Fix an issue where subcomponent factory method fails when defined with type parameters.

dagger-compiler/main/java/dagger/internal/codegen/binding/BindingGraph.java

@@ -27,7 +27,9 @@
 import static dagger.internal.codegen.extension.DaggerStreams.toImmutableSet;
 
 import androidx.room3.compiler.processing.XExecutableElement;
+import androidx.room3.compiler.processing.XExecutableType;
 import androidx.room3.compiler.processing.XMethodElement;
+import androidx.room3.compiler.processing.XType;
 import androidx.room3.compiler.processing.XTypeElement;
 import com.google.auto.value.AutoValue;
 import com.google.auto.value.extension.memoized.Memoized;
@@ -409,8 +411,10 @@ public final Optional<XMethodElement> factoryMethod() {
    */
   // TODO(dpb): Consider disallowing modules if none of their bindings are used.
   public final ImmutableSet<ComponentRequirement> factoryMethodRequirements() {
-    return factoryMethod().get().getParameters().stream()
-        .map(parameter -> ComponentRequirement.forModule(parameter.getType()))
+    XType parentType = componentPath().parentComponent().xprocessing().getType();
+    XExecutableType resolvedFactoryMethod = factoryMethod().get().asMemberOf(parentType);
+    return resolvedFactoryMethod.getParameterTypes().stream()
+        .map(ComponentRequirement::forModule)
         .collect(toImmutableSet());
   }
 

javatests/dagger/functional/kotlinsrc/subcomponent/GenericSubcomponentFactoryMethodTest.kt

@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2026 The Dagger Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dagger.functional.kotlinsrc.subcomponent
+
+import com.google.common.truth.Truth.assertThat
+import dagger.Component
+import dagger.Module
+import dagger.Provides
+import dagger.Subcomponent
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+/** Tests for subcomponent factory methods defined on generic supertypes. */
+@RunWith(JUnit4::class)
+class GenericSubcomponentFactoryMethodTest {
+  @Component(modules = [ParentModule::class])
+  internal interface Parent : SubcomponentProvider<Child, ChildModule> {}
+
+  @Module
+  internal class ParentModule {
+    @Provides fun provideInt(): Int = 42
+  }
+
+  @Subcomponent(modules = [ChildModule::class])
+  internal interface Child {
+    fun string(): String
+  }
+
+  @Module
+  internal class ChildModule(val s: String) {
+    @Provides fun provideString(i: Int): String = s + i
+  }
+
+  interface SubcomponentProvider<C, M> {
+    fun createSubcomponent(module: M): C
+  }
+
+  @Test
+  fun factoryMethod_genericSupertype() {
+    val parent: Parent = DaggerGenericSubcomponentFactoryMethodTest_Parent.create()
+    val child: Child = parent.createSubcomponent(ChildModule("hello "))
+    assertThat(child.string()).isEqualTo("hello 42")
+  }
+}

javatests/dagger/functional/subcomponent/GenericSubcomponentFactoryMethodTest.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2026 The Dagger Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dagger.functional.subcomponent;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import dagger.Component;
+import dagger.Module;
+import dagger.Provides;
+import dagger.Subcomponent;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for subcomponent factory methods defined on generic supertypes. */
+@RunWith(JUnit4.class)
+public final class GenericSubcomponentFactoryMethodTest {
+
+  @Component(modules = ParentModule.class)
+  interface Parent extends SubcomponentProvider<Child, ChildModule> {}
+
+  @Module
+  static class ParentModule {
+    @Provides
+    int provideInt() {
+      return 42;
+    }
+  }
+
+  @Subcomponent(modules = ChildModule.class)
+  interface Child {
+    String string();
+  }
+
+  @Module
+  static class ChildModule {
+    final String s;
+
+    ChildModule(String s) {
+      this.s = s;
+    }
+
+    @Provides
+    String provideString(int i) {
+      return s + i;
+    }
+  }
+
+  public interface SubcomponentProvider<C, M> {
+    C createSubcomponent(M module);
+  }
+
+  @Test
+  public void factoryMethod_genericSupertype() {
+    Parent parent = DaggerGenericSubcomponentFactoryMethodTest_Parent.create();
+    Child child = parent.createSubcomponent(new ChildModule("hello "));
+    assertThat(child.string()).isEqualTo("hello 42");
+  }
+}