[clang] [analyzer] Allow SVals as llvm::Immutable{Map, Set} keys (PR #205319)

[Benedek Kaibas via cfe-commits]

benedekaibas wrote:

> Works?
Yes, it works perfectly! Rebuilt the project and run the tests everything passed. The code looks so much cleaner now.


https://github.com/llvm/llvm-project/pull/205319