From 4c5f6eb74cfb3282513c0837c80a08705c1da844 Mon Sep 17 00:00:00 2001 From: Lars Knoll Date: Tue, 26 May 2020 14:53:14 +0200 Subject: [PATCH] Stabilize autotest calling emplace() on a std::vector with a reference pointing into the same vector is undefined behavior. Fix this by using a temporary inbetween. Change-Id: I47c28700dffa2107fb0cba302168c86b659eafb3 Reviewed-by: Thiago Macieira --- tests/auto/corelib/tools/qvector/tst_qvector.cpp | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/tests/auto/corelib/tools/qvector/tst_qvector.cpp b/tests/auto/corelib/tools/qvector/tst_qvector.cpp index 739c841ae1d..d4f2b8afd52 100644 --- a/tests/auto/corelib/tools/qvector/tst_qvector.cpp +++ b/tests/auto/corelib/tools/qvector/tst_qvector.cpp @@ -2793,36 +2793,40 @@ void tst_QVector::emplaceConsistentWithStdVectorImpl() const stdVec.emplace(stdVec.begin() + 3, 'g'); vecEq(qVec, stdVec); + T t; + // while QVector is safe with regards to emplacing elements moved form itself, it's UB + // for std::vector, so do the moving in two steps there. qVec.emplaceBack(std::move(qVec[0])); - stdVec.emplace_back(std::move(stdVec[0])); + stdVec.emplace_back(std::move(t = std::move(stdVec[0]))); vecEq(qVec, stdVec); squeezeVec(qVec, stdVec); qVec.emplaceBack(std::move(qVec[1])); - stdVec.emplace_back(std::move(stdVec[1])); + stdVec.emplace_back(std::move(t = std::move(stdVec[1]))); vecEq(qVec, stdVec); squeezeVec(qVec, stdVec); qVec.emplace(3, std::move(qVec[5])); - stdVec.emplace(stdVec.begin() + 3, std::move(stdVec[5])); + stdVec.emplace(stdVec.begin() + 3, std::move(t = std::move(stdVec[5]))); + vecEq(qVec, stdVec); qVec.emplaceBack(qVec[3]); - stdVec.emplace_back(stdVec[3]); + stdVec.emplace_back((t = stdVec[3])); vecEq(qVec, stdVec); squeezeVec(qVec, stdVec); qVec.emplaceBack(qVec[4]); - stdVec.emplace_back(stdVec[4]); + stdVec.emplace_back((t = stdVec[4])); vecEq(qVec, stdVec); squeezeVec(qVec, stdVec); qVec.emplace(5, qVec[7]); - stdVec.emplace(stdVec.begin() + 5, stdVec[7]); + stdVec.emplace(stdVec.begin() + 5, (t = stdVec[7])); vecEq(qVec, stdVec); }