tree 1063d6b61f4cb47f0b286129ce873600feccfd57
parent c75b9e4fd9106e0e954883a4a0a5cc38b333016b
author Matheus Izvekov <mizvekov@gmail.com> 1636760418 +0100
committer Copybara-Service <copybara-worker@google.com> 1636771278 -0800

[clang] retain type sugar in auto / template argument deduction

This implements the following changes:
* AutoType retains sugared deduced-as-type.
* Template argument deduction machinery analyses the sugared type all the way
down. It would previously lose the sugar on first recursion.
* Undeduced AutoType will be properly canonicalized, including the constraint
template arguments.
* Remove the decltype node created from the decltype(auto) deduction.

As a result, we start seeing sugared types in a lot more test cases,
including some which showed very unfriendly `type-parameter-*-*` types.

Signed-off-by: Matheus Izvekov <mizvekov@gmail.com>

Reviewed By: rsmith

Differential Revision: https://reviews.llvm.org/D110216

GitOrigin-RevId: 4d8fff477e024698facd89741cc6cf996708d598