openide/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/foldIntoStream/beforeConcatCharDelimiter.java

// "Fold expression into 'String.join'" "true-preview"
class Test {
  String  foo(String a, String b, String c) {
    String s = a + <caret>'_' + b + '_' + c ;
    return s;
  }
}