False positive: UnusedVariable for methods that unconditionally throw

[electrum]

Description of the problem / feature request:

UnusedVariable triggers for a method like this:

private static boolean compare(int left, int right)
{
    throw new AssertionError("this method should not be called");
}

We can rename the parameters to unusedLeft and unusedRight, which is often a good way to signal intent to readers of the code, but that is redundant in this case, since it's immediately obvious that this method will not use the parameters.

What version of Error Prone are you using?

2.4.0

[cushon]

Note that this check only reports unused parameters on private methods, and it doesn't seem that often that a private method that unconditionally throws would be useful? Do you have more context about the situation where you encountered this problem?

[electrum]

I admit this situation is quite specialized. Here's the specific example: https://github.com/trinodb/trino/blob/351/core/trino-main/src/main/java/io/trino/type/UnknownType.java#L138

This class the implementation of a type in a SQL engine. The method, annotated with @ScalarOperator, will be discovered and invoked via generated code. It's private because it's only for use by the engine and shouldn't be called directly -- it's not a public API for general consumption. The unused arguments are present because they are part of the expected "API" that the annotated method needs to implement.