QtCore: replace QLatin1String/QLatin1Char with _L1/u'' where applicable

As a drive-by, did also minor refactorings/improvements.

Task-number: QTBUG-98434
Change-Id: I81964176ae2f07ea63674c96f47f9c6aa046854f
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Anton Kudryavtsev <antkudr@mail.ru>

7 files changed, 118 insertions, 106 deletions

diff --git a/src/corelib/text/qlocale.cpp b/src/corelib/text/qlocale.cpp
index 1811304f51..73a41112a3 100644
--- a/src/corelib/text/qlocale.cpp
+++ b/src/corelib/text/qlocale.cpp
@@ -84,6 +84,8 @@ QT_WARNING_DISABLE_GCC("-Wfree-nonheap-object") // false positive tracking
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 #ifndef QT_NO_SYSTEMLOCALE
 static QSystemLocale *_systemLocale = nullptr;
 class QSystemLocaleSingleton: public QSystemLocale
@@ -221,7 +223,7 @@ QLatin1String QLocalePrivate::languageToCode(QLocale::Language language,
     if (language == QLocale::AnyLanguage || language > QLocale::LastLanguage)
         return QLatin1String();
     if (language == QLocale::C)
-        return QLatin1String("C");
+        return "C"_L1;
 
     const LanguageCodeEntry &i = languageCodeList[language];
 
@@ -636,22 +638,22 @@ QString qt_readEscapedFormatString(QStringView format, int *idx)
 {
     int &i = *idx;
 
-    Q_ASSERT(format.at(i) == QLatin1Char('\''));
+    Q_ASSERT(format.at(i) == u'\'');
     ++i;
     if (i == format.size())
         return QString();
     if (format.at(i).unicode() == '\'') { // "''" outside of a quoted string
         ++i;
-        return QLatin1String("'");
+        return "'"_L1;
     }
 
     QString result;
 
     while (i < format.size()) {
         if (format.at(i).unicode() == '\'') {
-            if (format.mid(i + 1).startsWith(QLatin1Char('\''))) {
+            if (format.mid(i + 1).startsWith(u'\'')) {
                 // "''" inside a quoted string
-                result.append(QLatin1Char('\''));
+                result.append(u'\'');
                 i += 2;
             } else {
                 break;
@@ -1357,7 +1359,7 @@ QString QLocale::name() const
     if (c == AnyTerritory)
         return d->languageCode();
 
-    return d->languageCode() + QLatin1Char('_') + d->territoryCode();
+    return d->languageCode() + u'_' + d->territoryCode();
 }
 
 static qlonglong toIntegral_helper(const QLocaleData *d, QStringView str, bool *ok,
@@ -1550,7 +1552,7 @@ QLocale::Script QLocale::codeToScript(QStringView scriptCode) noexcept
 QString QLocale::languageToString(Language language)
 {
     if (language > QLocale::LastLanguage)
-        return QLatin1String("Unknown");
+        return "Unknown"_L1;
     return QLatin1String(language_name_list + language_name_index[language]);
 }
 
@@ -1564,7 +1566,7 @@ QString QLocale::languageToString(Language language)
 QString QLocale::territoryToString(QLocale::Territory territory)
 {
     if (territory > QLocale::LastTerritory)
-        return QLatin1String("Unknown");
+        return "Unknown"_L1;
     return QLatin1String(territory_name_list + territory_name_index[territory]);
 }
 
@@ -1592,7 +1594,7 @@ QString QLocale::countryToString(Country country)
 QString QLocale::scriptToString(QLocale::Script script)
 {
     if (script > QLocale::LastScript)
-        return QLatin1String("Unknown");
+        return "Unknown"_L1;
     return QLatin1String(script_name_list + script_name_index[script]);
 }
 
@@ -2338,7 +2340,7 @@ QString QLocale::dateTimeFormat(FormatType format) const
         }
     }
 #endif
-    return dateFormat(format) + QLatin1Char(' ') + timeFormat(format);
+    return dateFormat(format) + u' ' + timeFormat(format);
 }
 
