Everywhere: Add `-Wdouble-promotion` warning

This warning informs of float-to-double conversions. The best solution
seems to be to do math *either* in 32-bit *or* in 64-bit, and only to
cross over when absolutely necessary.

26 files changed, 105 insertions, 98 deletions

diff --git a/AK/TestSuite.h b/AK/TestSuite.h
index 60819694b3..c2cac55543 100644
--- a/AK/TestSuite.h
+++ b/AK/TestSuite.h
@@ -325,15 +325,15 @@ using AK::TestSuite;
         }                                                                                      \
     } while (false)
 
-#define EXPECT_APPROXIMATE(a, b)                                                                    \
-    do {                                                                                            \
-        auto expect_close_lhs = a;                                                                  \
-        auto expect_close_rhs = b;                                                                  \
-        auto expect_close_diff = expect_close_lhs - expect_close_rhs;                               \
-        if (fabs(expect_close_diff) >= 0.000001) {                                                  \
-            warnln("\033[31;1mFAIL\033[0m: {}:{}: EXPECT_APPROXIMATE({}, {})"                       \
-                   " failed with lhs={}, rhs={}, (lhs-rhs)={}",                                     \
-                __FILE__, __LINE__, #a, #b, expect_close_lhs, expect_close_rhs, expect_close_diff); \
-            current_test_case_did_fail();                                                           \
-        }                                                                                           \
+#define EXPECT_APPROXIMATE(a, b)                                                                                \
+    do {                                                                                                        \
+        auto expect_close_lhs = a;                                                                              \
+        auto expect_close_rhs = b;                                                                              \
+        auto expect_close_diff = static_cast<double>(expect_close_lhs) - static_cast<double>(expect_close_rhs); \
+        if (abs(expect_close_diff) >= 0.000001) {                                                               \
+            warnln("\033[31;1mFAIL\033[0m: {}:{}: EXPECT_APPROXIMATE({}, {})"                                   \
+                   " failed with lhs={}, rhs={}, (lhs-rhs)={}",                                                 \
+                __FILE__, __LINE__, #a, #b, expect_close_lhs, expect_close_rhs, expect_close_diff);             \
+            current_test_case_did_fail();                                                                       \
+        }                                                                                                       \
     } while (false)
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f8ebf56909..ad27daa6d1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -167,6 +167,7 @@ add_compile_options(-Wcast-align)
 add_compile_options(-Wcast-qual)
 add_compile_options(-Wno-deprecated-copy)
 add_compile_options(-Wduplicated-cond)
+add_compile_options(-Wdouble-promotion)
 add_compile_options(-Wno-expansion-to-defined)
 add_compile_options(-Wformat=2)
 add_compile_options(-Wimplicit-fallthrough)
diff --git a/Userland/Applets/ResourceGraph/main.cpp b/Userland/Applets/ResourceGraph/main.cpp
index d686190246..f4e19525dd 100644
--- a/Userland/Applets/ResourceGraph/main.cpp
+++ b/Userland/Applets/ResourceGraph/main.cpp
@@ -74,7 +74,7 @@ private:
                 m_last_cpu_idle = idle;
                 float cpu = (float)busy_diff / (float)(busy_diff + idle_diff);
                 m_history.enqueue(cpu);
-                m_tooltip = String::format("CPU usage: %.1f%%", 100 * cpu);
+                m_tooltip = String::formatted("CPU usage: {:.1}%", 100 * cpu);
             } else {
                 m_history.enqueue(-1);
                 m_tooltip = StringView("Unable to determine CPU usage");
@@ -87,7 +87,7 @@ private:
                 double total_memory = allocated + available;
                 double memory = (double)allocated / total_memory;
                 m_history.enqueue(memory);
-                m_tooltip = String::format("Memory: %.1f MiB of %.1f MiB in use", (float)(allocated / MiB), (float)(total_memory / MiB));
+                m_tooltip = String::formatted("Memory: {} MiB of {:.1} MiB in use", allocated / MiB, total_memory / MiB);
             } else {
                 m_history.enqueue(-1);
                 m_tooltip = StringView("Unable to determine memory usage");
diff --git a/Userland/Applications/MouseSettings/MouseSettingsWindow.cpp b/Userland/Applications/MouseSettings/MouseSettingsWindow.cpp
index e31b657725..1fe132d3a4 100644
--- a/Userland/Applications/MouseSettings/MouseSettingsWindow.cpp
+++ b/Userland/Applications/MouseSettings/MouseSettingsWindow.cpp
@@ -68,7 +68,7 @@ MouseSettingsWindow::MouseSettingsWindow()
     m_speed_slider->on_change = [&](const int value) {
         m_speed_label->set_text(String::formatted("{} %", value));
     };
-    const int slider_value = speed_slider_scale * GUI::WindowServerConnection::the().send_sync<Messages::WindowServer::GetMouseAcceleration>()->factor();
+    const int slider_value = float { speed_slider_scale } * GUI::WindowServerConnection::the().send_sync<Messages::WindowServer::GetMouseAcceleration>()->factor();
     m_speed_slider->set_value(slider_value);
 
