From c34242c679aaea6ee1badf6c1e5f274f925f5f50 Mon Sep 17 00:00:00 2001
From: Ulf Hermann <ulf.hermann@qt.io>
Date: Mon, 1 Jul 2019 14:10:43 +0200
Subject: [PATCH] Make the default ctor of QVarLengthArray implicit

Otherwise "QVarLengthArray<Foo> x = {};" gives a warning. Also, some
compilers get confused about "QVarLengthArray()" this way.

Task-number: QTBUG-76199
Change-Id: I4296586c0181d3e6e82ca8b7b79aeb9a21645d1f
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
---
 src/corelib/tools/qvarlengtharray.h                        | 4 +++-
 .../corelib/tools/qvarlengtharray/tst_qvarlengtharray.cpp  | 7 +++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/corelib/tools/qvarlengtharray.h b/src/corelib/tools/qvarlengtharray.h
index a49e0af687a..ba65ae7ef2b 100644
--- a/src/corelib/tools/qvarlengtharray.h
+++ b/src/corelib/tools/qvarlengtharray.h
@@ -61,7 +61,9 @@ template<class T, int Prealloc>
 class QVarLengthArray
 {
 public:
-    inline explicit QVarLengthArray(int size = 0);
+    QVarLengthArray() : QVarLengthArray(0) {}
+
+    inline explicit QVarLengthArray(int size);
 
     inline QVarLengthArray(const QVarLengthArray<T, Prealloc> &other)
         : a(Prealloc), s(0), ptr(reinterpret_cast<T *>(array))
diff --git a/tests/auto/corelib/tools/qvarlengtharray/tst_qvarlengtharray.cpp b/tests/auto/corelib/tools/qvarlengtharray/tst_qvarlengtharray.cpp
index fff8c75a902..070c25368b3 100644
--- a/tests/auto/corelib/tools/qvarlengtharray/tst_qvarlengtharray.cpp
+++ b/tests/auto/corelib/tools/qvarlengtharray/tst_qvarlengtharray.cpp
@@ -57,6 +57,7 @@ private slots:
     void initializeListComplex();
     void insertMove();
     void nonCopyable();
+    void implicitDefaultCtor();
 
 private:
     template<typename T>
@@ -1078,5 +1079,11 @@ void tst_QVarLengthArray::nonCopyable()
     QVERIFY(ptr6 == vec.at(5).get());
 }
 
+void tst_QVarLengthArray::implicitDefaultCtor()
+{
+    QVarLengthArray<int> def = {};
+    QCOMPARE(def.size(), 0);
+}
+
 QTEST_APPLESS_MAIN(tst_QVarLengthArray)
 #include "tst_qvarlengtharray.moc"