Fix nullability annotations in ABSL code.

PiperOrigin-RevId: 667621254
Change-Id: Ibff25d275c1c6846f857d90ed905c70f9545d8dd
diff --git a/absl/log/CMakeLists.txt b/absl/log/CMakeLists.txt
index 4384465..5484206 100644
--- a/absl/log/CMakeLists.txt
+++ b/absl/log/CMakeLists.txt
@@ -49,6 +49,7 @@
     absl::log_internal_nullguard
     absl::log_internal_nullstream
     absl::log_internal_strip
+    absl::nullability
     absl::strings
 )
 
diff --git a/absl/log/internal/BUILD.bazel b/absl/log/internal/BUILD.bazel
index db8464e..daf864d 100644
--- a/absl/log/internal/BUILD.bazel
+++ b/absl/log/internal/BUILD.bazel
@@ -63,6 +63,7 @@
         ":strip",
         "//absl/base:config",
         "//absl/base:core_headers",
+        "//absl/base:nullability",
         "//absl/strings",
     ],
 )
diff --git a/absl/log/internal/check_op.h b/absl/log/internal/check_op.h
index 2159220..98b6c5a 100644
--- a/absl/log/internal/check_op.h
+++ b/absl/log/internal/check_op.h
@@ -33,6 +33,7 @@
 
 #include "absl/base/attributes.h"
 #include "absl/base/config.h"
+#include "absl/base/nullability.h"
 #include "absl/base/optimization.h"
 #include "absl/log/internal/nullguard.h"
 #include "absl/log/internal/nullstream.h"
@@ -166,8 +167,9 @@
 class StatusOr;
 
 namespace status_internal {
-ABSL_ATTRIBUTE_PURE_FUNCTION std::string* MakeCheckFailString(
-    const absl::Status* status, const char* prefix);
+ABSL_ATTRIBUTE_PURE_FUNCTION absl::Nonnull<std::string*> MakeCheckFailString(
+    absl::Nonnull<const absl::Status*> status,
+    absl::Nonnull<const char*> prefix);
 }  // namespace status_internal
 
 namespace log_internal {
diff --git a/absl/status/status.h b/absl/status/status.h
index 6cfe49f..02fd296 100644
--- a/absl/status/status.h
+++ b/absl/status/status.h
@@ -649,7 +649,7 @@
 
   // Converts between StatusRep* and the external uintptr_t representation used
   // by rep_. See rep_ for details.
-  static uintptr_t PointerToRep(status_internal::StatusRep* r);
+  static uintptr_t PointerToRep(absl::Nonnull<status_internal::StatusRep*> r);
   static absl::Nonnull<const status_internal::StatusRep*> RepToPointer(
       uintptr_t r);