Implement can_index solving for simple tuple

Summary: Implement can_index solving for simple tuple

Differential Revision: D77865850

fbshipit-source-id: e0a9fa1f795b1d62054777cd4594e5a91bcee5ac

Author: MarisaKirisame

hphp/hack/src/oxidized/copy_types.txt

@@ -109,6 +109,7 @@ type_counter::Category
 type_counter::LoggedType
 typing_defs::ClassConstKind
 typing_defs::VisibilityBehavior
+typing_defs_core::CanIndexShape
 typing_defs_core::ConsistentKind
 typing_defs_core::DestructureKind
 typing_defs_core::Enforcement

hphp/hack/src/oxidized/gen/typing_defs_core.rs

@@ -3,7 +3,7 @@
 // This source code is licensed under the MIT license found in the
 // LICENSE file in the "hack" directory of this source tree.
 //
-// @generated SignedSource<<c6b3687da54a645cd9a50f16647cec27>>
+// @generated SignedSource<<061a1baad55781ab7cbf6d30a6d839fd>>
 //
 // To regenerate this file, run:
 //   hphp/hack/src/oxidized_regen.sh
@@ -1122,6 +1122,30 @@ pub struct HasMember {
     pub explicit_targs: Option<Vec<nast::Targ>>,
 }
 
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    Deserialize,
+    Eq,
+    EqModuloPos,
+    FromOcamlRep,
+    FromOcamlRepIn,
+    Hash,
+    NoPosHash,
+    Ord,
+    PartialEq,
+    PartialOrd,
+    Serialize,
+    ToOcamlRep
+)]
+#[rust_to_ocaml(attr = "deriving show")]
+#[repr(C, u8)]
+pub enum CanIndexShape {
+    IntLit(isize),
+    Generic,
+}
+
 #[derive(
     Clone,
     Debug,
@@ -1142,7 +1166,7 @@ pub struct HasMember {
 #[repr(C)]
 pub struct CanIndex {
     pub key: Ty,
-    pub shape: Option<TshapeFieldName>,
+    pub shape: CanIndexShape,
     pub val: Ty,
     pub expr_pos: pos::Pos,
     pub index_pos: pos::Pos,

hphp/hack/src/oxidized_by_ref/copy_types.txt

@@ -182,6 +182,7 @@ t_shape_map::TShapeMap
 tast::CheckStatus
 typing_cont_key::TypingContKey
 typing_defs::VisibilityBehavior
+typing_defs_core::CanIndexShape
 typing_defs_core::Capability
 typing_defs_core::CeVisibility
 typing_defs_core::ClassRefinement

hphp/hack/src/oxidized_by_ref/gen/typing_defs_core.rs

@@ -3,7 +3,7 @@
 // This source code is licensed under the MIT license found in the
 // LICENSE file in the "hack" directory of this source tree.
 //
-// @generated SignedSource<<a3f5dd3a3e94f23bb77802ece593e841>>
+// @generated SignedSource<<ac83f45f6e5208cf1fc74d07be0e3f73>>
 //
 // To regenerate this file, run:
 //   hphp/hack/src/oxidized_regen.sh
@@ -1102,3 +1102,28 @@ pub enum TupleExtra<'a> {
 }
 impl<'a> TrivialDrop for TupleExtra<'a> {}
 arena_deserializer::impl_deserialize_in_arena!(TupleExtra<'arena>);
+
+#[derive(
+    Clone,
+    Copy,
+    Debug,
+    Deserialize,
+    Eq,
+    EqModuloPos,
+    FromOcamlRepIn,
+    Hash,
+    NoPosHash,
+    Ord,
+    PartialEq,
+    PartialOrd,
+    Serialize,
+    ToOcamlRep
+)]
+#[rust_to_ocaml(attr = "deriving show")]
+#[repr(C, u8)]
+pub enum CanIndexShape {
+    IntLit(isize),
+    Generic,
+}
+impl TrivialDrop for CanIndexShape {}
+arena_deserializer::impl_deserialize_in_arena!(CanIndexShape);

hphp/hack/src/oxidized_by_ref/owned_types.txt

@@ -22,6 +22,7 @@ tast::CheckStatus
 tast::FunTastInfo
 typing_cont_key::TypingContKey
 typing_defs::VisibilityBehavior
+typing_defs_core::CanIndexShape
 typing_defs_core::CollectionStyle
 typing_defs_core::ConsistentKind
 typing_defs_core::DependentType

hphp/hack/src/typing/typing.ml

@@ -3962,7 +3962,10 @@ end = struct
                     Tcan_index
                       {
                         ci_key = ty2;
-                        ci_shape = None;
+                        ci_shape =
+                          (match e2 with
+                          | (_, _, Int i) -> IntLit (int_of_string i)
+                          | _ -> Generic);
                         ci_val = res_ty;
                         ci_expr_pos = p;
                         ci_index_pos = snd3 e2;

hphp/hack/src/typing/typing_defs_core.ml

@@ -1443,9 +1443,14 @@ type has_member = {
 }
 [@@deriving show]
 
+type can_index_shape =
+  | IntLit of int
+  | Generic
+[@@deriving show]
+
 type can_index = {
   ci_key: locl_ty;
-  ci_shape: tshape_field_name option;
+  ci_shape: can_index_shape;
   ci_val: locl_ty;
   ci_expr_pos: Pos.t;
   ci_index_pos: Pos.t;
@@ -1573,11 +1578,18 @@ let has_member_compare ~normalize_lists hm1 hm2 =
     | comp -> comp)
   | comp -> comp
 
