OCaml 5.6 support

CHANGES.md

@@ -1,5 +1,6 @@
 # Unreleased
 
+- Support for OCaml 5.6 (@jonludlam, #1472)
 - Support for OxCaml unboxed named types (@art-w, #1407)
 - Support for OxCaml zero alloc definitions (@Leonidas-from-XIV, #1422, #1444)
 - Remove requirement for ppx_expect in tests (@jonludlam, #1445)

odoc.opam

@@ -45,7 +45,7 @@ depends: [
   "cppo" {build & >= "1.1.0"}
   "dune" {>= "3.21.0"}
   "fpath" {>= "0.7.3"}
-  "ocaml" {>= "4.08.0" & < "5.6"}
+  "ocaml" {>= "4.08.0" & < "5.7"}
   "tyxml" {>= "4.4.0"}
   "fmt"
   "crunch" {>= "1.4.1"}

src/loader/cmi.ml

@@ -46,7 +46,18 @@ module Compat = struct
        versions *)
   let repr x = Transient_expr.repr x
 
+#if OCAML_VERSION >= (5,6,0)
+  (** Since 5.6, abbreviation expansion happens in place in the type graph and
+      the original abbreviation is remembered in the [Texpand] edge that
+      replaced it. [Types.get_desc] walks past those edges and would hand us
+      the expanded type, so use the same accessor the compiler's own printer
+      uses ([Out_type.printer_get_desc]) to recover the abbreviation. *)
+  let get_desc ty = Btype.get_folded_desc ~keep_Tvar:true ty
+  let deep_occur = Btype.deep_occur
+#else
   let get_desc = Types.get_desc
+  let deep_occur = Ctype.deep_occur
+#endif
   let get_row_name = Types.row_name
   let row_field_repr = Types.row_field_repr
   let field_kind_repr = Types.field_kind_repr
@@ -69,6 +80,7 @@ module Compat = struct
   type repr_type_node = Types.type_expr
   let repr = Btype.repr
   let get_desc x = (repr x).Types.desc
+  let deep_occur = Ctype.deep_occur
   let get_row_name x = x.Types.row_name
   let row_field_repr = Btype.row_field_repr
   let field_kind_repr = Btype.field_kind_repr
@@ -313,6 +325,10 @@ let mark_type ty =
       | Tsubst (ty,_) -> loop visited ty
 #endif
       | Tlink _ -> assert false
+#if OCAML_VERSION >= (5,6,0)
+      (* [Compat.get_desc] walks past [Texpand] just as it does [Tlink]. *)
+      | Texpand _ -> assert false
+#endif
 #if defined OXCAML
       | Tquote typ -> loop visited typ
       | Tsplice typ -> loop visited typ
@@ -459,7 +475,7 @@ let rec mark_class_type params = function
       let sty = Compat.self_type cty in
       if is_row_visited (proxy sty)
       || List.exists aliasable params
-      || List.exists (Ctype.deep_occur sty) tyl
+      || List.exists (Compat.deep_occur sty) tyl
       then mark_class_type params cty
       else List.iter mark_type tyl
   | Cty_signature sign ->
@@ -663,6 +679,10 @@ let rec read_type_expr env typ =
 
 #endif
       | Tlink _ -> assert false
+#if OCAML_VERSION >= (5,6,0)
+      (* [Compat.get_desc] walks past [Texpand] just as it does [Tlink]. *)
+      | Texpand _ -> assert false
+#endif
 #if defined OXCAML
       | Tquote typ -> Quote (read_type_expr env typ)
       | Tsplice typ -> Splice (read_type_expr env typ)

src/loader/cmt.ml

@@ -524,8 +524,13 @@ and read_structure_item env parent item =
     | Tstr_eval _ -> []
     | Tstr_value(_, vbs) ->
         read_value_bindings env parent vbs
+#if OCAML_VERSION >= (5,6,0)
+    | Tstr_primitive pd ->
+        [Cmti.read_primitive_description env parent pd]
+#else
     | Tstr_primitive vd ->
         [Cmti.read_value_description env parent vd]
+#endif
     | Tstr_type (rec_flag, decls) ->
       let rec_flag =
         match rec_flag with

