[clang] [clang] Implement instantiation context note for checking template parameters (PR #126088)

[Nikita Popov via cfe-commits]

nikic wrote:

This causes a large compile-time regression for C++ code: https://llvm-compile-time-tracker.com/compare_clang.php?from=37aad2c1196ea3de242d855cfe38bc25a65d6f5e&to=a24523ac8dc07f3478311a5969184b922b520395&stat=instructions%3Au&sortBy=interestingness It adds 1-3% overhead per file during the stage2 build.

Please revert this change until the regression can be resolved.

https://github.com/llvm/llvm-project/pull/126088