deactivate recursive type alias check for case types under recursive_…

…case_types flag Summary: Under `recursive_case_types`, do not check whether case types are recursive. Differential Revision: D63026669 fbshipit-source-id: b81923f55b2d5847e14e63cb00f4fa20ff1642a5
facebook · Sep 20, 2024 · 781cdb1 · 781cdb1
1 parent 6090314
commit 781cdb1
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Showing 37 changed files with 33 additions and 147 deletions.
diff --git a/hphp/hack/src/client_and_server/serverConfig.ml b/hphp/hack/src/client_and_server/serverConfig.ml
@@ -492,6 +492,7 @@ let load_config config options =
  |> Option.map ~f:(function
  | true -> GlobalOptions.All_except []
  | false -> GlobalOptions.NNone))
+ ?recursive_case_types:(bool_opt "recursive_case_types" config)
  options
 
 let load

diff --git a/hphp/hack/src/options/globalOptions.ml b/hphp/hack/src/options/globalOptions.ml
@@ -191,6 +191,7 @@ type t = {
  hh_distc_should_disable_trace_store: bool;
  hh_distc_exponential_backoff_num_retries: int;
  tco_enable_abstract_method_optional_parameters: bool;
+ recursive_case_types: bool;
 }
 [@@deriving eq, show]
 
@@ -300,6 +301,7 @@ let default =
  hh_distc_should_disable_trace_store = false;
  hh_distc_exponential_backoff_num_retries = 10;
  tco_enable_abstract_method_optional_parameters = false;
+ recursive_case_types = false;
  }
 
 let set
@@ -407,6 +409,7 @@ let set
  ?hh_distc_should_disable_trace_store
  ?hh_distc_exponential_backoff_num_retries
  ?tco_enable_abstract_method_optional_parameters
+ ?recursive_case_types
  options =
  let setting setting option =
  match setting with
@@ -687,6 +690,8 @@ let set
  setting
  tco_enable_abstract_method_optional_parameters
  options.tco_enable_abstract_method_optional_parameters;
+ recursive_case_types =
+ setting recursive_case_types options.recursive_case_types;
  }
 
 let so_naming_sqlite_path t = t.so_naming_sqlite_path

diff --git a/hphp/hack/src/options/globalOptions.mli b/hphp/hack/src/options/globalOptions.mli
@@ -278,6 +278,7 @@ type t = {
  (** Number of retries when uploading/download/executing with hh_distc *)
  tco_enable_abstract_method_optional_parameters: bool;
  (** Enable use of optional on parameters in abstract methods *)
+ recursive_case_types: bool; (** Enable recursive case types *)
 }
 [@@deriving eq, show]
 
@@ -386,6 +387,7 @@ val set :
  ?hh_distc_should_disable_trace_store:bool ->
  ?hh_distc_exponential_backoff_num_retries:int ->
  ?tco_enable_abstract_method_optional_parameters:bool ->
+ ?recursive_case_types:bool ->
  t ->
  t
 

diff --git a/hphp/hack/src/oxidized/gen/global_options.rs b/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<<642754a417b3593b8bcb4cfa09c0f06c>>
+// @generated SignedSource<<77f6a8adb4a83aec208ba4b5d6133861>>
 //
 // To regenerate this file, run:
 // hphp/hack/src/oxidized_regen.sh
@@ -254,4 +254,5 @@ pub struct GlobalOptions {
  pub hh_distc_should_disable_trace_store: bool,
  pub hh_distc_exponential_backoff_num_retries: isize,
  pub tco_enable_abstract_method_optional_parameters: bool,
+ pub recursive_case_types: bool,
 }
diff --git a/hphp/hack/src/oxidized/manual/global_options_impl.rs b/hphp/hack/src/oxidized/manual/global_options_impl.rs
@@ -144,6 +144,7 @@ impl Default for GlobalOptions {
  hh_distc_should_disable_trace_store: false,
  hh_distc_exponential_backoff_num_retries: 10,
  tco_enable_abstract_method_optional_parameters: false,
+ recursive_case_types: false,
  }
  }
 }
diff --git a/hphp/hack/src/typing/typing_typedef.ml b/hphp/hack/src/typing/typing_typedef.ml
@@ -100,6 +100,18 @@ let casetype_def env typedef =
  env
  | _ -> env
 
