InvariantTypes.java

import org.checkerframework.checker.nullness.qual.*;

public class InvariantTypes {
    // The RHS is @NonNull [], but context decides to make it @Nullable
    @Nullable Object[] noa = {"non-null!"};

    // Type for array creation is propagated from LHS
    @MonotonicNonNull Object[] f = new Object[5];

    void testAsLocal() {
        @MonotonicNonNull Object[] lo;
        lo = new Object[5];
        //:: error: (assignment.type.incompatible)
        lo[0] = null;
        lo[0] = new Object();
        //:: error: (dereference.of.nullable)
        lo[1].toString();
    }

    // Type for array creation is propagated from LHS
    @PolyNull Object[] po = new Object[5];

    void testDecl(@MonotonicNonNull Object[] p) {}

    void testCall() {
        // Type for array creation is propaged from parameter type
        testDecl(new Object[5]);
    }
}