remove some unnecessary Boolean checks

- checks for true/false and nullptr

src/Mod/Drawing/App/FeatureViewSpreadsheet.cpp

@@ -169,7 +169,7 @@ App::DocumentObjectExecReturn *FeatureViewSpreadsheet::execute(void)
             // get the text
             App::Property* prop = sheet->getPropertyByName(address.toString().c_str());
             std::stringstream field;
-            if (prop != nullptr) {
+            if (prop) {
                 if (prop->isDerivedFrom((App::PropertyQuantity::getClassTypeId())))
                     field << static_cast<App::PropertyQuantity*>(prop)->getValue();
                 else if (prop->isDerivedFrom((App::PropertyFloat::getClassTypeId())))

src/Mod/Part/Gui/TaskCheckGeometry.cpp

@@ -172,7 +172,6 @@ QVector<QString> buildBOPCheckResultVector()
   return results;
 }
 
-
 QString getBOPCheckString(const BOPAlgo_CheckStatus &status)
 {
   static QVector<QString> strings = buildBOPCheckResultVector();
@@ -182,7 +181,6 @@ QString getBOPCheckString(const BOPAlgo_CheckStatus &status)
   return strings.at(index);
 }
 
-
 ResultEntry::ResultEntry()
 {
     viewProviderRoot = nullptr;
@@ -204,9 +202,9 @@ ResultEntry::~ResultEntry()
 
 void ResultEntry::buildEntryName()
 {
-  ResultEntry *parentEntry = this;
-    while (parentEntry->parent != nullptr) {
-        ResultEntry *temp = parentEntry->parent;
+    ResultEntry* parentEntry = this;
+    while (parentEntry->parent) {
+        ResultEntry* temp = parentEntry->parent;
         if (!temp->parent)
             break;
         parentEntry = parentEntry->parent;

src/Mod/Sketcher/Gui/TaskSketcherConstraints.cpp

@@ -967,7 +967,7 @@ void TaskSketcherConstraints::on_showHideButton_clicked(bool val)
     bool allSelected = true;
     for (int i = 0; i < ui->listWidgetConstraints->count(); ++i){
         QListWidgetItem* it = ui->listWidgetConstraints->item(i);
-        if (it->isHidden() == false && it->checkState() == Qt::Unchecked) {
+        if (!(it->isHidden()) && it->checkState() == Qt::Unchecked) {
             allSelected = false;
             break;
         }