private static boolean isStringOfVar(@NotNull LeafPsiElement e) {
    if (e.getElementType() != ShTypes.CLOSE_QUOTE) return false;
    PsiElement str = e.getParent();
    if (!(str instanceof ShString)) return false;

    ASTNode[] children = str.getNode().getChildren(null);
    return children.length == 3 &&
        children[0].getElementType() == ShTypes.OPEN_QUOTE &&
        children[1].getElementType() == ShTypes.VARIABLE &&
        children[2].getElementType() == ShTypes.CLOSE_QUOTE;
  }
private static boolean isStringOfVar(@NotNull LeafPsiElement e)