dart2js cps: Variables declared in finally block

[asgerf]

Variables declared in a finally block cause an assertion error in the CPS builder, because one variable is added to the environment multiple times.

This is the assertion that fails:

  void extend(Local element, ir.Primitive value) {
    // Assert that the name is not already in the environment.  `null` is used
    // as the name of anonymous variables.
    assert(!variable2index.containsKey(element));
    if (element != null) variable2index[element] = index2variable.length;
    index2variable.add(element);
    index2value.add(value);
  }

There are a bunch of tests that fail in checked-mode because of this; here is a minimal one:

main() {
  try {
    print("fdg");
  } finally {
    var x = 12345678;
    print(x);
  }
}

The variable may be assigned different indices because of different environment sizes at entry points to the finally. I can't see an easy fix to this short of wrapping all variable elements in a "finally element" so different copies of the variable can be distinguished.

The issue should go away when we introduce first-class finally to the IR. I'm not sure if it's worth fixing in the current form.

@kmillikin

[rakudrama]

Obsolete

[lrhn]

Tests are still marked as crashing with this issue number in pkg.status. Please investigate.

[asgerf]

The status file sections were obsolete. Fixed in 2d6c90a.