Compiler code related to finding type arguments associated with a generic type
was breaking when the type arguments were hidden behind a type alias.
The right fix would be to dig through arbitrary layers of type aliases
to find the appropriate type argument source location, but this fix
takes the lazy way out and just makes the compiler error messages
slightly less useful in this case by not having the source location
of the type argument (but still showing enough information to
understand the issue and debug the problem).
Maybe we'll fix this in a nicer way after the later overhaul of
type inference and type checking.
Compiler code related to finding type arguments associated with a generic type was breaking when the type arguments were hidden behind a type alias.
The right fix would be to dig through arbitrary layers of type aliases to find the appropriate type argument source location, but this fix takes the lazy way out and just makes the compiler error messages slightly less useful in this case by not having the source location of the type argument (but still showing enough information to understand the issue and debug the problem).
Maybe we'll fix this in a nicer way after the later overhaul of type inference and type checking.