Annotate checkNotNull's input and output as @NonNull.

We don't want to go down the road of annotating most things @NonNull, as we eventually want to use tools that assume that that's the default. However, it's pretty weird for checkNotNull() to return a @Nullable value in the minds of some tools, so let's annotate just that method and see how it goes.

RELNOTES=Annotated `checkNotNull`'s input and output as `@NonNull`.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=233963788

2 files changed, 132 insertions, 70 deletions

diff --git a/android/guava/src/com/google/common/base/Preconditions.java b/android/guava/src/com/google/common/base/Preconditions.java
index ecf9c40f6..ca81c66b7 100644
--- a/android/guava/src/com/google/common/base/Preconditions.java
+++ b/android/guava/src/com/google/common/base/Preconditions.java
@@ -18,6 +18,7 @@ import static com.google.common.base.Strings.lenientFormat;
 
 import com.google.common.annotations.GwtCompatible;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import org.checkerframework.checker.nullness.compatqual.NonNullDecl;
 import org.checkerframework.checker.nullness.compatqual.NullableDecl;
 
 /**
@@ -883,7 +884,8 @@ public final class Preconditions {
    * @see Verify#verifyNotNull Verify.verifyNotNull()
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T reference) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(@NonNullDecl T reference) {
     if (reference == null) {
       throw new NullPointerException();
     }
@@ -901,7 +903,9 @@ public final class Preconditions {
    * @see Verify#verifyNotNull Verify.verifyNotNull()
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T reference, @NullableDecl Object errorMessage) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T reference, @NullableDecl Object errorMessage) {
     if (reference == null) {
       throw new NullPointerException(String.valueOf(errorMessage));
     }
@@ -924,8 +928,9 @@ public final class Preconditions {
    * @see Verify#verifyNotNull Verify.verifyNotNull()
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T reference,
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T reference,
       @NullableDecl String errorMessageTemplate,
       @NullableDecl Object... errorMessageArgs) {
     if (reference == null) {
@@ -942,7 +947,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @NullableDecl String errorMessageTemplate, char p1) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, char p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
     }
@@ -957,7 +964,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @NullableDecl String errorMessageTemplate, int p1) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, int p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
     }
@@ -972,7 +981,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @NullableDecl String errorMessageTemplate, long p1) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, long p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
     }
@@ -987,8 +998,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, @NullableDecl Object p1) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, @NullableDecl Object p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
     }
@@ -1003,8 +1015,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, char p1, char p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, char p1, char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1019,8 +1032,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, char p1, int p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, char p1, int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1035,8 +1049,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, char p1, long p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, char p1, long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1051,8 +1066,12 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, char p1, @NullableDecl Object p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
+      @NullableDecl String errorMessageTemplate,
+      char p1,
+      @NullableDecl Object p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1067,8 +1086,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, int p1, char p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, int p1, char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1083,8 +1103,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, int p1, int p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, int p1, int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1099,8 +1120,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, int p1, long p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, int p1, long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1115,8 +1137,12 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, int p1, @NullableDecl Object p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
+      @NullableDecl String errorMessageTemplate,
+      int p1,
+      @NullableDecl Object p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1131,8 +1157,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, long p1, char p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, long p1, char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1147,8 +1174,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, long p1, int p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, long p1, int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1163,8 +1191,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, long p1, long p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj, @NullableDecl String errorMessageTemplate, long p1, long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1179,8 +1208,12 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, long p1, @NullableDecl Object p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
+      @NullableDecl String errorMessageTemplate,
+      long p1,
+      @NullableDecl Object p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1195,8 +1228,12 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, @NullableDecl Object p1, char p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
+      @NullableDecl String errorMessageTemplate,
+      @NullableDecl Object p1,
+      char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1211,8 +1248,12 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, @NullableDecl Object p1, int p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
+      @NullableDecl String errorMessageTemplate,
+      @NullableDecl Object p1,
+      int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1227,8 +1268,12 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj, @NullableDecl String errorMessageTemplate, @NullableDecl Object p1, long p2) {
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
+      @NullableDecl String errorMessageTemplate,
+      @NullableDecl Object p1,
+      long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1243,8 +1288,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj,
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
       @NullableDecl String errorMessageTemplate,
       @NullableDecl Object p1,
       @NullableDecl Object p2) {
@@ -1262,8 +1308,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj,
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
       @NullableDecl String errorMessageTemplate,
       @NullableDecl Object p1,
       @NullableDecl Object p2,
@@ -1282,8 +1329,9 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
-      T obj,
+  @NonNullDecl
+  public static <T extends Object> T checkNotNull(
+      @NonNullDecl T obj,
       @NullableDecl String errorMessageTemplate,
       @NullableDecl Object p1,
       @NullableDecl Object p2,
diff --git a/guava/src/com/google/common/base/Preconditions.java b/guava/src/com/google/common/base/Preconditions.java
index 681294ed2..f62b88005 100644
--- a/guava/src/com/google/common/base/Preconditions.java
+++ b/guava/src/com/google/common/base/Preconditions.java
@@ -18,6 +18,7 @@ import static com.google.common.base.Strings.lenientFormat;
 
