diff --git a/java/com/google/gerrit/acceptance/AbstractNotificationTest.java b/java/com/google/gerrit/acceptance/AbstractNotificationTest.java
index c6f9d32..f62ccfb 100644
--- a/java/com/google/gerrit/acceptance/AbstractNotificationTest.java
+++ b/java/com/google/gerrit/acceptance/AbstractNotificationTest.java
@@ -95,8 +95,7 @@
     gApi.accounts().self().setPreferences(prefs);
   }
 
-  protected static class FakeEmailSenderSubject
-      extends Subject<FakeEmailSenderSubject, FakeEmailSender> {
+  protected static class FakeEmailSenderSubject extends Subject {
     private final FakeEmailSender fakeEmailSender;
     private Message message;
     private StagedUsers users;
diff --git a/java/com/google/gerrit/common/data/testing/GroupReferenceSubject.java b/java/com/google/gerrit/common/data/testing/GroupReferenceSubject.java
index 61263fc..b65f64b 100644
--- a/java/com/google/gerrit/common/data/testing/GroupReferenceSubject.java
+++ b/java/com/google/gerrit/common/data/testing/GroupReferenceSubject.java
@@ -21,9 +21,8 @@
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
 import com.google.gerrit.common.data.GroupReference;
-import com.google.gerrit.reviewdb.client.AccountGroup;
 
-public class GroupReferenceSubject extends Subject<GroupReferenceSubject, GroupReference> {
+public class GroupReferenceSubject extends Subject {
 
   public static GroupReferenceSubject assertThat(GroupReference group) {
     return assertAbout(groupReferences()).that(group);
@@ -40,7 +39,7 @@
     this.group = group;
   }
 
-  public ComparableSubject<?, AccountGroup.UUID> groupUuid() {
+  public ComparableSubject groupUuid() {
     isNotNull();
     return check("getUUID()").that(group.getUUID());
   }
diff --git a/java/com/google/gerrit/extensions/common/testing/CommitInfoSubject.java b/java/com/google/gerrit/extensions/common/testing/CommitInfoSubject.java
index d827108..d6fcb37 100644
--- a/java/com/google/gerrit/extensions/common/testing/CommitInfoSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/CommitInfoSubject.java
@@ -24,7 +24,7 @@
 import com.google.gerrit.extensions.common.CommitInfo;
 import com.google.gerrit.truth.ListSubject;
 
-public class CommitInfoSubject extends Subject<CommitInfoSubject, CommitInfo> {
+public class CommitInfoSubject extends Subject {
 
   public static CommitInfoSubject assertThat(CommitInfo commitInfo) {
     return assertAbout(commits()).that(commitInfo);
diff --git a/java/com/google/gerrit/extensions/common/testing/ContentEntrySubject.java b/java/com/google/gerrit/extensions/common/testing/ContentEntrySubject.java
index e7aa01d..b55f7c2 100644
--- a/java/com/google/gerrit/extensions/common/testing/ContentEntrySubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/ContentEntrySubject.java
@@ -27,7 +27,7 @@
 import com.google.gerrit.extensions.common.DiffInfo.ContentEntry;
 import com.google.gerrit.truth.ListSubject;
 
-public class ContentEntrySubject extends Subject<ContentEntrySubject, ContentEntry> {
+public class ContentEntrySubject extends Subject {
 
   public static ContentEntrySubject assertThat(ContentEntry contentEntry) {
     return assertAbout(contentEntries()).that(contentEntry);
diff --git a/java/com/google/gerrit/extensions/common/testing/DiffInfoSubject.java b/java/com/google/gerrit/extensions/common/testing/DiffInfoSubject.java
index 1322793..c94dc27 100644
--- a/java/com/google/gerrit/extensions/common/testing/DiffInfoSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/DiffInfoSubject.java
@@ -21,12 +21,11 @@
 import com.google.common.truth.ComparableSubject;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
-import com.google.gerrit.extensions.common.ChangeType;
 import com.google.gerrit.extensions.common.DiffInfo;
 import com.google.gerrit.extensions.common.DiffInfo.ContentEntry;
 import com.google.gerrit.truth.ListSubject;
 
