Fix bad misalignment of short-syntax functor arguments

Author: Julow

lib/Fmt_ast.ml

@@ -4162,10 +4162,19 @@ and fmt_module c ctx ?rec_ ?epi ?(can_sparse = false) keyword ?(eqty = "=")
   let ext = attrs.attrs_extension in
   let blk_t =
     Option.value_map xmty ~default:empty ~f:(fun xmty ->
+        let break_before_ty =
+          match xmty.ast.pmty_desc with
+          (* Break functor types that use the short syntax and avoid
+             misaligning the parameter types. *)
+          | Pmty_functor (Pfunctorty_unnamed _, _) -> break 1 2
+          | _ -> str " "
+        in
         let blk = fmt_module_type ?rec_ c xmty in
+        let pro =
+          str " " $ str eqty $ opt blk.pro (fun pro -> break_before_ty $ pro)
+        in
         { blk with
-          pro=
-            Some (str " " $ str eqty $ opt blk.pro (fun pro -> str " " $ pro))
+          pro= Some pro
         ; psp= fmt_if (Option.is_none blk.pro) (break 1 2) $ blk.psp } )
   in
   let blk_b = Option.value_map xbody ~default:empty ~f:(fmt_module_expr c) in

test/passing/refs.ahrefs/functor-414.ml.ref

@@ -143,10 +143,14 @@ module M = struct
 end
 
 module Simple : (Parameters with type update_result := state) -> S = M
+module Simple : S -> Parameters with type update_result := state = M
 
-module Left_variadic : (Parameters
-                         with type update_result := state * left array)
+module Left_variadic :
+  (Parameters with type update_result := state * left array)
   -> S =
   M
+module Left_variadic : S ->
+  Parameters with type update_result := state * left array =
+  M
 
 module N : S with module type T = (U -> U) = struct end

test/passing/refs.ahrefs/functor.ml.ref

@@ -143,10 +143,14 @@ module M = struct
 end
 
 module Simple : (Parameters with type update_result := state) -> S = M
+module Simple : S -> Parameters with type update_result := state = M
 
-module Left_variadic : (Parameters
-                         with type update_result := state * left array)
+module Left_variadic :
+  (Parameters with type update_result := state * left array)
   -> S =
   M
+module Left_variadic : S ->
+  Parameters with type update_result := state * left array =
+  M
 
 module N : S with module type T = (U -> U) = struct end

test/passing/refs.ahrefs/functor.mli.ref

@@ -4,6 +4,6 @@ end) : S
 
 module Simple : (Parameters with type update_result := state) -> S
 
-module Left_variadic : (Parameters
-                         with type update_result := state * left array)
+module Left_variadic :
+  (Parameters with type update_result := state * left array)
   -> S

test/passing/refs.default/functor-414.ml.ref

@@ -123,10 +123,15 @@ module M = struct
 end
 
 module Simple : (Parameters with type update_result := state) -> S = M
+module Simple : S -> Parameters with type update_result := state = M
 
-module Left_variadic : (Parameters
-                         with type update_result := state * left array)
+module Left_variadic :
+  (Parameters with type update_result := state * left array)
   -> S =
   M
 
+module Left_variadic : S ->
+  Parameters with type update_result := state * left array =
+  M
+
 module N : S with module type T = (U -> U) = struct end

test/passing/refs.default/functor.ml.ref

@@ -123,10 +123,15 @@ module M = struct
 end
 
 module Simple : (Parameters with type update_result := state) -> S = M
+module Simple : S -> Parameters with type update_result := state = M
 
-module Left_variadic : (Parameters
-                         with type update_result := state * left array)
+module Left_variadic :
+  (Parameters with type update_result := state * left array)
   -> S =
   M
 
+module Left_variadic : S ->
+  Parameters with type update_result := state * left array =
+  M
+
 module N : S with module type T = (U -> U) = struct end

test/passing/refs.default/functor.mli.ref

@@ -4,6 +4,6 @@ end) : S
 
 module Simple : (Parameters with type update_result := state) -> S
 
-module Left_variadic : (Parameters
-                         with type update_result := state * left array)
+module Left_variadic :
+  (Parameters with type update_result := state * left array)
   -> S

test/passing/refs.janestreet/functor-414.ml.ref

@@ -122,5 +122,7 @@ module M = struct
 end
 
 module Simple : (Parameters with type update_result := state) -> S = M
+module Simple : S -> Parameters with type update_result := state = M
 module Left_variadic : (Parameters with type update_result := state * left array) -> S = M
+module Left_variadic : S -> Parameters with type update_result := state * left array = M
 module N : S with module type T = (U -> U) = struct end

test/passing/refs.janestreet/functor.ml.ref

@@ -122,5 +122,7 @@ module M = struct
 end
 
 module Simple : (Parameters with type update_result := state) -> S = M
+module Simple : S -> Parameters with type update_result := state = M
 module Left_variadic : (Parameters with type update_result := state * left array) -> S = M
+module Left_variadic : S -> Parameters with type update_result := state * left array = M
 module N : S with module type T = (U -> U) = struct end

test/passing/refs.ocamlformat/functor-414.ml.ref

@@ -159,9 +159,15 @@ end
 
 module Simple : (Parameters with type update_result := state) -> S = M
 
-module Left_variadic : (Parameters
-                         with type update_result := state * left array)
+module Simple : S -> Parameters with type update_result := state = M
+
+module Left_variadic :
+  (Parameters with type update_result := state * left array)
   -> S =
   M
 
+module Left_variadic : S ->
+  Parameters with type update_result := state * left array =
+  M
+
 module N : S with module type T = (U -> U) = struct end