Introduce scope tracking in the parser (#9493)

* Introduce scope tracking

* Fix tests

* Add new tests

* Remove constructor-super check from transform as it is now in parser

* Correctly handle class properties and class scope

* Fix duplicate name check

* Convert scope identifier storage to array

* Enter a new scope in typescript module blocks

* Add test for duplicate declaration

* Rename error for duplicate exports

* Treat class declarations as lexical declaration

* Update whitelist

* Add tests

* Fix scope tracking for function declarations

* Migrate try-catch duplicate error

* Fix test

* More tests

* One more test

* Make scope a separate class and fix review comments

* Do not allow new.target in top scope arrow function

* Correctly enter new scope for declare module and treat type aliases as lexical declarations

* Tests for typescript scope tracking to not mark type aliases as duplicate

* Fix flow scope tracking

* Remove ident from test names as redundant

* Add test case for var and function

* Improve error messages

* Improve literal regex

packages/babel-parser/src/tokenizer/context.js

@@ -60,7 +60,7 @@ tt.name.updateContext = function(prevType) {
   if (prevType !== tt.dot) {
     if (
       (this.state.value === "of" && !this.state.exprAllowed) ||
-      (this.state.value === "yield" && this.state.inGenerator)
+      (this.state.value === "yield" && this.scope.inGenerator)
     ) {
       allowed = true;
     }

packages/babel-parser/src/tokenizer/state.js

@@ -66,13 +66,9 @@ export default class State {
   // and then convert them, we need to track it.
   commaAfterSpreadAt: number = -1;
 
-  // Flags to track whether we are in a function, a generator.
-  inFunction: boolean = false;
+  // Flags to track
   inParameters: boolean = false;
   maybeInArrowParameters: boolean = false;
-  inGenerator: boolean = false;
-  inMethod: boolean | N.MethodKind = false;
-  inAsync: boolean = false;
   inPipeline: boolean = false;
   inType: boolean = false;
   noAnonFunctionType: boolean = false;