Export of internal Abseil changes

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3e6352709da9a529e608eabff862a12bfaecb587 by Gennadiy Rozental <rogeeff@google.com>:

Replace local copy of FastTypeId with one shared in absl/base/internal.

PiperOrigin-RevId: 304181357

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c89ea428f732226f4dceb508cd6ba3955a1e49e1 by Andy Getzendanner <durandal@google.com>:

Typo fix: add a missing colon.

PiperOrigin-RevId: 304064210

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de2ee7a96bdc7193ffcceb6a2fd6bf464955cbe7 by Samuel Benzaquen <sbenza@google.com>:

Reduce the overhead of the registration token by using an empty struct instead
of bool.

PiperOrigin-RevId: 304054311

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222f05d24fb1df7e815946543a7dc78847c83f92 by Derek Mauro <dmauro@google.com>:

Turn off hashtablez in opensource builds.

Hashtablez is an unsupported, internal-only feature for collecting
information about hashtable usage and performance. By turning it off
in builds where it is unsupported, we get just a little more performance.

PiperOrigin-RevId: 304035460
GitOrigin-RevId: 3e6352709da9a529e608eabff862a12bfaecb587
Change-Id: I0bfe9b5df808a7e35c154b39e6c80e68b0da2b70

1 files changed, 5 insertions, 3 deletions

diff --git a/absl/flags/internal/flag.h b/absl/flags/internal/flag.h
index c1bf8652815d..ae42dedcd633 100644
--- a/absl/flags/internal/flag.h
+++ b/absl/flags/internal/flag.h
@@ -648,6 +648,7 @@ void* FlagOps(FlagOp op, const void* v1, void* v2, void* v3) {
 // This class facilitates Flag object registration and tail expression-based
 // flag definition, for example:
 // ABSL_FLAG(int, foo, 42, "Foo help").OnUpdate(NotifyFooWatcher);
+struct FlagRegistrarEmpty {};
 template <typename T, bool do_register>
 class FlagRegistrar {
  public:
@@ -660,9 +661,10 @@ class FlagRegistrar {
     return *this;
   }
 
-  // Make the registrar "die" gracefully as a bool on a line where registration
-  // happens. Registrar objects are intended to live only as temporary.
-  operator bool() const { return true; }  // NOLINT
+  // Make the registrar "die" gracefully as an empty struct on a line where
+  // registration happens. Registrar objects are intended to live only as
+  // temporary.
+  operator FlagRegistrarEmpty() const { return {}; }  // NOLINT
 
  private:
   Flag<T>* flag_;  // Flag being registered (not owned).