diff --git a/error-prone-contrib/pom.xml b/error-prone-contrib/pom.xml
index 6cd4ee80116..b35abc27261 100644
--- a/error-prone-contrib/pom.xml
+++ b/error-prone-contrib/pom.xml
@@ -138,6 +138,11 @@
             <artifactId>value-annotations</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.jspecify</groupId>
+            <artifactId>jspecify</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJava2AdapterTemplates.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJava2AdapterTemplates.java
index ef99623aa09..5384b9fbf70 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJava2AdapterTemplates.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJava2AdapterTemplates.java
@@ -9,6 +9,7 @@
 import io.reactivex.Maybe;
 import io.reactivex.Observable;
 import io.reactivex.Single;
+import org.jspecify.nullness.Nullable;
 import reactor.adapter.rxjava.RxJava2Adapter;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -20,14 +21,14 @@ private RxJava2AdapterTemplates() {}
   /** Use the fluent API style when using {@link RxJava2Adapter#completableToMono}. */
   static final class CompletableToMono {
     @BeforeTemplate
-    Mono<Void> before(Completable completable) {
+    Mono<@Nullable Void> before(Completable completable) {
       return Refaster.anyOf(
           RxJava2Adapter.completableToMono(completable),
           completable.to(RxJava2Adapter::completableToMono));
     }
 
     @AfterTemplate
-    Mono<Void> after(Completable completable) {
+    Mono<@Nullable Void> after(Completable completable) {
       return completable.as(RxJava2Adapter::completableToMono);
     }
   }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/StringTemplates.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/StringTemplates.java
index 2b5c7894ff2..7b7707bfed6 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/StringTemplates.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/StringTemplates.java
@@ -130,7 +130,7 @@ String after(Object object) {
    */
   // XXX: This template is analogous to `StringValueOf` above. Arguably this is its generalization.
   // If/when Refaster is extended to understand this, delete the template above.
-  static final class StringValueOfMethodReference<T> {
+  static final class StringValueOfMethodReference {
     @BeforeTemplate
     Function<Object, String> before() {
       return Objects::toString;
diff --git a/pom.xml b/pom.xml
index a28469b6f80..7501b465b8f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -378,6 +378,11 @@
                 <artifactId>value-annotations</artifactId>
                 <version>2.9.2</version>
             </dependency>
+            <dependency>
+                <groupId>org.jspecify</groupId>
+                <artifactId>jspecify</artifactId>
+                <version>0.2.0</version>
+            </dependency>
             <dependency>
                 <groupId>org.junit</groupId>
                 <artifactId>junit-bom</artifactId>