1 files changed, 41 insertions, 0 deletions
diff --git a/guava-testlib/src/com/google/common/collect/testing/ElementTypesAreNonnullByDefault.java b/guava-testlib/src/com/google/common/collect/testing/ElementTypesAreNonnullByDefault.java
new file mode 100644
index 000000000..80379ccb8
--- /dev/null
+++ b/guava-testlib/src/com/google/common/collect/testing/ElementTypesAreNonnullByDefault.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2021 The Guava Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.common.collect.testing;
+
+import static java.lang.annotation.ElementType.FIELD;
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.ElementType.PARAMETER;
+import static java.lang.annotation.ElementType.TYPE;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+import com.google.common.annotations.GwtCompatible;
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+import javax.annotation.Nonnull;
+import javax.annotation.meta.TypeQualifierDefault;
+
+/**
+ * Marks all "top-level" types as non-null in a way that is recognized by Kotlin. Note that this
+ * unfortunately includes type-variable usages, so we also provide {@link ParametricNullness} to
+ * "undo" it as best we can.
+ */
+@GwtCompatible
+@Retention(RUNTIME)
+@Target(TYPE)
+@TypeQualifierDefault({FIELD, METHOD, PARAMETER})
+@Nonnull
+@interface ElementTypesAreNonnullByDefault {}