Suggestions

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/MapRules.java

@@ -45,18 +45,17 @@ V after(Map<K, V> map, T key) {
     }
   }
 
-  /**
-   * Prefer {@link Map#getOrDefault(Object, Object)} over more contrived alternatives. Note that
-   * this method may return null instead of throwing a NPE.
-   */
+  /** Prefer {@link Map#getOrDefault(Object, Object)} over more contrived alternatives. */
+  // Note that
+  // XXX: `requireNonNullElse` throws an NPE if the second argument is `null`, while the alternative
+  // does not.
   static final class MapGetOrDefault<K, V, T> {
     @BeforeTemplate
     V before(Map<K, V> map, T key, V defaultValue) {
       return requireNonNullElse(map.get(key), defaultValue);
     }
 
     @AfterTemplate
-    @Nullable
     V after(Map<K, V> map, T key, V defaultValue) {
       return map.getOrDefault(key, defaultValue);
     }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/MapRulesTestInput.java

@@ -13,7 +13,7 @@
 final class MapRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<?> elidedTypesAndStaticImports() {
-    return ImmutableSet.of(HashMap.class, requireNonNullElse("foo", "bar"));
+    return ImmutableSet.of(HashMap.class, requireNonNullElse(null, null));
   }
 
   Map<RoundingMode, String> testCreateEnumMap() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/MapRulesTestOutput.java

@@ -14,7 +14,7 @@
 final class MapRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<?> elidedTypesAndStaticImports() {
-    return ImmutableSet.of(HashMap.class, requireNonNullElse("foo", "bar"));
+    return ImmutableSet.of(HashMap.class, requireNonNullElse(null, null));
   }
 
   Map<RoundingMode, String> testCreateEnumMap() {