Support 5.2 raw identifiers

Raw identifier syntax is added to the vendored lexer.

Contrary to upstream, the escape sequence (`\#`) is part of the ident.
This avoids the need to classify identifiers later in Fmt_ast.

test/passing/gen/dune.inc

@@ -3832,6 +3832,21 @@
  (alias runtest)
  (action (diff quoted_strings.ml.err quoted_strings.ml.stderr)))
 
+(rule
+ (deps .ocamlformat dune-project)
+ (action
+  (with-stdout-to raw_identifiers.ml.stdout
+   (with-stderr-to raw_identifiers.ml.stderr
+     (run %{bin:ocamlformat} --name raw_identifiers.ml --margin-check %{dep:../tests/raw_identifiers.ml})))))
+
+(rule
+ (alias runtest)
+ (action (diff raw_identifiers.ml.ref raw_identifiers.ml.stdout)))
+
+(rule
+ (alias runtest)
+ (action (diff raw_identifiers.ml.err raw_identifiers.ml.stderr)))
+
 (rule
  (deps .ocamlformat dune-project)
  (action

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

@@ -0,0 +1,152 @@
+module M : sig
+  class \#and : object
+    val mutable \#and : int
+    method \#and : int
+  end
+end = struct
+  class \#and =
+    let \#and = 1 in
+    object
+      val mutable \#and = \#and
+      method \#and = 2
+    end
+end
+
+let obj = new M.\#and
+
+module M : sig
+  type \#and = int
+end = struct
+  type \#and = string
+end
+
+let x = (`\#let `\#and : [ `\#let of [ `\#and ] ])
+let (`\#let \#rec) = x
+let f g ~\#let ?\#and ?(\#for = \#and) () = g ~\#let ?\#and ()
+
+type t = '\#let
+type \#mutable = { mutable \#mutable : \#mutable }
+
+let rec \#rec = { \#mutable = \#rec }
+
+type \#and = ..
+type \#and += Foo
+(* Not allowed in parser: type t += \#and *)
+
+let x = ( ++ )
+let x = \#let
+let f ~\#let ?\#and () = 1
+
+module type A = sig
+  type ('\#let, 'a) \#virtual = '\#let * 'a as '\#mutable
+
+  val foo : '\#let 'a. 'a -> '\#let -> unit
+
+  type foo = { \#let : int }
+end
+
+module M = struct
+  let ((\#let, foo) as \#val) = (\#mutable, baz)
+  let _ = fun (type \#let foo) -> 1
+  let f g ~\#let ?\#and ?(\#for = \#and) () = g ~\#let ?\#and ()
+
+  class \#let =
+    object
+      inherit \#val \#let as \#mutable
+    end
+end
+
+type 'a \#for = 'a list
+type 'a \#sig = 'a \#for
+type \#true = bool
+type _ t = \#in t
+type '\#in t
+
+class ['\#in] c = c
+
+let f \#false = \#false
+
+type t = { x : int \#let }
+
+let x \#let = 42
+let x = f ~\#let:42 ~\#and:43
+let f ~\#let ~\#and : \#let * \#and = x;;
+
+kind_abbrev_ \#let = \#and
+
+type t = T : 'a list -> t
+
+let g x =
+  let (T (type \#for) (_ : \#for list)) = x in
+  ()
+
+let ( lsl ) x y = x lsl y
+let \#lsl x y = x lsl y
+
+module type \#sig = sig end
+
+module M = struct
+  let \#mod = 1
+end
+
+let _ = M.\#mod
+
+module type \#sig = M
+module type M = \#sig
+module type M = M with module type \#sig = \#sig
+module type M = M with module type \#sig := \#sig
+
+let _ = \#sig.(())
+
+(* Raw idents in module names are not allowed in parser: *)
+(* let (module \#sig : S) = () *)
+(* module \#sig (A : S) = M *)
+(* module \#sig = M *)
+(* module M (\#sig : S) = M *)
+(* module M = M (functor (\#sig : S) -> struct end) *)
+(* module type S = functor (\#sig : S) -> S' *)
+(* module type M = M with module \#sig = \#sig *)
+(* module type M = M with module \#sig := \#sig *)
+let _ =
+  (* let module \#sig = \#sig in *)
+  (* let open \#sig in *)
+  ()
+
+let%\#let _ = ()
+let _ = [%\#let ()]
+let _ = () [@\#let]
+let _ = () [@@\#let]
+let f : type \#in. t = ()
+let f : '\#in. t = ()
+let \#mod : '\#mod. \#mod = \#mod
+let mlet = M.\#let
+let mtrue = M.\#true
+let mmod = M.\#mod
+
+type tmod = M.\#mod
+type tlet = M.\#let
+type ttrue = M.\#true
+
+(* class \#mod = object end *)
+let f : #M.\#mod -> _ = (new \#mod, new M.\#mod)
+
+class type \#mod = object end
+class type \#let = \#mod
+
+module type \#mod = sig
+  type \#mod
+
+  module type \#mod
+end
+
+module type t = \#mod with type \#mod = M.\#mod and module type \#mod = M.\#mod
+
+type \#mod = [ `A | `B ]
+
+let g = function #\#mod | #M.\#mod -> ()
+
+type \#mod = ..
+type M.\#mod += A
+type t = true of int
+
+let x = true 0

