normalizeTypeT, exprSyntaxEq in simplifyExprR
Fixed whenChangedR; optimizeCoercionR & optimizeCastR.
isUnitTy: coreView
walkE; fix varOccCount
saveDefT/findDefT; ReProg
reAlt, isCoercionE, onAltRhs, saveDefT & saveDefNoFloatT plumbing
memoChat using observeR