diff --git a/components/contentselector/model/contentmodel.cpp b/components/contentselector/model/contentmodel.cpp
index e51c1809a9..141ad13517 100644
--- a/components/contentselector/model/contentmodel.cpp
+++ b/components/contentselector/model/contentmodel.cpp
@@ -543,7 +543,7 @@ bool ContentSelectorModel::ContentModel::isChecked(const QString& filepath) cons
     return false;
 }
 
-bool ContentSelectorModel::ContentModel::isEnabled (QModelIndex index) const
+bool ContentSelectorModel::ContentModel::isEnabled (const QModelIndex& index) const
 {
     return (flags(index) & Qt::ItemIsEnabled);
 }
diff --git a/components/contentselector/model/contentmodel.hpp b/components/contentselector/model/contentmodel.hpp
index 030865b35a..d245a0dcbf 100644
--- a/components/contentselector/model/contentmodel.hpp
+++ b/components/contentselector/model/contentmodel.hpp
@@ -52,7 +52,7 @@ namespace ContentSelectorModel
         EsmFile *item(int row);
         QStringList gameFiles() const;
 
-        bool isEnabled (QModelIndex index) const;
+        bool isEnabled (const QModelIndex& index) const;
         bool isChecked(const QString &filepath) const;
         bool setCheckState(const QString &filepath, bool isChecked);
         void setContentList(const QStringList &fileList);
diff --git a/components/detournavigator/cachedrecastmeshmanager.cpp b/components/detournavigator/cachedrecastmeshmanager.cpp
index 2788b80461..4666b66a83 100644
--- a/components/detournavigator/cachedrecastmeshmanager.cpp
+++ b/components/detournavigator/cachedrecastmeshmanager.cpp
@@ -62,7 +62,7 @@ namespace DetourNavigator
         return mImpl.isEmpty();
     }
 
-    void CachedRecastMeshManager::reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion)
+    void CachedRecastMeshManager::reportNavMeshChange(const Version& recastMeshVersion, const Version& navMeshVersion)
     {
         mImpl.reportNavMeshChange(recastMeshVersion, navMeshVersion);
     }
diff --git a/components/detournavigator/cachedrecastmeshmanager.hpp b/components/detournavigator/cachedrecastmeshmanager.hpp
index ea55348f70..96604c3628 100644
--- a/components/detournavigator/cachedrecastmeshmanager.hpp
+++ b/components/detournavigator/cachedrecastmeshmanager.hpp
@@ -26,7 +26,7 @@ namespace DetourNavigator
 
         bool isEmpty() const;
 
-        void reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion);
+        void reportNavMeshChange(const Version& recastMeshVersion, const Version& navMeshVersion);
 
         Version getVersion() const;
 
diff --git a/components/detournavigator/recastmeshmanager.cpp b/components/detournavigator/recastmeshmanager.cpp
index bfc0409a51..e79d58de9d 100644
--- a/components/detournavigator/recastmeshmanager.cpp
+++ b/components/detournavigator/recastmeshmanager.cpp
@@ -83,7 +83,7 @@ namespace DetourNavigator
         return mObjects.empty();
     }
 
-    void RecastMeshManager::reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion)
+    void RecastMeshManager::reportNavMeshChange(const Version& recastMeshVersion, const Version& navMeshVersion)
     {
         if (recastMeshVersion.mGeneration != mGeneration)
             return;
diff --git a/components/detournavigator/recastmeshmanager.hpp b/components/detournavigator/recastmeshmanager.hpp
index 5922821f26..850865b95e 100644
--- a/components/detournavigator/recastmeshmanager.hpp
+++ b/components/detournavigator/recastmeshmanager.hpp
@@ -50,7 +50,7 @@ namespace DetourNavigator
 
         bool isEmpty() const;
 
-        void reportNavMeshChange(Version recastMeshVersion, Version navMeshVersion);
+        void reportNavMeshChange(const Version& recastMeshVersion, const Version& navMeshVersion);
 
         Version getVersion() const;
 
diff --git a/components/interpreter/defines.cpp b/components/interpreter/defines.cpp
index d2e7067c6c..48d2ceaa45 100644
--- a/components/interpreter/defines.cpp
+++ b/components/interpreter/defines.cpp
@@ -26,7 +26,7 @@ namespace Interpreter{
         return a.length() > b.length();
     }
 
-    std::string fixDefinesReal(std::string text, bool dialogue, Context& context)
+    static std::string fixDefinesReal(const std::string& text, bool dialogue, Context& context)
     {
         unsigned int start = 0;
         std::ostringstream retval;
diff --git a/components/misc/stringops.hpp b/components/misc/stringops.hpp
index 9f3dfe7c5f..2a865606fd 100644
--- a/components/misc/stringops.hpp
+++ b/components/misc/stringops.hpp
@@ -290,7 +290,7 @@ public:
         }
     }
 
-     static inline void replaceLast(std::string& str, std::string substr, std::string with)
+     static inline void replaceLast(std::string& str, const std::string& substr, const std::string& with)
      {
          size_t pos = str.rfind(substr);
          if (pos == std::string::npos)