Mutex: Remove MSVC 2015 workarounds

PiperOrigin-RevId: 526653332
Change-Id: I0a20d4ac636da3f1a930f96e0cdb9275527e4688

1 files changed, 20 insertions, 0 deletions

diff --git a/absl/synchronization/mutex.h b/absl/synchronization/mutex.h
index 148fa191..29c049df 100644
--- a/absl/synchronization/mutex.h
+++ b/absl/synchronization/mutex.h
@@ -695,6 +695,20 @@ class Condition {
   template<typename T>
   Condition(bool (*func)(T *), T *arg);
 
+  // Same as above, but allows for cases where `arg` comes from a pointer that
+  // is convertible to the function parameter type `T*` but not an exact match.
+  //
+  // For example, the argument might be `X*` but the function takes `const X*`,
+  // or the argument might be `Derived*` while the function takes `Base*`, and
+  // so on for cases where the argument pointer can be implicitly converted.
+  //
+  // Implementation notes: This constructor overload is required in addition to
+  // the one above to allow deduction of `T` from `arg` for cases such as where
+  // a function template is passed as `func`. Also, the dummy `typename = void`
+  // template parameter exists just to work around a MSVC mangling bug.
+  template <typename T, typename = void>
+  Condition(bool (*func)(T *), typename absl::internal::identity<T>::type *arg);
+
   // Templated version for invoking a method that returns a `bool`.
   //
   // `Condition(object, &Class::Method)` constructs a `Condition` that evaluates
@@ -1023,6 +1037,12 @@ inline Condition::Condition(bool (*func)(T *), T *arg)
   StoreCallback(func);
 }
 
+template <typename T, typename>
+inline Condition::Condition(bool (*func)(T *),
+                            typename absl::internal::identity<T>::type *arg)
+    // Just delegate to the overload above.
+    : Condition(func, arg) {}
+
 template <typename T>
 inline Condition::Condition(T *object,
                             bool (absl::internal::identity<T>::type::*method)())