How is ghc compiled at all without bootstrapping? Or is there a magic binary in tree that is unreproducible? I have compiled ghc a few times and had no problems.
And where did you get the haskel compiler to do so?
You seem to be missing the point of bootstrapping
Quite literally all distros today build it by downloading an existing magic binary to compile the latest sources. Even if they claim the package is reproducible, all bets are off on trust if it downloads a prebuilt binary in the build process. It is a prime Trusting Trust attack target.
The only other somewhat widely used language I am aware of in this bad of a position is Ada. Every other language I am aware of has a clear bootstrap path.