go/types: fix errors in recording type information
In my previous change, I didn't use the correct functions for continuing
to record type informations after errors. Change to using the correct
functions, and add a comment to clarify in expr.go.
Updates #22467
Change-Id: I66ebb636ceb2b994db652343430f0551db0050c3
Reviewed-on: https://go-review.googlesource.com/128835
Run-TryBot: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>