Having trouble building LLVM from source

[aleph-oh]

Output of brew config

HOMEBREW_VERSION: 4.1.11
ORIGIN: https://github.com/Homebrew/brew
HEAD: 4afb8e5602f3ecc9edf67a44257d8eceeaa8a108
Last commit: 5 days ago
Core tap JSON: 16 Sep 20:21 UTC
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: dhcp-10-29-254-30.dyn.MIT.EDU
HOMEBREW_MAKE_JOBS: 16
Homebrew Ruby: 2.6.10 => /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby
CPU: 16-core 64-bit kabylake
Clang: 14.0.3 build 1403
Git: 2.39.2 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 7.86.0 => /usr/bin/curl
macOS: 13.2.1-x86_64
CLT: 14.3.0.0.1.1679647830
Xcode: 14.3.1

Output of brew doctor

Your system is ready to brew.

Description of issue

I'm trying to make a formula which is very similar to LLVM, for an LLVM fork, so I'd like to at least be able to build LLVM from source as a formula so I can tell that my changes to LLVM's formula are responsible for the failures. When I try to install the llvm formula via llvm.rb, I get the following output (HOMEBREW_NO_INSTALL_FROM_API is already set):

Error: Failed to load cask: llvm.rb
Cask 'llvm' is unreadable: wrong constant name #<Class:0x00007fe4732c7900>
Warning: Treating llvm.rb as a formula.
==> Fetching llvm
==> Downloading https://github.com/llvm/llvm-project/commit/ab8d4f5a122fde5740f8c084c8165f51a26c93c7.patch?full_index=1
Already downloaded: /Users/jay/Library/Caches/Homebrew/downloads/bcdd47b01f07ed9e81c99c94a9062d8463a09b66fc936cada03f30eef529a2e9--ab8d4f5a122fde5740f8c084c8165f51a26c93c7.patch
==> Downloading https://github.com/llvm/llvm-project/releases/download/llvmorg-16.0.6/llvm-project-16.0.6.src.tar.xz
Already downloaded: /Users/jay/Library/Caches/Homebrew/downloads/8cbb1836057b964f8f1bea2eee120bd27a78aa698ba2d5263996f3071234b47e--llvm-project-16.0.6.src.tar.xz
Cannot read termcap database;
using dumb terminal settings.
==> Patching
==> Applying ab8d4f5a122fde5740f8c084c8165f51a26c93c7.patch
patching file 'llvm/cmake/modules/LLVM-Config.cmake'
Error: An exception occurred within a child process:
  NoMethodError: undefined method `user' for nil:NilClass

[SMillerDev]

Without seeing the code it's hard to tell what could be wrong, but formulae are meant to be in a tap. They don't always work when you install them based on the file name.

[aleph-oh]

Ah sorry, the formula is what's linked here. Putting the formula into a tap seems to have revealed issues when building LLVM itself, so I think this has solved my problem, thanks!