diff --git a/src/plugins/coreplugin/manhattanstyle.cpp b/src/plugins/coreplugin/manhattanstyle.cpp
index a6bf33491a0..c8bb751ef59 100644
--- a/src/plugins/coreplugin/manhattanstyle.cpp
+++ b/src/plugins/coreplugin/manhattanstyle.cpp
@@ -492,7 +492,7 @@ static void drawPrimitiveTweakedForDarkTheme(QStyle::PrimitiveElement element,
             QPen outline(indicatorColor, 1, Qt::SolidLine, Qt::FlatCap, Qt::MiterJoin);
             painter->setPen(outline);
             QColor fill(frameColor);
-            fill.setAlphaF(0.8);
+            fill.setAlphaF(0.8f);
             painter->setBrush(fill);
             const double o = 3.5;
             painter->drawRect(QRectF(option->rect).adjusted(o, o, -o, -o));
@@ -675,9 +675,9 @@ void ManhattanStyle::drawPrimitive(PrimitiveElement element, const QStyleOption
                 }
                 if (option->state & State_HasFocus && (option->state & State_KeyboardFocusChange)) {
                     QColor highlight = option->palette.highlight().color();
-                    highlight.setAlphaF(0.4);
+                    highlight.setAlphaF(0.4f);
                     painter->setPen(QPen(highlight.lighter(), 1));
-                    highlight.setAlphaF(0.3);
+                    highlight.setAlphaF(0.3f);
                     painter->setBrush(highlight);
                     painter->setRenderHint(QPainter::Antialiasing);
                     const QRectF rect = option->rect;
@@ -743,10 +743,10 @@ void ManhattanStyle::drawPrimitive(PrimitiveElement element, const QStyleOption
 
             painter->setPen(Qt::NoPen);
             QColor dark = StyleHelper::borderColor();
-            dark.setAlphaF(0.4);
+            dark.setAlphaF(0.4f);
 
             QColor light = StyleHelper::baseColor();
-            light.setAlphaF(0.4);
+            light.setAlphaF(0.4f);
 
             painter->fillPath(path, light);
             painter->save();
@@ -908,7 +908,7 @@ void ManhattanStyle::drawControl(ControlElement element, const QStyleOption *opt
     case CE_SizeGrip: {
             painter->save();
             QColor dark = Qt::white;
-            dark.setAlphaF(0.1);
+            dark.setAlphaF(0.1f);
             int x, y, w, h;
             option->rect.getRect(&x, &y, &w, &h);
             int sw = qMin(h, w);
diff --git a/src/plugins/qmldesigner/components/navigator/navigatortreeview.cpp b/src/plugins/qmldesigner/components/navigator/navigatortreeview.cpp
index 3327fefcb44..2d1ef6f554d 100644
--- a/src/plugins/qmldesigner/components/navigator/navigatortreeview.cpp
+++ b/src/plugins/qmldesigner/components/navigator/navigatortreeview.cpp
@@ -169,13 +169,13 @@ private: // functions
     QColor highlightBrushColor() const
     {
         QColor color = Theme::getColor(Theme::Color::DSnavigatorDropIndicatorBackground);
-        color.setAlphaF(0.7);
+        color.setAlphaF(0.7f);
         return color;
     }
     QColor highlightLineColor() const
     {
         QColor color = Theme::getColor(Theme::Color::DSnavigatorDropIndicatorOutline);
-        color.setAlphaF(0.7);
+        color.setAlphaF(0.7f);
         return color;
     }
 
diff --git a/src/plugins/texteditor/textmark.cpp b/src/plugins/texteditor/textmark.cpp
index 110f451eed9..43aaf3e54b5 100644
--- a/src/plugins/texteditor/textmark.cpp
+++ b/src/plugins/texteditor/textmark.cpp
@@ -504,7 +504,7 @@ AnnotationColors &AnnotationColors::getAnnotationColors(const QColor &markColor,
                 : highClipHsl(backgroundLightness + 0.5);
 
         colors.rectColor = markColor;
-        colors.rectColor.setAlphaF(0.15);
+        colors.rectColor.setAlphaF(0.15f);
 
         colors.textColor.setHslF(markColor.hslHueF(),
                                  markColor.hslSaturationF(),