     m_scroll_length_spinbox = *main_widget.find_descendant_of_type_named<GUI::SpinBox>("scroll_length_spinbox");
diff --git a/Userland/Applications/PixelPaint/BrushTool.cpp b/Userland/Applications/PixelPaint/BrushTool.cpp
index df0eec7acc..66638da0f3 100644
--- a/Userland/Applications/PixelPaint/BrushTool.cpp
+++ b/Userland/Applications/PixelPaint/BrushTool.cpp
@@ -82,7 +82,7 @@ void BrushTool::draw_point(Gfx::Bitmap& bitmap, const Gfx::Color& color, const G
             if (distance >= m_size)
                 continue;
 
-            auto falloff = (1.0 - (distance / (float)m_size)) * (1.0f / (100 - m_hardness));
+            auto falloff = (1.0 - double { distance / m_size }) * (1.0 / (100 - m_hardness));
             auto pixel_color = color;
             pixel_color.set_alpha(falloff * 255);
             bitmap.set_pixel(x, y, bitmap.get_pixel(x, y).blend(pixel_color));
diff --git a/Userland/Applications/PixelPaint/FilterParams.h b/Userland/Applications/PixelPaint/FilterParams.h
index 398caecf9f..8440d27e5c 100644
--- a/Userland/Applications/PixelPaint/FilterParams.h
+++ b/Userland/Applications/PixelPaint/FilterParams.h
@@ -127,8 +127,8 @@ struct FilterParameters<Gfx::SpatialGaussianBlurFilter<N>> {
 
         for (auto x = -offset; x <= offset; x++) {
             for (auto y = -offset; y <= offset; y++) {
-                auto r = sqrt(x * x + y * y);
-                kernel.elements()[x + offset][y + offset] = (exp(-(r * r) / s)) / (M_PI * s);
+                auto r = sqrtf(x * x + y * y);
+                kernel.elements()[x + offset][y + offset] = (expf(-(r * r) / s)) / (float { M_PI } * s);
             }
         }
 
diff --git a/Userland/Applications/PixelPaint/ImageEditor.cpp b/Userland/Applications/PixelPaint/ImageEditor.cpp
index 0198b49eca..e91cbcf275 100644
--- a/Userland/Applications/PixelPaint/ImageEditor.cpp
+++ b/Userland/Applications/PixelPaint/ImageEditor.cpp
@@ -380,9 +380,10 @@ void ImageEditor::scale_centered_on_position(const Gfx::IntPoint& position, floa
     if (m_scale > 100.0f)
         m_scale = 100.0f;
 
-    auto focus_point = Gfx::FloatPoint(
-        m_pan_origin.x() - ((float)position.x() - (float)width() / 2.0) / old_scale,
-        m_pan_origin.y() - ((float)position.y() - (float)height() / 2.0) / old_scale);
+    Gfx::FloatPoint focus_point {
+        m_pan_origin.x() - (position.x() - width() / 2.0f) / old_scale,
+        m_pan_origin.y() - (position.y() - height() / 2.0f) / old_scale
+    };
 
     m_pan_origin = Gfx::FloatPoint(
         focus_point.x() - m_scale / old_scale * (focus_point.x() - m_pan_origin.x()),
diff --git a/Userland/Applications/PixelPaint/LineTool.cpp b/Userland/Applications/PixelPaint/LineTool.cpp
index 7c3e37e836..2f5738872a 100644
--- a/Userland/Applications/PixelPaint/LineTool.cpp
+++ b/Userland/Applications/PixelPaint/LineTool.cpp
@@ -36,15 +36,15 @@ namespace PixelPaint {
 
 static Gfx::IntPoint constrain_line_angle(const Gfx::IntPoint& start_pos, const Gfx::IntPoint& end_pos, float angle_increment)
 {
-    float current_angle = atan2(end_pos.y() - start_pos.y(), end_pos.x() - start_pos.x()) + M_PI * 2.;
+    float current_angle = atan2f(end_pos.y() - start_pos.y(), end_pos.x() - start_pos.x()) + float { M_PI * 2 };
 
-    float constrained_angle = ((int)((current_angle + angle_increment / 2.) / angle_increment)) * angle_increment;
+    float constrained_angle = ((int)((current_angle + angle_increment / 2) / angle_increment)) * angle_increment;
 
     auto diff = end_pos - start_pos;
     float line_length = sqrt(diff.x() * diff.x() + diff.y() * diff.y());
 
-    return { start_pos.x() + (int)(cos(constrained_angle) * line_length),
-        start_pos.y() + (int)(sin(constrained_angle) * line_length) };
+    return { start_pos.x() + (int)(cosf(constrained_angle) * line_length),
+        start_pos.y() + (int)(sinf(constrained_angle) * line_length) };
 }
 
