refactor(compiler): ensure compiler passes closure conformance checks (#62500)

This commit adjusts some code of the compiler that currently results in
conformance checks failures with JSCompiler/Closure.

PR Close #62500

packages/compiler/src/expression_parser/lexer.ts

@@ -133,11 +133,13 @@ export class Token {
   }
 
   isTemplateLiteralPart(): this is StringToken {
-    return this.isString() && this.kind === StringTokenKind.TemplateLiteralPart;
+    // Note: Explicit type is needed for Closure.
+    return this.isString() && (this as StringToken).kind === StringTokenKind.TemplateLiteralPart;
   }
 
   isTemplateLiteralEnd(): this is StringToken {
-    return this.isString() && this.kind === StringTokenKind.TemplateLiteralEnd;
+    // Note: Explicit type is needed for Closure.
+    return this.isString() && (this as StringToken).kind === StringTokenKind.TemplateLiteralEnd;
   }
 
   isTemplateLiteralInterpolationStart(): boolean {

packages/compiler/src/ml_parser/lexer.ts

@@ -1725,9 +1725,15 @@ class EscapedCharacterCursor extends PlainCharacterCursor {
   }
 }
 
-export class CursorError {
+export class CursorError extends Error {
   constructor(
     public msg: string,
     public cursor: CharacterCursor,
-  ) {}
+  ) {
+    super(msg);
+
+    // Extending `Error` does not always work when code is transpiled. See:
+    // https://stackoverflow.com/questions/41102060/typescript-extending-error-class
+    Object.setPrototypeOf(this, new.target.prototype);
+  }
 }

packages/compiler/src/parse_util.ts

@@ -148,7 +148,7 @@ export enum ParseErrorLevel {
   ERROR,
 }
 
-export class ParseError {
+export class ParseError extends Error {
   constructor(
     /** Location of the error. */
     readonly span: ParseSourceSpan,
@@ -161,7 +161,14 @@ export class ParseError {
      * couldn't be parsed. Not guaranteed to be defined, but can be used to provide more context.
      */
     readonly relatedError?: unknown,
-  ) {}
+  ) {
+    super(msg);
+
+    // Extending `Error` ends up breaking some internal tests. This appears to be a known issue
+    // when extending errors in TS and the workaround is to explicitly set the prototype.
+    // https://stackoverflow.com/questions/41102060/typescript-extending-error-class
+    Object.setPrototypeOf(this, new.target.prototype);
+  }
 
   contextualMessage(): string {
     const ctx = this.span.start.getContext(100, 3);
@@ -170,7 +177,7 @@ export class ParseError {
       : this.msg;
   }
 
-  toString(): string {
+  override toString(): string {
     const details = this.span.details ? `, ${this.span.details}` : '';
     return `${this.contextualMessage()}: ${this.span.start}${details}`;
   }