The parser confuses TS constrained mixins with JSX

[fcrozatier]

Here's a minimal reproduction code:

export const Triggerable = <C extends HTMLElement = HTMLElement>(superClass: C) => {
  return class extends superClass {
    initTriggerable(options) {
      this.#options = options;
	}
    };
};

This is just a standard ts mixin

Trying to parse a file containing this code yields an error

> const options = { sourceType: 'module', ecmaVersion: 'latest', locations: true };
> const code = 'export const Triggerable = <C extends HTMLElement = HTMLElement>(superClass: C) => {\n' +
  '\treturn class extends superClass {\n' +
  '\t\tinitTriggerable(options) {\n' +
  '\t\t\tthis.#options = options;\n' +
  '\t\t}\n' +
  '\t};\n' +
  '};\n'
> parser.parse(code, options)
Uncaught:
[SyntaxError: JSX value should be either an expression or a quoted JSX text (1:52)
] {
  pos: 52,
  loc: Position { line: 1, column: 52 },
  raisedAt: 63
}

This prevents me from using acorn-typescript for parsing some ts files

[dummdidumm]

FYI even after the fix the code snippet will throw, since #options is not defined

[fcrozatier]

Hey Simon, thanks for working on this in sveltejs/acorn-typescript#1! Yes I realized afterwards that my snippet wasn't self-contained but didn't update as this repo seems abandonned... Hopefully you got the gist of it for your tests