 LineTool::LineTool()
@@ -90,7 +90,7 @@ void LineTool::on_mousemove(Layer&, GUI::MouseEvent& layer_event, GUI::MouseEven
     if (!m_constrain_angle) {
         m_line_end_position = layer_event.position();
     } else {
-        const float ANGLE_STEP = M_PI / 8.0f;
+        constexpr auto ANGLE_STEP = M_PI / 8;
         m_line_end_position = constrain_line_angle(m_line_start_position, layer_event.position(), ANGLE_STEP);
     }
     m_editor->update();
diff --git a/Userland/Applications/PixelPaint/SprayTool.cpp b/Userland/Applications/PixelPaint/SprayTool.cpp
index 51d5a7e83b..523a7a0850 100644
--- a/Userland/Applications/PixelPaint/SprayTool.cpp
+++ b/Userland/Applications/PixelPaint/SprayTool.cpp
@@ -70,7 +70,7 @@ void SprayTool::paint_it()
     m_editor->update();
     const double minimal_radius = 2;
     const double base_radius = minimal_radius * m_thickness;
-    for (int i = 0; i < M_PI * base_radius * base_radius * (m_density / 100.0f); i++) {
+    for (int i = 0; i < M_PI * base_radius * base_radius * (m_density / 100.0); i++) {
         double radius = base_radius * nrand();
         double angle = 2 * M_PI * nrand();
         const int xpos = m_last_pos.x() + radius * cos(angle);
diff --git a/Userland/Applications/QuickShow/QSWidget.cpp b/Userland/Applications/QuickShow/QSWidget.cpp
index 7a52e43fe6..8b2ffbdccf 100644
--- a/Userland/Applications/QuickShow/QSWidget.cpp
+++ b/Userland/Applications/QuickShow/QSWidget.cpp
@@ -235,9 +235,10 @@ void QSWidget::mousewheel_event(GUI::MouseEvent& event)
     // We want the image after scaling to be panned in such a way that the cursor
     // will still point to the same image pixel. Basically, we need to solve
     // (m_pan_origin + focus_point) / old_scale_factor = (new_m_pan_origin + focus_point) / new_scale_factor.
-    auto focus_point = Gfx::FloatPoint(
-        (float)event.x() - (float)width() / 2.0,
-        (float)event.y() - (float)height() / 2.0);
+    Gfx::FloatPoint focus_point {
+        event.x() - width() / 2.0f,
+        event.y() - height() / 2.0f
+    };
 
     // A little algebra shows that new m_pan_origin equals to:
     m_pan_origin = (m_pan_origin + focus_point) * (new_scale_factor / old_scale_factor) - focus_point;
diff --git a/Userland/Demos/Cube/Cube.cpp b/Userland/Demos/Cube/Cube.cpp
index 807fcf8595..0758c71981 100644
--- a/Userland/Demos/Cube/Cube.cpp
+++ b/Userland/Demos/Cube/Cube.cpp
@@ -177,12 +177,12 @@ void Cube::timer_event(Core::TimerEvent&)
         normal.normalize();
 
         // Perspective projection
-        a.set_x(WIDTH / 2 + a.x() / (1 + a.z() * 0.35) * WIDTH / 3);
-        a.set_y(HEIGHT / 2 - a.y() / (1 + a.z() * 0.35) * WIDTH / 3);
-        b.set_x(WIDTH / 2 + b.x() / (1 + b.z() * 0.35) * WIDTH / 3);
-        b.set_y(HEIGHT / 2 - b.y() / (1 + b.z() * 0.35) * WIDTH / 3);
-        c.set_x(WIDTH / 2 + c.x() / (1 + c.z() * 0.35) * WIDTH / 3);
-        c.set_y(HEIGHT / 2 - c.y() / (1 + c.z() * 0.35) * WIDTH / 3);
+        a.set_x(WIDTH / 2 + a.x() / (1 + a.z() * 0.35f) * WIDTH / 3);
+        a.set_y(HEIGHT / 2 - a.y() / (1 + a.z() * 0.35f) * WIDTH / 3);
+        b.set_x(WIDTH / 2 + b.x() / (1 + b.z() * 0.35f) * WIDTH / 3);
+        b.set_y(HEIGHT / 2 - b.y() / (1 + b.z() * 0.35f) * WIDTH / 3);
+        c.set_x(WIDTH / 2 + c.x() / (1 + c.z() * 0.35f) * WIDTH / 3);
+        c.set_y(HEIGHT / 2 - c.y() / (1 + c.z() * 0.35f) * WIDTH / 3);
 
