cue/load: check some errors that were ignored
Claude pointed out that these error returns were ignored.
Fixing them pointed out some errors in our own tests,
which we fix.
Signed-off-by: Roger Peppe <rogpeppe@gmail.com>
Change-Id: I662ea83dec665523f98a9de869bb6a5afe24cab4
Reviewed-on: https://cue.gerrithub.io/c/cue-lang/cue/+/1232172
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: CUEcueckoo <cueckoo@cuelang.org>
Unity-Result: CUE porcuepine <cue.porcuepine@gmail.com>