Fix 'performance-unnecessary-copy-initialization' warnings

Also, treat all performance-* warnings as errors

Change-Id: I571e6c2cc6f0d269309b0e9999cff45c9db5c723
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

5 files changed, 10 insertions, 12 deletions

diff --git a/src/app/qbs-setup-toolchains/iarewprobe.cpp b/src/app/qbs-setup-toolchains/iarewprobe.cpp
index e1a56b072..d0da1a2c1 100644
--- a/src/app/qbs-setup-toolchains/iarewprobe.cpp
+++ b/src/app/qbs-setup-toolchains/iarewprobe.cpp
@@ -215,8 +215,7 @@ static std::vector<ToolchainInstallInfo> installedIarsFromRegistry()
                             const QFileInfo iarPath(rootPath + entry.subExePath);
                             if (iarPath.exists()) {
                                 // Note: threeLevelKey is a guessed toolchain version.
-                                const QString version = threeLevelKey;
-                                infos.push_back({iarPath, Version::fromString(version)});
+                                infos.push_back({iarPath, Version::fromString(threeLevelKey)});
                             }
                         }
                         registry.endGroup();
diff --git a/src/lib/corelib/api/qmljsrewriter.cpp b/src/lib/corelib/api/qmljsrewriter.cpp
index 16817d682..55db2e6e8 100644
--- a/src/lib/corelib/api/qmljsrewriter.cpp
+++ b/src/lib/corelib/api/qmljsrewriter.cpp
@@ -260,7 +260,7 @@ UiObjectMemberList *Rewriter::searchMemberToInsertAfter(UiObjectMemberList *memb
         idx = propertyOrder.size() - 1;
 
     for (; idx > 0; --idx) {
-        const QString prop = propertyOrder.at(idx - 1);
+        const QString &prop = propertyOrder.at(idx - 1);
         UiObjectMemberList *candidate = orderedMembers.value(prop, 0);
         if (candidate != nullptr)
             return candidate;
diff --git a/src/lib/corelib/language/moduleloader.cpp b/src/lib/corelib/language/moduleloader.cpp
index b621bdcab..fea7d934e 100644
--- a/src/lib/corelib/language/moduleloader.cpp
+++ b/src/lib/corelib/language/moduleloader.cpp
@@ -2725,7 +2725,7 @@ void ModuleLoader::resolveParameterDeclarations(const Item *module)
     for (Item *param : moduleChildren) {
         if (param->type() != ItemType::Parameter)
             continue;
-        const auto paramDecls = param->propertyDeclarations();
+        const auto &paramDecls = param->propertyDeclarations();
         for (auto it = paramDecls.begin(); it != paramDecls.end(); ++it)
             decls.insert(it.key(), it.value());
     }
diff --git a/src/lib/corelib/language/scriptengine.cpp b/src/lib/corelib/language/scriptengine.cpp
index 7c531e764..e79ec54d7 100644
--- a/src/lib/corelib/language/scriptengine.cpp
+++ b/src/lib/corelib/language/scriptengine.cpp
@@ -478,19 +478,18 @@ QScriptValue ScriptEngine::js_require(QScriptContext *context, QScriptEngine *qt
             return context->throwError(
                         ScriptEngine::tr("require: internal error. No search paths."));
 
-        const QString uri = moduleName;
         if (engine->m_logger.debugEnabled()) {
             engine->m_logger.qbsDebug()
-                    << "[require] loading extension " << uri;
+                    << "[require] loading extension " << moduleName;
         }
 
-        QString uriAsPath = uri;
-        uriAsPath.replace(QLatin1Char('.'), QLatin1Char('/'));
+        QString moduleNameAsPath = moduleName;
+        moduleNameAsPath.replace(QLatin1Char('.'), QLatin1Char('/'));
         const QStringList searchPaths = engine->m_extensionSearchPathsStack.top();
-        const QString dirPath = findExtensionDir(searchPaths, uriAsPath);
+        const QString dirPath = findExtensionDir(searchPaths, moduleNameAsPath);
         if (dirPath.isEmpty()) {
-            if (uri.startsWith(QStringLiteral("qbs.")))
-                return loadInternalExtension(context, engine, uri);
+            if (moduleName.startsWith(QStringLiteral("qbs.")))
+                return loadInternalExtension(context, engine, moduleName);
         } else {
             QDirIterator dit(dirPath, StringConstants::jsFileWildcards(),
                              QDir::Files | QDir::Readable);
diff --git a/src/lib/corelib/tools/setupprojectparameters.cpp b/src/lib/corelib/tools/setupprojectparameters.cpp
index 996f6b273..a06ffc4bd 100644
--- a/src/lib/corelib/tools/setupprojectparameters.cpp
+++ b/src/lib/corelib/tools/setupprojectparameters.cpp
@@ -349,7 +349,7 @@ static void provideValuesTree(const QVariantMap &values, QVariantMap *valueTree)
 
     valueTree->clear();
     for (QVariantMap::const_iterator it = values.constBegin(); it != values.constEnd(); ++it) {
-        const QString name = it.key();
+        const QString &name = it.key();
         int idx = name.lastIndexOf(QLatin1Char('.'));
         const QStringList nameElements = (idx == -1)
                 ? QStringList() << name