         float winding = (b.x() - a.x()) * (c.y() - a.y()) - (b.y() - a.y()) * (c.x() - a.x());
         if (winding < 0)
diff --git a/Userland/DevTools/Profiler/main.cpp b/Userland/DevTools/Profiler/main.cpp
index 76c8aff332..96912eacc8 100644
--- a/Userland/DevTools/Profiler/main.cpp
+++ b/Userland/DevTools/Profiler/main.cpp
@@ -194,7 +194,7 @@ static bool prompt_to_stop_profiling(pid_t pid, const String& process_name)
     Core::ElapsedTimer clock;
     clock.start();
     auto update_timer = Core::Timer::construct(100, [&] {
-        timer_label.set_text(String::format("%.1f seconds", (float)clock.elapsed() / 1000.0f));
+        timer_label.set_text(String::formatted("{:.1} seconds", clock.elapsed() / 1000.0f));
     });
 
     auto& stop_button = widget.add<GUI::Button>("Stop");
diff --git a/Userland/Games/Chess/ChessWidget.cpp b/Userland/Games/Chess/ChessWidget.cpp
index e3b31b33e3..c96ef0715c 100644
--- a/Userland/Games/Chess/ChessWidget.cpp
+++ b/Userland/Games/Chess/ChessWidget.cpp
@@ -111,15 +111,18 @@ void ChessWidget::paint_event(GUI::PaintEvent& event)
         float dx = B.x() - A.x();
         float dy = A.y() - B.y();
         float phi = atan2f(dy, dx);
-        float hdx = h * cos(phi);
-        float hdy = h * sin(phi);
+        float hdx = h * cosf(phi);
+        float hdy = h * sinf(phi);
 
-        Gfx::FloatPoint A1(A.x() - (w1 / 2) * cos(M_PI_2 - phi), A.y() - (w1 / 2) * sin(M_PI_2 - phi));
-        Gfx::FloatPoint B3(A.x() + (w1 / 2) * cos(M_PI_2 - phi), A.y() + (w1 / 2) * sin(M_PI_2 - phi));
+        const auto cos_pi_2_phi = cosf(float { M_PI_2 } - phi);
+        const auto sin_pi_2_phi = sinf(float { M_PI_2 } - phi);
+
+        Gfx::FloatPoint A1(A.x() - (w1 / 2) * cos_pi_2_phi, A.y() - (w1 / 2) * sin_pi_2_phi);
+        Gfx::FloatPoint B3(A.x() + (w1 / 2) * cos_pi_2_phi, A.y() + (w1 / 2) * sin_pi_2_phi);
         Gfx::FloatPoint A2(A1.x() + (dx - hdx), A1.y() - (dy - hdy));
         Gfx::FloatPoint B2(B3.x() + (dx - hdx), B3.y() - (dy - hdy));
-        Gfx::FloatPoint A3(A2.x() - w2 * cos(M_PI_2 - phi), A2.y() - w2 * sin(M_PI_2 - phi));
-        Gfx::FloatPoint B1(B2.x() + w2 * cos(M_PI_2 - phi), B2.y() + w2 * sin(M_PI_2 - phi));
+        Gfx::FloatPoint A3(A2.x() - w2 * cos_pi_2_phi, A2.y() - w2 * sin_pi_2_phi);
+        Gfx::FloatPoint B1(B2.x() + w2 * cos_pi_2_phi, B2.y() + w2 * sin_pi_2_phi);
 
         auto path = Gfx::Path();
         path.move_to(A);
diff --git a/Userland/Games/Solitaire/SolitaireWidget.cpp b/Userland/Games/Solitaire/SolitaireWidget.cpp
index fbf1cc7eb1..0a2e04c643 100644
--- a/Userland/Games/Solitaire/SolitaireWidget.cpp
+++ b/Userland/Games/Solitaire/SolitaireWidget.cpp
@@ -92,7 +92,7 @@ void SolitaireWidget::create_new_animation_card()
     card->set_position({ rand() % (SolitaireWidget::width - Card::width), rand() % (SolitaireWidget::height / 8) });
 
     int x_sgn = card->position().x() > (SolitaireWidget::width / 2) ? -1 : 1;
-    m_animation = Animation(card, rand_float() + .4, x_sgn * ((rand() % 3) + 2), .6 + rand_float() * .4);
+    m_animation = Animation(card, rand_float() + .4f, x_sgn * ((rand() % 3) + 2), .6f + rand_float() * .4f);
 }
 
 void SolitaireWidget::start_game_over_animation()
diff --git a/Userland/Libraries/LibGfx/Gamma.h b/Userland/Libraries/LibGfx/Gamma.h
index f0f3b86f25..345e30bff5 100644
--- a/Userland/Libraries/LibGfx/Gamma.h
+++ b/Userland/Libraries/LibGfx/Gamma.h
@@ -95,7 +95,7 @@ inline f32x4 gamma_accurate_lerp4(f32x4 v1, f32x4 v2, float mix)
 // Assumes x is in range [0, 1]
 constexpr float gamma_to_linear(float x)
 {
-    return (0.8 + 0.2 * x) * x * x;
+    return (0.8f + 0.2f * x) * x * x;
 }
 