-public class DiffInfoSubject extends Subject<DiffInfoSubject, DiffInfo> {
+public class DiffInfoSubject extends Subject {
 
   public static DiffInfoSubject assertThat(DiffInfo diffInfo) {
     return assertAbout(DiffInfoSubject::new).that(diffInfo);
@@ -46,7 +45,7 @@
         .thatCustom(diffInfo.content, ContentEntrySubject.contentEntries());
   }
 
-  public ComparableSubject<?, ChangeType> changeType() {
+  public ComparableSubject changeType() {
     isNotNull();
     return check("changeType").that(diffInfo.changeType);
   }
diff --git a/java/com/google/gerrit/extensions/common/testing/EditInfoSubject.java b/java/com/google/gerrit/extensions/common/testing/EditInfoSubject.java
index 25db1fe..b5622e0 100644
--- a/java/com/google/gerrit/extensions/common/testing/EditInfoSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/EditInfoSubject.java
@@ -24,7 +24,7 @@
 import com.google.gerrit.truth.OptionalSubject;
 import java.util.Optional;
 
-public class EditInfoSubject extends Subject<EditInfoSubject, EditInfo> {
+public class EditInfoSubject extends Subject {
 
   public static EditInfoSubject assertThat(EditInfo editInfo) {
     return assertAbout(edits()).that(editInfo);
diff --git a/java/com/google/gerrit/extensions/common/testing/FileInfoSubject.java b/java/com/google/gerrit/extensions/common/testing/FileInfoSubject.java
index 27d3f0e..35e67a6 100644
--- a/java/com/google/gerrit/extensions/common/testing/FileInfoSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/FileInfoSubject.java
@@ -22,7 +22,7 @@
 import com.google.common.truth.Subject;
 import com.google.gerrit.extensions.common.FileInfo;
 
-public class FileInfoSubject extends Subject<FileInfoSubject, FileInfo> {
+public class FileInfoSubject extends Subject {
 
   public static FileInfoSubject assertThat(FileInfo fileInfo) {
     return assertAbout(FileInfoSubject::new).that(fileInfo);
@@ -45,7 +45,7 @@
     return check("linesDeleted").that(fileInfo.linesDeleted);
   }
 
-  public ComparableSubject<?, Character> status() {
+  public ComparableSubject status() {
     isNotNull();
     return check("status").that(fileInfo.status);
   }
diff --git a/java/com/google/gerrit/extensions/common/testing/FileMetaSubject.java b/java/com/google/gerrit/extensions/common/testing/FileMetaSubject.java
index 6cac80dd..fb09a1f 100644
--- a/java/com/google/gerrit/extensions/common/testing/FileMetaSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/FileMetaSubject.java
@@ -21,7 +21,7 @@
 import com.google.common.truth.Subject;
 import com.google.gerrit.extensions.common.DiffInfo.FileMeta;
 
-public class FileMetaSubject extends Subject<FileMetaSubject, FileMeta> {
+public class FileMetaSubject extends Subject {
 
   public static FileMetaSubject assertThat(FileMeta fileMeta) {
     return assertAbout(fileMetas()).that(fileMeta);
diff --git a/java/com/google/gerrit/extensions/common/testing/FixReplacementInfoSubject.java b/java/com/google/gerrit/extensions/common/testing/FixReplacementInfoSubject.java
index 1ecc604..9ba69dc 100644
--- a/java/com/google/gerrit/extensions/common/testing/FixReplacementInfoSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/FixReplacementInfoSubject.java
@@ -22,8 +22,7 @@
 import com.google.common.truth.Subject;
 import com.google.gerrit.extensions.common.FixReplacementInfo;
 
