qdoc: Fix various clang warnings

- remove unused variables
- Use QString::arg() with multiple string arguments
- Avoid detaching containers in loops

Pick-to: 6.4
Change-Id: I9b29f5a0269f288b7de862eccdcee9750248dce8
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
Reviewed-by: Topi Reiniö <topi.reinio@qt.io>
Reviewed-by: Luca Di Sera <luca.disera@qt.io>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/qdoc/clangcodeparser.cpp b/src/qdoc/clangcodeparser.cpp
index 64389ead9..2caa39ede 100644
--- a/src/qdoc/clangcodeparser.cpp
+++ b/src/qdoc/clangcodeparser.cpp
@@ -1585,7 +1585,7 @@ void ClangCodeParser::parseSourceFile(const Location & /*location*/, const QStri
             } else if (CodeParser::isWorthWarningAbout(doc)) {
                 bool future = false;
                 if (doc.metaCommandsUsed().contains(COMMAND_SINCE)) {
-                    QString sinceVersion = doc.metaCommandArgs(COMMAND_SINCE)[0].first;
+                    QString sinceVersion = doc.metaCommandArgs(COMMAND_SINCE).at(0).first;
                     if (getUnpatchedVersion(sinceVersion) > getUnpatchedVersion(m_version))
                         future = true;
                 }