`normalizeType` could be implemented more efficiently

[alex-mckenna]

Working on the partial evaluator, I found the following case where normalizeType doesn't seem to work as advertised.
Attempting to normalize

BitSize (Maybe (Vec 2 (Maybe Bool)))

gives

CLog 2 (GConstructorCount (Rep (Maybe (Vec 2 (Maybe Bool))))) + GFieldSize (Rep (Maybe (Vec 2 (Maybe Bool))))

but using normalizeType tcm (normalizeType tcm ty) gives

LitTy (NumTy 5)

which is what was initially expected.

[martijnbastiaan]

An (naive?) implementation could change

clash-compiler/clash-lib/src/Clash/Core/Type.hs

Lines 648 to 650 in 5477a2f

	in case reduceTypeFamily tcMap ty' of
	Just ty'' -> ty''
	Nothing -> ty'

to

             in case reduceTypeFamily tcMap ty' of
               Just ty'' -> go ty''
               Nothing  -> ty'

right?

[alex-mckenna]

This appears to solve the issue, and with what must be one of the shortest diffs known to this project.
I give it ⭐ ⭐ ⭐ ⭐ ⭐

[martijnbastiaan]

This still needs a proper fix described in the TODO.