For some reason, halive tries to open a GHC that doesn't exist. It's probably saving an incorrect path:
$ halive My/File.hs
██╗ ██╗ █████╗ ██╗ ██╗██╗ ██╗███████╗
██║ ██║██╔══██╗██║ ██║██║ ██║██╔════╝
███████║███████║██║ ██║██║ ██║█████╗
██╔══██║██╔══██║██║ ██║╚██╗ ██╔╝██╔══╝
██║ ██║██║ ██║███████╗██║ ╚████╔╝ ███████╗
╚═╝ ╚═╝╚═╝ ╚═╝╚══════╝╚═╝ ╚═══╝ ╚══════╝
engaged
halive: /nix/store/mz4mmizf0h33q3sybibkp476a7ixkpq7-ghc-8.6.5-with-packages/lib/ghc-8.6.5/settings: openFile: does not exist (No such file or directory)
halive: thread blocked indefinitely in an MVar operation
For some reason, halive tries to open a GHC that doesn't exist. It's probably saving an incorrect path: