How to install LLVM 12?

[Knarkzel]

I see LLVM 12 is already in nixpkgs, but how can I install it? llvm is by default 11.1.0.

• https://github.com/NixOS/nixpkgs/blob/13cbe534ebe63a0bc2619c57661a2150569d0443/pkgs/development/compilers/llvm/12/llvm/default.nix

[tejing]

pkgs.llvm_12, I expect.