diff --git a/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/NonEmptyMonoTest.java b/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/NonEmptyMonoTest.java
index 09b95549de..c4e79c91a8 100644
--- a/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/NonEmptyMonoTest.java
+++ b/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/NonEmptyMonoTest.java
@@ -22,54 +22,88 @@ void identification() {
             "",
             "import com.google.common.collect.ImmutableList;",
             "import com.google.common.collect.ImmutableMap;",
+            "import java.util.ArrayList;",
+            "import java.util.HashMap;",
+            "import java.util.List;",
             "import reactor.core.publisher.Flux;",
             "import reactor.core.publisher.Mono;",
             "",
             "class A {",
             "  void m() {",
+            "    Mono.just(1).defaultIfEmpty(2);",
+            "    Mono.just(1).single();",
+            "    Mono.just(1).switchIfEmpty(Mono.just(2));",
+            "",
             "    // BUG: Diagnostic contains:",
             "    Flux.just(1).all(x -> true).defaultIfEmpty(true);",
+            "",
             "    // BUG: Diagnostic contains:",
             "    Flux.just(1).any(x -> true).single();",
             "",
             "    // BUG: Diagnostic contains:",
             "    Flux.just(1).collect(toImmutableList()).switchIfEmpty(Mono.just(ImmutableList.of()));",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).collectList().defaultIfEmpty(ImmutableList.of());",
+            "    Flux.just(1).collect(ArrayList::new, List::add).defaultIfEmpty(new ArrayList<>());",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectList().single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMap(identity()).switchIfEmpty(Mono.just(ImmutableMap.of()));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMap(identity(), identity()).defaultIfEmpty(ImmutableMap.of());",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMap(identity(), identity(), HashMap::new).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMultimap(identity()).switchIfEmpty(Mono.just(ImmutableMap.of()));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMultimap(identity(), identity()).defaultIfEmpty(ImmutableMap.of());",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).collectMap(identity()).single();",
-            "    Flux.just(1)",
-            "        .collectMultimap(identity(), identity(), ImmutableMap::of)",
-            "        // BUG: Diagnostic contains:",
-            "        .switchIfEmpty(Mono.just(ImmutableMap.of()));",
+            "    Flux.just(1).collectMultimap(identity(), identity(), HashMap::new).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectSortedList().defaultIfEmpty(ImmutableList.of());",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).collectSortedList((o1, o2) -> 1).defaultIfEmpty(ImmutableList.of());",
+            "    Flux.just(1).collectSortedList((o1, o2) -> 0).single();",
             "",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).count().single();",
+            "    Flux.just(1).count().switchIfEmpty(Mono.just(2L));",
+            "",
             "    // BUG: Diagnostic contains:",
             "    Flux.just(1).elementAt(0).defaultIfEmpty(1);",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).hasElement(0).single();",
+            "    Flux.just(1).elementAt(0, 2).single();",
+            "",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).hasElements().switchIfEmpty(Mono.just(true));",
+            "    Flux.just(1).hasElement(2).switchIfEmpty(Mono.just(true));",
+            "",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).last().defaultIfEmpty(1);",
+            "    Flux.just(1).hasElements().defaultIfEmpty(true);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).last().single();",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).last(2).switchIfEmpty(Mono.just(3));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).reduceWith(() -> 0, Integer::sum).defaultIfEmpty(2);",
+            "",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).reduceWith(() -> 1, (x, y) -> x).single();",
+            "    Flux.just(1).single().single();",
             "    // BUG: Diagnostic contains:",
-            "    Flux.just(1).single().switchIfEmpty(Mono.just(1));",
+            "    Flux.just(1).single(2).switchIfEmpty(Mono.just(3));",
             "",
-            "    Flux.just(1).reduce(Integer::sum).single();",
+            "    Flux.just(1).reduce(Integer::sum).defaultIfEmpty(2);",
             "    // BUG: Diagnostic contains:",
             "    Flux.just(1).reduce(2, Integer::sum).single();",
             "",
             "    // BUG: Diagnostic contains:",
-            "    Mono.just(1).defaultIfEmpty(1).defaultIfEmpty(2);",
+            "    Mono.just(1).defaultIfEmpty(1).switchIfEmpty(Mono.just(2));",
             "    // BUG: Diagnostic contains:",
-            "    Mono.just(1).hasElement().single();",
+            "    Mono.just(1).hasElement().defaultIfEmpty(true);",
             "    // BUG: Diagnostic contains:",
-            "    Mono.just(1).single().switchIfEmpty(Mono.just(2));",
+            "    Mono.just(1).single().single();",
             "  }",
             "}")
         .doTest();
@@ -93,8 +127,8 @@ void replacement() {
             "    Flux.just(1).collect(toImmutableList()).switchIfEmpty(Mono.just(ImmutableList.of()));",
             "",
             "    Mono.just(2).hasElement().single();",
-            "    Mono.just(2).hasElement().defaultIfEmpty(Boolean.TRUE);",
-            "    Mono.just(2).hasElement().switchIfEmpty(Mono.just(Boolean.TRUE));",
+            "    Mono.just(2).hasElement().defaultIfEmpty(true);",
+            "    Mono.just(2).hasElement().switchIfEmpty(Mono.just(true));",
             "  }",
             "}")
         .addOutputLines(