+let can_index_shape_compare cis1 cis2 =
+  match (cis1, cis2) with
+  | (IntLit i1, IntLit i2) -> Int.compare i1 i2
+  | (IntLit _, _) -> -1
+  | (_, IntLit _) -> 1
+  | (Generic, Generic) -> 0
+
 let can_index_compare ~normalize_lists ci1 ci2 =
   match ty_compare ~normalize_lists ci1.ci_key ci2.ci_key with
   | 0 ->
     (match ty_compare ~normalize_lists ci1.ci_val ci2.ci_val with
-    | 0 -> Option.compare compare_tshape_field_name ci1.ci_shape ci2.ci_shape
+    | 0 -> can_index_shape_compare ci1.ci_shape ci2.ci_shape
     | comp -> comp)
   | comp -> comp
 

hphp/hack/src/typing/typing_defs_core.mli

@@ -645,9 +645,14 @@ type destructure = {
  * indexed with certain literals, and so in those cases it is not sufficient to
  * record simply the type of the index.
  *)
+type can_index_shape =
+  | IntLit of int
+  | Generic
+[@@deriving show]
+
 type can_index = {
   ci_key: locl_ty;
-  ci_shape: tshape_field_name option;
+  ci_shape: can_index_shape;
   ci_val: locl_ty;
   ci_expr_pos: Pos.t;
   ci_index_pos: Pos.t;

hphp/hack/src/typing/typing_print.ml

@@ -652,10 +652,10 @@ module Full = struct
     let (fuel, val_doc) = k ~fuel ci.ci_val in
     ( fuel,
       match ci.ci_shape with
-      | None ->
+      | Generic ->
         Concat
           [text "can_index"; text "("; key_doc; comma_sep; val_doc; text ")"]
-      | Some _ft ->
+      | _ ->
         Concat
           [
             text "can_index";

hphp/hack/src/typing/typing_subtype.ml

@@ -6178,23 +6178,17 @@ end = struct
     let mk_prop ~subtype_env ~this_ty ~lhs ~rhs =
       simplify ~subtype_env ~this_ty ~lhs ~rhs
     in
-    let is_container tk tv =
+    let simplify_default ~subtype_env lhs rhs env =
       Subtype.simplify
         ~subtype_env
         ~this_ty
-        ~lhs:{ sub_supportdyn; ty_sub = can_index.ci_key }
-        ~rhs:{ super_like = false; super_supportdyn = false; ty_super = tk }
+        ~lhs:{ sub_supportdyn; ty_sub = lhs }
+        ~rhs:{ super_like = false; super_supportdyn = false; ty_super = rhs }
         env
-      &&& Subtype.simplify
-            ~subtype_env
-            ~this_ty
-            ~lhs:{ sub_supportdyn; ty_sub = tv }
-            ~rhs:
-              {
-                super_like = false;
-                super_supportdyn = false;
-                ty_super = can_index.ci_val;
-              }
+    in
+    let is_container tk tv =
+      simplify_default ~subtype_env can_index.ci_key tk env
+      &&& simplify_default ~subtype_env tv can_index.ci_val
     in
     match deref ty_sub with
     | (_, Tvar _) ->
@@ -6206,16 +6200,10 @@ end = struct
         (ConstraintType
            (mk_constraint_type (reason_super, Tcan_index can_index)))
     | (_, Tdynamic) ->
-      Subtype.simplify
+      simplify_default
         ~subtype_env
-        ~this_ty
-        ~lhs:{ sub_supportdyn; ty_sub = MakeType.dynamic reason_super }
-        ~rhs:
-          {
-            super_like = false;
-            super_supportdyn = false;
-            ty_super = can_index.ci_val;
-          }
+        (MakeType.dynamic reason_super)
+        can_index.ci_val
         env
       &&&
       if
@@ -6225,16 +6213,10 @@ end = struct
         let subtype_env =
           { subtype_env with coerce = Some Typing_logic.CoerceToDynamic }
         in
-        Subtype.simplify
+        simplify_default
           ~subtype_env
-          ~this_ty
-          ~lhs:{ sub_supportdyn; ty_sub = can_index.ci_key }
-          ~rhs:
-            {
-              super_like = false;
-              super_supportdyn = false;
-              ty_super = MakeType.dynamic (get_reason ty_sub);
-            }
+          can_index.ci_key
+          (MakeType.dynamic (get_reason ty_sub))
       else
         valid
     | (_, Tclass ((_, n), _, [tv]))
@@ -6264,6 +6246,35 @@ end = struct
         (sub_supportdyn, ty_subs)
         rhs
         env
+    | (_, Ttuple tup) ->
+      (match can_index.ci_shape with
+      | IntLit i ->
+        (match List.nth tup.t_required i with
+        | Some ty -> simplify_default ~subtype_env ty can_index.ci_val env
+        | None ->
+          invalid
+            ~fail:
+              (Some
+                 Typing_error.(
+                   primary
+                   @@ Primary.Generic_unify
+                        {
+                          pos = can_index.ci_index_pos;
+                          msg = Reason.string_of_ureason Reason.index_tuple;
+                        }))
+            env)
+      | _ ->
+        invalid
+          ~fail:
+            (Some
+               Typing_error.(
+                 primary
+                 @@ Primary.Generic_unify
+                      {
+                        pos = can_index.ci_index_pos;
+                        msg = Reason.string_of_ureason Reason.URtuple_access;
+                      }))
+          env)
     | _ -> invalid ~fail env
 end