Cleanup: There is no need to clear a string directly after its creation.

lib/checkbufferoverrun.cpp

@@ -195,7 +195,7 @@ void CheckBufferOverrun::pointerOutOfBoundsError(const Token *tok, const Token *
     // The severity is portability instead of error since this ub doesn't
     // cause bad behaviour on most implementations. people create out
     // of bounds pointers by intention.
-    const std::string expr(tok ? tok->expressionString() : std::string(""));
+    const std::string expr(tok ? tok->expressionString() : std::string());
     std::string errmsg;
     if (index && !index->isNumber()) {
         errmsg = "Undefined behaviour, when '" +

lib/settings.cpp

@@ -106,7 +106,7 @@ std::string Settings::addEnabled(const std::string &str)
             return std::string("cppcheck: there is no --enable parameter with the name '" + str + "'");
     }
 
-    return std::string("");
+    return std::string();
 }