Line 6, characters 2-14:
6 |   type t1 := A
      ^^^^^^^^^^^^
Error: Only type synonyms are allowed on the right of :=
Line 3, characters 2-24:
3 |   type t2 := { x : int }
      ^^^^^^^^^^^^^^^^^^^^^^
Error: Only type synonyms are allowed on the right of :=
Line 3, characters 15-18:
3 |   module M1 := sig end
                   ^^^
Error: Syntax error: module path expected.
module F : functor (X : sig type t end) -> sig type t = X.t end
Line 3, characters 17-23:
3 |   module M2 := F(struct type t = int end)
                     ^^^^^^
Error: Syntax error: module path expected.
Line 2, characters 7-9:
2 | type t := int;;
           ^^
Error: Syntax error
Line 2, characters 9-11:
2 | module M := List;;
             ^^
Error: Syntax error
Line 4, characters 9-10:
4 |   and u3 = char
             ^
Error: Syntax error: 'end' expected
Line 2, characters 24-27:
2 | module type Rejected3 = sig
                            ^^^
  This 'sig' might be unmatched
Line 3, characters 7-13:
3 |   type nonrec t := int
           ^^^^^^
Error: Syntax error: nonrec flag not expected.