Sdk: Switch fallthrough fails in DDC

[seanburke-wf]

Using SDK version 2.2.0 and DDC, the following test program will generate a SyntaxError due to the use of the switch fallthrough continue syntax described at https://www.dartlang.org/guides/language/language-tour#switch-and-case:

void main() {
  String startsWith = 'HI';
  switch (startsWith) {
    case 'HI':
      print('H');
      continue i;
    i:
    case 'I':
      print('I');
      break;
  }
}

[eernstg]

I can't reconstruct this: Trying this with dart and dart2js version 2.1.1-dev.3.2 as well as a fresh one from commit b7a5e478bbdd3d439db2726578585bc6346eaa2f, I get no compile-time errors, plus it prints both H and I. I see the same behavior with an ancient dart 1.10.1.

Could your installation of the Dart tools and system be out of order?

[evanweible-wf]

@eernstg It works as expected with dart2js, but it does not work when compiled with DDC.

DDC:

pub run build_runner serve web:8080

// Console output:
H
require.js:143 Uncaught SyntaxError: Undefined label 'i'
    at main.dart.bootstrap.js:237
    at Object.execCb (require.js:1696)
    at Module.check (require.js:878)
    at Module.<anonymous> (require.js:1139)
    at require.js:134
    at require.js:1189
    at each (require.js:59)
    at Module.emit (require.js:1188)
    at Module.check (require.js:938)
    at Module.<anonymous> (require.js:1139)
    at require.js:134
    at require.js:1189
    at each (require.js:59)
    at Module.emit (require.js:1188)
    at Module.check (require.js:938)
    at Module.enable (require.js:1176)
    at Module.init (require.js:788)
    at callGetModule (require.js:1203)
    at Object.completeLoad (require.js:1590)
    at HTMLScriptElement.onScriptLoad (require.js:1717)

dart2js:

pub run build_runner serve web:8080 -r

// Console output:
H
I

[vsmenon]

This appears to be fixed in 2.3.1 (both ddc-analyzer and ddc-kernel).