go/types, types2: missing type due to delayed type-type inference

[findleyr]

This is a follow-up on #51233: in type declarations, it is possible to substitute for type arguments before they are fully resolved.

While investigating this afternoon I was able to construct another crasher:
https://go.dev/play/p/V5Jl7-WDV4K?v=gotip

This may be complicated, but the mechanism is simple: force an expansion of T before R[int] is resolved. In this case, this is forced by the call to var x = T[int]{}.F. We currently lack controls to ensure that inference happens before substitution. I am not sure whether it is trivial to introduce such a mechanism.

CC @griesemer

[gopherbot]

Change https://go.dev/cl/390040 mentions this issue: go/types: add a check to detect invalid substitution for inferred types

[findleyr]

In #51527 we have disabled type-type inference for 1.18, so this can be moved to 1.19.