anchor.diff:          libraries.add(library);
         }
       }
  -    return new List.from(libraries);
  +    return libraries.toList(growable: false);
     }
   
     @override
  
positive.code:       ResynthesizerContext context = enclosingUnit.resynthesizerContext;
        _interfaces = _unlinkedClass.interfaces
            .map((EntityRef t) => context.resolveTypeRef(t, this))
            .toList();
      }
      return _interfaces ?? const <InterfaceType>[];
    }
  
negative.code:           prefixes.add(prefix);
          }
        }
        _prefixes = prefixes.toList(growable: false);
      }
      return _prefixes;
    }
  