If we reach a generic type that is part of a cycle
and we are in a type parameter list, we have a cycle
through a type parameter list, which is invalid.
Fixes#49439.
Change-Id: Ia6cf97e1748ca0c0e61c02841202050091365b0b
Reviewed-on: https://go-review.googlesource.com/c/go/+/361922
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
gri@ reports that types2 now correctly handles when type parameters
recursively refer back to the parameterized type, so we might as well
add tests to exercise that. Unified IR also correctly handles
importing and exporting these types, but -G=3 currently does not.
Updates #46461.
Change-Id: I272102aa08c40c980b9aeeca9f834291dfbbcc3e
Reviewed-on: https://go-review.googlesource.com/c/go/+/348738
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>