 #if QT_CONFIG(datestring)
@@ -3497,7 +3499,7 @@ QString QCalendarBackend::dateTimeToString(QStringView format, const QDateTime &
                 QString text = time.hour() < 12 ? locale.amText() : locale.pmText();
                 used = true;
                 repeat = 1;
-                if (format.mid(i + 1).startsWith(QLatin1Char('p'), Qt::CaseInsensitive))
+                if (format.mid(i + 1).startsWith(u'p', Qt::CaseInsensitive))
                     ++repeat;
                 if (c.unicode() == 'A' && (repeat == 1 || format.at(i + 1).unicode() == 'P'))
                     text = std::move(text).toUpper();
@@ -4403,7 +4405,7 @@ QString QLocale::formattedDataSize(qint64 bytes, int precision, DataSizeFormats
         unit = d->m_data->byteCount().viewData(byte_unit_data);
     }
 
-    return number + QLatin1Char(' ') + unit;
+    return number + u' ' + unit;
 }
 
 /*!
diff --git a/src/corelib/text/qlocale_mac.mm b/src/corelib/text/qlocale_mac.mm
index 7d75db31d0..6ca4045dc2 100644
--- a/src/corelib/text/qlocale_mac.mm
+++ b/src/corelib/text/qlocale_mac.mm
@@ -52,6 +52,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 /******************************************************************************
 ** Wrappers for Mac locale system functions
 */
@@ -293,10 +295,10 @@ static QVariant macToQtFormat(QStringView sys_fmt)
     while (i < sys_fmt.size()) {
         if (sys_fmt.at(i).unicode() == '\'') {
             QString text = qt_readEscapedFormatString(sys_fmt, &i);
-            if (text == QLatin1String("'"))
-                result += QLatin1String("''");
+            if (text == "'"_L1)
+                result += "''"_L1;
             else
-                result += QLatin1Char('\'') + text + QLatin1Char('\'');
+                result += u'\'' + text + u'\'';
             continue;
         }
 
@@ -322,17 +324,17 @@ static QVariant macToQtFormat(QStringView sys_fmt)
             case 'u': // Extended Year (1..n): 2 = short year, 1 & 3..n = padded number
                 // Qt only supports long (4) or short (2) year, use long for all others
                 if (repeat == 2)
-                    result += QLatin1String("yy");
+                    result += "yy"_L1;
                 else
-                    result += QLatin1String("yyyy");
+                    result += "yyyy"_L1;
                 break;
             case 'M': // Month (1..5): 4 = long, 3 = short, 1..2 = number, 5 = narrow
             case 'L': // Standalone Month (1..5): 4 = long, 3 = short, 1..2 = number, 5 = narrow
                 // Qt only supports long, short and number, use short for narrow
                 if (repeat == 5)
-                    result += QLatin1String("MMM");
+                    result += "MMM"_L1;
                 else
-                    result += QString(repeat, QLatin1Char('M'));
+                    result += QString(repeat, u'M');
                 break;
             case 'd': // Day of Month (1..2): 1..2 padded number
                 result += QString(repeat, c);
@@ -340,32 +342,32 @@ static QVariant macToQtFormat(QStringView sys_fmt)
             case 'E': // Day of Week (1..6): 4 = long, 1..3 = short, 5..6 = narrow
                 // Qt only supports long, short and padded number, use short for narrow
                 if (repeat == 4)
-                    result += QLatin1String("dddd");
+                    result += "dddd"_L1;
                 else
-                    result += QLatin1String("ddd");
+                    result += "ddd"_L1;
                 break;
             case 'e': // Local Day of Week (1..6): 4 = long, 3 = short, 5..6 = narrow, 1..2 padded number
             case 'c': // Standalone Local Day of Week (1..6): 4 = long, 3 = short, 5..6 = narrow, 1..2 padded number
                 // Qt only supports long, short and padded number, use short for narrow
                 if (repeat >= 5)
-                    result += QLatin1String("ddd");
+                    result += "ddd"_L1;
                 else
-                    result += QString(repeat, QLatin1Char('d'));
+                    result += QString(repeat, 'd'_L1);
                 break;
             case 'a': // AM/PM (1): 1 = short
                 // Translate to Qt uppercase AM/PM
-                result += QLatin1String("AP");
+                result += "AP"_L1;
                 break;
             case 'h': // Hour [1..12] (1..2): 1..2 = padded number
             case 'K': // Hour [0..11] (1..2): 1..2 = padded number
             case 'j': // Local Hour [12 or 24] (1..2): 1..2 = padded number
                 // Qt h is local hour
-                result += QString(repeat, QLatin1Char('h'));
+                result += QString(repeat, 'h'_L1);
                 break;
             case 'H': // Hour [0..23] (1..2): 1..2 = padded number
             case 'k': // Hour [1..24] (1..2): 1..2 = padded number
                 // Qt H is 0..23 hour
-                result += QString(repeat, QLatin1Char('H'));
+                result += QString(repeat, 'H'_L1);
                 break;
             case 'm': // Minutes (1..2): 1..2 = padded number
             case 's': // Seconds (1..2): 1..2 = padded number
@@ -374,9 +376,9 @@ static QVariant macToQtFormat(QStringView sys_fmt)
             case 'S': // Fractional second (1..n): 1..n = truncates to decimal places
                 // Qt uses msecs either unpadded or padded to 3 places
                 if (repeat < 3)
-                    result += QLatin1Char('z');
+                    result += u'z';
                 else
-                    result += QLatin1String("zzz");
+                    result += "zzz"_L1;
                 break;
             case 'z': // Time Zone (1..4)
             case 'Z': // Time Zone (1..5)
@@ -385,16 +387,14 @@ static QVariant macToQtFormat(QStringView sys_fmt)
             case 'V': // Time Zone (1..4)
             case 'X': // Time Zone (1..5)
             case 'x': // Time Zone (1..5)
-                result += QLatin1Char('t');
+                result += u't';
                 break;
             default:
                 // a..z and A..Z are reserved for format codes, so any occurrence of these not
                 // already processed are not known and so unsupported formats to be ignored.
                 // All other chars are allowed as literals.
-                if (c < QLatin1Char('A') || c > QLatin1Char('z') ||
-                    (c > QLatin1Char('Z') && c < QLatin1Char('a'))) {
+                if (c < u'A' || c > u'z' || (c > u'Z' && c < u'a'))
                     result += QString(repeat, c);
-                }
                 break;
         }
 
