为什么 IntelliJ 有时会抛出未使用的警告，但有时不会？

Question

I have many Java classes with two constructors:

1. a private constructor with no arguments and with unused warning suppression called by gson;
2. a public constructor with arguments.

In one class IntelliJ informs me with a warning that the public constructor is never used. In all other classes there isn't the warning, but if I click Find Usage for the method it displays "Nothing found in project files".

Why is there a warning in some cases and not in others? How can I make IntelliJ always behave in the same way?

This is the class where the public constructor throws the warning:

public class ShopMarketAction extends Action {

    private Boolean inRow = null;
    private Integer index = null;

    @SuppressWarnings("unused") // Called by gson
    private ShopMarketAction() {
        super(ActionType.SHOP_MARKET);
    }

    // THIS METHOD THROWS AN UNUSED WARNING
    public ShopMarketAction(boolean inRow, int index) {
        super(ActionType.SHOP_MARKET);
        this.inRow = inRow;
        this.index = index;
    }

}

This is an example class where the public constructor doesn't throw the warning:

public class ProductionAction extends Action {

    private Integer cardIndex = null;

    @SuppressWarnings("unused") // Called by gson
    private ProductionAction() {
        super(ActionType.PRODUCE);
    }

    // THIS METHOD DOESN'T THROW THE WARNING BUT IS NEVER USED
    public ProductionAction(int cardIndex) {
        super(ActionType.PRODUCE);
        this.cardIndex = cardIndex;
    }

}

I specify that in both classes the method is not used yet.

The Action class that both classes extends:

public abstract class Action {

    @SuppressWarnings({"unused", "FieldCanBeLocal"})
    private final ActionType type; // Used by gson

    protected Action(ActionType type) {
        this.type = type;
    }

}

The ActionType enum:

public enum ActionType {
    SHOP_MARKET, PRODUCE;
}

Answer 1

I found what causes the problem: I have a non-Java file (an UXF file created by another application) which contains the name of all these methods and for some reason IntelliJ consider them as used because of this.