src/loader/cmti.ml

@@ -200,14 +200,64 @@ let read_value_description env parent vd =
   let doc = Doc_attr.attached_no_tag ~warnings_tag:env.warnings_tag container vd.val_attributes in
   let type_ = read_core_type env container vd.val_desc in
   let value =
+#if OCAML_VERSION >= (5,6,0)
+    (* Since 5.6 externals have their own node, so a [val] is never one. *)
+    Value.Abstract
+#else
     match vd.val_prim with
     | [] -> Value.Abstract
     | primitives -> External primitives
+#endif
   in
   let ext_attrs = Doc_attr.attrs_of_value_description vd.val_val in
   let modalities = Cmi.read_value_descr_modalities vd.val_val in
   Value { Value.id; source_loc; doc; type_; value; ext_attrs; modalities }
 
+#if OCAML_VERSION >= (5,6,0)
+(* Since 5.6 (RFC 44) [external] declarations have their own Typedtree node,
+   because they can now also be written as an alias of an existing primitive:
+   [external x : t = M.y], or [external x = M.y] with the type left implicit.
+   An alias carries no primitive strings of its own, so recover them from the
+   resolved [Types.value_description] the way the .cmi reader does. *)
+let read_primitive_description env parent pd =
+  let open Signature in
+  let id = Env.find_value_identifier env.ident_env pd.prim_id in
+  let source_loc = None in
+  let container =
+    (parent : Identifier.Signature.t :> Identifier.LabelParent.t)
+  in
+  let doc =
+    Doc_attr.attached_no_tag ~warnings_tag:env.warnings_tag container
+      pd.prim_attributes
+  in
+  let type_ =
+    match pd.prim_kind with
+    | Tprim_decl (core_type, _) | Tprim_alias (Some core_type, _, _) ->
+        read_core_type env container core_type
+    | Tprim_alias (None, _, _) ->
+        (* No type written at the declaration site: use the inferred one. *)
+        Cmi.mark_type_expr pd.prim_val.val_type;
+        Cmi.read_type_expr env pd.prim_val.val_type
+  in
+  let value =
+    match pd.prim_kind with
+    | Tprim_decl (_, primitives) -> Value.External primitives
+    | Tprim_alias _ -> (
+        match pd.prim_val.val_kind with
+        | Val_prim desc ->
+            let open Primitive in
+            Value.External
+              (desc.prim_name
+              :: (match desc.prim_native_name with
+                 | "" -> []
+                 | name -> [ name ]))
+        | _ -> Value.Abstract)
+  in
+  let ext_attrs = Doc_attr.attrs_of_value_description pd.prim_val in
+  let modalities = Cmi.read_value_descr_modalities pd.prim_val in
+  Value { Value.id; source_loc; doc; type_; value; ext_attrs; modalities }
+#endif
+
 let read_type_parameter (ctyp, var_and_injectivity)  =
   let open TypeDecl in
   let desc, kind =
@@ -804,6 +854,10 @@ and read_signature_item env parent item =
     match item.sig_desc with
     | Tsig_value vd ->
         [read_value_description env parent vd]
+#if OCAML_VERSION >= (5,6,0)
+    | Tsig_primitive pd ->
+        [read_primitive_description env parent pd]
+#endif
     | Tsig_type (rec_flag, decls) ->
       let rec_flag =
         match rec_flag with

src/loader/cmti.mli

@@ -49,6 +49,14 @@ val read_value_description :
   Typedtree.value_description ->
   Odoc_model.Lang.Signature.item
 
