Type inference for TypeClassLang

Type inference for TypeClassLang must perform ordinary type inference and further resolve overloading. We can pursue either a traditional approach or a constraint-based approach like PureLang's current type inference. Either way, inference must annotate untyped TypeClassLang programs to produce typed ones, and this annotation must be sound with respect to TypeClassLang's elaboration rules.

Start by reading TypeClassLang's elaboration rules and PureLang's current type inference, which the issue identifies as the possible constraint-based model. Compare a traditional approach with that model before choosing a design. Done means untyped TypeClassLang programs are annotated with typed ones and the annotations are sound with respect to elaboration.

Written by the indexing model from the issue text.