[GROOVY-9652] SC: ClassCastException for comparison to single-character string literal in closure

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.5.13
• Fix Version/s: 4.0.0-alpha-1, 2.5.14, 3.0.6
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 23/Jul/20 18:24
• Updated: 11/Nov/20 02:00
• Resolved: 02/Aug/20 10:11

Description

This started failing with Groovy 2.5.13:

class Node {
  String name, text
}
class Root implements Iterable<Node> {
  @Override
  Iterator<Node> iterator() {
    return [
      new Node(name: 'term', text: 'foo'),
      new Node(name: 'dash', text: '-'  ),
      new Node(name: 'term', text: 'bar')
    ].iterator()
  }
}

@groovy.transform.CompileStatic
void test() {
  Root root = new Root()

  root[0].with {
    assert name == 'term'
    assert text == 'foo'
  }
  root[1].with {
    assert name == 'dash'
    assert text == '-' // GroovyCastException: Cannot cast object 'script@b91d8c4' with class 'script' to class 'bugs.Node'
  }
}

test()

Adding a cast to String in front of "-" fixes and @CompileDynamic also fixes. I'm guessing @TypeChecked would not have the issue. I noticed some changes in BinaryExpressionTransformer#tryOptimizeCharComparison that may be relevant.