anchor.diff:  class SuperMethodInvocation extends InvocationExpression {
     Name name;
     Arguments arguments;
  +  DispatchCategory get dispatchCategory => DispatchCategory.viaThis;
   
     Reference interfaceTargetReference;
   
  
positive.code:   Expression receiver;
    Name name;
    Arguments arguments;
  
    Reference interfaceTargetReference;
  
  
negative.code:   /// be set to the root class for type parameters without an explicit bound.
    DartType bound;
  
    /// If this is a type parameter of a concrete generic method, its formal
    /// safety.  Otherwise ignored.
    ///
    /// See [FormalSafety] for details.
    FormalSafety formalSafety = FormalSafety.safe;
  
    /// If this is a type parameter of a generic method, its interface safety.
    /// Otherwise ignored.
    ///
    /// See [InterfaceSafety] for details.
    InterfaceSafety interfaceSafety = InterfaceSafety.typed;
  
    TypeParameter([this.name, this.bound]);
  
    accept(TreeVisitor v) => v.visitTypeParameter(this);
  