+tcOverloadedLit orig lit@(HsIsString s fr) res_ty
+ | not (fr `isHsVar` fromStringName) -- c.f. HsIntegral case
+ = do { str_ty <- tcMetaTy stringTyConName
+ ; fr' <- tcSyntaxOp orig fr (mkFunTy str_ty res_ty)
+ ; return (HsIsString s (HsApp (noLoc fr') (nlHsLit (HsString s)))) }
+
+ | Just expr <- shortCutStringLit s res_ty
+ = return (HsIsString s expr)
+
+ | otherwise
+ = do { expr <- newLitInst orig lit res_ty
+ ; return (HsIsString s expr) }
+