warning

[pmags]

    $ nim --version
    Nim Compiler Version 1.0.2 [MacOSX: amd64]
    Compiled at 2019-10-22
    Copyright (c) 2006-2019 by Andreas Rumpf
    
    git hash: 193b3c66bbeffafaebff166d24b9866f1eaaac0e
    active boot switches: -d:release
    
    
    Run

As I noted, it compiles (and gives the right output) but gives the warning I 
described above.