 // Transform scalar from linear space to gamma2.2 space
@@ -105,7 +105,7 @@ inline float linear_to_gamma(float x)
     // Source for approximation: https://mimosa-pudica.net/fast-gamma/
     constexpr float a = 0.00279491;
     constexpr float b = 1.15907984;
-    float c = (b / sqrt(1 + a)) - 1;
+    float c = (b / sqrtf(1 + a)) - 1;
     return ((b / __builtin_sqrtf(x + a)) - c) * x;
 }
 
@@ -135,9 +135,9 @@ inline Color gamma_accurate_blend(Color a, Color b, float mix)
     return Color(out[0], out[1], out[2]);
 #    else
     return {
-        static_cast<u8>(255. * gamma_accurate_lerp(a.red() / 255., b.red() / 255., mix)),
-        static_cast<u8>(255. * gamma_accurate_lerp(a.green() / 255., b.green() / 255., mix)),
-        static_cast<u8>(255. * gamma_accurate_lerp(a.blue() / 255., b.blue() / 255., mix)),
+        static_cast<u8>(255.f * gamma_accurate_lerp(a.red() / 255.f, b.red() / 255.f, mix)),
+        static_cast<u8>(255.f * gamma_accurate_lerp(a.green() / 255.f, b.green() / 255.f, mix)),
+        static_cast<u8>(255.f * gamma_accurate_lerp(a.blue() / 255.f, b.blue() / 255.f, mix)),
     };
 #    endif
 }
diff --git a/Userland/Libraries/LibGfx/Painter.cpp b/Userland/Libraries/LibGfx/Painter.cpp
index e16792f716..2ad3624c7a 100644
--- a/Userland/Libraries/LibGfx/Painter.cpp
+++ b/Userland/Libraries/LibGfx/Painter.cpp
@@ -299,7 +299,7 @@ void Painter::draw_ellipse_intersecting(const IntRect& rect, Color color, int th
         return (sin(theta) * rect.height() / sqrt(2)) + rect.center().y();
     };
 
-    for (float theta = 0; theta < 2 * M_PI; theta += increment) {
+    for (auto theta = 0.0; theta < 2 * M_PI; theta += increment) {
         draw_line({ ellipse_x(theta), ellipse_y(theta) }, { ellipse_x(theta + increment), ellipse_y(theta + increment) }, color, thickness);
     }
 }
diff --git a/Userland/Libraries/LibGfx/Path.cpp b/Userland/Libraries/LibGfx/Path.cpp
index 9bb4e7fa53..18378d3be8 100644
--- a/Userland/Libraries/LibGfx/Path.cpp
+++ b/Userland/Libraries/LibGfx/Path.cpp
@@ -75,8 +75,8 @@ void Path::elliptical_arc_to(const FloatPoint& point, const FloatPoint& radii, d
 
     // Find (cx, cy), theta_1, theta_delta
     // Step 1: Compute (x1', y1')
-    auto x_avg = (last_point.x() - next_point.x()) / 2.0f;
-    auto y_avg = (last_point.y() - next_point.y()) / 2.0f;
+    auto x_avg = static_cast<double>(last_point.x() - next_point.x()) / 2.0;
+    auto y_avg = static_cast<double>(last_point.y() - next_point.y()) / 2.0;
     auto x1p = x_axis_rotation_c * x_avg + x_axis_rotation_s * y_avg;
     auto y1p = -x_axis_rotation_s * x_avg + x_axis_rotation_c * y_avg;
 
@@ -118,7 +118,7 @@ void Path::elliptical_arc_to(const FloatPoint& point, const FloatPoint& radii, d
 
     auto theta_delta = theta_2 - theta_1;
 
-    if (!sweep && theta_delta > 0.0f) {
+    if (!sweep && theta_delta > 0.0) {
         theta_delta -= 2 * M_PI;
     } else if (sweep && theta_delta < 0) {
         theta_delta += 2 * M_PI;
@@ -226,7 +226,7 @@ String Path::to_string() const
             break;
         case Segment::Type::EllipticalArcTo: {
             auto& arc = static_cast<const EllipticalArcSegment&>(segment);
-            builder.appendf(", %s, %s, %f, %f, %f",
+            builder.appendff(", {}, {}, {}, {}, {}",
                 arc.radii().to_string().characters(),
                 arc.center().to_string().characters(),
                 arc.x_axis_rotation(),
diff --git a/Userland/Libraries/LibGfx/Rect.cpp b/Userland/Libraries/LibGfx/Rect.cpp
index 0a9ce4fc3b..ff135e6afd 100644
--- a/Userland/Libraries/LibGfx/Rect.cpp
+++ b/Userland/Libraries/LibGfx/Rect.cpp
@@ -160,7 +160,7 @@ String IntRect::to_string() const
 template<>
 String FloatRect::to_string() const
 {
-    return String::format("[%f,%f %fx%f]", x(), y(), width(), height());
+    return String::formatted("[{},{} {}x{}]", x(), y(), width(), height());
 }
 
