`codeFact` returns `nil, err` on errors, which results in error messages like:
panic: internal error: encoding of nil fact failed in [analyzer]
Though that and the stacktrace are often enough to identify the cause, the nil
hides the actual source of the problem.
Change-Id: Iddcdee386a5c64c6567d2727ebe7a77fe21927e9
GitHub-Last-Rev: 92163c2a5a631817319c992f7445f86d95130514
GitHub-Pull-Request: golang/tools#78
Reviewed-on: https://go-review.googlesource.com/c/tools/+/167997
Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>