Add new configuration option "tco_constraint_array_index"

Summary: Add new configuration option "tco_constraint_array_index", which will gate constraint based typechecking of array indexing expression

Differential Revision: D77380458

fbshipit-source-id: ba1f3f7afa9bf23a37e79c3207b06ca80a776442

Author: MarisaKirisame

hphp/hack/src/client_and_server/serverConfig.ml

@@ -382,6 +382,7 @@ let load_config (config : Config_file_common.t) (options : GlobalOptions.t) :
     ?tco_language_feature_logging:(bool_opt "language_feature_logging" config)
     ?tco_timeout:(int_opt "timeout" config)
     ?tco_disallow_invalid_arraykey:(bool_opt "disallow_invalid_arraykey" config)
+    ?tco_constraint_array_index:(bool_opt "constraint_array_index" config)
     ?code_agnostic_fixme:(bool_opt "code_agnostic_fixme" config)
     ?allowed_fixme_codes_strict:
       (prepare_iset config "allowed_fixme_codes_strict")

hphp/hack/src/options/globalOptions.ml

@@ -103,6 +103,7 @@ type t = {
   tco_language_feature_logging: bool;
   tco_timeout: int;
   tco_disallow_invalid_arraykey: bool;
+  tco_constraint_array_index: bool;
   code_agnostic_fixme: bool;
   allowed_fixme_codes_strict: ISet.t;
   log_levels: int SMap.t;
@@ -224,6 +225,7 @@ let default =
     tco_language_feature_logging = false;
     tco_timeout = 0;
     tco_disallow_invalid_arraykey = true;
+    tco_constraint_array_index = false;
     code_agnostic_fixme = false;
     allowed_fixme_codes_strict = ISet.empty;
     log_levels = SMap.empty;
@@ -344,6 +346,7 @@ let set
     ?tco_language_feature_logging
     ?tco_timeout
     ?tco_disallow_invalid_arraykey
+    ?tco_constraint_array_index
     ?code_agnostic_fixme
     ?allowed_fixme_codes_strict
     ?log_levels
@@ -500,6 +503,8 @@ let set
       setting
         tco_disallow_invalid_arraykey
         options.tco_disallow_invalid_arraykey;
+    tco_constraint_array_index =
+      setting tco_constraint_array_index options.tco_constraint_array_index;
     log_levels = setting log_levels options.log_levels;
     tco_remote_old_decls_no_limit =
       setting

hphp/hack/src/options/globalOptions.mli

@@ -97,6 +97,8 @@ type t = {
   tco_disallow_invalid_arraykey: bool;
       (** Flag to disallow using values that get casted to array keys at runtime;
         like bools, floats, or null; as array keys. *)
+  tco_constraint_array_index: bool;
+      (** Flag to enable the constraint solver to infer that a type can be indexed *)
   code_agnostic_fixme: bool;
       (** HH_FIXME should silence *any* error, not just the one specified by code *)
   allowed_fixme_codes_strict: ISet.t;
@@ -324,6 +326,7 @@ val set :
   ?tco_language_feature_logging:bool ->
   ?tco_timeout:int ->
   ?tco_disallow_invalid_arraykey:bool ->
+  ?tco_constraint_array_index:bool ->
   ?code_agnostic_fixme:bool ->
   ?allowed_fixme_codes_strict:ISet.t ->
   ?log_levels:int SMap.t ->

hphp/hack/src/options/typecheckerOptions.ml

@@ -91,6 +91,8 @@ let timeout t = t.GlobalOptions.tco_timeout
 
 let disallow_invalid_arraykey t = t.GlobalOptions.tco_disallow_invalid_arraykey
 
+let constraint_array_index t = t.GlobalOptions.tco_constraint_array_index
+
 let log_levels t = t.GlobalOptions.log_levels
 
 let remote_old_decls_no_limit t = t.GlobalOptions.tco_remote_old_decls_no_limit

hphp/hack/src/oxidized/gen/global_options.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<<4bbf7b8ca7578ba93659f67d2b642806>>
+// @generated SignedSource<<4e9edccd68800485daea4b4b0079141e>>
 //
 // To regenerate this file, run:
 //   hphp/hack/src/oxidized_regen.sh
@@ -166,6 +166,7 @@ pub struct GlobalOptions {
     pub tco_language_feature_logging: bool,
     pub tco_timeout: isize,
     pub tco_disallow_invalid_arraykey: bool,
+    pub tco_constraint_array_index: bool,
     pub code_agnostic_fixme: bool,
     pub allowed_fixme_codes_strict: i_set::ISet,
     pub log_levels: s_map::SMap<isize>,

hphp/hack/src/oxidized/manual/global_options_impl.rs

@@ -54,6 +54,7 @@ impl Default for GlobalOptions {
             tco_language_feature_logging: false,
             tco_timeout: 0,
             tco_disallow_invalid_arraykey: false, // true in ocaml, true in .hhconfig
+            tco_constraint_array_index: false,
             code_agnostic_fixme: false,
             allowed_fixme_codes_strict: i_set::ISet::new(),
             log_levels: s_map::SMap::new(),

hphp/hack/src/utils/hh_config/hh_config.rs

@@ -352,6 +352,8 @@ impl HhConfig {
                 "disallow_invalid_arraykey",
                 default.tco_disallow_invalid_arraykey,
             )?,
+            tco_constraint_array_index: hhconfig
+                .get_bool_or("constraint_array_index", default.code_agnostic_fixme)?,
             code_agnostic_fixme: hhconfig
                 .get_bool_or("code_agnostic_fixme", default.code_agnostic_fixme)?,
             allowed_fixme_codes_strict: hhconfig.get_int_set_or(