We've recently started instantiating methods on instantiated types, to simplify their API. However, this introduces an infinite recursion in cases like this:

package p
type List[P any] struct{}
func (_ List[P]) m() (_ List[List[P]]) { return }

This is similar to #48098, but will require a different fix; we need to allow these types of methods to be written.

I think there is a straightforward fix: we already have a lazy resolution mechanism for Named types, and can use it to expand methods lazily the first time they are accessed (see also #47910). We just need to allow types to escape the type-checking pass with their methods unexpanded, which is a bit subtle.

CC @griesemer