8e98a161e9
Make QPair an alias for std::pair, and qMakePair just a forwarder towards std::make_pair. Why? Fundamentally to ditch a bunch of NIH code; gain for free structured bindings, std::tuple and std::reference_wrapper compatibility, and so on. Breakages: * Some that code manually forward declares QPair. We don't care about it (<QContainerFwd> is the proper way). * Some code that overloads on std::pair and QPair. Luckily it's mostly centralized: debug, metatypes, testing macros. Just remove the QPair overload. * Usages of qMakePair forcing the template type parameters. There are a handful of these in qtbase, but only one was actually broken. * std::pair is NOT (and will never likely be) trivially copiable. This is agreed to be a mistake done by practically all implementations in C++11, can can't be fixed without breaking ABI. Some code using QPair assuming it's trivially copiable may break; exactly one occurrence was in qtbase. * QMetaType logic extracts the type names in two different ways, one by looking at the source code string (e.g. extracted by moc) and one via some ad-hoc reflection in C++. We need to make "QPair" (as spelled in the source code) be the same as "std::pair" (gathered via reflection, which will see through the alias) when compared. The way it's already done e.g. for QList is by actually replacing the moc-extracted name with the name of the actual type used in C++; do the same here. On libc++, std::pair is actually in an inline namespace -- i.e. std::__1::pair; the reflection will extract and store "std::__1::pair" so we need an ad-hoc fix to QMetaType. [ChangeLog][QtCore][QPair] QPair is now an alias to std::pair, and does not exist as a class in Qt any more. This may break code such as functions overloaded for both QPair and std::pair. Usually, the overload taking a QPair can be safely discarded, leaving only the one taking a std::pair. QPair API has not changed, and qMakePair is still available for compatibility (although new code is encouraged to use std::pair and std::make_pair directly instead). Change-Id: I7725c751bf23946cde577b1406e86a336c0a3dcf Reviewed-by: Lars Knoll <lars.knoll@qt.io>
22 lines
901 B
XML
22 lines
901 B
XML
<?xml version="1.0" encoding="UTF-8" ?>
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<testsuite errors="0" failures="2" tests="4" name="tst_PairDiagnostics">
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<properties>
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<property value="@INSERT_QT_VERSION_HERE@" name="QTestVersion"/>
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<property value="@INSERT_QT_VERSION_HERE@" name="QtVersion"/>
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<property value="" name="QtBuild"/>
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</properties>
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<testcase result="pass" name="initTestCase"/>
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<testcase result="fail" name="testQPair">
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<failure message="Compared values are not the same
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Actual (pair1): "std::pair(1,1)"
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Expected (pair2): "std::pair(1,2)"" result="fail"/>
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</testcase>
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<testcase result="fail" name="testStdPair">
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<failure message="Compared values are not the same
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Actual (pair1): "std::pair(1,1)"
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Expected (pair2): "std::pair(1,2)"" result="fail"/>
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</testcase>
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<testcase result="pass" name="cleanupTestCase"/>
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<system-err/>
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</testsuite>
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