Describe the PR

Note: This fixes a false positive: intervening calls to toString() are no longer ignored, as the result of toString() would
change if the consecutive append calls would be merged. The same of length().

E.g.

StringBuilder sb = new StringBuilder();
sb.append("a");
System.out.println(sb.toString());
System.out.println(sb.length());
sb.append("b");

This is no longer flagged since merging the two append calls into sb.append("ab"); will change the result of the program....

Related issues

• Part of [java] Java-grammar progress document #2701

Ready?

• Added unit tests for fixed bug/feature
• Passing all unit tests
• Complete build ./mvnw clean verify passes (checked automatically by github actions)
• Added (in-code) documentation (if needed)