QVector/QList/QLinkedList/QVarLengthArray/QSet: add missing deduction guides

Amends 2e1763d83a1dacfc5b747934fb77fa7cec7bfe47.

The new range ctors need deduction guides, since the compiler can't
deduce the value_type from a pair of iterators.

Change-Id: I3ec1e5f91305b317c443b6a70246be416b55bad9
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/tests/auto/corelib/tools/qset/tst_qset.cpp b/tests/auto/corelib/tools/qset/tst_qset.cpp
index 31b4c0449e..8a545712a2 100644
--- a/tests/auto/corelib/tools/qset/tst_qset.cpp
+++ b/tests/auto/corelib/tools/qset/tst_qset.cpp
@@ -54,6 +54,7 @@ private slots:
     void detach();
     void isDetached();
     void clear();
+    void cpp17ctad();
     void remove();
     void contains();
     void containsSet();
@@ -325,6 +326,33 @@ void tst_QSet::clear()
     QVERIFY(set2.size() == 0);
 }
 
+void tst_QSet::cpp17ctad()
+{
+#ifdef __cpp_deduction_guides
+#define QVERIFY_IS_SET_OF(obj, Type) \
+    QVERIFY2((std::is_same<decltype(obj), QSet<Type>>::value), \
+             QMetaType::typeName(qMetaTypeId<decltype(obj)::value_type>()))
+#define CHECK(Type, One, Two, Three) \
+    do { \
+        const Type v[] = {One, Two, Three}; \
+        QSet v1 = {One, Two, Three}; \
+        QVERIFY_IS_SET_OF(v1, Type); \
+        QSet v2(v1.begin(), v1.end()); \
+        QVERIFY_IS_SET_OF(v2, Type); \
+        QSet v3(std::begin(v), std::end(v)); \
+        QVERIFY_IS_SET_OF(v3, Type); \
+    } while (false) \
+    /*end*/
+    CHECK(int, 1, 2, 3);
+    CHECK(double, 1.0, 2.0, 3.0);
+    CHECK(QString, QStringLiteral("one"), QStringLiteral("two"), QStringLiteral("three"));
+#undef QVERIFY_IS_SET_OF
+#undef CHECK
+#else
+    QSKIP("This test requires C++17 Constructor Template Argument Deduction support enabled in the compiler.");
+#endif
+}
+
 void tst_QSet::remove()
 {
     QSet<QString> set1;