[flow] Emit errors for the 7 reserved keywords for class definitions

Summary: Changelog: [error] Flow will error for the following reserved keywords: `$NonMaybeType`, `NonNullable`, `$ReadOnly`, `Readonly`, `$Keys`, `$Values`, `Values` when defining or declaring a class.

Reviewed By: SamChou19815

Differential Revision: D84752605

fbshipit-source-id: 9d72c76c447fa19a5d4751729ac5c56d6fb8de13

Author: marcoww6

src/analysis/env_builder/name_resolver.ml

@@ -4519,14 +4519,32 @@ module Make (Context : C) (FlowAPIUtils : F with type cx = Context.t) :
         class_stack <- class_stack_old;
         cls
 
+      method private check_class_name name_loc name =
+        let open Flow_intermediate_error_types in
+        match IncorrectType.from_str name with
+        | Some keyword when IncorrectType.is_type_reserved keyword ->
+          add_output
+            Error_message.(
+              EBindingError (EReservedKeyword { keyword }, name_loc, OrdinaryName name, name_loc)
+            )
+        | _ -> ()
+
+      method! class_identifier ((name_loc, { Ast.Identifier.name; comments = _ }) as id) =
+        (* Called by `declare class` *)
+        this#check_class_name name_loc name;
+        super#class_identifier id
+
       method! class_identifier_opt ~class_loc:loc id =
         let (class_write_loc, class_self_reason) =
           match id with
           | Some ((name_loc, { Ast.Identifier.name; comments = _ }) as id) ->
+            (* Process `class <name> {}` *)
+            this#check_class_name name_loc name;
             this#bind_pattern_identifier_customized ~kind:ClassBinding name_loc name;
             ignore @@ super#identifier id;
             (name_loc, mk_reason (RType (OrdinaryName name)) name_loc)
           | None ->
+            (* Process annonymous class *)
             let reason = mk_reason (RType (OrdinaryName "<<anonymous class>>")) loc in
             env_state <-
               {

tests/ts_syntax/reserved_type.js

@@ -16,3 +16,23 @@
    declare type $Values<T> = Array<T>;
    declare type Values = Array<string>;
 }
+
+{
+   declare class $NonMaybeType {}
+   declare class NonNullable {}
+   declare class $ReadOnly {}
+   declare class Readonly {}
+   declare class $Keys<TT> {}
+   declare class $Values<T> {}
+   declare class Values {}
+}
+
+{
+   class $NonMaybeType {}
+   class NonNullable {}
+   class $ReadOnly {}
+   class Readonly {}
+   class $Keys<TT> {}
+   class $Values<T> {}
+   class Values {}
+}

tests/ts_syntax/ts_syntax.exp

@@ -845,6 +845,118 @@ Cannot declare `Values` [1], because `Values` is a reserved type name. [reserved
                        ^^^^^^ [1]
 
 
+Error ------------------------------------------------------------------------------------------- reserved_type.js:21:18
+
+Cannot declare `$NonMaybeType` [1], because `$NonMaybeType` is a reserved type name. [reserved-keyword]
+
+   21|    declare class $NonMaybeType {}
+                        ^^^^^^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:22:18
+
+Cannot declare `NonNullable` [1], because `NonNullable` is a reserved type name. [reserved-keyword]
+
+   22|    declare class NonNullable {}
+                        ^^^^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:23:18
+
+Cannot declare `$ReadOnly` [1], because `$ReadOnly` is a reserved type name. [reserved-keyword]
+
+   23|    declare class $ReadOnly {}
+                        ^^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:24:18
+
+Cannot declare `Readonly` [1], because `Readonly` is a reserved type name. [reserved-keyword]
+
+   24|    declare class Readonly {}
+                        ^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:25:18
+
+Cannot declare `$Keys` [1], because `$Keys` is a reserved type name. [reserved-keyword]
+
+   25|    declare class $Keys<TT> {}
+                        ^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:26:18
+
+Cannot declare `$Values` [1], because `$Values` is a reserved type name. [reserved-keyword]
+
+   26|    declare class $Values<T> {}
+                        ^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:27:18
+
+Cannot declare `Values` [1], because `Values` is a reserved type name. [reserved-keyword]
+
+   27|    declare class Values {}
+                        ^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:31:10
+
+Cannot declare `$NonMaybeType` [1], because `$NonMaybeType` is a reserved type name. [reserved-keyword]
+
+   31|    class $NonMaybeType {}
+                ^^^^^^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:32:10
+
+Cannot declare `NonNullable` [1], because `NonNullable` is a reserved type name. [reserved-keyword]
+
+   32|    class NonNullable {}
+                ^^^^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:33:10
+
+Cannot declare `$ReadOnly` [1], because `$ReadOnly` is a reserved type name. [reserved-keyword]
+
+   33|    class $ReadOnly {}
+                ^^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:34:10
+
+Cannot declare `Readonly` [1], because `Readonly` is a reserved type name. [reserved-keyword]
+
+   34|    class Readonly {}
+                ^^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:35:10
+
+Cannot declare `$Keys` [1], because `$Keys` is a reserved type name. [reserved-keyword]
+
+   35|    class $Keys<TT> {}
+                ^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:36:10
+
+Cannot declare `$Values` [1], because `$Values` is a reserved type name. [reserved-keyword]
+
+   36|    class $Values<T> {}
+                ^^^^^^^ [1]
+
+
+Error ------------------------------------------------------------------------------------------- reserved_type.js:37:10
+
+Cannot declare `Values` [1], because `Values` is a reserved type name. [reserved-keyword]
+
+   37|    class Values {}
+                ^^^^^^ [1]
+
+
 Error ------------------------------------------------------------------------------------------------ satisfies.js:4:18
 
 Cannot build a typed interface for this module. You should annotate the exports of this module with types. Cannot
@@ -910,4 +1022,4 @@ types. [ts-syntax]
 
 
 
-Found 108 errors
+Found 122 errors