...and then I discovered Haskell.
...Until I found out that Haskell is just a fancy C for-loop generator.
GHC is considerably more sophisticated than that. It can do weird and wonderful things C programmers might only dream of.
Considering GHC is still implemented in C I would consider this not true. Impractical: probably. Impossibru: No.
I'd hardly call 81% Haskell "implemented in C".

https://github.com/ghc/ghc