@@ -433,7 +433,7 @@ static QVariant macMeasurementSystem()
 {
     QCFType<CFLocaleRef> locale = CFLocaleCopyCurrent();
     CFStringRef system = static_cast<CFStringRef>(CFLocaleGetValue(locale, kCFLocaleMeasurementSystem));
-    if (QString::fromCFString(system) == QLatin1String("Metric")) {
+    if (QString::fromCFString(system) == "Metric"_L1) {
         return QLocale::MetricSystem;
     } else {
         return QLocale::ImperialSystem;
diff --git a/src/corelib/text/qlocale_unix.cpp b/src/corelib/text/qlocale_unix.cpp
index 84afaa377c..13346c5506 100644
--- a/src/corelib/text/qlocale_unix.cpp
+++ b/src/corelib/text/qlocale_unix.cpp
@@ -47,6 +47,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 #ifndef QT_NO_SYSTEMLOCALE
 struct QSystemLocaleData
 {
@@ -144,12 +146,12 @@ QLocale QSystemLocale::fallbackLocale() const
     if (lang.isEmpty())
         lang = qEnvironmentVariable("LANG");
     // if the locale is the "C" locale, then we can return the language we found here:
-    if (lang.isEmpty() || lang == QLatin1String("C") || lang == QLatin1String("POSIX"))
+    if (lang.isEmpty() || lang == "C"_L1 || lang == "POSIX"_L1)
         return QLocale(lang);
 
     // ... otherwise, if the first part of LANGUAGE says more than or
     // contradicts what we have, use that:
-    for (const auto &language : qEnvironmentVariable("LANGUAGE").tokenize(QLatin1Char(':'))) {
+    for (const auto &language : qEnvironmentVariable("LANGUAGE").tokenize(u':')) {
         if (contradicts(language, lang))
             return QLocale(language);
         break; // We only look at the first entry.
@@ -260,9 +262,9 @@ QVariant QSystemLocale::query(QueryType type, QVariant in) const
     }
     case MeasurementSystem: {
         const QString meas_locale = QString::fromLatin1(d->lc_measurement_var);
-        if (meas_locale.compare(QLatin1String("Metric"), Qt::CaseInsensitive) == 0)
+        if (meas_locale.compare("Metric"_L1, Qt::CaseInsensitive) == 0)
             return QLocale::MetricSystem;
-        if (meas_locale.compare(QLatin1String("Other"), Qt::CaseInsensitive) == 0)
+        if (meas_locale.compare("Other"_L1, Qt::CaseInsensitive) == 0)
             return QLocale::MetricSystem;
         return QVariant((int)QLocale(meas_locale).measurementSystem());
     }
@@ -276,7 +278,7 @@ QVariant QSystemLocale::query(QueryType type, QVariant in) const
         if (languages.isEmpty())
             lst.append(QString::fromLatin1(d->lc_messages_var));
         else
-            lst = languages.split(QLatin1Char(':'));
+            lst = languages.split(u':');
 