+let do_report_cycles env (vis : typedef_visibility) =
+ match vis with
+ | Transparent
+ | Opaque
+ | OpaqueModule ->
+ true
+ | CaseType ->
+ let recursive_case_types env =
+ (Env.get_tcopt env).GlobalOptions.recursive_case_types
+ in
+ not (recursive_case_types env)
+
 let typedef_def ctx typedef =
  let env = EnvFromDef.typedef_env ~origin:Decl_counters.TopLevel ctx typedef in
  let {
@@ -152,8 +164,9 @@ let typedef_def ctx typedef =
  ~report_cycle:(t_pos, Type_expansions.Expandable.Type_alias t_name_)
  t_kind
  in
- Type_expansions.report cycles
- |> Option.iter ~f:(Typing_error_utils.add_typing_error ~env);
+ if do_report_cycles env t_vis then
+ Type_expansions.report cycles
+ |> Option.iter ~f:(Typing_error_utils.add_typing_error ~env);
  let env = casetype_def env typedef in
  Option.iter ~f:(Typing_error_utils.add_typing_error ~env) ty_err_opt2;
 

diff --git a/hphp/hack/src/utils/hh_config/hh_config.rs b/hphp/hack/src/utils/hh_config/hh_config.rs
@@ -452,6 +452,7 @@ impl HhConfig {
  hh_distc_exponential_backoff_num_retries: hhconfig.get_int_or(
  "hh_distc_exponential_backoff_num_retries", default.hh_distc_exponential_backoff_num_retries)?,
  tco_enable_abstract_method_optional_parameters: hhconfig.get_bool_or("enable_abstract_method_optional_parameters", default.tco_enable_abstract_method_optional_parameters)?,
+ recursive_case_types: hhconfig.get_bool_or("recursive_case_types", default.recursive_case_types)?,
  };
  let mut c = Self {
  local_config,