+#if OCAML_VERSION >= (5,6,0)
+val read_primitive_description :
+  Cmi.env ->
+  Paths.Identifier.Signature.t ->
+  Typedtree.primitive_description ->
+  Odoc_model.Lang.Signature.item
+#endif
+
 val read_type_declarations :
   Cmi.env ->
   Paths.Identifier.Signature.t ->

src/loader/ident_env.ml

@@ -253,7 +253,11 @@ let rec extract_signature_tree_items : bool -> Typedtree.signature_item list ->
       mds @ extract_signature_tree_items hide_item rest
 #endif
   | { sig_desc = Tsig_value {val_id; _}; sig_loc; _ } :: rest->
-      [`Value (val_id, hide_item, Some sig_loc)] @ extract_signature_tree_items hide_item rest 
+      [`Value (val_id, hide_item, Some sig_loc)] @ extract_signature_tree_items hide_item rest
+#if OCAML_VERSION >= (5,6,0)
+  | { sig_desc = Tsig_primitive {prim_id; _}; sig_loc; _ } :: rest->
+      [`Value (prim_id, hide_item, Some sig_loc)] @ extract_signature_tree_items hide_item rest
+#endif
   | { sig_desc = Tsig_modtype mtd; sig_loc; _} :: rest ->
       [`ModuleType (mtd.mtd_id, hide_item, Some sig_loc)] @ extract_signature_tree_items hide_item rest
 #if defined OXCAML
@@ -450,8 +454,13 @@ let rec extract_structure_tree_items : bool -> Typedtree.structure_item list ->
              )) cltyps @ extract_structure_tree_items hide_item rest
     | { str_desc = Tstr_open o; _ } :: rest ->
         ((extract_extended_open o) :> items list)  @ extract_structure_tree_items hide_item rest
+#if OCAML_VERSION >= (5,6,0)
+    | { str_desc = Tstr_primitive {prim_id; _}; str_loc; _ } :: rest ->
+      [`Value (prim_id, false, Some str_loc)] @ extract_structure_tree_items hide_item rest
+#else
     | { str_desc = Tstr_primitive {val_id; _}; str_loc; _ } :: rest ->
       [`Value (val_id, false, Some str_loc)] @ extract_structure_tree_items hide_item rest
+#endif
     | { str_desc = Tstr_eval _; _} :: rest -> extract_structure_tree_items hide_item rest
 #if defined OXCAML
     | { str_desc = Tstr_jkind _; _ } :: rest -> extract_structure_tree_items hide_item rest

src/loader/implementation.ml

@@ -38,6 +38,9 @@ module Env = struct
     | Tsig_exception _ | Tsig_modsubst _ | Tsig_open _ | Tsig_include _
     | Tsig_class _ | Tsig_class_type _ | Tsig_attribute _ ->
         ()
+#if OCAML_VERSION >= (5,6,0)
+    | Tsig_primitive _ -> ()
+#endif
 #if defined OXCAML
     | Tsig_jkind _ -> ()
 #endif

src/model/compat.cppo.ml

@@ -210,6 +210,9 @@ let shape_info_of_cmt_infos : Cmt_format.cmt_infos -> (shape * uid_to_loc) optio
     let open Typedtree in
     function
     | Value v -> v.val_loc
+#if OCAML_VERSION >= (5,6,0)
+    | Primitive p -> p.prim_loc
+#endif
     | Value_binding vb -> vb.vb_pat.pat_loc
     | Type t -> t.typ_loc
     | Constructor c -> c.cd_loc

test/generators/cases/ocaml_56.mli

@@ -0,0 +1,13 @@
+(** Features introduced in OCaml 5.6. *)
+
+type ext = external "gmp"
+(** An external type declaration. *)
+
+external classic : int -> int = "caml_classic" "caml_classic_native"
+(** A classic external declaration. *)
+
+external alias_with_type : int -> int = classic
+(** A primitive alias declaring its type. *)
+
+external alias_no_type = classic
+(** A primitive alias leaving its type implicit. *)

test/generators/gen_rules/gen_rules.ml

@@ -68,6 +68,7 @@ let constraints =
     ("class_comments.mli", Min "4.08");
     ("functor_ml.ml", Min "4.14");
     ("ocaml_55.mli", Min "5.5");
+    ("ocaml_56.mli", Min "5.6");
     ("oxcaml.mli", OxCaml);
     ("oxcaml_impl.ml", OxCaml);
   ]