         // Inadequate for various cases of a language that's written in more
         // than one script in the same country, e.g. Sindhi in India.
@@ -285,7 +287,7 @@ QVariant QSystemLocale::query(QueryType type, QVariant in) const
             QStringView lang, cntry;
             if (qt_splitLocaleName(lst.at(i), &lang, nullptr, &cntry)) {
                 d->uiLanguages.append(
-                    cntry.size() ? lang % QLatin1Char('-') % cntry : lang.toString());
+                    cntry.size() ? lang % u'-' % cntry : lang.toString());
             }
         }
         return d->uiLanguages.isEmpty() ? QVariant() : QVariant(d->uiLanguages);
diff --git a/src/corelib/text/qlocale_win.cpp b/src/corelib/text/qlocale_win.cpp
index 695b363e5f..c5f82b9500 100644
--- a/src/corelib/text/qlocale_win.cpp
+++ b/src/corelib/text/qlocale_win.cpp
@@ -69,6 +69,8 @@ namespace winrt::impl
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 static QByteArray getWinLocaleName(LCID id = LOCALE_USER_DEFAULT);
 static QString winIso639LangName(LCID id = LOCALE_USER_DEFAULT);
 static QString winIso3116CtryName(LCID id = LOCALE_USER_DEFAULT);
@@ -351,7 +353,7 @@ QVariant QSystemLocalePrivate::timeFormat(QLocale::FormatType type)
 
 QVariant QSystemLocalePrivate::dateTimeFormat(QLocale::FormatType type)
 {
-    return QString(dateFormat(type).toString() + QLatin1Char(' ') + timeFormat(type).toString());
+    return QString(dateFormat(type).toString() + u' ' + timeFormat(type).toString());
 }
 
 QVariant QSystemLocalePrivate::dayName(int day, QLocale::FormatType type)
@@ -444,7 +446,7 @@ QString QSystemLocalePrivate::yearFix(int year, int fakeYear, QString &&formatte
     Q_ASSERT(fakeYear >= 1970 && fakeYear <= 2400);
     const bool matchTwo = year >= 0 && year % 100 == fakeYear % 100;
     auto yearUsed = fourDigitYear(fakeYear);
-    QString sign(year < 0 ? 1 : 0, QLatin1Char('-'));
+    QString sign(year < 0 ? 1 : 0, u'-');
     auto trueYear = fourDigitYear(year < 0 ? -year : year);
     if (formatted.contains(yearUsed))
         return std::move(formatted).replace(yearUsed, sign + trueYear);
@@ -534,7 +536,8 @@ QVariant QSystemLocalePrivate::toString(QTime time, QLocale::FormatType type)
 
 QVariant QSystemLocalePrivate::toString(const QDateTime &dt, QLocale::FormatType type)
 {
-    return QString(toString(dt.date(), type).toString() + QLatin1Char(' ') + toString(dt.time(), type).toString());
+    return QString(toString(dt.date(), type).toString() + u' '
+                   + toString(dt.time(), type).toString());
 }
 
 QVariant QSystemLocalePrivate::measurementSystem()
@@ -665,7 +668,7 @@ QVariant QSystemLocalePrivate::toCurrencyString(const QSystemLocale::CurrencyToS
         // int(32) == "12,34,56,789.00" == string("3;2;0")
         // int(320)== "1234,56,789.00"  == string("3;2")
         QString groupingStr = getLocaleInfo(LOCALE_SMONGROUPING).toString();
-        format.Grouping = groupingStr.remove(QLatin1Char(';')).toInt();
+        format.Grouping = groupingStr.remove(u';').toInt();
         if (format.Grouping % 10 == 0) // magic
             format.Grouping /= 10;
         else
@@ -752,12 +755,12 @@ QString QSystemLocalePrivate::winToQtFormat(QStringView sys_fmt)
     int i = 0;
 
     while (i < sys_fmt.size()) {
-        if (sys_fmt.at(i).unicode() == QLatin1Char('\'')) {
+        if (sys_fmt.at(i).unicode() == u'\'') {
             QString text = qt_readEscapedFormatString(sys_fmt, &i);
-            if (text == QLatin1String("'"))
-                result += QLatin1String("''");
+            if (text == "'"_L1)
+                result += "''"_L1;
             else
-                result += QLatin1Char('\'') + text + QLatin1Char('\'');
+                result += u'\'' + text + u'\'';
             continue;
         }
 