 }
diff --git a/Userland/Libraries/LibM/math.cpp b/Userland/Libraries/LibM/math.cpp
index dc162a5873..12facc0850 100644
--- a/Userland/Libraries/LibM/math.cpp
+++ b/Userland/Libraries/LibM/math.cpp
@@ -172,9 +172,9 @@ static FloatType internal_to_integer(FloatType x, RoundingMode rounding_mode)
         // We could do this ourselves, but this saves us from manually
         // handling overflow.
         if (extractor.sign)
-            extractor.d -= 1.0;
+            extractor.d -= static_cast<FloatType>(1.0);
         else
-            extractor.d += 1.0;
+            extractor.d += static_cast<FloatType>(1.0);
     }
 
     return extractor.d;
@@ -339,7 +339,7 @@ static FloatT internal_gamma(FloatT x) NOEXCEPT
     }
 
     // Stirling approximation
-    return sqrtl(2.0 * M_PI / x) * powl(x / M_E, x);
+    return sqrtl(2.0 * M_PI / static_cast<long double>(x)) * powl(static_cast<long double>(x) / M_E, static_cast<long double>(x));
 }
 
 extern "C" {
@@ -386,7 +386,7 @@ double cos(double angle) NOEXCEPT
 
 float cosf(float angle) NOEXCEPT
 {
-    return sinf(angle + M_PI_2);
+    return sinf(angle + static_cast<float>(M_PI_2));
 }
 
 long double sinl(long double angle) NOEXCEPT
@@ -636,7 +636,7 @@ double fmod(double index, double period) NOEXCEPT
 
 float fmodf(float index, float period) NOEXCEPT
 {
-    return index - trunc(index / period) * period;
+    return index - truncf(index / period) * period;
 }
 
 // FIXME: These aren't exactly like fmod, but these definitions are probably good enough for now
@@ -818,7 +818,7 @@ double acos(double x) NOEXCEPT
 
 float acosf(float x) NOEXCEPT
 {
-    return M_PI_2 - asinf(x);
+    return static_cast<float>(M_PI_2) - asinf(x);
 }
 
 long double fabsl(long double value) NOEXCEPT
@@ -1104,9 +1104,9 @@ double lgamma_r(double value, int* sign) NOEXCEPT
 
 float lgammaf_r(float value, int* sign) NOEXCEPT
 {
-    if (value == 1.0 || value == 2.0)
+    if (value == 1.0f || value == 2.0f)
         return 0.0;
-    if (isinf(value) || value == 0.0)
+    if (isinf(value) || value == 0.0f)
         return INFINITY;
     float result = logf(internal_gamma(value));
     *sign = signbit(result) ? -1 : 1;
diff --git a/Userland/Libraries/LibTTF/Glyf.cpp b/Userland/Libraries/LibTTF/Glyf.cpp
index de1b5a292c..8c07ed5030 100644
--- a/Userland/Libraries/LibTTF/Glyf.cpp
+++ b/Userland/Libraries/LibTTF/Glyf.cpp
@@ -214,7 +214,7 @@ Rasterizer::Rasterizer(Gfx::IntSize size)
 {
     m_data.resize(m_size.width() * m_size.height());
     for (int i = 0; i < m_size.width() * m_size.height(); i++) {
-        m_data[i] = 0.0;
+        m_data[i] = 0.0f;
     }
 }
 
@@ -234,13 +234,13 @@ RefPtr<Gfx::Bitmap> Rasterizer::accumulate()
         for (int x = 0; x < m_size.width(); x++) {
             accumulator += m_data[y * m_size.width() + x];
             float value = accumulator;
-            if (value < 0.0) {
+            if (value < 0.0f) {
                 value = -value;
             }
-            if (value > 1.0) {
+            if (value > 1.0f) {
                 value = 1.0;
             }
-            u8 alpha = value * 255.0;
+            u8 alpha = value * 255.0f;
             bitmap->set_pixel(x, y, base_color.with_alpha(alpha));
         }
     }
@@ -250,31 +250,31 @@ RefPtr<Gfx::Bitmap> Rasterizer::accumulate()
 void Rasterizer::draw_line(Gfx::FloatPoint p0, Gfx::FloatPoint p1)
 {
     // FIXME: Shift x and y according to dy/dx
-    if (p0.x() < 0.0) {
+    if (p0.x() < 0.0f) {
         p0.set_x(roundf(p0.x()));
     }
-    if (p0.y() < 0.0) {
+    if (p0.y() < 0.0f) {
         p0.set_y(roundf(p0.y()));
     }
-    if (p1.x() < 0.0) {
+    if (p1.x() < 0.0f) {
         p1.set_x(roundf(p1.x()));
     }
-    if (p1.y() < 0.0) {
+    if (p1.y() < 0.0f) {
         p1.set_y(roundf(p1.y()));
     }
 
