Stubs missing imports produce unclear errors

[nicbec]

Checker Framework version 2.5.2

We wanted to add a stub to our codebase that would annotate java.lang.reflect.Constructor in keeping with the Checker-Framework stubs version and the related issue below
#1365
Checker Framework stubs:
https://github.com/typetools/checker-framework/blob/460863bf1612581de76a783b4ad254b816bfe8b7/checker/jdk/nullness/src/java/lang/reflect/Constructor.java

I overlooked to add the @nonnull import to the stub. Static analysis tests that reference the stub below will compile and run, but will produce unusual errors ([assignment.type.incompatible], [return.type.incompatible], [type.argument.type.incompatible]) in classes that reference this stub that don't make it apparent that the real issue is a missing import.

It would be great to receive more clear messages for cases where stubs are missing imports.

Please let me know if other information is needed, thanks.

package java.lang.reflect;

// Missing import below.
// import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

public final class Constructor<T> extends Executable {

  public @NonNull T newInstance(Object ... initargs) throws InstantiationException,IllegalAccessException,IllegalArgumentException,InvocationTargetException {}
}

[wmdietl]

Can you try adding -AstubWarnIfNotFound as an option?

    // Whether to print warnings about types/members in a stub file
    // that were not found on the class path
    // org.checkerframework.framework.stub.StubParser.warnIfNotFound
    "stubWarnIfNotFound",

This should give you a warning about the unknown @nonnull annotation.

[nicbec]

Thanks for the response. I added "-AstubWarnIfNotFound" and see warnings for other locations in our code base, but nothing referencing @nonnull, Constructor, newInstance, or java.lang.reflect. There are no new warnings between the output when I comment out/uncomment the NonNull import though there is an unclear "error: [assignment.type.incompatible] incompatible types in assignment" when the import is commented out.

[nicbec]

Just wanted to check in on this to see if there's anything else I should try. Please let me know, thanks.

[wmdietl]

Pull request #2072 should fix this.
Now, when using -AstubWarnIfNotFound one also gets a warning about unknown annotations.
Please give it a spin and let us know whether this solves the issue.

[nicbec]

Was able to verify this fix on our build infrastructure. Thanks!