@@ -773,13 +776,13 @@ QString QSystemLocalePrivate::winToQtFormat(QStringView sys_fmt)
                     repeat = 2;
                 switch (repeat) {
                     case 1:
-                        result += QLatin1String("yy"); // "y" unsupported by Qt, use "yy"
+                        result += "yy"_L1; // "y" unsupported by Qt, use "yy"
                         break;
                     case 5:
-                        result += QLatin1String("yyyy"); // "yyyyy" same as "yyyy" on Windows
+                        result += "yyyy"_L1; // "yyyyy" same as "yyyy" on Windows
                         break;
                     default:
-                        result += QString(repeat, QLatin1Char('y'));
+                        result += QString(repeat, u'y');
                         break;
                 }
                 break;
@@ -790,14 +793,14 @@ QString QSystemLocalePrivate::winToQtFormat(QStringView sys_fmt)
                     case 2:
                         break; // no equivalent of "gg" in Qt
                     default:
-                        result += QLatin1Char('g');
+                        result += u'g';
                         break;
                 }
                 break;
             case 't':
                 if (repeat > 2)
                     repeat = 2;
-                result += QLatin1String("AP"); // "t" unsupported, use "AP"
+                result += "AP"_L1; // "t" unsupported, use "AP"
                 break;
             default:
                 result += QString(repeat, c);
@@ -1110,7 +1113,7 @@ static QString winIso639LangName(LCID id)
         if (ok && *endptr == '\0') {
             switch (i) {
                 case 0x814:
-                    result = QLatin1String("nn"); // Nynorsk
+                    result = u"nn"_qs; // Nynorsk
                     break;
                 default:
                     break;
@@ -1160,7 +1163,7 @@ static QByteArray getWinLocaleName(LCID id)
     QString resultusage = winIso639LangName(id);
     QString country = winIso3116CtryName(id);
     if (!country.isEmpty())
-        resultusage += QLatin1Char('_') + country;
+        resultusage += u'_' + country;
 
     return std::move(resultusage).toLatin1();
 }
diff --git a/src/corelib/text/qregularexpression.cpp b/src/corelib/text/qregularexpression.cpp
index c6aa26b619..e90ec6b1e6 100644
--- a/src/corelib/text/qregularexpression.cpp
+++ b/src/corelib/text/qregularexpression.cpp
@@ -61,6 +61,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 /*!
     \class QRegularExpression
     \inmodule QtCore
@@ -1211,8 +1213,8 @@ void QRegularExpressionPrivate::doMatch(QRegularExpressionMatchPrivate *priv,
 
             if (usingCrLfNewlines
                     && offset < subjectLength
-                    && subjectUtf16[offset - 1] == QLatin1Char('\r')
-                    && subjectUtf16[offset] == QLatin1Char('\n')) {
+                    && subjectUtf16[offset - 1] == u'\r'
+                    && subjectUtf16[offset] == u'\n') {
                 ++offset;
             } else if (offset < subjectLength
                        && QChar::isLowSurrogate(subjectUtf16[offset])) {
@@ -1595,7 +1597,7 @@ QString QRegularExpression::errorString() const
 #endif
     }
 #ifdef QT_NO_TRANSLATION
-        return QLatin1String("no error");
+        return u"no error"_qs;
 #else
     return QCoreApplication::translate("QRegularExpression", "no error");
 #endif
@@ -1837,14 +1839,13 @@ QString QRegularExpression::escape(QStringView str)
             // unlike Perl, a literal NUL must be escaped with
             // "\\0" (backslash + 0) and not "\\\0" (backslash + NUL),
             // because pcre16_compile uses a NUL-terminated string
-            result.append(QLatin1Char('\\'));
-            result.append(QLatin1Char('0'));
-        } else if ( (current < QLatin1Char('a') || current > QLatin1Char('z')) &&
-                    (current < QLatin1Char('A') || current > QLatin1Char('Z')) &&
-                    (current < QLatin1Char('0') || current > QLatin1Char('9')) &&
-                     current != QLatin1Char('_') )
-        {
-            result.append(QLatin1Char('\\'));
+            result.append(u'\\');
+            result.append(u'0');
+        } else if ((current < u'a' || current > u'z') &&
+                   (current < u'A' || current > u'Z') &&
+                   (current < u'0' || current > u'9') &&
+                   current != u'_') {
+            result.append(u'\\');
             result.append(current);
             if (current.isHighSurrogate() && i < (count - 1))
                 result.append(str.at(++i));
@@ -1940,13 +1941,13 @@ QString QRegularExpression::wildcardToRegularExpression(QStringView pattern, Wil
     const QChar *wc = pattern.data();
 