-    if (!(p0.x() >= 0.0 && p0.y() >= 0.0 && p0.x() <= m_size.width() && p0.y() <= m_size.height())) {
+    if (!(p0.x() >= 0.0f && p0.y() >= 0.0f && p0.x() <= m_size.width() && p0.y() <= m_size.height())) {
         dbgln("!P0({},{})", p0.x(), p0.y());
         return;
     }
 
-    if (!(p1.x() >= 0.0 && p1.y() >= 0.0 && p1.x() <= m_size.width() && p1.y() <= m_size.height())) {
+    if (!(p1.x() >= 0.0f && p1.y() >= 0.0f && p1.x() <= m_size.width() && p1.y() <= m_size.height())) {
         dbgln("!P1({},{})", p1.x(), p1.y());
         return;
     }
 
-    VERIFY(p0.x() >= 0.0 && p0.y() >= 0.0 && p0.x() <= m_size.width() && p0.y() <= m_size.height());
-    VERIFY(p1.x() >= 0.0 && p1.y() >= 0.0 && p1.x() <= m_size.width() && p1.y() <= m_size.height());
+    VERIFY(p0.x() >= 0.0f && p0.y() >= 0.0f && p0.x() <= m_size.width() && p0.y() <= m_size.height());
+    VERIFY(p1.x() >= 0.0f && p1.y() >= 0.0f && p1.x() <= m_size.width() && p1.y() <= m_size.height());
 
     // If we're on the same Y, there's no need to draw
     if (p0.y() == p1.y()) {
@@ -300,8 +300,8 @@ void Rasterizer::draw_line(Gfx::FloatPoint p0, Gfx::FloatPoint p1)
         float dy = min(y + 1.0f, p1.y()) - max((float)y, p0.y());
         float directed_dy = dy * direction;
         float x_next = x_cur + dy * dxdy;
-        if (x_next < 0.0) {
-            x_next = 0.0;
+        if (x_next < 0.0f) {
+            x_next = 0.0f;
         }
         float x0 = x_cur;
         float x1 = x_next;
@@ -313,19 +313,19 @@ void Rasterizer::draw_line(Gfx::FloatPoint p0, Gfx::FloatPoint p1)
         float x1_ceil = ceil(x1);
         u32 x0i = x0_floor;
 
-        if (x1_ceil <= x0_floor + 1.0) {
+        if (x1_ceil <= x0_floor + 1.0f) {
             // If x0 and x1 are within the same pixel, then area to the right is (1 - (mid(x0, x1) - x0_floor)) * dy
-            float area = ((x0 + x1) * 0.5) - x0_floor;
-            m_data[line_offset + x0i] += directed_dy * (1.0 - area);
+            float area = ((x0 + x1) * 0.5f) - x0_floor;
+            m_data[line_offset + x0i] += directed_dy * (1.0f - area);
             m_data[line_offset + x0i + 1] += directed_dy * area;
         } else {
-            float dydx = 1.0 / dxdy;
+            float dydx = 1.0f / dxdy;
             if (dydx < 0)
                 dydx = -dydx;
 
-            float x0_right = 1.0 - (x0 - x0_floor);
+            float x0_right = 1.0f - (x0 - x0_floor);
             u32 x1_floor_i = floor(x1);
-            float area_upto_here = 0.5 * x0_right * x0_right * dydx;
+            float area_upto_here = 0.5f * x0_right * x0_right * dydx;
             m_data[line_offset + x0i] += direction * area_upto_here;
             for (u32 x = x0i + 1; x < x1_floor_i; x++) {
                 m_data[line_offset + x] += direction * dydx;
diff --git a/Userland/Libraries/LibWeb/CSS/Length.h b/Userland/Libraries/LibWeb/CSS/Length.h
index 322d741227..c7ca87bbf3 100644
--- a/Userland/Libraries/LibWeb/CSS/Length.h
+++ b/Userland/Libraries/LibWeb/CSS/Length.h
@@ -73,7 +73,7 @@ public:
         if (is_undefined())
             return fallback_for_undefined;
         if (is_percentage())
-            return make_px(raw_value() / 100.0 * reference_for_percent);
+            return make_px(raw_value() / 100.0f * reference_for_percent);
         if (is_relative())
             return make_px(to_px(layout_node));
         return *this;
diff --git a/Userland/Libraries/LibWeb/Dump.cpp b/Userland/Libraries/LibWeb/Dump.cpp
index a9f721dfef..e0353009bd 100644
--- a/Userland/Libraries/LibWeb/Dump.cpp
+++ b/Userland/Libraries/LibWeb/Dump.cpp
@@ -189,7 +189,7 @@ void dump_tree(StringBuilder& builder, const Layout::Node& layout_node, bool sho
 
         if (show_box_model) {
             // Dump the horizontal box properties
-            builder.appendf(" [%g+%g+%g %g %g+%g+%g]",
+            builder.appendff(" [{}+{}+{} {} {}+{}+{}]",
                 box.box_model().margin.left,
                 box.box_model().border.left,
                 box.box_model().padding.left,
@@ -199,7 +199,7 @@ void dump_tree(StringBuilder& builder, const Layout::Node& layout_node, bool sho
                 box.box_model().margin.right);
 
