diff options
| author | Marc Mutz <marc.mutz@qt.io> | 2021-11-26 16:31:59 +0100 |
|---|---|---|
| committer | Marc Mutz <marc.mutz@qt.io> | 2021-11-29 18:55:10 +0000 |
| commit | ccaeffe5655cba23b4f708ec575e34f03cf08a1c (patch) | |
| tree | 428371a2b2822c61b634ed61a5390d1bc32b6779 | |
| parent | 95ccdfa43276652f1b9ca5944a94b7e15c510dbd (diff) | |
QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH: use unqualified qHash() lookup
... instead of QT_PREPEND_NAMESPACE(qHash), which is qualified (prepends at least '::'), and therefore disables ADL.
This is not a problem as long as we wrote our qHash() overloads as free functions (incl. non-hidden friends), but it should™ fail for hidden friends, so use the old using-std::swap() trick to bring QT_PREPEND_NAMESPACE(qHash) into scope, proceeding with an unqualified lookup.
Pick-to: 6.2
Change-Id: I00860b2313699849f86bfe3dd9f41db4ce993cd3
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
| -rw-r--r-- | src/corelib/tools/qhashfunctions.h | 11 | ||||
| -rw-r--r-- | tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp | 26 |
2 files changed, 33 insertions, 4 deletions
diff --git a/src/corelib/tools/qhashfunctions.h b/src/corelib/tools/qhashfunctions.h index 4f8e4066ee9..4d0b2d95194 100644 --- a/src/corelib/tools/qhashfunctions.h +++ b/src/corelib/tools/qhashfunctions.h @@ -251,6 +251,9 @@ struct QNothrowHashable : std::false_type {}; template <typename T> struct QNothrowHashable<T, std::enable_if_t<QNothrowHashableHelper_v<T>>> : std::true_type {}; +template <typename T> +constexpr inline bool QNothrowHashable_v = QNothrowHashable<T>::value; + } // namespace QtPrivate template <typename... T> @@ -317,15 +320,15 @@ template <typename T1, typename T2> inline size_t qHash(const std::pair<T1, T2> using argument_type = QT_PREPEND_NAMESPACE(Class); \ using result_type = size_t; \ size_t operator()(Arguments s) const \ - noexcept(noexcept(QT_PREPEND_NAMESPACE(qHash)(s))) \ + noexcept(QT_PREPEND_NAMESPACE( \ + QtPrivate::QNothrowHashable_v)<argument_type>) \ { \ /* this seeds qHash with the result of */ \ /* std::hash applied to an int, to reap */ \ /* any protection against predictable hash */ \ /* values the std implementation may provide */ \ - return QT_PREPEND_NAMESPACE(qHash)(s, \ - QT_PREPEND_NAMESPACE(qHash)( \ - std::hash<int>{}(0))); \ + using QT_PREPEND_NAMESPACE(qHash); \ + return qHash(s, qHash(std::hash<int>{}(0))); \ } \ }; \ } \ diff --git a/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp b/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp index 86305b101fc..3281c4cefd5 100644 --- a/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp +++ b/tests/auto/corelib/tools/qhashfunctions/tst_qhashfunctions.cpp @@ -303,9 +303,35 @@ void tst_QHashFunctions::rangeCommutative() } } +// QVarLengthArray these days has a qHash() as a hidden friend. +// This checks that QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH can deal with that: + +QT_BEGIN_NAMESPACE +QT_SPECIALIZE_STD_HASH_TO_CALL_QHASH_BY_CREF(QVarLengthArray<QVector<int>>) +QT_END_NAMESPACE + void tst_QHashFunctions::stdHash() { { + std::unordered_set<QVarLengthArray<QVector<int>>> s = { + { + {0, 1, 2}, + {42, 43, 44}, + {}, + }, { + {11, 12, 13}, + {}, + }, + }; + QCOMPARE(s.size(), 2UL); + s.insert({ + {11, 12, 13}, + {}, + }); + QCOMPARE(s.size(), 2UL); + } + + { std::unordered_set<QString> s = {QStringLiteral("Hello"), QStringLiteral("World")}; QCOMPARE(s.size(), 2UL); s.insert(QStringLiteral("Hello")); |