diff --git a/hphp/hack/test/typecheck/case_type/recursive/HH_FLAGS b/hphp/hack/test/typecheck/case_type/recursive/HH_FLAGS
@@ -0,0 +1 @@
+--config recursive_case_types=true
diff --git a/hphp/hack/test/typecheck/case_type/recursive/forest.php.exp b/hphp/hack/test/typecheck/case_type/recursive/forest.php.exp
@@ -1,11 +1,3 @@
-ERROR: File "forest.php", line 4, characters 11-16:
-Cyclic type definition (Typing[4014])
- File "forest.php", line 4, characters 33-41:
- Cyclic use is here
-ERROR: File "forest.php", line 16, characters 11-13:
-Cyclic type definition (Typing[4014])
- File "forest.php", line 16, characters 24-29:
- Cyclic use is here
 ERROR: File "forest.php", line 10, characters 10-18:
 Invalid return type (Typing[4336])
  File "forest.php", line 10, characters 39-39:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/forest_w_type_alias.php.exp b/hphp/hack/test/typecheck/case_type/recursive/forest_w_type_alias.php.exp
@@ -1,8 +1 @@
-ERROR: File "forest_w_type_alias.php", line 4, characters 11-13:
-Cyclic type definition (Typing[4014])
- File "forest_w_type_alias.php", line 4, characters 24-29:
- Cyclic use is here
-ERROR: File "forest_w_type_alias.php", line 32, characters 11-16:
-Cyclic type definition (Typing[4014])
- File "forest_w_type_alias.php", line 35, characters 15-23:
- Cyclic use is here
+No errors
diff --git a/hphp/hack/test/typecheck/case_type/recursive/int_tree.php.exp b/hphp/hack/test/typecheck/case_type/recursive/int_tree.php.exp
@@ -1,4 +1 @@
-ERROR: File "int_tree.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "int_tree.php", line 4, characters 19-19:
- Cyclic use is here
+No errors
diff --git a/hphp/hack/test/typecheck/case_type/recursive/list_w_type_alias.php.exp b/hphp/hack/test/typecheck/case_type/recursive/list_w_type_alias.php.exp
@@ -1,4 +1 @@
-ERROR: File "list_w_type_alias.php", line 4, characters 11-13:
-Cyclic type definition (Typing[4014])
- File "list_w_type_alias.php", line 5, characters 20-25:
- Cyclic use is here
+No errors
diff --git a/hphp/hack/test/typecheck/case_type/recursive/non_termination_bug_inter1.php.exp b/hphp/hack/test/typecheck/case_type/recursive/non_termination_bug_inter1.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "non_termination_bug_inter1.php", line 4, characters 11-13:
-Cyclic type definition (Typing[4014])
- File "non_termination_bug_inter1.php", line 4, characters 27-32:
- Cyclic use is here
 ERROR: File "non_termination_bug_inter1.php", line 9, characters 13-29:
 Invalid `is` expression hint (Typing[4195])
  File "non_termination_bug_inter1.php", line 9, characters 20-28:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/non_termination_bug_inter2.php.exp b/hphp/hack/test/typecheck/case_type/recursive/non_termination_bug_inter2.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "non_termination_bug_inter2.php", line 4, characters 11-13:
-Cyclic type definition (Typing[4014])
- File "non_termination_bug_inter2.php", line 5, characters 23-28:
- Cyclic use is here
 ERROR: File "non_termination_bug_inter2.php", line 10, characters 13-22:
 Invalid `is` expression hint (Typing[4195])
  File "non_termination_bug_inter2.php", line 10, characters 13-22:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3b.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3b.php.exp
@@ -1,11 +1,3 @@
-ERROR: File "subtyping_mutual3b.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual3b.php", line 6, characters 16-16:
- Cyclic use is here
-ERROR: File "subtyping_mutual3b.php", line 6, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual3b.php", line 4, characters 16-16:
- Cyclic use is here
 ERROR: File "subtyping_mutual3b.php", line 29, characters 5-6:
 Invalid argument (Typing[4110])
  File "subtyping_mutual3b.php", line 10, characters 22-27:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3c.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3c.php.exp
@@ -1,11 +1,3 @@
-ERROR: File "subtyping_mutual3c.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual3c.php", line 6, characters 20-20:
- Cyclic use is here
-ERROR: File "subtyping_mutual3c.php", line 6, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual3c.php", line 4, characters 16-16:
- Cyclic use is here
 ERROR: File "subtyping_mutual3c.php", line 29, characters 5-6:
 Invalid argument (Typing[4110])
  File "subtyping_mutual3c.php", line 10, characters 26-26:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3d.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3d.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_mutual3d.php", line 6, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual3d.php", line 4, characters 16-16:
- Cyclic use is here
 ERROR: File "subtyping_mutual3d.php", line 26, characters 15-16:
 Invalid argument (Typing[4110])
  File "subtyping_mutual3d.php", line 10, characters 22-27:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3d.php.imp_pess_exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual3d.php.imp_pess_exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_mutual3d.php", line 6, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual3d.php", line 4, characters 16-16:
- Cyclic use is here
 ERROR: File "subtyping_mutual3d.php", line 26, characters 15-16:
 Invalid argument (Typing[4110])
  File "subtyping_mutual3d.php", line 10, characters 22-27:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5b.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5b.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_mutual5b.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual5b.php", line 6, characters 16-16:
- Cyclic use is here
 ERROR: File "subtyping_mutual5b.php", line 26, characters 12-13:
 Invalid argument (Typing[4110])
  File "subtyping_mutual5b.php", line 9, characters 19-19:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5b.php.imp_pess_exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5b.php.imp_pess_exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_mutual5b.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual5b.php", line 6, characters 16-16:
- Cyclic use is here
 ERROR: File "subtyping_mutual5b.php", line 26, characters 12-13:
 Invalid argument (Typing[4110])
  File "subtyping_mutual5b.php", line 9, characters 19-19:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5c.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5c.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_mutual5c.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual5c.php", line 6, characters 20-20:
- Cyclic use is here
 ERROR: File "subtyping_mutual5c.php", line 26, characters 12-13:
 Invalid argument (Typing[4110])
  File "subtyping_mutual5c.php", line 9, characters 19-19:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5c.php.imp_pess_exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_mutual5c.php.imp_pess_exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_mutual5c.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_mutual5c.php", line 6, characters 20-20:
- Cyclic use is here
 ERROR: File "subtyping_mutual5c.php", line 26, characters 12-13:
 Invalid argument (Typing[4110])
  File "subtyping_mutual5c.php", line 9, characters 19-19:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple1.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple1.php", line 4, characters 15-15:
- Cyclic use is here
 ERROR: File "subtyping_simple1.php", line 11, characters 17-18:
 Invalid argument (Typing[4110])
  File "subtyping_simple1.php", line 7, characters 24-29:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1.php.imp_pess_exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1.php.imp_pess_exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple1.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple1.php", line 4, characters 15-15:
- Cyclic use is here
 ERROR: File "subtyping_simple1.php", line 11, characters 17-18:
 Invalid argument (Typing[4110])
  File "subtyping_simple1.php", line 7, characters 24-29:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1b.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1b.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple1b.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple1b.php", line 4, characters 20-20:
- Cyclic use is here
 ERROR: File "subtyping_simple1b.php", line 11, characters 17-18:
 Invalid argument (Typing[4110])
  File "subtyping_simple1b.php", line 7, characters 24-29:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1c.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple1c.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple1c.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple1c.php", line 4, characters 25-25:
- Cyclic use is here
 ERROR: File "subtyping_simple1c.php", line 12, characters 12-13:
 Invalid argument (Typing[4110])
  File "subtyping_simple1c.php", line 6, characters 19-19:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple2.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple2.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple2.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple2.php", line 4, characters 15-15:
- Cyclic use is here
 ERROR: File "subtyping_simple2.php", line 11, characters 14-15:
 Invalid argument (Typing[4110])
  File "subtyping_simple2.php", line 7, characters 21-23:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple2.php.imp_pess_exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple2.php.imp_pess_exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple2.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple2.php", line 4, characters 15-15:
- Cyclic use is here
 ERROR: File "subtyping_simple2.php", line 11, characters 14-15:
 Invalid argument (Typing[4110])
  File "subtyping_simple2.php", line 7, characters 21-23:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple2b.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple2b.php.exp
@@ -1,8 +1,4 @@
 ERROR: File "subtyping_simple2b.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple2b.php", line 4, characters 22-22:
- Cyclic use is here
-ERROR: File "subtyping_simple2b.php", line 4, characters 11-11:
 Invalid constraint on `newtype` (Typing[4332])
  File "subtyping_simple2b.php", line 4, characters 16-18:
  Expected `int`

