From a5592293f8b093b325c4cb8bd5e98dc07bfc4419 Mon Sep 17 00:00:00 2001
From: Andrei Golubev <andrei.golubev@qt.io>
Date: Wed, 28 Oct 2020 12:33:35 +0100
Subject: [PATCH] Reject `const T*`-convertible types in
 QCommonArrayOps::copyAppend<It>
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In many cases (e.g. relocatable and pod), generic version is more
expensive. Let's not expect array data ops to only get QADP iterators
as input. Instead, reject generic version for any const T* -convertible
iterator and force compiler to select copyAppend(const T *b, const T *e)
as a suitable overload

Change-Id: I47a09d35a8ff15322381c2aa28258bfc7deebbad
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
---
 src/corelib/tools/qarraydataops.h        | 4 ++--
 src/corelib/tools/qcontainertools_impl.h | 3 +++
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/corelib/tools/qarraydataops.h b/src/corelib/tools/qarraydataops.h
index 2162512883a..c6ab3b1c483 100644
--- a/src/corelib/tools/qarraydataops.h
+++ b/src/corelib/tools/qarraydataops.h
@@ -1267,8 +1267,8 @@ public:
 
     template<typename It>
     void copyAppend(It b, It e, QtPrivate::IfIsForwardIterator<It> = true,
-                    QtPrivate::IfIsNotSame<std::decay_t<It>, iterator> = true,
-                    QtPrivate::IfIsNotSame<std::decay_t<It>, const_iterator> = true)
+                    QtPrivate::IfIsNotConvertible<It, const T *> = true,
+                    QtPrivate::IfIsNotConvertible<It, const T *> = true)
     {
         Q_ASSERT(this->isMutable() || b == e);
         Q_ASSERT(!this->isShared() || b == e);
diff --git a/src/corelib/tools/qcontainertools_impl.h b/src/corelib/tools/qcontainertools_impl.h
index 0f9225e461c..f4dfecffcec 100644
--- a/src/corelib/tools/qcontainertools_impl.h
+++ b/src/corelib/tools/qcontainertools_impl.h
@@ -147,6 +147,9 @@ using IfAssociativeIteratorHasFirstAndSecond =
 template <typename T, typename U>
 using IfIsNotSame =
     typename std::enable_if<!std::is_same<T, U>::value, bool>::type;
+
+template<typename T, typename U>
+using IfIsNotConvertible = typename std::enable_if<!std::is_convertible<T, U>::value, bool>::type;
 } // namespace QtPrivate
 
 QT_END_NAMESPACE