commit 4517aacf2fa6888d9d4f8e75e308f19b33271001
author brettw <brettw@chromium.org> Tue Aug 09 16:43:55 2016 -0700
committer Commit bot <commit-bot@chromium.org> Tue Aug 09 23:45:41 2016 +0000
tree 16266618ee3cde0c0c0a2f0a13484a4e822979a6
parent 2265f3540cd880466a506fce7cad5aa8fe01cd70

GN: Throw an error overwriting a nonempty scope.

Previously GN would throw an error if you assigned a nonempty list to another
nonempty list. This is easy to mess up when you actually meant to append.
However, it did not have this protection for "scope"-type values.

Adds such protection to scope-type values, and add unit tests for both
behaviors.

Does some unit test cleanup for the operators unit tests to make them easier to
write.

BUG=

Review-Url: https://codereview.chromium.org/2224343003
Cr-Original-Commit-Position: refs/heads/master@{#410874}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 56350de24ed370f955b299022e93229f8643ace8