Agressively mark all LHS variables in assignments as used if there
is any error in the (entire) assignment. This reduces the number of
spurious "declared but not used" errors in programs that are invalid
in the first place. This behavior is closer to the behavior of the
compiler's original type checker (types1) and lets us remove lines
of the form "_ = variable" just to satisfy test cases. It also makes
more important errors visible by not crowding them out.
Remove the Checker.useLHS function and use Checker.use instead:
useLHS didn't evaluate top-level variables, but we actually want
them to be evaluated in an error scenario so that they are getting
used (and thus we don't get the "declared but not used" error).
Fixes#42937.
Change-Id: Idda460f6b81c66735bf9fd597c54188949bf12b8
Reviewed-on: https://go-review.googlesource.com/c/go/+/351730
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
With this CL, the first ~500 errorcheck tests pass when running
go run run.go -v -G
in the $GOROOT/test directory (the log output includes a few dozen
tests that are currently skipped).
Change-Id: I9eaa2319fb39a090df54f8699ddc29ffe58b1bf1
Reviewed-on: https://go-review.googlesource.com/c/go/+/274975
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
I haven't looked at the source, but the gc compiler appears to
omit "not used" errors when there is an error in the
initializer. This is harder to do in gccgo, and frankly I
think the "not used" error is still useful even if the
initializer has a problem. This CL tweaks some tests to avoid
the error, which is not the point of these tests in any case.
R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5561059