-public class FixReplacementInfoSubject
-    extends Subject<FixReplacementInfoSubject, FixReplacementInfo> {
+public class FixReplacementInfoSubject extends Subject {
 
   public static FixReplacementInfoSubject assertThat(FixReplacementInfo fixReplacementInfo) {
     return assertAbout(fixReplacements()).that(fixReplacementInfo);
diff --git a/java/com/google/gerrit/extensions/common/testing/FixSuggestionInfoSubject.java b/java/com/google/gerrit/extensions/common/testing/FixSuggestionInfoSubject.java
index 1e95907..4ac725a 100644
--- a/java/com/google/gerrit/extensions/common/testing/FixSuggestionInfoSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/FixSuggestionInfoSubject.java
@@ -25,7 +25,7 @@
 import com.google.gerrit.extensions.common.FixSuggestionInfo;
 import com.google.gerrit.truth.ListSubject;
 
-public class FixSuggestionInfoSubject extends Subject<FixSuggestionInfoSubject, FixSuggestionInfo> {
+public class FixSuggestionInfoSubject extends Subject {
 
   public static FixSuggestionInfoSubject assertThat(FixSuggestionInfo fixSuggestionInfo) {
     return assertAbout(fixSuggestions()).that(fixSuggestionInfo);
diff --git a/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java b/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java
index c9f5a79..5564642 100644
--- a/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/GitPersonSubject.java
@@ -23,11 +23,10 @@
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
 import com.google.gerrit.extensions.common.GitPerson;
-import java.sql.Timestamp;
 import java.util.Date;
 import org.eclipse.jgit.lib.PersonIdent;
 
-public class GitPersonSubject extends Subject<GitPersonSubject, GitPerson> {
+public class GitPersonSubject extends Subject {
 
   public static GitPersonSubject assertThat(GitPerson gitPerson) {
     return assertAbout(gitPersons()).that(gitPerson);
@@ -54,7 +53,7 @@
     return check("email").that(gitPerson.email);
   }
 
-  public ComparableSubject<?, Timestamp> date() {
+  public ComparableSubject date() {
     isNotNull();
     return check("date").that(gitPerson.date);
   }
diff --git a/java/com/google/gerrit/extensions/common/testing/RangeSubject.java b/java/com/google/gerrit/extensions/common/testing/RangeSubject.java
index 0d049e0..10abca2 100644
--- a/java/com/google/gerrit/extensions/common/testing/RangeSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/RangeSubject.java
@@ -22,7 +22,7 @@
 import com.google.common.truth.Subject;
 import com.google.gerrit.extensions.client.Comment;
 
-public class RangeSubject extends Subject<RangeSubject, Comment.Range> {
+public class RangeSubject extends Subject {
 
   public static RangeSubject assertThat(Comment.Range range) {
     return assertAbout(ranges()).that(range);
diff --git a/java/com/google/gerrit/extensions/common/testing/RobotCommentInfoSubject.java b/java/com/google/gerrit/extensions/common/testing/RobotCommentInfoSubject.java
index 0a53154..0698735 100644
--- a/java/com/google/gerrit/extensions/common/testing/RobotCommentInfoSubject.java
+++ b/java/com/google/gerrit/extensions/common/testing/RobotCommentInfoSubject.java
@@ -24,7 +24,7 @@
 import com.google.gerrit.truth.ListSubject;
 import java.util.List;
 
-public class RobotCommentInfoSubject extends Subject<RobotCommentInfoSubject, RobotCommentInfo> {
+public class RobotCommentInfoSubject extends Subject {
 
   public static ListSubject<RobotCommentInfoSubject, RobotCommentInfo> assertThatList(
       List<RobotCommentInfo> robotCommentInfos) {
diff --git a/java/com/google/gerrit/extensions/restapi/testing/BinaryResultSubject.java b/java/com/google/gerrit/extensions/restapi/testing/BinaryResultSubject.java
index d492aa2..c5304e3 100644
--- a/java/com/google/gerrit/extensions/restapi/testing/BinaryResultSubject.java
+++ b/java/com/google/gerrit/extensions/restapi/testing/BinaryResultSubject.java
@@ -26,7 +26,7 @@
 import java.io.IOException;
 import java.util.Optional;
 
