go/types, types2: cleanup of code handling type switch cases
Move logic for type-specific variable type into typeCases function
which already does all the relevant work.
Add more detailed documentation to typeCases function.
Uncomment alernative typeCases function so that it is being type-
checked and kept up-to-date. Since it's not (yet) used, the code
will not appear in the binary.
Follow-up on CL 592555.
Change-Id: I6e746503827d512a1dbf7b99b48345c480e61200
Reviewed-on: https://go-review.googlesource.com/c/go/+/592616
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Robert Findley <rfindley@google.com> Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>