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/parser/util.js

@@ -3,7 +3,9 @@
 import { types as tt, type TokenType } from "../tokenizer/types";
 import Tokenizer from "../tokenizer";
 import type { Node } from "../types";
-import { lineBreak } from "../util/whitespace";
+import { lineBreak, skipWhiteSpace } from "../util/whitespace";
+
+const literal = /^(?:;|('|")((?:\\?.)*?)\1)/;
 
 // ## Parser utilities
 
@@ -165,4 +167,18 @@ export default class UtilParser extends Tokenizer {
       );
     }
   }
+
+  strictDirective(start: number): boolean {
+    for (;;) {
+      skipWhiteSpace.lastIndex = start;
+      // $FlowIgnore
+      start += skipWhiteSpace.exec(this.state.input)[0].length;
+      const match = literal.exec(this.state.input.slice(start));
+      if (!match) break;
+      if (match[2] === "use strict") return true;
+      start += match[0].length;
+    }
+
+    return false;
+  }
 }