[false-negative]ToStringReturnsNull can not detect the case that return a variable which is initially null, and there is no subsequent re-assignment.

[wuchiuwong]

Description of the problem / feature request:

ToStringReturnsNull can not detect the case that return a variable which is initially null, and there is no subsequent re-assignment.
This rule is implemented in error_prone_core-2.3.4-sources.jar!\com\google\errorprone\bugpatterns\ToStringReturnsNull.java,
and use node.getExpression().getKind() == NULL_LITERAL; to check whether null is returned,
Therefore, it will not detect those return a variable which may be null

Bugs: what's the simplest, easiest way to reproduce this bug? Please provide a minimal example if possible.

@Override
public String toString() {
    String result = null;
	try {
		result = new ObjectMapper().defaultPrettyPrintingWriter().writeValueAsString(this);
	} catch (IOException e) {
		logger.warn(e,e);
	}
    return result;
}

What version of Error Prone are you using?

2.3.4

Have you found anything relevant by searching the web?

no

[graememorgan]

There are a lot of cases ToStringReturnsNull will miss. :)

Do you have a suggested improvement?