-public class BinaryResultSubject extends Subject<BinaryResultSubject, BinaryResult> {
+public class BinaryResultSubject extends Subject {
 
   public static BinaryResultSubject assertThat(BinaryResult binaryResult) {
     return assertAbout(binaryResults()).that(binaryResult);
diff --git a/java/com/google/gerrit/git/testing/CommitSubject.java b/java/com/google/gerrit/git/testing/CommitSubject.java
index 4d02313..41eb45b 100644
--- a/java/com/google/gerrit/git/testing/CommitSubject.java
+++ b/java/com/google/gerrit/git/testing/CommitSubject.java
@@ -24,7 +24,7 @@
 import org.eclipse.jgit.revwalk.RevCommit;
 
 /** Subject over JGit {@link RevCommit}s. */
-public class CommitSubject extends Subject<CommitSubject, RevCommit> {
+public class CommitSubject extends Subject {
 
   /**
    * Constructs a new subject.
diff --git a/java/com/google/gerrit/git/testing/ObjectIdSubject.java b/java/com/google/gerrit/git/testing/ObjectIdSubject.java
index 5a99229..0cfc563 100644
--- a/java/com/google/gerrit/git/testing/ObjectIdSubject.java
+++ b/java/com/google/gerrit/git/testing/ObjectIdSubject.java
@@ -20,7 +20,7 @@
 import com.google.common.truth.Subject;
 import org.eclipse.jgit.lib.ObjectId;
 
-public class ObjectIdSubject extends Subject<ObjectIdSubject, ObjectId> {
+public class ObjectIdSubject extends Subject {
   public static ObjectIdSubject assertThat(ObjectId objectId) {
     return assertAbout(objectIds()).that(objectId);
   }
diff --git a/java/com/google/gerrit/git/testing/PushResultSubject.java b/java/com/google/gerrit/git/testing/PushResultSubject.java
index 9ff4c3b..9a46632 100644
--- a/java/com/google/gerrit/git/testing/PushResultSubject.java
+++ b/java/com/google/gerrit/git/testing/PushResultSubject.java
@@ -32,7 +32,7 @@
 import org.eclipse.jgit.transport.PushResult;
 import org.eclipse.jgit.transport.RemoteRefUpdate;
 
-public class PushResultSubject extends Subject<PushResultSubject, PushResult> {
+public class PushResultSubject extends Subject {
   public static PushResultSubject assertThat(PushResult actual) {
     return assertAbout(PushResultSubject::new).that(actual);
   }
@@ -139,8 +139,7 @@
     return ref(refName);
   }
 
-  public static class RemoteRefUpdateSubject
-      extends Subject<RemoteRefUpdateSubject, RemoteRefUpdate> {
+  public static class RemoteRefUpdateSubject extends Subject {
     private final RemoteRefUpdate remoteRefUpdate;
 
     private RemoteRefUpdateSubject(FailureMetadata metadata, RemoteRefUpdate remoteRefUpdate) {
diff --git a/java/com/google/gerrit/index/query/testing/TreeSubject.java b/java/com/google/gerrit/index/query/testing/TreeSubject.java
index 46c3895..7d2b868 100644
--- a/java/com/google/gerrit/index/query/testing/TreeSubject.java
+++ b/java/com/google/gerrit/index/query/testing/TreeSubject.java
@@ -23,7 +23,7 @@
 import com.google.gerrit.index.query.QueryParser;
 import org.antlr.runtime.tree.Tree;
 
