private static boolean isLengthOf(PsiExpression stringLengthCandidate, PsiExpression stringExpression) {
      PsiMethodCallExpression argCall = tryCast(PsiUtil.skipParenthesizedExprDown(stringLengthCandidate), PsiMethodCallExpression.class);
      return STRING_LENGTH.test(argCall) &&
             EquivalenceChecker.getCanonicalPsiEquivalence()
               .expressionsAreEquivalent(stringExpression, argCall.getMethodExpression().getQualifierExpression());
    }
private static boolean isLengthOf(PsiExpression stringLengthCandidate, PsiExpression stringExpression)