typing/predef support for atomic locations

This type will be used for ['a Atomic.Loc.t], as proposed
in the RFC
  ocaml/RFCs#39

We implement this here to be able to use it in the stdlib later,
after a bootstrap.

Author: gasche

typing/predef.ml

@@ -47,6 +47,7 @@ and ident_lazy_t = ident_create "lazy_t"
 and ident_string = ident_create "string"
 and ident_extension_constructor = ident_create "extension_constructor"
 and ident_floatarray = ident_create "floatarray"
+and ident_atomic_loc = ident_create "atomic_loc"
 
 let path_int = Pident ident_int
 and path_char = Pident ident_char
@@ -67,6 +68,7 @@ and path_lazy_t = Pident ident_lazy_t
 and path_string = Pident ident_string
 and path_extension_constructor = Pident ident_extension_constructor
 and path_floatarray = Pident ident_floatarray
+and path_atomic_loc = Pident ident_atomic_loc
 
 let type_int = newgenty (Tconstr(path_int, [], ref Mnil))
 and type_char = newgenty (Tconstr(path_char, [], ref Mnil))
@@ -89,6 +91,7 @@ and type_string = newgenty (Tconstr(path_string, [], ref Mnil))
 and type_extension_constructor =
       newgenty (Tconstr(path_extension_constructor, [], ref Mnil))
 and type_floatarray = newgenty (Tconstr(path_floatarray, [], ref Mnil))
+and type_atomic_loc t = newgenty (Tconstr(path_atomic_loc, [t], ref Mnil))
 
 let ident_match_failure = ident_create "Match_failure"
 and ident_out_of_memory = ident_create "Out_of_memory"
@@ -244,6 +247,9 @@ let build_initial_env add_type add_extension empty_env =
   |> add_type ident_extension_constructor
   |> add_type ident_float
   |> add_type ident_floatarray
+  |> add_type1 ident_atomic_loc
+       ~variance:Variance.full
+       ~separability:Separability.Ind
   |> add_type ident_int ~immediate:Always
   |> add_type ident_int32
   |> add_type ident_int64

typing/predef.mli

@@ -34,8 +34,9 @@ val type_nativeint: type_expr
 val type_int32: type_expr
 val type_int64: type_expr
 val type_lazy_t: type_expr -> type_expr
-val type_extension_constructor:type_expr
-val type_floatarray:type_expr
+val type_extension_constructor: type_expr
+val type_floatarray: type_expr
+val type_atomic_loc: type_expr -> type_expr
 
 val path_int: Path.t
 val path_char: Path.t