From 9ea3087d365fa9184d06d4f164ad73f905bab7bd Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Tue, 27 Feb 2024 12:24:08 +0000
Subject: [PATCH] Revert "QStringView: simplify the constructor from QString"

This reverts commit 7d18ad49a37440835bb38bd77bc4e0991387ada0.

Reason for revert: This changes the constructor from being a template
to being a normal function, so changes overload resolution. The commit
message gave no indication on why this is safe. Since it's just a nice
to have, revert instead of running the risk of breaking code.

Change-Id: Icd506e7221bb50c99f276f6a43c15403ec0be7a9
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
(cherry picked from commit ff7e5987ecdd09f87cfcdb4c42039214627dcdb6)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/corelib/text/qstring.h     |  7 -------
 src/corelib/text/qstringview.h | 11 ++++++++++-
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index 3e28d7727c2..c2628c6f7d3 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -1486,13 +1486,6 @@ inline QString &&asString(QString &&s)              { return std::move(s); }
     static_cast<const wchar_t*>(static_cast<const void*>(QtPrivate::asString(string).utf16()))
 #endif
 
-//
-// QStringView::QStringView(const QString &) implementation
-//
-
-inline QStringView::QStringView(const QString &str) noexcept
-    : QStringView(str.isNull() ? nullptr : str.data(), qsizetype(str.size())) {}
-
 //
 // QStringView::arg() implementation
 //
diff --git a/src/corelib/text/qstringview.h b/src/corelib/text/qstringview.h
index e91bb6978c6..d9a4d4ba652 100644
--- a/src/corelib/text/qstringview.h
+++ b/src/corelib/text/qstringview.h
@@ -97,6 +97,9 @@ private:
     template <typename Pointer>
     using if_compatible_pointer = typename std::enable_if<QtPrivate::IsCompatiblePointer<Pointer>::value, bool>::type;
 
+    template <typename T>
+    using if_compatible_qstring_like = typename std::enable_if<std::is_same<T, QString>::value, bool>::type;
+
     template <typename T>
     using if_compatible_container = typename std::enable_if<QtPrivate::IsContainerCompatibleWithQStringView<T>::value, bool>::type;
 
@@ -151,7 +154,13 @@ public:
         : QStringView(str, str ? lengthHelperPointer(str) : 0) {}
 #endif
 
-    inline QStringView(const QString &str) noexcept;
+#ifdef Q_QDOC
+    QStringView(const QString &str) noexcept;
+#else
+    template <typename String, if_compatible_qstring_like<String> = true>
+    QStringView(const String &str) noexcept
+        : QStringView(str.isNull() ? nullptr : str.data(), qsizetype(str.size())) {}
+#endif
 
     template <typename Container, if_compatible_container<Container> = true>
     constexpr Q_ALWAYS_INLINE QStringView(const Container &c) noexcept