My in-path ghc version is 8.4.4, as show by running $ ghc -- version.
$ ghc --version
The Glorious Glasgow Haskell Compilation System, version 8.4.4.
Somehow, however, my stack is using a different version, as shown by running $ stack ghc -- --version.
$ stack ghc -- --version
The Glorious Glasgow Haskell Compilation System, version 8.0.2.
I have no idea where the 8.0.2 of ghc is even installed on my system. How is this possible, and how can I update the version of ghc my stack uses?