mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe,
splitFunTys, splitFunTysN,
- funResultTy, funArgTy, zipFunTys,
+ funResultTy, funArgTy, zipFunTys, typeArity,
mkTyConApp, mkTyConTy,
tyConAppTyCon, tyConAppArgs,
import Name
import Class
import TyCon
+import BasicTypes ( Arity )
-- others
import StaticFlags
import Data.List
import Data.Maybe ( isJust )
+
+infixr 3 `mkFunTy` -- Associates to the right
\end{code}
\begin{code}
funArgTy ty | Just ty' <- coreView ty = funArgTy ty'
funArgTy (FunTy arg _res) = arg
funArgTy ty = pprPanic "funArgTy" (ppr ty)
+
+typeArity :: Type -> Arity
+-- How many value arrows are visible in the type?
+-- We look through foralls, but not through newtypes, dictionaries etc
+typeArity ty | Just ty' <- coreView ty = typeArity ty'
+typeArity (FunTy _ ty) = 1 + typeArity ty
+typeArity (ForAllTy _ ty) = typeArity ty
+typeArity _ = 0
\end{code}
---------------------------------------------------------------------
For example, consider:
(/\a. /\b:(a~Int). ...b..) Int
We substitute Int for 'a'. The Unique of 'b' does not change, but
-nevertheless we add 'b' to the TvSubstEnv, because b's type does change
+nevertheless we add 'b' to the TvSubstEnv, because b's kind does change
This invariant has several crucial consequences: