From 7d18ad49a37440835bb38bd77bc4e0991387ada0 Mon Sep 17 00:00:00 2001
From: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Date: Wed, 4 Oct 2023 13:24:31 +0200
Subject: [PATCH] QStringView: simplify the constructor from QString

We have to single QString out because of the isNull/isEmpty distinction.
Still, we can avoid having a constructor template on it constrained on
the argument being precisely QString. This is a historic remnant; in Qt
5 the constructor also worked with QStringRef.

Change-Id: I5457a83d5b77887f57ea9910a826f729ec276d28
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 src/corelib/text/qstring.h     |  7 +++++++
 src/corelib/text/qstringview.h | 11 +----------
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/corelib/text/qstring.h b/src/corelib/text/qstring.h
index 06c6f668c4..31d19f7fe6 100644
--- a/src/corelib/text/qstring.h
+++ b/src/corelib/text/qstring.h
@@ -1436,6 +1436,13 @@ 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 05e5ec3fdb..d62dd71bdf 100644
--- a/src/corelib/text/qstringview.h
+++ b/src/corelib/text/qstringview.h
@@ -96,9 +96,6 @@ 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;
 
@@ -155,13 +152,7 @@ public:
         : QStringView(str, str ? lengthHelperPointer(str) : 0) {}
 #endif
 
-#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
+    inline QStringView(const QString &str) noexcept;
 
     template <typename Container, if_compatible_container<Container> = true>
     constexpr Q_ALWAYS_INLINE QStringView(const Container &c) noexcept