[clang] [Sema] Check arg count for builtins with CustomTypeChecking (PR #222841)

[via cfe-commits]

im-lunex wrote:

so i was using `checkArgCountAtMost(TheCall, FPT->getNumParams())` but this wasn't on sync with the builtins-wasm.c soo changed this to `checkArgCount(TheCall, FPT->getNumParams())` now this should be good 


https://github.com/llvm/llvm-project/pull/222841