anchor.diff:    }
   
     test_const_length_ofClassConstField_imported() {
  -    shouldCompareConstValues = true;
       addLibrarySource(
           '/a.dart',
           r'''
  
positive.code:       VariableElementImpl original, String desc) {
      compareElements(resynthesized, original, desc);
      compareTypes(resynthesized.type, original.type, desc);
      // TODO(scheglov) enable for any ConstVariableElement
      if (shouldCompareConstValues) {
        if (original is ConstVariableElement) {
          compareConstantExpressions(resynthesized.constantInitializer,
              original.constantInitializer, desc);
        }
      }
    }
  
  
negative.code: @reflectiveTest
  class ResynthTest extends ResolverTestCase {
    Set<Source> otherLibrarySources = new Set<Source>();
  
    /**
     * Determine the analysis options that should be used for this test.
  