 #ifdef Q_OS_WIN
-    const QLatin1Char nativePathSeparator('\\');
-    const QLatin1String starEscape("[^/\\\\]*");
-    const QLatin1String questionMarkEscape("[^/\\\\]");
+    const char16_t nativePathSeparator = u'\\';
+    const auto starEscape = "[^/\\\\]*"_L1;
+    const auto questionMarkEscape = "[^/\\\\]"_L1;
 #else
-    const QLatin1Char nativePathSeparator('/');
-    const QLatin1String starEscape("[^/]*");
-    const QLatin1String questionMarkEscape("[^/]");
+    const char16_t nativePathSeparator = u'/';
+    const auto starEscape = "[^/]*"_L1;
+    const auto questionMarkEscape = "[^/]"_L1;
 #endif
 
     while (i < wclen) {
@@ -1961,7 +1962,7 @@ QString QRegularExpression::wildcardToRegularExpression(QStringView pattern, Wil
         case '\\':
 #ifdef Q_OS_WIN
         case '/':
-            rx += QLatin1String("[/\\\\]");
+            rx += "[/\\\\]"_L1;
             break;
 #endif
         case '$':
@@ -1973,29 +1974,29 @@ QString QRegularExpression::wildcardToRegularExpression(QStringView pattern, Wil
         case '{':
         case '|':
         case '}':
-            rx += QLatin1Char('\\');
+            rx += u'\\';
             rx += c;
             break;
         case '[':
             rx += c;
             // Support for the [!abc] or [!a-c] syntax
             if (i < wclen) {
-                if (wc[i] == QLatin1Char('!')) {
-                    rx += QLatin1Char('^');
+                if (wc[i] == u'!') {
+                    rx += u'^';
                     ++i;
                 }
 
-                if (i < wclen && wc[i] == QLatin1Char(']'))
+                if (i < wclen && wc[i] == u']')
                     rx += wc[i++];
 
-                while (i < wclen && wc[i] != QLatin1Char(']')) {
+                while (i < wclen && wc[i] != u']') {
                     // The '/' appearing in a character class invalidates the
                     // regular expression parsing. It also concerns '\\' on
                     // Windows OS types.
-                    if (wc[i] == QLatin1Char('/') || wc[i] == nativePathSeparator)
+                    if (wc[i] == u'/' || wc[i] == nativePathSeparator)
                         return rx;
-                    if (wc[i] == QLatin1Char('\\'))
-                        rx += QLatin1Char('\\');
+                    if (wc[i] == u'\\')
+                        rx += u'\\';
                     rx += wc[i++];
                 }
             }
@@ -2050,9 +2051,9 @@ QRegularExpression QRegularExpression::fromWildcard(QStringView pattern, Qt::Cas
 QString QRegularExpression::anchoredPattern(QStringView expression)
 {
     return QString()
-           + QLatin1String("\\A(?:")
+           + "\\A(?:"_L1
            + expression
-           + QLatin1String(")\\z");
+           + ")\\z"_L1;
 }
 
 /*!
diff --git a/src/corelib/text/qstring.cpp b/src/corelib/text/qstring.cpp
index de4df9fff3..644078f779 100644
--- a/src/corelib/text/qstring.cpp
+++ b/src/corelib/text/qstring.cpp
@@ -110,6 +110,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 const char16_t QString::_empty = 0;
 
