openide/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/quickFix/stringConcatInLoop/afterConcatSimple.java

// "Convert variable 'res' from String to StringBuilder" "true-preview"

public class Main {
    String test(String[] strings) {
        StringBuilder res = new StringBuilder();
        for (String s : strings) {
            res.append(s).append("\n");
            res.append(s);
        }
        return res.toString();
    }
}