Add support for initializing QSharedPointer from nullptr

std::shared_ptr supports it. To resolve an ambiguous overload when a
literal 0 is passed as a parameter, the normal constructors needed to be
made a template, like std::shared_ptr.

Task-number: QTBUG-52569
Change-Id: Id75834dab9ed466e94c7ffff14451417892d2148
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h
index 6a5c8f4fe5..b9b29e926d 100644
--- a/src/corelib/tools/qsharedpointer_impl.h
+++ b/src/corelib/tools/qsharedpointer_impl.h
@@ -313,16 +313,22 @@ public:
     inline T &operator*() const { return *data(); }
     inline T *operator->() const { return data(); }
 
-    QSharedPointer() Q_DECL_NOTHROW : value(Q_NULLPTR), d(Q_NULLPTR) {}
+    Q_DECL_CONSTEXPR QSharedPointer() Q_DECL_NOTHROW : value(nullptr), d(nullptr) { }
     ~QSharedPointer() { deref(); }
 
-    inline explicit QSharedPointer(T *ptr) : value(ptr) // noexcept
+    Q_DECL_CONSTEXPR QSharedPointer(std::nullptr_t) Q_DECL_NOTHROW : value(nullptr), d(nullptr) { }
+
+    template <class X>
+    inline explicit QSharedPointer(X *ptr) : value(ptr) // noexcept
     { internalConstruct(ptr, QtSharedPointer::NormalDeleter()); }
 
-    template <typename Deleter>
-    inline QSharedPointer(T *ptr, Deleter deleter) : value(ptr) // throws
+    template <class X, typename Deleter>
+    inline QSharedPointer(X *ptr, Deleter deleter) : value(ptr) // throws
     { internalConstruct(ptr, deleter); }
 
+    template <typename Deleter>
+    QSharedPointer(std::nullptr_t, Deleter) : value(nullptr), d(nullptr) { }
+
     QSharedPointer(const QSharedPointer &other) Q_DECL_NOTHROW : value(other.value), d(other.d)
     { if (d) ref(); }
     QSharedPointer &operator=(const QSharedPointer &other) Q_DECL_NOTHROW