[thewakalix]

Why? Is it mostly because of Haskell's purity (side-effect-freeness), so optimizations can change expressions more freely and safely?

[fooker]

That, and the uniform s-expr/gadt representation of data structures instead of going wild with clever pointers.

[dmytrish]

I am not sure I understand what you mean in the context of Haskell.

[fooker]

https://wiki.haskell.org/GADTs_for_dummies