Add a unit test that simulates a base class already compiled in a module

butterknife/src/test/java/butterknife/InheritanceTest.java

@@ -0,0 +1,62 @@
+package butterknife;
+
+import butterknife.compiler.ButterKnifeProcessor;
+import com.google.common.collect.ImmutableList;
+import com.google.testing.compile.JavaFileObjects;
+import javax.tools.JavaFileObject;
+import javax.tools.StandardLocation;
+import org.junit.Test;
+
+import static com.google.common.truth.Truth.assertAbout;
+import static com.google.testing.compile.JavaSourceSubjectFactory.javaSource;
+import static com.google.testing.compile.JavaSourcesSubjectFactory.javaSources;
+import static java.util.Arrays.asList;
+
+public class InheritanceTest {
+
+  @Test public void bindingViewFinalClassWithBaseClassAlreadyCompiledInDifferentModule() {
+    JavaFileObject testSource = JavaFileObjects.forSourceString("test.Test", ""
+        + "package test;\n"
+        + "import android.view.View;\n"
+        + "import butterknife.BindView;\n"
+        + "import butterknife.precompiled.Base;\n"
+        + "public final class Test extends Base {\n"
+        + "    @BindView(1) View thing;\n"
+        + "}"
+    );
+
+    JavaFileObject bindingTestSource = JavaFileObjects.forSourceString("test/Test_ViewBinding", ""
+        + "package test;\n"
+        + "import android.support.annotation.UiThread;\n"
+        + "import android.view.View;\n"
+        + "import butterknife.internal.Utils;\n"
+        + "import butterknife.precompiled.Base_ViewBinding;\n"
+        + "import java.lang.IllegalStateException;\n"
+        + "import java.lang.Override;\n"
+        + "public final class Test_ViewBinding extends Base_ViewBinding {\n"
+        + "  private Test target;\n"
+        + "  @UiThread\n"
+        + "  public Test_ViewBinding(Test target, View source) {\n"
+        + "    super(target, source);\n"
+        + "    this.target = target;\n"
+        + "    target.thing = Utils.findRequiredView(source, 1, \"field 'thing'\");\n"
+        + "  }\n"
+        + "  @Override\n"
+        + "  public void unbind() {\n"
+        + "    Test target = this.target;\n"
+        + "    if (target == null) throw new IllegalStateException(\"Bindings already cleared.\");\n"
+        + "    this.target = null\n"
+        + "    target.thing = null;\n"
+        + "    super.unbind();\n"
+        + "  }\n"
+        + "}"
+    );
+
+    assertAbout(javaSources()).that(asList(testSource))
+        .withCompilerOptions("-Xlint:-processing")
+        .processedWith(new ButterKnifeProcessor())
+        .compilesWithoutWarnings()
+        .and()
+        .generatesSources(bindingTestSource);
+  }
+}

butterknife/src/test/java/butterknife/precompiled/Base.java

@@ -0,0 +1,8 @@
+package butterknife.precompiled;
+
+import android.view.View;
+import butterknife.BindView;
+
+public class Base {
+    @BindView(1) View thing;
+}