Fix bug in Capability invoke

core/src/main/java/feign/Capability.java

@@ -57,7 +57,7 @@ static Object enrich(Object componentToEnrich,
   static Object invoke(Object target, Capability capability, Class<?> capabilityToEnrich) {
     return Arrays.stream(capability.getClass().getMethods())
         .filter(method -> method.getName().equals("enrich"))
-        .filter(method -> method.getReturnType().isAssignableFrom(capabilityToEnrich))
+        .filter(method -> method.getReturnType() == capabilityToEnrich)
         .findFirst()
         .map(method -> {
           try {

core/src/test/java/feign/CapabilityTest.java

@@ -18,6 +18,7 @@
 import java.io.IOException;
 import java.util.Arrays;
 import org.hamcrest.CoreMatchers;
+import org.junit.Assert;
 import org.junit.Test;
 
 public class CapabilityTest {
@@ -72,4 +73,34 @@ public Client enrich(Client client) {
     assertThat(enriched, CoreMatchers.instanceOf(BClient.class));
   }
 
+  private static class FamilyCapability implements Capability {
+    public Father enrich(Father father) {
+        father.balance = 10;
+        return father;
+    }
+    public Son enrich(Son son) {
+        son.balance = 5;
+        return son;
+    }
+  }
+
+  private static class Father {
+      int balance;
+  }
+
+  private static class Son extends Father {}
+
+  @Test
+  public void enrichTest() {
+    Son son = new Son();
+    Father father = new Father();
+    // enrich Son
+    Capability.invoke(son, new FamilyCapability(), Son.class);
+    Assert.assertEquals(son.balance, 5);
+    // enrich Father
+    Capability.invoke(father, new FamilyCapability(), Father.class);
+    Assert.assertEquals(father.balance, 10);
+  }
+
+
 }