Mark some objects as unused when getting them from an API whose return value should not be ignored.

PiperOrigin-RevId: 496605827
Change-Id: I87a63e34a931acce8610cdef9be0aa01d01e7c3b
diff --git a/src/test/java/com/google/crypto/tink/internal/KeyParserTest.java b/src/test/java/com/google/crypto/tink/internal/KeyParserTest.java
index 071f860..13b5379 100644
--- a/src/test/java/com/google/crypto/tink/internal/KeyParserTest.java
+++ b/src/test/java/com/google/crypto/tink/internal/KeyParserTest.java
@@ -71,7 +71,9 @@
 
   @Test
   public void createParser_works() throws Exception {
-    KeyParser.create(KeyParserTest::parse, Bytes.copyFrom(new byte[0]), ExampleSerialization.class);
+    Object unused =
+        KeyParser.create(
+            KeyParserTest::parse, Bytes.copyFrom(new byte[0]), ExampleSerialization.class);
   }
 
   @Test
diff --git a/src/test/java/com/google/crypto/tink/internal/KeySerializerTest.java b/src/test/java/com/google/crypto/tink/internal/KeySerializerTest.java
index e68e2fe..721942e 100644
--- a/src/test/java/com/google/crypto/tink/internal/KeySerializerTest.java
+++ b/src/test/java/com/google/crypto/tink/internal/KeySerializerTest.java
@@ -70,8 +70,9 @@
 
   @Test
   public void createSerializer_works() throws Exception {
-    KeySerializer.create(
-        KeySerializerTest::serialize, ExampleKey.class, ExampleSerialization.class);
+    Object unused =
+        KeySerializer.create(
+            KeySerializerTest::serialize, ExampleKey.class, ExampleSerialization.class);
   }
 
   @Test
diff --git a/src/test/java/com/google/crypto/tink/internal/MutableSerializationRegistryMultithreadTest.java b/src/test/java/com/google/crypto/tink/internal/MutableSerializationRegistryMultithreadTest.java
index a3c5d65..af278a2 100644
--- a/src/test/java/com/google/crypto/tink/internal/MutableSerializationRegistryMultithreadTest.java
+++ b/src/test/java/com/google/crypto/tink/internal/MutableSerializationRegistryMultithreadTest.java
@@ -291,7 +291,7 @@
             () -> {
               try {
                 for (int i = 0; i < REPETITIONS; ++i) {
-                  registry.parseKey(new TestSerializationA(A_1), ACCESS);
+                  Object unused = registry.parseKey(new TestSerializationA(A_1), ACCESS);
                 }
               } catch (GeneralSecurityException e) {
                 throw new RuntimeException(e);
@@ -302,7 +302,8 @@
             () -> {
               try {
                 for (int i = 0; i < REPETITIONS; ++i) {
-                  registry.serializeKey(new TestKey1(), TestSerializationA.class, ACCESS);
+                  Object unused =
+                      registry.serializeKey(new TestKey1(), TestSerializationA.class, ACCESS);
                 }
               } catch (GeneralSecurityException e) {
                 throw new RuntimeException(e);
@@ -363,7 +364,7 @@
             () -> {
               try {
                 for (int i = 0; i < REPETITIONS; ++i) {
-                  registry.parseParameters(new TestSerializationA(A_1));
+                  Object unused = registry.parseParameters(new TestSerializationA(A_1));
                 }
               } catch (GeneralSecurityException e) {
                 throw new RuntimeException(e);
@@ -374,7 +375,8 @@
             () -> {
               try {
                 for (int i = 0; i < REPETITIONS; ++i) {
-                  registry.serializeParameters(new TestParameters1(), TestSerializationA.class);
+                  Object unused =
+                      registry.serializeParameters(new TestParameters1(), TestSerializationA.class);
                 }
               } catch (GeneralSecurityException e) {
                 throw new RuntimeException(e);
diff --git a/src/test/java/com/google/crypto/tink/internal/ParametersParserTest.java b/src/test/java/com/google/crypto/tink/internal/ParametersParserTest.java
index 1a654ae..7849a6c 100644
--- a/src/test/java/com/google/crypto/tink/internal/ParametersParserTest.java
+++ b/src/test/java/com/google/crypto/tink/internal/ParametersParserTest.java
@@ -53,8 +53,9 @@
 
   @Test
   public void createParser_works() throws Exception {
-    ParametersParser.create(
-        ParametersParserTest::parse, Bytes.copyFrom(new byte[0]), ExampleSerialization.class);
+    Object unused =
+        ParametersParser.create(
+            ParametersParserTest::parse, Bytes.copyFrom(new byte[0]), ExampleSerialization.class);
   }
 
   @Test
diff --git a/src/test/java/com/google/crypto/tink/internal/ParametersSerializerTest.java b/src/test/java/com/google/crypto/tink/internal/ParametersSerializerTest.java
index 210aaef..9752ef4 100644
--- a/src/test/java/com/google/crypto/tink/internal/ParametersSerializerTest.java
+++ b/src/test/java/com/google/crypto/tink/internal/ParametersSerializerTest.java
@@ -53,8 +53,11 @@
 
   @Test
   public void createSerializer_works() throws Exception {
-    ParametersSerializer.create(
-        ParametersSerializerTest::serialize, ExampleParameters.class, ExampleSerialization.class);
+    Object unused =
+        ParametersSerializer.create(
+            ParametersSerializerTest::serialize,
+            ExampleParameters.class,
+            ExampleSerialization.class);
   }
 
   @Test
diff --git a/src/test/java/com/google/crypto/tink/internal/ProtoKeySerializationTest.java b/src/test/java/com/google/crypto/tink/internal/ProtoKeySerializationTest.java
index b0edf5e..23e330b 100644
--- a/src/test/java/com/google/crypto/tink/internal/ProtoKeySerializationTest.java
+++ b/src/test/java/com/google/crypto/tink/internal/ProtoKeySerializationTest.java
@@ -69,11 +69,16 @@
     final ByteString value = ByteString.copyFrom(new byte[] {10, 11, 12});
     final KeyMaterialType keyMaterialType = KeyMaterialType.SYMMETRIC;
 
-    ProtoKeySerialization.create(
-        typeUrl, value, keyMaterialType, OutputPrefixType.RAW, /* idRequirement = */ null);
-    ProtoKeySerialization.create(typeUrl, value, keyMaterialType, OutputPrefixType.TINK, 123);
-    ProtoKeySerialization.create(typeUrl, value, keyMaterialType, OutputPrefixType.CRUNCHY, 123);
-    ProtoKeySerialization.create(typeUrl, value, keyMaterialType, OutputPrefixType.LEGACY, 123);
+    Object unused =
+        ProtoKeySerialization.create(
+            typeUrl, value, keyMaterialType, OutputPrefixType.RAW, /* idRequirement= */ null);
+    unused =
+        ProtoKeySerialization.create(typeUrl, value, keyMaterialType, OutputPrefixType.TINK, 123);
+    unused =
+        ProtoKeySerialization.create(
+            typeUrl, value, keyMaterialType, OutputPrefixType.CRUNCHY, 123);
+    unused =
+        ProtoKeySerialization.create(typeUrl, value, keyMaterialType, OutputPrefixType.LEGACY, 123);
 
     assertThrows(
         GeneralSecurityException.class,