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

@@ -0,0 +1,159 @@
+module M : sig
+  class \#and : object
+    val mutable \#and : int
+    method \#and : int
+  end
+end = struct
+  class \#and =
+    let \#and = 1 in
+    object
+      val mutable \#and = \#and
+      method \#and = 2
+    end
+end
+
+let obj = new M.\#and
+
+module M : sig
+  type \#and = int
+end = struct
+  type \#and = string
+end
+
+let x = (`\#let `\#and : [ `\#let of [ `\#and ] ])
+let (`\#let \#rec) = x
+let f g ~\#let ?\#and ?(\#for = \#and) () = g ~\#let ?\#and ()
+
+type t = '\#let
+type \#mutable = { mutable \#mutable : \#mutable }
+
+let rec \#rec = { \#mutable = \#rec }
+
+type \#and = ..
+type \#and += Foo
+(* Not allowed in parser: type t += \#and *)
+
+let x = ( ++ )
+let x = \#let
+let f ~\#let ?\#and () = 1
+
+module type A = sig
+  type ('\#let, 'a) \#virtual = '\#let * 'a as '\#mutable
+
+  val foo : '\#let 'a. 'a -> '\#let -> unit
+
+  type foo = { \#let : int }
+end
+
+module M = struct
+  let ((\#let, foo) as \#val) = \#mutable, baz
+  let _ = fun (type \#let foo) -> 1
+  let f g ~\#let ?\#and ?(\#for = \#and) () = g ~\#let ?\#and ()
+
+  class \#let =
+    object
+      inherit \#val \#let as \#mutable
+    end
+end
+
+type 'a \#for = 'a list
+type 'a \#sig = 'a \#for
+type \#true = bool
+type _ t = \#in t
+type '\#in t
+
+class ['\#in] c = c
+
+let f \#false = \#false
+
+type t = { x : int \#let }
+
+let x \#let = 42
+let x = f ~\#let:42 ~\#and:43
+let f ~\#let ~\#and : \#let * \#and = x;;
+
+kind_abbrev_ \#let = \#and
+
+type t = T : 'a list -> t
+
+let g x =
+  let (T (type \#for) (_ : \#for list)) = x in
+  ()
+;;
+
+let ( lsl ) x y = x lsl y
+let \#lsl x y = x lsl y
+
+module type \#sig = sig end
+
+module M = struct
+  let \#mod = 1
+end
+
+let _ = M.\#mod
+
+module type \#sig = M
+module type M = \#sig
+module type M = M with module type \#sig = \#sig
+module type M = M with module type \#sig := \#sig
+
+let _ = \#sig.(())
+
+(* Raw idents in module names are not allowed in parser: *)
+(* let (module \#sig : S) = () *)
+(* module \#sig (A : S) = M *)
+(* module \#sig = M *)
+(* module M (\#sig : S) = M *)
+(* module M = M (functor (\#sig : S) -> struct end) *)
+(* module type S = functor (\#sig : S) -> S' *)
+(* module type M = M with module \#sig = \#sig *)
+(* module type M = M with module \#sig := \#sig *)
+let _ =
+  (* let module \#sig = \#sig in *)
+  (* let open \#sig in *)
+  ()
+;;
+
+let%\#let _ = ()
+let _ = [%\#let ()]
+let _ = () [@\#let]
+let _ = () [@@\#let]
+let f : type \#in. t = ()
+let f : '\#in. t = ()
+let \#mod : '\#mod. \#mod = \#mod
+let mlet = M.\#let
+let mtrue = M.\#true
+let mmod = M.\#mod
+
+type tmod = M.\#mod
+type tlet = M.\#let
+type ttrue = M.\#true
+
+(* class \#mod = object end *)
+let f : #M.\#mod -> _ = new \#mod, new M.\#mod
+
+class type \#mod = object end
+class type \#let = \#mod
+
+module type \#mod = sig
+  type \#mod
+
+  module type \#mod
+end
+
+module type t = \#mod with type \#mod = M.\#mod and module type \#mod = M.\#mod
+
+type \#mod =
+  [ `A
+  | `B
+  ]
+
+let g = function
+  | #\#mod | #M.\#mod -> ()
+;;
+
+type \#mod = ..
+type M.\#mod += A
+type t = true of int
+
+let x = true 0