* @param fromClass
     *            The source class. Must not be {@literal null}.
     * @return Whether assignment is possible.
     * @see Class#isAssignableFrom(Class)
     */
    public static boolean isAssignableFrom(final Class<?> toClass, Class<?> fromClass) {
        assertArgumentNotNull("toClass", toClass);
        assertArgumentNotNull("fromClass", fromClass);

        populateTypeMappings(mappings, fromArrayType.getGenericComponentType(), componentType);
      }

      @Override
      void visitClass(Class<?> fromClass) {
        if (to instanceof WildcardType) {
          return; // Okay to say Foo is <?>
        }
        // Can't map from a raw class to anything other than itself or a wildcard.

        populateTypeMappings(mappings, fromArrayType.getGenericComponentType(), componentType);
      }

      @Override
      void visitClass(Class<?> fromClass) {
        if (to instanceof WildcardType) {
          return; // Okay to say Foo is <?>
        }
        // Can't map from a raw class to anything other than itself or a wildcard.

		}
		return pkg, nil
	}
	w.imported[name] = &importing

	// Determine package files.
	dir := w.importDir[name]
	if dir == "" {
		dir = filepath.Join(w.root, filepath.FromSlash(name))
	}
	if fi, err := os.Stat(dir); err != nil || !fi.IsDir() {
		log.Panicf("no source in tree for import %q (from import %s in %s): %v", name, fromPath, fromDir, err)
	}

	context := w.context