go/types, types2: use "undefined type" rather than "<T>" in have/want error messages
In assignments and return statements, if we have the wrong number
of LHS or return values, we report the pattern that we have and
the pattern that we want. For untyped constants we use "number"
(to be not overly specific). For unknown types (due to earlier
errors), now use "unknown type" rather than the (cryptic) "<T>".
Fixes #58742.
Change-Id: I69c84ee29fb64badb0121e26a96f003b381024aa
Reviewed-on: https://go-review.googlesource.com/c/go/+/473255 Reviewed-by: Ian Lance Taylor <iant@google.com> Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Griesemer <gri@google.com>
Run-TryBot: Robert Griesemer <gri@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>