(* TEST
   * expect *)

(* #9623 *)

module RhsScopeCheck = struct
  module type Sig1 = sig
    type t
    type u = t
  end

  (* A scoping error here is intentional:
     with-constraints "with <lhs> = <rhs>"
     have their <rhs> evaluated in the current
     typing environment, not within the signature
     that they are constraining. [t] is unbound
     in the current environment, so [with u = t]
     must be rejected. *)
  module type Check1 = Sig1
    with type u = t
end
[%%expect{|
Line 15, characters 18-19:
15 |     with type u = t
                       ^
Error: Unbound type constructor t
|}]


module VarianceEnv = struct
  module type Sig = sig
    type +'a abstract
    type +'a user = Foo of 'a abstract
  end

  module type Problem = sig
    include Sig
    module M : Sig
      with type 'a abstract = 'a abstract
       and type 'a user = 'a user

    (* the variance annotation of [+'a foo] should be accepted, which
       would not be the case if the with-constraint [and type 'a
       user = 'a user] had its variance type-checked in the wrong typing
       environment: see #9624 *)
    type +'a foo = 'a M.user
  end
end
[%%expect{|
module VarianceEnv :
  sig
    module type Sig =
      sig type +'a abstract type 'a user = Foo of 'a abstract end
    module type Problem =
      sig
        type +'a abstract
        type 'a user = Foo of 'a abstract
        module M :
          sig
            type 'a abstract = 'a abstract
            type 'a user = 'a user = Foo of 'a abstract
          end
        type 'a foo = 'a M.user
      end
  end
|}]

module UnboxedEnv = struct
  module type Sig = sig
    type 'a ind = 'a * int
    type t = T : 'e ind -> t [@@unboxed]
  end

  module type Problem = sig
    include Sig
    module type ReboundSig = Sig
      with type 'a ind = 'a ind
       and type t = t
    (* the with-definition [and type t = t] above should be accepted,
       which would not be the case if its definition had separability
       checked in the wrong typing environment: see #9624 *)
  end
end
[%%expect{|
module UnboxedEnv :
  sig
    module type Sig =
      sig type 'a ind = 'a * int type t = T : 'e ind -> t [@@unboxed] end
    module type Problem =
      sig
        type 'a ind = 'a * int
        type t = T : 'e ind -> t [@@unboxed]
        module type ReboundSig =
          sig
            type 'a ind = 'a ind
            type t = t/2 = T : 'a ind -> t/1 [@@unboxed]
          end
      end
  end
|}]

(* We can also have environment issues when unifying type parameters;
   regression test contributed by Jacques Garrigue in #9623. *)
module ParamsUnificationEnv = struct
  module type Sig =
    sig type 'a u = 'a list type +'a t constraint 'a = 'b u end
  type +'a t = 'b constraint 'a = 'b list
  module type Sig2 = Sig with type +'a t = 'a t
end
[%%expect{|
module ParamsUnificationEnv :
  sig
    module type Sig =
      sig type 'a u = 'a list type +'a t constraint 'a = 'b u end
    type +'a t = 'b constraint 'a = 'b list
    module type Sig2 =
      sig type 'a u = 'a list type +'a t = 'a t constraint 'a = 'b u end
  end
|}]


(* The construction of the "signature environment" was also broken
   in earlier versions of the code. Regression test by Leo White in #9623. *)
module CorrectEnvConstructionTest = struct
  module type Sig = sig
    type +'a user = Foo of 'a abstract
    and +'a abstract
  end

  module type Problem = sig
    include Sig
    module M : Sig
      with type 'a abstract = 'a abstract
       and type 'a user = 'a user
    type +'a foo = 'a M.user
  end
end
[%%expect{|
module CorrectEnvConstructionTest :
  sig
    module type Sig =
      sig type 'a user = Foo of 'a abstract and +'a abstract end
    module type Problem =
      sig
        type 'a user = Foo of 'a abstract
        and +'a abstract
        module M :
          sig
            type 'a user = 'a user = Foo of 'a abstract
            and 'a abstract = 'a abstract
          end
        type 'a foo = 'a M.user
      end
  end
|}]

(* #9640 *)

module type Packet_type = sig
  type t
end
module type Unpacked_header = sig
  module Packet_type : Packet_type
  type t
  val f : t -> Packet_type.t -> unit
end
module type Header = sig
  module Packet_type : Packet_type
  module Unpacked : Unpacked_header with module Packet_type := Packet_type
end
module type S = sig
  module Packet_type : Packet_type
  module Header : Header with module Packet_type = Packet_type
end
[%%expect{|
module type Packet_type = sig type t end
module type Unpacked_header =
  sig
    module Packet_type : Packet_type
    type t
    val f : t -> Packet_type.t -> unit
  end
module type Header =
  sig
    module Packet_type : Packet_type
    module Unpacked : sig type t val f : t -> Packet_type.t -> unit end
  end
module type S =
  sig
    module Packet_type : Packet_type
    module Header :
      sig
        module Packet_type : sig type t = Packet_type.t end
        module Unpacked : sig type t val f : t -> Packet_type.t -> unit end
      end
  end
|}]
module type Iobuf_packet = sig
  module Make (Header : Header) () :
    S
    with module Packet_type = Header.Packet_type
    with module Header.Unpacked = Header.Unpacked
end
[%%expect{|
module type Iobuf_packet =
  sig
    module Make :
      functor (Header : Header) () ->
        sig
          module Packet_type : sig type t = Header.Packet_type.t end
          module Header :
            sig
              module Packet_type : sig type t = Packet_type.t end
              module Unpacked :
                sig
                  type t = Header.Unpacked.t
                  val f : t -> Header.Packet_type.t -> unit
                end
            end
        end
  end
|}]

(* Simpler example by @gasche *)
module type S = sig
  type t
  type u = t
end
module type Pack = sig
  module M : S
end
[%%expect{|
module type S = sig type t type u = t end
module type Pack = sig module M : S end
|}]
module type Weird = sig
  module M : S
  module P : Pack
    with type M.t = M.t
    with type M.u = M.u
end
[%%expect{|
module type Weird =
  sig
    module M : S
    module P : sig module M : sig type t = M.t type u = M.u end end
  end
|}]