anchor.diff:            kind == ElementKind.TYPEDEF ||
             kind == ElementKind.LIBRARY) {
           bool fixedName = false;
  -        if (kind == ElementKind.CLASS) {
  -          ClassElement classElement = element;
  -        }
           if (Elements.isInstanceField(element)) {
             fixedName = element.hasFixedBackendName();
           }
  
positive.code:         ? library
          : shortPrivateNameOwners.putIfAbsent(nameString, () => library);
  
      // If a private name could clash with a mangled private name we don't
      // use the short name. For example a private name "_lib3_foo" would
      // clash with "_foo" from "lib3".
      if (owner == library &&
          !nameString.startsWith('_$LIBRARY_PREFIX') &&
          !shouldMinify) {
        return nameString;
      }
  
      // If a library name does not start with the [LIBRARY_PREFIX] then our
      // assumptions about clashing with mangled private members do not hold.
      String libraryName = getNameOfLibrary(library);
      assert(shouldMinify || libraryName.startsWith(LIBRARY_PREFIX));
      // TODO(erikcorry): Fix this with other manglings to avoid clashes.
      return '_lib$libraryName\$$nameString';
    }
  
    String instanceMethodName(FunctionElement element) {
  
negative.code:         name = element.name.slowToString().replaceAll('+', '_');
        }
      } else if (element.isLibrary()) {
        LibraryElement library = element;
        name = library.getLibraryOrScriptName();
        if (name.contains('.')) {
          // For libraries that have a library tag, we use the last part
          // of the fully qualified name as their base name. For all other
          // libraries, we use the first part of their filename.
          name = library.hasLibraryName()
              ? name.substring(name.lastIndexOf('.') + 1)
              : name.substring(0, name.indexOf('.'));
        }
      } else {
        name = element.name.slowToString();
      }
  