Please merge b20ab412bf838a8a87e5cc1c8c6399c3c9255354 to release/10.x

[zmodem]

Bugzilla Link	45316
Resolution	FIXED
Resolved on	Apr 14, 2020 20:34
Version	trunk
OS	Linux
Blocks	#44654
CC	@zygoloid,@saarraz,@tstellar
Fixed by commit(s)	b20ab41 e3ac79a

Extended Description

As requested by Saar.

commit b20ab41
Author: Richard Smith richard@metafoo.co.uk
Date: Thu Mar 19 12:38:40 2020 -0700

Teach TreeTransform to substitute into resolved TemplateArguments.

This comes up when substituting into an already-substituted template
argument during constraint satisfaction checking.

[zmodem]

assigned to @tstellar

[tstellar]

Richard, is this OK to backport?

https://github.com/tstellar/llvm-project/pull/76/files

[zygoloid]

Yes, I think this has been in tree for long enough that we can be confident that it's stable.

[tstellar]

Merged: e3ac79a