anchor.diff:        var verifier = _ConstLiteralVerifier(
           this,
           errorCode: CompileTimeErrorCode.NON_CONSTANT_LIST_ELEMENT,
  -        forList: true,
           listElementType: elementType,
         );
         for (CollectionElement element in node.elements) {
  
positive.code:   }
  
    bool _validateMapLiteralEntry(MapLiteralEntry entry) {
      if (!forMap) return false;
  
      var keyExpression = entry.key;
      var valueExpression = entry.value;
  
negative.code:   bool _validateListOrSetSpread(SpreadElement element, DartObjectImpl value) {
      var listValue = value.toListValue();
      var setValue = value.toSetValue();
      var iterableValue = listValue ?? setValue;
  
      if (iterableValue == null) {
        if (value.isNull && element.isNullAware) {
          return true;
        }
        verifier._errorReporter.reportErrorForNode(
  