-dsExpr (HsDo DoExpr stmts res_ty) = dsDo stmts res_ty
-dsExpr (HsDo GhciStmt stmts res_ty) = dsDo stmts res_ty
-dsExpr (HsDo MDoExpr stmts res_ty) = dsDo stmts res_ty
-dsExpr (HsDo MonadComp stmts res_ty) = dsMonadComp stmts res_ty
+dsExpr (HsDo DoExpr stmts _) = dsDo stmts
+dsExpr (HsDo GhciStmt stmts _) = dsDo stmts
+dsExpr (HsDo MDoExpr stmts _) = dsDo stmts
+dsExpr (HsDo MonadComp stmts _) = dsMonadComp stmts