enabled and fixed -Wuseless-cast GCC warnings

cli/stacktrace.cpp

@@ -65,7 +65,7 @@ void print_stacktrace(FILE* output, int start_idx, bool demangling, int maxdepth
         const char * const secondBracketAddress = strchr(firstBracketAddress, ']');
         const char * const beginAddress         = firstBracketAddress+3;
         const int addressLen = int(secondBracketAddress-beginAddress);
-        const int padLen     = int(ADDRESSDISPLAYLENGTH-addressLen);
+        const int padLen     = (ADDRESSDISPLAYLENGTH-addressLen);
         if (demangling && firstBracketName) {
             const char * const plus = strchr(firstBracketName, '+');
             if (plus && (plus>(firstBracketName+1))) {

cmake/compileroptions.cmake

@@ -68,6 +68,7 @@ if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     add_compile_options(-Wno-maybe-uninitialized)   # there are some false positives
     add_compile_options(-Wsuggest-attribute=noreturn)
     add_compile_options(-Wno-shadow)                # whenever a local variable or type declaration shadows another one
+    add_compile_options_safe(-Wuseless-cast)
 elseif(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
     if(CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL 14 OR CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 14)
         # TODO: verify this regression still exists in clang-15

gui/checkstatistics.cpp

@@ -113,5 +113,5 @@ QStringList CheckStatistics::getTools() const
     for (const QString& tool: mPerformance.keys()) ret.insert(tool);
     for (const QString& tool: mPortability.keys()) ret.insert(tool);
     for (const QString& tool: mError.keys()) ret.insert(tool);
-    return QStringList(ret.values());
+    return ret.values();
 }

gui/common.cpp

@@ -56,7 +56,7 @@ QString toFilterString(const QMap<QString,QString>& filters, bool addAllSupporte
 
     if (addAllSupported) {
         entries << QCoreApplication::translate("toFilterString", "All supported files (%1)")
-            .arg(QStringList(filters.values()).join(" "));
+            .arg(filters.values().join(" "));
     }
 
     if (addAll) {

gui/librarydialog.cpp

@@ -351,7 +351,7 @@ QString LibraryDialog::getArgText(const CppcheckLibraryData::Function::Arg &arg)
     s += "\n    not uninit: " +  QString(bool_to_string(arg.notuninit));
     s += "\n    format string: " +  QString(bool_to_string(arg.formatstr));
     s += "\n    strz: " +  QString(bool_to_string(arg.strz));
-    s += "\n    valid: " + QString(arg.valid.isEmpty() ? "any" : arg.valid);
+    s += "\n    valid: " + (arg.valid.isEmpty() ? "any" : arg.valid);
     for (const CppcheckLibraryData::Function::Arg::MinSize &minsize : arg.minsizes) {
         s += "\n    minsize: " + minsize.type + " " + minsize.arg + " " + minsize.arg2;
     }

gui/mainwindow.cpp

@@ -2018,7 +2018,7 @@ void MainWindow::editProjectFile()
     if (!mProjectFile) {
         QMessageBox msg(QMessageBox::Critical,
                         tr("Cppcheck"),
-                        QString(tr("No project file loaded")),
+                        tr("No project file loaded"),
                         QMessageBox::Ok,
                         this);
         msg.exec();

lib/checkclass.cpp

@@ -2189,7 +2189,7 @@ void CheckClass::checkConst()
             std::string classname = scope->className;
             const Scope *nest = scope->nestedIn;
             while (nest && nest->type != Scope::eGlobal) {
-                classname = std::string(nest->className + "::" + classname);
+                classname = nest->className + "::" + classname;
                 nest = nest->nestedIn;
             }
 

lib/checkstl.cpp

@@ -340,7 +340,7 @@ void CheckStl::outOfBoundsIndexExpression()
 void CheckStl::outOfBoundsIndexExpressionError(const Token *tok, const Token *index)
 {
     const std::string varname = tok ? tok->str() : std::string("var");
-    const std::string i = index ? index->expressionString() : std::string(varname + ".size()");
+    const std::string i = index ? index->expressionString() : (varname + ".size()");
 
     std::string errmsg = "Out of bounds access of $symbol, index '" + i + "' is out of bounds.";
 

lib/checkuninitvar.cpp

@@ -467,7 +467,7 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
             conditionAlwaysTrueOrFalse(tok->next()->astOperand2(), variableValue, &alwaysTrue, &alwaysFalse);
 
             // initialization / usage in condition..
-            if (!alwaysTrue && checkIfForWhileHead(tok->next(), var, suppressErrors, bool(number_of_if == 0), *alloc, membervar))
+            if (!alwaysTrue && checkIfForWhileHead(tok->next(), var, suppressErrors, (number_of_if == 0), *alloc, membervar))
                 return true;
 
             // checking if a not-zero variable is zero => bail out
@@ -643,7 +643,7 @@ bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var
                 bool initcond = false;
                 if (!suppressErrors) {
                     const Token *startCond = forwhile ? tok->next() : tok->linkAt(1)->tokAt(2);
-                    initcond = checkIfForWhileHead(startCond, var, false, bool(number_of_if == 0), *alloc, membervar);
+                    initcond = checkIfForWhileHead(startCond, var, false, (number_of_if == 0), *alloc, membervar);
                 }
 
                 // goto "}"

lib/json.h

@@ -22,6 +22,7 @@
 #include "config.h"
 
 SUPPRESS_WARNING_PUSH("-Wfloat-equal")
+SUPPRESS_WARNING_GCC_PUSH("-Wuseless-cast")
 SUPPRESS_WARNING_CLANG_PUSH("-Wtautological-type-limit-compare")
 SUPPRESS_WARNING_CLANG_PUSH("-Wextra-semi-stmt")
 SUPPRESS_WARNING_CLANG_PUSH("-Wzero-as-null-pointer-constant")
@@ -34,6 +35,7 @@ SUPPRESS_WARNING_CLANG_POP
 SUPPRESS_WARNING_CLANG_POP
 SUPPRESS_WARNING_CLANG_POP
 SUPPRESS_WARNING_CLANG_POP
+SUPPRESS_WARNING_GCC_POP
 SUPPRESS_WARNING_POP
 
 #endif // jsonH

test/CMakeLists.txt

@@ -37,6 +37,10 @@ if (BUILD_TESTS)
         target_compile_definitions(testrunner PRIVATE CPPCHECKLIB_IMPORT SIMPLECPP_IMPORT)
         target_link_libraries(testrunner cppcheck-core)
     endif()
+    if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
+        # (void) in ASSERT_THROW* macros might trigger this
+        target_compile_options_safe(testrunner -Wno-useless-cast)
+    endif()
     if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
         # $ is used in dinit() designated initialization helper
         target_compile_options_safe(testrunner -Wno-dollar-in-identifier-extension)