diff options
author | Fabian Kosmale <fabian.kosmale@qt.io> | 2021-01-14 23:23:37 +0100 |
---|---|---|
committer | Fabian Kosmale <fabian.kosmale@qt.io> | 2021-01-18 15:51:18 +0100 |
commit | 2d8757f879d8f410319aae41ff902ba5a679d9dd (patch) | |
tree | 4ef80a0f475f6aeff3a7ae4b2c1ead34dc838a82 | |
parent | ec12c302493e69deb9b3019ecb182068518691ac (diff) |
QVariant::fromValue<T>: require T to be copy constructible
In Qt 5, QVariant::fromValue<T> would not compile unless
Q_DECLARE_METATYPE(T) was used, and Q_DECLARE_METATYPE(T) would lead to
a compile error if T were not copy constructible.
In Qt 6, we do not require Q_DECLARE_METATYPE before using fromValue,
and QMetaType itself works with non-copy constructible types just fine.
However, QVariant still requires it, thus we need to now enforce this in
fromValue itself.
Change-Id: Ib6964a438d8c46033dd3a037b9d871de2b42e175
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
-rw-r--r-- | src/corelib/kernel/qvariant.h | 5 | ||||
-rw-r--r-- | tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp | 15 |
2 files changed, 20 insertions, 0 deletions
diff --git a/src/corelib/kernel/qvariant.h b/src/corelib/kernel/qvariant.h index 8c3a27e3ca..b7d347a61e 100644 --- a/src/corelib/kernel/qvariant.h +++ b/src/corelib/kernel/qvariant.h @@ -392,7 +392,12 @@ class Q_CORE_EXPORT QVariant } template<typename T> +#ifndef Q_CLANG_QDOC + static inline auto fromValue(const T &value) -> + std::enable_if_t<std::is_copy_constructible_v<T>, QVariant> +#else static inline QVariant fromValue(const T &value) +#endif { return QVariant(QMetaType::fromType<T>(), std::addressof(value)); } diff --git a/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp b/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp index 6b30419bb8..23ee85ee46 100644 --- a/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp +++ b/tests/auto/corelib/kernel/qvariant/tst_qvariant.cpp @@ -68,6 +68,21 @@ class CustomNonQObject; +template<typename T, typename = void> +struct QVariantFromValueCompiles +{ + static inline constexpr bool value = false; +}; + +template<typename T> +struct QVariantFromValueCompiles<T, std::void_t<decltype (QVariant::fromValue(std::declval<T>()))>> +{ + static inline constexpr bool value = true; +}; + +static_assert(QVariantFromValueCompiles<int>::value); +static_assert(!QVariantFromValueCompiles<QObject>::value); + class tst_QVariant : public QObject { Q_OBJECT |