 // in qstringmatcher.cpp
@@ -4394,7 +4396,7 @@ QString &QString::replace(const QRegularExpression &re, const QString &after)
     const QChar *ac = after.unicode();
 
     for (qsizetype i = 0; i < al - 1; i++) {
-        if (ac[i] == QLatin1Char('\\')) {
+        if (ac[i] == u'\\') {
             int no = ac[i + 1].digitValue();
             if (no > 0 && no <= numCaptures) {
                 QStringCapture backReference;
@@ -6878,11 +6880,11 @@ QString QString::vasprintf(const char *cformat, va_list ap)
         ++c;
 
         if (*c == '\0') {
-            result.append(QLatin1Char('%')); // a % at the end of the string - treat as non-escape text
+            result.append(u'%'); // a % at the end of the string - treat as non-escape text
             break;
         }
         if (*c == '%') {
-            result.append(QLatin1Char('%')); // %%
+            result.append(u'%'); // %%
             ++c;
             continue;
         }
@@ -8327,13 +8329,13 @@ QString QString::arg(qlonglong a, int fieldWidth, int base, QChar fillChar) cons
 
     unsigned flags = QLocaleData::NoFlags;
     // ZeroPadded sorts out left-padding when the fill is zero, to the right of sign:
-    if (fillChar == QLatin1Char('0'))
+    if (fillChar == u'0')
         flags = QLocaleData::ZeroPadded;
 
     QString arg;
     if (d.occurrences > d.locale_occurrences) {
         arg = QLocaleData::c()->longLongToString(a, -1, base, fieldWidth, flags);
-        Q_ASSERT(fillChar != QLatin1Char('0') || !qIsFinite(a)
+        Q_ASSERT(fillChar != u'0' || !qIsFinite(a)
                  || fieldWidth <= arg.length());
     }
 
@@ -8343,7 +8345,7 @@ QString QString::arg(qlonglong a, int fieldWidth, int base, QChar fillChar) cons
         if (!(locale.numberOptions() & QLocale::OmitGroupSeparator))
             flags |= QLocaleData::GroupDigits;
         localeArg = locale.d->m_data->longLongToString(a, -1, base, fieldWidth, flags);
-        Q_ASSERT(fillChar != QLatin1Char('0') || !qIsFinite(a)
+        Q_ASSERT(fillChar != u'0' || !qIsFinite(a)
                  || fieldWidth <= localeArg.length());
     }
 
@@ -8375,13 +8377,13 @@ QString QString::arg(qulonglong a, int fieldWidth, int base, QChar fillChar) con
 
     unsigned flags = QLocaleData::NoFlags;
     // ZeroPadded sorts out left-padding when the fill is zero, to the right of sign:
-    if (fillChar == QLatin1Char('0'))
+    if (fillChar == u'0')
         flags = QLocaleData::ZeroPadded;
 
     QString arg;
     if (d.occurrences > d.locale_occurrences) {
         arg = QLocaleData::c()->unsLongLongToString(a, -1, base, fieldWidth, flags);
-        Q_ASSERT(fillChar != QLatin1Char('0') || !qIsFinite(a)
+        Q_ASSERT(fillChar != u'0' || !qIsFinite(a)
                  || fieldWidth <= arg.length());
     }
 
@@ -8391,7 +8393,7 @@ QString QString::arg(qulonglong a, int fieldWidth, int base, QChar fillChar) con
         if (!(locale.numberOptions() & QLocale::OmitGroupSeparator))
             flags |= QLocaleData::GroupDigits;
         localeArg = locale.d->m_data->unsLongLongToString(a, -1, base, fieldWidth, flags);
-        Q_ASSERT(fillChar != QLatin1Char('0') || !qIsFinite(a)
+        Q_ASSERT(fillChar != u'0' || !qIsFinite(a)
                  || fieldWidth <= localeArg.length());
     }
 