-public class TreeSubject extends Subject<TreeSubject, Tree> {
+public class TreeSubject extends Subject {
   public static TreeSubject assertThat(Tree actual) {
     return assertAbout(TreeSubject::new).that(actual);
   }
diff --git a/java/com/google/gerrit/proto/testing/SerializedClassSubject.java b/java/com/google/gerrit/proto/testing/SerializedClassSubject.java
index b078217..e7dc276 100644
--- a/java/com/google/gerrit/proto/testing/SerializedClassSubject.java
+++ b/java/com/google/gerrit/proto/testing/SerializedClassSubject.java
@@ -48,7 +48,7 @@
  * the hand-written serializer. Usually, serializer implementations should be written in such a way
  * that new fields are considered optional, and won't require bumping the version.
  */
-public class SerializedClassSubject extends Subject<SerializedClassSubject, Class<?>> {
+public class SerializedClassSubject extends Subject {
   public static SerializedClassSubject assertThatSerializedClass(Class<?> actual) {
     // This formulation fails in Eclipse 4.7.3a with "The type
     // SerializedClassSubject does not define SerializedClassSubject() that is
diff --git a/java/com/google/gerrit/server/group/testing/InternalGroupSubject.java b/java/com/google/gerrit/server/group/testing/InternalGroupSubject.java
index 0b24f8c..79bd005 100644
--- a/java/com/google/gerrit/server/group/testing/InternalGroupSubject.java
+++ b/java/com/google/gerrit/server/group/testing/InternalGroupSubject.java
@@ -22,12 +22,9 @@
 import com.google.common.truth.IterableSubject;
 import com.google.common.truth.StringSubject;
 import com.google.common.truth.Subject;
-import com.google.gerrit.reviewdb.client.AccountGroup;
 import com.google.gerrit.server.group.InternalGroup;
-import java.sql.Timestamp;
-import org.eclipse.jgit.lib.ObjectId;
 
-public class InternalGroupSubject extends Subject<InternalGroupSubject, InternalGroup> {
+public class InternalGroupSubject extends Subject {
 
   public static InternalGroupSubject assertThat(InternalGroup group) {
     return assertAbout(internalGroups()).that(group);
@@ -44,12 +41,12 @@
     this.group = group;
   }
 
-  public ComparableSubject<?, AccountGroup.UUID> groupUuid() {
+  public ComparableSubject groupUuid() {
     isNotNull();
     return check("getGroupUUID()").that(group.getGroupUUID());
   }
 
-  public ComparableSubject<?, AccountGroup.NameKey> nameKey() {
+  public ComparableSubject nameKey() {
     isNotNull();
     return check("getNameKey()").that(group.getNameKey());
   }
@@ -59,7 +56,7 @@
     return check("getName()").that(group.getName());
   }
 
-  public Subject<?, ?> id() {
+  public Subject id() {
     isNotNull();
     return check("getId()").that(group.getId());
   }
@@ -69,7 +66,7 @@
     return check("getDescription()").that(group.getDescription());
   }
 
-  public ComparableSubject<?, AccountGroup.UUID> ownerGroupUuid() {
+  public ComparableSubject ownerGroupUuid() {
     isNotNull();
     return check("getOwnerGroupUUID()").that(group.getOwnerGroupUUID());
   }
@@ -79,7 +76,7 @@
     return check("isVisibleToAll()").that(group.isVisibleToAll());
   }
 
-  public ComparableSubject<?, Timestamp> createdOn() {
+  public ComparableSubject createdOn() {
     isNotNull();
     return check("getCreatedOn()").that(group.getCreatedOn());
   }
@@ -94,7 +91,7 @@
     return check("getSubgroups()").that(group.getSubgroups());
   }
 
-  public ComparableSubject<?, ObjectId> refState() {
+  public ComparableSubject refState() {
     isNotNull();
     return check("getRefState()").that(group.getRefState());
   }
diff --git a/java/com/google/gerrit/truth/CacheStatsSubject.java b/java/com/google/gerrit/truth/CacheStatsSubject.java
index 22c33c2..ff94334 100644
--- a/java/com/google/gerrit/truth/CacheStatsSubject.java
+++ b/java/com/google/gerrit/truth/CacheStatsSubject.java
@@ -24,7 +24,7 @@
 import com.google.gerrit.common.UsedAt.Project;
 
