Typescript 4.7 A extends B<infer C extends D> fails with a syntax error

[IgnusG]

This code seems to fail even with the latest version of esbuild and I'm not sure if I configured something wrong or if this syntax isn't supported by esbuild yet:

type JoinDot<Items extends string[], Accumulator extends string = ""> = Items extends [
	infer Item extends string,
	...infer Rest extends string[],
]
	? [] extends Rest
		? `${Accumulator}${Item}`
		: JoinDot<Rest, `${Accumulator}${Item}.`>
	: never;

This new TS 4.7 syntax simplifies the definitions slightly but esbuild seems to not like it. I could rewrite it to use the old syntax but it just adds a lot of nesting.

Error Stack

Error: Transform failed with 1 error:
/.../file.ts:45:26: ERROR: Expected "?" but found ","
    at failureErrorWithLog (/.../node_modules/esbuild/lib/main.js:1612:15)
    at /.../node_modules/esbuild/lib/main.js:1401:29
    at /.../node_modules/esbuild/lib/main.js:675:9
    at handleIncomingPacket (/.../node_modules/esbuild/lib/main.js:772:9)
    at Socket.readFromStdout (/.../node_modules/esbuild/lib/main.js:641:7)
    at Socket.emit (node:events:527:28)
    at addChunk (node:internal/streams/readable:324:12)
    at readableAddChunk (node:internal/streams/readable:297:9)
    at Socket.Readable.push (node:internal/streams/readable:234:10)
    at Pipe.onStreamRead (node:internal/stream_base_commons:190:23) {
  errors: [
    {
      detail: undefined,
      id: '',
      location: {
        column: 26,
        file: '/.../file.ts',
        length: 1,
        line: 45,
        lineText: '\tinfer Item extends string,',
        namespace: '',
        suggestion: '?'
      },
      notes: [],
      pluginName: '',
      text: 'Expected "?" but found ","'
    }
  ],
  warnings: [],
  frame: '\n' +
    '\x1B[33mExpected "?" but found ","\x1B[39m\n' +
    '43 |  \n' +
    '44 |  type JoinDot = Items extends [\n' +
    '45 |  \tinfer Item extends string,\n' +
    '   |                            ^\n' +
    '46 |  \t...infer Rest extends string[],\n' +
    '47 |  ]\n',
  loc: {
    column: 26,
    file: '/.../file.ts',
    length: 1,
    line: 45,
    lineText: '\tinfer Item extends string,',
    namespace: '',
    suggestion: '?'
  },
  plugin: 'vite:esbuild',
  id: '/.../file.ts',
  pluginCode: '...'
}

I'm using vite but forced esbuild to the latest version 0.14.45. If this isn't an esbuild issue but rather a vite issue, apologies in advance!

[IgnusG]

I've added a test to ts_parser_test.go and it also seems to fail:

expectPrintedTS(t, "let x: A extends B<infer C extends D> ? D : never", "let x;\n")

--- FAIL: TestTSTypes (0.02s)
    --- FAIL: TestTSTypes/let_x:_A_extends_B<infer_C_extends_D>_?_D_:_never (0.00s)
        ts_parser_test.go:136: +<stdin>: ERROR: Expected "?" but found ">"

FAIL
FAIL    github.com/evanw/esbuild/internal/js_parser     0.674s