@@ -8475,7 +8477,7 @@ QString QString::arg(double a, int fieldWidth, char format, int precision, QChar
 
     unsigned flags = QLocaleData::NoFlags;
     // ZeroPadded sorts out left-padding when the fill is zero, to the right of sign:
-    if (fillChar == QLatin1Char('0'))
+    if (fillChar == u'0')
         flags |= QLocaleData::ZeroPadded;
 
     if (qIsUpper(format))
@@ -8503,7 +8505,7 @@ QString QString::arg(double a, int fieldWidth, char format, int precision, QChar
     if (d.occurrences > d.locale_occurrences) {
         arg = QLocaleData::c()->doubleToString(a, precision, form, fieldWidth,
                                                flags | QLocaleData::ZeroPadExponent);
-        Q_ASSERT(fillChar != QLatin1Char('0') || !qIsFinite(a)
+        Q_ASSERT(fillChar != u'0' || !qIsFinite(a)
                  || fieldWidth <= arg.length());
     }
 
@@ -8519,7 +8521,7 @@ QString QString::arg(double a, int fieldWidth, char format, int precision, QChar
         if (numberOptions & QLocale::IncludeTrailingZeroesAfterDot)
             flags |= QLocaleData::AddTrailingZeroes;
         localeArg = locale.d->m_data->doubleToString(a, precision, form, fieldWidth, flags);
-        Q_ASSERT(fillChar != QLatin1Char('0') || !qIsFinite(a)
+        Q_ASSERT(fillChar != u'0' || !qIsFinite(a)
                  || fieldWidth <= localeArg.length());
     }
 
@@ -8534,7 +8536,7 @@ static int getEscape(const Char *uc, qsizetype *pos, qsizetype len, int maxNumbe
 {
     int i = *pos;
     ++i;
-    if (i < len && uc[i] == QLatin1Char('L'))
+    if (i < len && uc[i] == u'L')
         ++i;
     if (i < len) {
         int escape = to_unicode(uc[i]) - '0';
@@ -8630,7 +8632,7 @@ static ParseResult parseMultiArgFormatString(StringView s)
     qsizetype last = 0;
 
     while (i < end) {
-        if (uc[i] == QLatin1Char('%')) {
+        if (uc[i] == u'%') {
             qsizetype percent = i;
             int number = getEscape(uc, &i, len);
             if (number != -1) {
@@ -10899,14 +10901,14 @@ QString QString::toHtmlEscaped() const
     const int len = length();
     rich.reserve(qsizetype(len * 1.1));
     for (int i = 0; i < len; ++i) {
-        if (at(i) == QLatin1Char('<'))
-            rich += QLatin1String("&lt;");
-        else if (at(i) == QLatin1Char('>'))
-            rich += QLatin1String("&gt;");
-        else if (at(i) == QLatin1Char('&'))
-            rich += QLatin1String("&amp;");
-        else if (at(i) == QLatin1Char('"'))
-            rich += QLatin1String("&quot;");
+        if (at(i) == u'<')
+            rich += "&lt;"_L1;
+        else if (at(i) == u'>')
+            rich += "&gt;"_L1;
+        else if (at(i) == u'&')
+            rich += "&amp;"_L1;
+        else if (at(i) == u'"')
+            rich += "&quot;"_L1;
         else
             rich += at(i);
     }
diff --git a/src/corelib/text/qunicodetools.cpp b/src/corelib/text/qunicodetools.cpp
index 8223c759e9..bba950102e 100644
--- a/src/corelib/text/qunicodetools.cpp
+++ b/src/corelib/text/qunicodetools.cpp
@@ -51,6 +51,8 @@
 
 QT_BEGIN_NAMESPACE
 
+using namespace Qt::StringLiterals;
+
 Q_AUTOTEST_EXPORT int qt_initcharattributes_default_algorithm_only = 0;
 
 namespace QUnicodeTools {
@@ -1409,8 +1411,8 @@ static int init_libthai() {
 #if QT_CONFIG(library)
     static bool initialized = false;
     if (!initialized && (!th_brk || !th_next_cell)) {
-        th_brk = reinterpret_cast<th_brk_def>(QLibrary::resolve(QLatin1String("thai"), static_cast<int>(LIBTHAI_MAJOR), "th_brk"));
-        th_next_cell = (th_next_cell_def)QLibrary::resolve(QLatin1String("thai"), LIBTHAI_MAJOR, "th_next_cell");
+        th_brk = reinterpret_cast<th_brk_def>(QLibrary::resolve("thai"_L1, static_cast<int>(LIBTHAI_MAJOR), "th_brk"));
+        th_next_cell = (th_next_cell_def)QLibrary::resolve("thai"_L1, LIBTHAI_MAJOR, "th_next_cell");
         initialized = true;
     }
     if (th_brk && th_next_cell)