b4acbe4233
Assert that args are actually compatible with their generics, rather than just their count Right now we just check that the number of args is right, rather than actually checking the kinds. Uplift a helper fn that I wrote from trait selection to do just that. Found a couple bugs along the way. r? `@lcnr` or `@fmease` (or anyone really lol)
For high-level intro to how type checking works in rustc, see the type checking chapter of the rustc dev guide.