solidity Visiting type class bodies in experimental analysis

Visiting type class bodies in experimental analysis

Open cameel opened this issue 10 months ago • 7 comments

~Depends on #14566.~

This adds "pass 3" as described in Experimental Type System Notes, which is responsible for collecting types of type class member functions.

I also moved builtin class registration to TypeClassRegistration, though builtin classes are going to be removed soon (we'll instead have specific class members marked as builtin).

Sep 28 '23 14:09 cameel

Based on our discussions on the call and on the chat today, here's how I understand what needs to be done in this PR next:

Keep it as a separate pass.
Create a helper for a specific use case pattern of unification for typing function applications

Unification is pretty much the most basic operation on types there is - so we should have more helpers for specific patterns involving unification, in particular for the "function application" pattern...
- E.g. a unification helper that gives you the return type of a function given its generic type and concrete argument types. Currently that usually done ad-hoc inline.
- If there are any other uses for types, they could also be separate helpers needed only in the new pass.
- The if (!m_activeInstantiations.empty()) block in TypeInference::unify() should become unnecessary after the PR and can be removed.
Visit function definitions, including the whole parameter list and return type.
- The new pass should have a copy of the type annotation (maybe use a more specific name to keep things clear).
- Anything needed to fill the type annotation of a function definition inside a type class should be moved to the new pass. For unify() use the new helpers.
- Basically everything from TypeInference::visit(TypeClassDefinition) should be moved, including the unification.
- The unification should give us a complete type, with no type variables other than the class variable (validate that).
- The back and forth visitation between type classes and the instantiation is no longer necessary.
- Also keep the current logic of visiting non-class functions in type inference.
Move all the visitation in type and sort context to the new pass
- We don't really need the distinction between type and sort context. Do it inline and remove the context mechanism.

Oct 04 '23 15:10 cameel