Remove unused exception handling code.

typing/typer.ml

@@ -966,10 +966,8 @@ and type_check' loc env ed constr precise = match ed with
     in
     let t =
       (* try Types.Arrow.check_strenghten a.fun_typ constr *)
-      try begin
-        if Types.is_squaresubtype env.delta a.fun_typ constr then a.fun_typ
-        else raise Not_found
-      end with Not_found ->
+      if Types.is_squaresubtype env.delta a.fun_typ constr then a.fun_typ
+      else
         should_have loc constr
           "but the interface of the abstraction is not compatible"
     in