QStringBuilder: DRY: simplify the if constexpr conditionals a bit

Both sides of it were calling the same appendTo(), so we can avoid
repeating ourselves. This MAY fix a warning with VS2019.

Fixes: QTBUG-124117
Pick-to: 6.7
Change-Id: I40526efc4e93413794c3fffd17c4f9c96ee187f9
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

1 files changed, 9 insertions, 10 deletions

diff --git a/src/corelib/text/qstringbuilder.h b/src/corelib/text/qstringbuilder.h
index dfe9863b74..52dbd52b47 100644
--- a/src/corelib/text/qstringbuilder.h
+++ b/src/corelib/text/qstringbuilder.h
@@ -109,18 +109,17 @@ private:
         // both QString and QByteArray's data() and constData(). The result is
         // the same if len != 0.
         auto d = reinterpret_cast<typename T::iterator>(s.data_ptr().data());
+        const auto start = d;
+        QConcatenable<QStringBuilder<A, B>>::appendTo(*this, d);
 
         if constexpr (QConcatenable<QStringBuilder<A, B>>::ExactSize) {
-            QConcatenable<QStringBuilder<A, B>>::appendTo(*this, d);
-            return s;
-        }
-
-        typename T::const_iterator const start = d;
-        QConcatenable<QStringBuilder<A, B>>::appendTo(*this, d);
-        if (len != d - start) {
-            // this resize is necessary since we allocate a bit too much
-            // when dealing with variable sized 8-bit encodings
-            s.resize(d - start);
+            Q_UNUSED(start)
+        } else {
+            if (len != d - start) {
+                // this resize is necessary since we allocate a bit too much
+                // when dealing with variable sized 8-bit encodings
+                s.resize(d - start);
+            }
         }
         return s;
     }