I'm handwaving a bit here, but if it's possible to defer checking templates until they're actually instantiated (as a CXXTemplateSpecializationDecl, I think?), I think that will help us achieve the right behavior: I'm hoping we would be able to use things like hasTrivialDestructor() to determine whether or not a templated type can be treated as trivial.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9d17488d4ed2bfecab3d6e723881e1d9cedfb90a

commit 9d17488d4ed2bfecab3d6e723881e1d9cedfb90a
Author: palmer <palmer@chromium.org>
Date: Tue Nov 08 23:54:58 2016

Treat atomic_int as a trivial class member when checking for non-trivial classes.

This is a quick hack to unblock work on
https://codereview.chromium.org/2484803003. The real fix will be to check the
class after template instantiation.

BUG=663463

Review-Url: https://codereview.chromium.org/2483973003
Cr-Commit-Position: refs/heads/master@{#430773}

[modify] https://crrev.com/9d17488d4ed2bfecab3d6e723881e1d9cedfb90a/tools/clang/plugins/FindBadConstructsConsumer.cpp
[add] https://crrev.com/9d17488d4ed2bfecab3d6e723881e1d9cedfb90a/tools/clang/plugins/tests/trivial_ctor.cpp
[add] https://crrev.com/9d17488d4ed2bfecab3d6e723881e1d9cedfb90a/tools/clang/plugins/tests/trivial_ctor.h
[modify] https://crrev.com/9d17488d4ed2bfecab3d6e723881e1d9cedfb90a/tools/clang/plugins/tests/virtual_bodies.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/11cb6892af5990d0e4430a8624d5643a1d658d46

commit 11cb6892af5990d0e4430a8624d5643a1d658d46
Author: thakis <thakis@chromium.org>
Date: Wed Nov 09 15:05:29 2016

Revert of Treat std::atomic_int as a trivial class member when checking for non-trivial classes. (patchset #2 id:20001 of https://codereview.chromium.org/2483973003/ )

Reason for revert:
This broke all clang tot bots, e.g. here:

https://build.chromium.org/p/chromium.fyi/builders/ClangToTLinux%20%28dbg%29/builds/4709/steps/gclient%20runhooks/logs/stdio

Testing trivial_ctor.cpp... failed: no expected file found
...
Ran 18 tests: 17 succeeded, 1 failed
    trivial_ctor

Original issue's description:
> Treat atomic_int as a trivial class member when checking for non-trivial classes.
>
> This is a quick hack to unblock work on
> https://codereview.chromium.org/2484803003. The real fix will be to check the
> class after template instantiation.
>
> BUG=663463
>
> Committed: https://crrev.com/9d17488d4ed2bfecab3d6e723881e1d9cedfb90a
> Cr-Commit-Position: refs/heads/master@{#430773}

TBR=dcheng@chromium.org,erg@chromium.org,palmer@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=663463

Review-Url: https://codereview.chromium.org/2491523002
Cr-Commit-Position: refs/heads/master@{#430930}

[modify] https://crrev.com/11cb6892af5990d0e4430a8624d5643a1d658d46/tools/clang/plugins/FindBadConstructsConsumer.cpp
[delete] https://crrev.com/4e2a6810fd84198ce9d8062d69393076b48a91e9/tools/clang/plugins/tests/trivial_ctor.cpp
[delete] https://crrev.com/4e2a6810fd84198ce9d8062d69393076b48a91e9/tools/clang/plugins/tests/trivial_ctor.h
[modify] https://crrev.com/11cb6892af5990d0e4430a8624d5643a1d658d46/tools/clang/plugins/tests/virtual_bodies.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/59b560a688614d2d283ff12f8b36e2fc29d92932

commit 59b560a688614d2d283ff12f8b36e2fc29d92932
Author: palmer <palmer@chromium.org>
Date: Fri Nov 11 01:47:28 2016

Improved check for trivial templates.

This is a follow-up to/fix for https://codereview.chromium.org/2483973003 (Treat
std::atomic_int as a trivial class member when checking for non-trivial
classes.).

BUG=663463

Review-Url: https://codereview.chromium.org/2490473007
Cr-Commit-Position: refs/heads/master@{#431450}

[modify] https://crrev.com/59b560a688614d2d283ff12f8b36e2fc29d92932/tools/clang/plugins/FindBadConstructsConsumer.cpp
[add] https://crrev.com/59b560a688614d2d283ff12f8b36e2fc29d92932/tools/clang/plugins/tests/trivial_ctor.cpp
[add] https://crrev.com/59b560a688614d2d283ff12f8b36e2fc29d92932/tools/clang/plugins/tests/trivial_ctor.h
[add] https://crrev.com/59b560a688614d2d283ff12f8b36e2fc29d92932/tools/clang/plugins/tests/trivial_ctor.txt

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d57e2e35e306be47b0dc96337a131c6e28f1c387

commit d57e2e35e306be47b0dc96337a131c6e28f1c387
Author: hans <hans@chromium.org>
Date: Tue Nov 15 00:05:23 2016

Roll clang 284979-1:284979-2 (update style plugin)

Ran `tools/clang/scripts/upload_revision.py 284979 2`.

This doesn't change the Clang version, but picks up Chromium #431450
which contains a fix for the style plugin.

BUG=663463

Review-Url: https://codereview.chromium.org/2493243002
Cr-Commit-Position: refs/heads/master@{#431999}

[modify] https://crrev.com/d57e2e35e306be47b0dc96337a131c6e28f1c387/tools/clang/scripts/update.py

Passing the long-term fix off to dcheng.

This came up for std::atomic<uint_fast8_t> here - https://chromium-review.googlesource.com/c/chromium/src/+/1278425/4/base/synchronization/atomic_flag.h#24

(Just adding a note).