 import com.google.common.annotations.GwtCompatible;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
+import org.checkerframework.checker.nullness.qual.NonNull;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
 /**
@@ -872,7 +873,7 @@ public final class Preconditions {
    * @see Verify#verifyNotNull Verify.verifyNotNull()
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T reference) {
+  public static <T extends @NonNull Object> T checkNotNull(T reference) {
     if (reference == null) {
       throw new NullPointerException();
     }
@@ -890,7 +891,8 @@ public final class Preconditions {
    * @see Verify#verifyNotNull Verify.verifyNotNull()
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T reference, @Nullable Object errorMessage) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T reference, @Nullable Object errorMessage) {
     if (reference == null) {
       throw new NullPointerException(String.valueOf(errorMessage));
     }
@@ -913,7 +915,7 @@ public final class Preconditions {
    * @see Verify#verifyNotNull Verify.verifyNotNull()
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T reference, @Nullable String errorMessageTemplate, Object @Nullable ... errorMessageArgs) {
     if (reference == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, errorMessageArgs));
@@ -929,7 +931,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, char p1) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, char p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
     }
@@ -944,7 +947,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, int p1) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, int p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
     }
@@ -959,7 +963,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, long p1) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, long p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
     }
@@ -974,7 +979,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, @Nullable Object p1) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1));
@@ -990,7 +995,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, char p1, char p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, char p1, char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1005,7 +1011,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, char p1, int p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, char p1, int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1020,7 +1027,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, char p1, long p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, char p1, long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1035,7 +1043,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, char p1, @Nullable Object p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
@@ -1051,7 +1059,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, int p1, char p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, int p1, char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1066,7 +1075,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, int p1, int p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, int p1, int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1081,7 +1091,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, int p1, long p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, int p1, long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1096,7 +1107,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, int p1, @Nullable Object p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
@@ -1112,7 +1123,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, long p1, char p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, long p1, char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1127,7 +1139,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, long p1, int p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, long p1, int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1142,7 +1155,8 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(T obj, @Nullable String errorMessageTemplate, long p1, long p2) {
+  public static <T extends @NonNull Object> T checkNotNull(
+      T obj, @Nullable String errorMessageTemplate, long p1, long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
     }
@@ -1157,7 +1171,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, long p1, @Nullable Object p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
@@ -1173,7 +1187,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, @Nullable Object p1, char p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
@@ -1189,7 +1203,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, @Nullable Object p1, int p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
@@ -1205,7 +1219,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, @Nullable Object p1, long p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
@@ -1221,7 +1235,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj, @Nullable String errorMessageTemplate, @Nullable Object p1, @Nullable Object p2) {
     if (obj == null) {
       throw new NullPointerException(lenientFormat(errorMessageTemplate, p1, p2));
@@ -1237,7 +1251,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj,
       @Nullable String errorMessageTemplate,
       @Nullable Object p1,
@@ -1257,7 +1271,7 @@ public final class Preconditions {
    * @since 20.0 (varargs overload since 2.0)
    */
   @CanIgnoreReturnValue
-  public static <T> T checkNotNull(
+  public static <T extends @NonNull Object> T checkNotNull(
       T obj,
       @Nullable String errorMessageTemplate,
       @Nullable Object p1,