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple3.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple3.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple3.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple3.php", line 4, characters 19-19:
- Cyclic use is here
 ERROR: File "subtyping_simple3.php", line 20, characters 15-16:
 Invalid argument (Typing[4110])
  File "subtyping_simple3.php", line 7, characters 22-27:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple3.php.imp_pess_exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple3.php.imp_pess_exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple3.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple3.php", line 4, characters 19-19:
- Cyclic use is here
 ERROR: File "subtyping_simple3.php", line 20, characters 15-16:
 Invalid argument (Typing[4110])
  File "subtyping_simple3.php", line 7, characters 22-27:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple4.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple4.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple4.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple4.php", line 4, characters 19-19:
- Cyclic use is here
 ERROR: File "subtyping_simple4.php", line 22, characters 15-16:
 Invalid argument (Typing[4110])
  File "subtyping_simple4.php", line 7, characters 22-27:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple4.php.imp_pess_exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple4.php.imp_pess_exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple4.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple4.php", line 4, characters 19-19:
- Cyclic use is here
 ERROR: File "subtyping_simple4.php", line 22, characters 15-16:
 Invalid argument (Typing[4110])
  File "subtyping_simple4.php", line 7, characters 22-27:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple4b.php.exp b/hphp/hack/test/typecheck/case_type/recursive/subtyping_simple4b.php.exp
@@ -1,7 +1,3 @@
-ERROR: File "subtyping_simple4b.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "subtyping_simple4b.php", line 4, characters 29-29:
- Cyclic use is here
 ERROR: File "subtyping_simple4b.php", line 22, characters 15-16:
 Invalid argument (Typing[4110])
  File "subtyping_simple4b.php", line 7, characters 26-26:

diff --git a/hphp/hack/test/typecheck/case_type/recursive/tree_without_elements.php.exp b/hphp/hack/test/typecheck/case_type/recursive/tree_without_elements.php.exp
@@ -1,4 +1 @@
-ERROR: File "tree_without_elements.php", line 4, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "tree_without_elements.php", line 4, characters 19-19:
- Cyclic use is here
+No errors
diff --git a/hphp/hack/test/typecheck/case_type/recursive/union1.php.exp b/hphp/hack/test/typecheck/case_type/recursive/union1.php.exp
@@ -1,4 +1 @@
-ERROR: File "union1.php", line 4, characters 11-13:
-Cyclic type definition (Typing[4014])
- File "union1.php", line 4, characters 24-29:
- Cyclic use is here
+No errors
diff --git a/hphp/hack/test/typecheck/case_type/recursive/variance1.php.exp b/hphp/hack/test/typecheck/case_type/recursive/variance1.php.exp
@@ -1,19 +1,3 @@
-ERROR: File "variance1.php", line 8, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "variance1.php", line 8, characters 23-26:
- Cyclic use is here
-ERROR: File "variance1.php", line 9, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "variance1.php", line 9, characters 23-26:
- Cyclic use is here
-ERROR: File "variance1.php", line 10, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "variance1.php", line 10, characters 26-29:
- Cyclic use is here
-ERROR: File "variance1.php", line 11, characters 11-11:
-Cyclic type definition (Typing[4014])
- File "variance1.php", line 11, characters 26-29:
- Cyclic use is here
 ERROR: File "variance1.php", line 11, characters 28-28:
 Illegal usage of a covariant type parameter (Typing[4120])
  File "variance1.php", line 11, characters 14-14: