anchor.diff:          case UnlinkedExprOperation.pushParameter:
             String name = _uc.strings[stringPtr++];
             SimpleIdentifier identifier = AstTestFactory.identifier3(name);
  -          identifier.staticElement = parametersInScope[name];
  +          identifier.staticElement = variablesInScope[name];
             _push(identifier);
             break;
           case UnlinkedExprOperation.ifNull:
  
positive.code:   ///
    /// If [context] is (or contains) a constructor, then its parameters are used.
    /// Otherwise, no parameters are considered to be in scope.
    static Map<String, ParameterElement> _parametersInScope(Element context) {
      var result = <String, ParameterElement>{};
      for (Element e = context; e != null; e = e.enclosingElement) {
        if (e is ConstructorElement) {
          for (var parameter in e.parameters) {
            result[parameter.name] = parameter;
          }
          return result;
        }
  
negative.code:     this._uc, {
      this.requireValidConst: true,
      this.localFunctions,
      _VariablesInScope variablesInScope,
      this.becomeSetOrMap: true,
    })  : this.variablesInScope = variablesInScope ?? _parametersInScope(context),
          this.isSpreadOrControlFlowEnabled = _isSpreadOrControlFlowEnabled(
              (resynthesizer.library.context.analysisOptions
                      as AnalysisOptionsImpl)
  