test/generators/html/Ocaml_56.html

@@ -0,0 +1,60 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml">
+ <head><title>Ocaml_56 (Ocaml_56)</title><meta charset="utf-8"/>
+  <link rel="stylesheet" href="odoc.css"/>
+  <meta name="generator" content="odoc %%VERSION%%"/>
+  <meta name="viewport" content="width=device-width,initial-scale=1.0"/>
+  <script src="highlight.pack.js"></script>
+  <script>hljs.initHighlightingOnLoad();</script>
+ </head>
+ <body class="odoc">
+  <nav class="odoc-nav"><a href="index.html">Up</a> – 
+   <a href="index.html">Index</a> &#x00BB; Ocaml_56
+  </nav>
+  <header class="odoc-preamble">
+   <h1>Module <code><span>Ocaml_56</span></code></h1>
+   <p>Features introduced in OCaml 5.6.</p>
+  </header>
+  <div class="odoc-content">
+   <div class="odoc-spec">
+    <div class="spec type anchored" id="type-ext">
+     <a href="#type-ext" class="anchor"></a>
+     <code><span><span class="keyword">type</span> ext</span></code>
+    </div><div class="spec-doc"><p>An external type declaration.</p></div>
+   </div>
+   <div class="odoc-spec">
+    <div class="spec value external anchored" id="val-classic">
+     <a href="#val-classic" class="anchor"></a>
+     <code>
+      <span><span class="keyword">val</span> classic : 
+       <span>int <span class="arrow">&#45;&gt;</span></span> int
+      </span>
+     </code>
+    </div><div class="spec-doc"><p>A classic external declaration.</p></div>
+   </div>
+   <div class="odoc-spec">
+    <div class="spec value external anchored" id="val-alias_with_type">
+     <a href="#val-alias_with_type" class="anchor"></a>
+     <code>
+      <span><span class="keyword">val</span> alias_with_type : 
+       <span>int <span class="arrow">&#45;&gt;</span></span> int
+      </span>
+     </code>
+    </div>
+    <div class="spec-doc"><p>A primitive alias declaring its type.</p></div>
+   </div>
+   <div class="odoc-spec">
+    <div class="spec value external anchored" id="val-alias_no_type">
+     <a href="#val-alias_no_type" class="anchor"></a>
+     <code>
+      <span><span class="keyword">val</span> alias_no_type : 
+       <span>int <span class="arrow">&#45;&gt;</span></span> int
+      </span>
+     </code>
+    </div>
+    <div class="spec-doc"><p>A primitive alias leaving its type implicit.</p>
+    </div>
+   </div>
+  </div>
+ </body>
+</html>

test/generators/html/ocaml_56.targets

@@ -0,0 +1 @@
+Ocaml_56.html

test/generators/latex/Ocaml_56.tex

@@ -0,0 +1,13 @@
+\section{Module \ocamlinlinecode{Ocaml\_\allowbreak{}56}}\label{Ocaml_56}%
+Features introduced in OCaml 5.6.
+
+\label{Ocaml_56--type-ext}\ocamlcodefragment{\ocamltag{keyword}{type} ext}\begin{ocamlindent}An external type declaration.\end{ocamlindent}%
+\medbreak
+\label{Ocaml_56--val-classic}\ocamlcodefragment{\ocamltag{keyword}{val} classic : int \ocamltag{arrow}{$\rightarrow$} int}\begin{ocamlindent}A classic external declaration.\end{ocamlindent}%
+\medbreak
+\label{Ocaml_56--val-alias_with_type}\ocamlcodefragment{\ocamltag{keyword}{val} alias\_\allowbreak{}with\_\allowbreak{}type : int \ocamltag{arrow}{$\rightarrow$} int}\begin{ocamlindent}A primitive alias declaring its type.\end{ocamlindent}%
+\medbreak
+\label{Ocaml_56--val-alias_no_type}\ocamlcodefragment{\ocamltag{keyword}{val} alias\_\allowbreak{}no\_\allowbreak{}type : int \ocamltag{arrow}{$\rightarrow$} int}\begin{ocamlindent}A primitive alias leaving its type implicit.\end{ocamlindent}%
+\medbreak
+
+

test/generators/latex/ocaml_56.targets

@@ -0,0 +1 @@
+Ocaml_56.tex