Remove useless assignment

Please provide

  • Operating system: MacOS (Sequoia 15.7.1)
  • SonarQube for IntelliJ plugin version:
  • IntelliJ version: 11.2.0.82481
  • Programming language you’re coding in: Java
  • Is connected mode used: No
    • SonarQube Cloud, SonarQube Server, or SonarQube Community Build? (if one of the latter two, which version?):

And a thorough description of the problem / question:

I frequently get warnings to “Remove useless assignments”. These are frequently false positives:

For example:

class Partial {

    private final Map<Class<?>, Supplier<?>> registry = new HashMap<>();

    ...

    private <T> T build(Class<?> clazz, Supplier<T> supplier) {
        return (T) registry.computeIfAbsent(clazz, k -> supplier).get();
    }

    public void activateSubdomain(Subdomain.ActivateSubdomainRequest ... requests) {
        // WARNING: Remove this useless assignment to local variable "subdomains".
        var subdomains = build(SubdomainsDAO.class, () -> new PostgresSubdomainsDAO(jdbi, ids));
        for (var request : requests) {
            subdomains.activateSubdomain(request.subdomainId(), request.labelId(), null);
        }
    }
}

Hey there.

We often see FPs on this rule when the semantic is not complete (Jira).

In your IDE, has your project been rebuilt? Does doing so make the issue go away?