Make the Name field of a Var strict - it doesn't hurt performance (in
fact it makes a tiny improvement) but it can help residency.
\begin{code}
data Var
= Var {
\begin{code}
data Var
= Var {
realUnique :: FastInt, -- Key for fast comparison
-- Identical to the Unique in the name,
-- cached here for speed
realUnique :: FastInt, -- Key for fast comparison
-- Identical to the Unique in the name,
-- cached here for speed