go/types: when type hashing, use placeholders for type parameters
Type parameter names don't matter for the purposes of generic type
identity, so mask them with numeric placeholders when hashing.
Change-Id: Iacb4c23abecdd733fc292ae13ecac6baa2c5524c
Reviewed-on: https://go-review.googlesource.com/c/go/+/363114
Trust: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>