insert-annotations-to-source may add irrelevant import statements

[pbsf]

Consider the content of two Java classes C1 and C2, each on a separate .java file:

public class C1<T extends Object> {
  public <A extends Object> C1<A> foo(A a) {
      return null;
  }
}

public class C2 {}

Consider the following content of a .jaif file for the class C1:

package org.checkerframework.checker.nullness.qual:
annotation @Nullable:

package :
class C1:

    method foo(Ljava/lang/Object;)Lplume/C1;:
        return:
        parameter #0:
            type: @org.checkerframework.checker.nullness.qual.Nullable

After running
$ insert-annotations-to-source C1.java C2.java C1.jaif

the annotated C2.java should have stayed the same, but instead it imports Nullable:

import org.checkerframework.checker.nullness.qual.Nullable;
public class C2 {}

The files used to reproduce this bug are attached.

bug.zip