 @UsedAt(Project.PLUGINS_ALL)
-public class CacheStatsSubject extends Subject<CacheStatsSubject, CacheStats> {
+public class CacheStatsSubject extends Subject {
   public static CacheStatsSubject assertThat(CacheStats stats) {
     return assertAbout(CacheStatsSubject::new).that(stats);
   }
diff --git a/java/com/google/gerrit/truth/ConfigSubject.java b/java/com/google/gerrit/truth/ConfigSubject.java
index 615719a..dd55b71 100644
--- a/java/com/google/gerrit/truth/ConfigSubject.java
+++ b/java/com/google/gerrit/truth/ConfigSubject.java
@@ -30,7 +30,7 @@
 import java.util.Arrays;
 import org.eclipse.jgit.lib.Config;
 
-public class ConfigSubject extends Subject<ConfigSubject, Config> {
+public class ConfigSubject extends Subject {
   public static ConfigSubject assertThat(Config config) {
     return assertAbout(ConfigSubject::new).that(config);
   }
diff --git a/java/com/google/gerrit/truth/ListSubject.java b/java/com/google/gerrit/truth/ListSubject.java
index 0da16f8..bee7408 100644
--- a/java/com/google/gerrit/truth/ListSubject.java
+++ b/java/com/google/gerrit/truth/ListSubject.java
@@ -27,12 +27,12 @@
 import java.util.List;
 import java.util.function.BiFunction;
 
-public class ListSubject<S extends Subject<S, E>, E> extends IterableSubject {
+public class ListSubject<S extends Subject, E> extends IterableSubject {
 
   private final List<E> list;
   private final BiFunction<StandardSubjectBuilder, E, S> elementSubjectCreator;
 
-  public static <S extends Subject<S, E>, E> ListSubject<S, E> assertThat(
+  public static <S extends Subject, E> ListSubject<S, E> assertThat(
       List<E> list, Subject.Factory<S, E> subjectFactory) {
     return assertAbout(elements()).thatCustom(list, subjectFactory);
   }
@@ -77,12 +77,12 @@
       super(failureMetadata);
     }
 
-    public <S extends Subject<S, E>, E> ListSubject<S, E> thatCustom(
+    public <S extends Subject, E> ListSubject<S, E> thatCustom(
         List<E> list, Subject.Factory<S, E> subjectFactory) {
       return that(list, (builder, element) -> builder.about(subjectFactory).that(element));
     }
 
-    public <S extends Subject<S, E>, E> ListSubject<S, E> that(
+    public <S extends Subject, E> ListSubject<S, E> that(
         List<E> list, BiFunction<StandardSubjectBuilder, E, S> elementSubjectCreator) {
       return new ListSubject<>(metadata(), list, elementSubjectCreator);
     }
diff --git a/java/com/google/gerrit/truth/OptionalSubject.java b/java/com/google/gerrit/truth/OptionalSubject.java
index dd1e419..a87dff1 100644
--- a/java/com/google/gerrit/truth/OptionalSubject.java
+++ b/java/com/google/gerrit/truth/OptionalSubject.java
@@ -18,7 +18,6 @@
 import static com.google.common.truth.Truth.assertAbout;
 
 import com.google.common.truth.CustomSubjectBuilder;
-import com.google.common.truth.DefaultSubject;
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.StandardSubjectBuilder;
 import com.google.common.truth.Subject;
@@ -26,32 +25,26 @@
 import java.util.function.BiFunction;
 import java.util.function.Function;
 
-public class OptionalSubject<S extends Subject<S, ? super T>, T>
-    extends Subject<OptionalSubject<S, T>, Optional<T>> {
+public class OptionalSubject<S extends Subject, T> extends Subject {
 
   private final Optional<T> optional;
   private final BiFunction<StandardSubjectBuilder, ? super T, ? extends S> valueSubjectCreator;
 
   // TODO(aliceks): Remove when all relevant usages are adapted to new check()/factory approach.
-  public static <S extends Subject<S, T>, T> OptionalSubject<S, T> assertThat(
+  public static <S extends Subject, T> OptionalSubject<S, T> assertThat(
       Optional<T> optional, Function<? super T, ? extends S> elementAssertThatFunction) {
     Subject.Factory<S, T> valueSubjectFactory =
         (metadata, value) -> elementAssertThatFunction.apply(value);
     return assertThat(optional, valueSubjectFactory);
   }
 
