Assignment to 'catch' block parameter

Reports assignments to, catch block parameters.

Changing a catch block parameter is very confusing and should be discouraged.

The quick-fix adds a declaration of a new variable.

Example:

void processFile(String fileName) throws Exception {
  try {
    doProcessFile(fileName);
  } catch(Exception ex) {
    if (ex instanceof UncheckedIOException) {
      // Warning: catch block parameter reassigned
      ex = ((UncheckedIOException) ex).getCause();
    }
    throw ex;
  }
}

After the quick-fix is applied:

void processFile(String fileName) throws Exception {
  try {
    doProcessFile(fileName);
  } catch(Exception ex) {
    Exception unwrapped = ex;
    if (unwrapped instanceof UncheckedIOException) {
      unwrapped = ((UncheckedIOException)
        unwrapped).getCause();
    }
    throw unwrapped;
  }
}

Inspection Details
Available in:	IntelliJ IDEA 2023.3, Qodana for JVM 2023.3
Plugin:	Java, 233.SNAPSHOT

Last modified: 13 July 2023