code: @Nullable
    public static JSTypeExpression getDeclaredTypeExpression(Node declaration) {
      checkArgument(declaration.isName() || declaration.isStringKey());
      JSDocInfo nameJsdoc = getBestJSDocInfo(declaration);
      if (nameJsdoc != null) {
        return nameJsdoc.getType();
      }
      Node parent = declaration.getParent();
      if (parent.isRest() || parent.isDefaultValue()) {
        parent = parent.getParent();
      }
      if (parent.isParamList()) {
        JSDocInfo functionJsdoc = getBestJSDocInfo(parent.getParent());
        if (functionJsdoc != null) {
          return functionJsdoc.getParameterType(declaration.getString());
        }
      }
      return null;
    }
docs: Return declared JSDoc type for the given name declaration, or null if none present.