-  public static <S extends Subject<S, T>, T> OptionalSubject<S, T> assertThat(
+  public static <S extends Subject, T> OptionalSubject<S, T> assertThat(
       Optional<T> optional, Subject.Factory<S, T> valueSubjectFactory) {
     return assertAbout(optionals()).thatCustom(optional, valueSubjectFactory);
   }
 
-  public static OptionalSubject<DefaultSubject, ?> assertThat(Optional<?> optional) {
-    // Unfortunately, we need to cast to DefaultSubject as StandardSubjectBuilder#that
-    // only returns Subject<DefaultSubject, Object>. There shouldn't be a way
-    // for that method not to return a DefaultSubject because the generic type
-    // definitions of a Subject are quite strict.
-    return assertAbout(optionals())
-        .that(optional, (builder, value) -> (DefaultSubject) builder.that(value));
+  public static OptionalSubject<Subject, ?> assertThat(Optional<?> optional) {
+    return assertAbout(optionals()).that(optional);
   }
 
   public static CustomSubjectBuilder.Factory<OptionalSubjectBuilder> optionals() {
@@ -97,16 +90,16 @@
       super(failureMetadata);
     }
 
-    public <S extends Subject<S, T>, T> OptionalSubject<S, T> thatCustom(
+    public <S extends Subject, T> OptionalSubject<S, T> thatCustom(
         Optional<T> optional, Subject.Factory<S, T> valueSubjectFactory) {
       return that(optional, (builder, value) -> builder.about(valueSubjectFactory).that(value));
     }
 
-    public OptionalSubject<DefaultSubject, ?> that(Optional<?> optional) {
-      return that(optional, (builder, value) -> (DefaultSubject) builder.that(value));
+    public OptionalSubject<Subject, ?> that(Optional<?> optional) {
+      return that(optional, StandardSubjectBuilder::that);
     }
 
-    public <S extends Subject<S, ? super T>, T> OptionalSubject<S, T> that(
+    public <S extends Subject, T> OptionalSubject<S, T> that(
         Optional<T> optional,
         BiFunction<StandardSubjectBuilder, ? super T, ? extends S> valueSubjectCreator) {
       return new OptionalSubject<>(metadata(), optional, valueSubjectCreator);
diff --git a/javatests/com/google/gerrit/server/edit/tree/ChangeFileContentModificationSubject.java b/javatests/com/google/gerrit/server/edit/tree/ChangeFileContentModificationSubject.java
index b23c47a..a618c9e 100644
--- a/javatests/com/google/gerrit/server/edit/tree/ChangeFileContentModificationSubject.java
+++ b/javatests/com/google/gerrit/server/edit/tree/ChangeFileContentModificationSubject.java
@@ -25,8 +25,7 @@
 import java.io.InputStreamReader;
 import java.nio.charset.StandardCharsets;
 
-public class ChangeFileContentModificationSubject
-    extends Subject<ChangeFileContentModificationSubject, ChangeFileContentModification> {
+public class ChangeFileContentModificationSubject extends Subject {
 
   public static ChangeFileContentModificationSubject assertThat(
       ChangeFileContentModification modification) {
diff --git a/javatests/com/google/gerrit/server/edit/tree/TreeModificationSubject.java b/javatests/com/google/gerrit/server/edit/tree/TreeModificationSubject.java
index 72759cd..d5b70bb 100644
--- a/javatests/com/google/gerrit/server/edit/tree/TreeModificationSubject.java
+++ b/javatests/com/google/gerrit/server/edit/tree/TreeModificationSubject.java
@@ -21,7 +21,7 @@
 import com.google.gerrit.truth.ListSubject;
 import java.util.List;
 
-public class TreeModificationSubject extends Subject<TreeModificationSubject, TreeModification> {
+public class TreeModificationSubject extends Subject {
 
   public static TreeModificationSubject assertThat(TreeModification treeModification) {
     return assertAbout(treeModifications()).that(treeModification);