             // And the vertical box properties
-            builder.appendf(" [%g+%g+%g %g %g+%g+%g]",
+            builder.appendff(" [{}+{}+{} {} {}+{}+{}]",
                 box.box_model().margin.top,
                 box.box_model().border.top,
                 box.box_model().padding.top,
diff --git a/Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp b/Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp
index da74eb1f50..db4c3052f8 100644
--- a/Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp
+++ b/Userland/Libraries/LibWeb/HTML/CanvasRenderingContext2D.cpp
@@ -219,13 +219,13 @@ DOM::ExceptionOr<void> CanvasRenderingContext2D::ellipse(float x, float y, float
     if (radius_y < 0)
         return DOM::IndexSizeError::create(String::formatted("The minor-axis radius provided ({}) is negative.", radius_y));
 
-    if ((!counter_clockwise && (end_angle - start_angle) >= M_TAU)
-        || (counter_clockwise && (start_angle - end_angle) >= M_TAU)) {
+    if (constexpr float tau = M_TAU; (!counter_clockwise && (end_angle - start_angle) >= tau)
+        || (counter_clockwise && (start_angle - end_angle) >= tau)) {
         start_angle = 0;
-        end_angle = M_TAU;
+        end_angle = tau;
     } else {
-        start_angle = fmodf(start_angle, M_TAU);
-        end_angle = fmodf(end_angle, M_TAU);
+        start_angle = fmodf(start_angle, tau);
+        end_angle = fmodf(end_angle, tau);
     }
 
     // Then, figure out where the ends of the arc are.
@@ -263,7 +263,7 @@ DOM::ExceptionOr<void> CanvasRenderingContext2D::ellipse(float x, float y, float
 
     m_path.move_to(start_point);
 
-    auto delta_theta = end_angle - start_angle;
+    double delta_theta = end_angle - start_angle;
 
     // FIXME: This is still goofy for some values.
     m_path.elliptical_arc_to(end_point, { radius_x, radius_y }, rotation, delta_theta > M_PI, !counter_clockwise);
diff --git a/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp b/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp
index a6a718aa8d..d97bc13852 100644
--- a/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp
+++ b/Userland/Libraries/LibWeb/SVG/SVGPathElement.cpp
@@ -516,7 +516,7 @@ Gfx::Path& SVGPathElement::get_path()
         case PathInstructionType::EllipticalArc: {
             double rx = data[0];
             double ry = data[1];
-            double x_axis_rotation = data[2] * M_DEG2RAD;
+            double x_axis_rotation = double { data[2] } * M_DEG2RAD;
             double large_arc_flag = data[3];
             double sweep_flag = data[4];
             auto& last_point = path.segments().last().point();
diff --git a/Userland/Services/WindowServer/ClientConnection.cpp b/Userland/Services/WindowServer/ClientConnection.cpp
index 0a4bdc3ed3..926f6cf212 100644
--- a/Userland/Services/WindowServer/ClientConnection.cpp
+++ b/Userland/Services/WindowServer/ClientConnection.cpp
@@ -616,7 +616,7 @@ void ClientConnection::handle(const Messages::WindowServer::DidFinishPainting& m
     auto& window = *(*it).value;
     for (auto& rect : message.rects())
         window.invalidate(rect);
-    if (window.has_alpha_channel() && window.alpha_hit_threshold() > 0.0)
+    if (window.has_alpha_channel() && window.alpha_hit_threshold() > 0.0f)
         WindowManager::the().reevaluate_hovered_window(&window);
 
     WindowSwitcher::the().refresh_if_needed();
@@ -940,11 +940,12 @@ OwnPtr<Messages::WindowServer::GetGlobalCursorPositionResponse> ClientConnection
 
 OwnPtr<Messages::WindowServer::SetMouseAccelerationResponse> ClientConnection::handle(const Messages::WindowServer::SetMouseAcceleration& message)
 {
-    if (message.factor() < mouse_accel_min || message.factor() > mouse_accel_max) {
+    double factor = message.factor();
+    if (factor < mouse_accel_min || factor > mouse_accel_max) {
         did_misbehave("SetMouseAcceleration with bad acceleration factor");
         return {};
     }
-    WindowManager::the().set_acceleration_factor(message.factor());
+    WindowManager::the().set_acceleration_factor(factor);
     return make<Messages::WindowServer::SetMouseAccelerationResponse>();
 }
 
diff --git a/Userland/Services/WindowServer/Screen.h b/Userland/Services/WindowServer/Screen.h
index b43ba22cea..54d088e466 100644
--- a/Userland/Services/WindowServer/Screen.h
+++ b/Userland/Services/WindowServer/Screen.h
@@ -35,9 +35,9 @@ struct MousePacket;
 
 namespace WindowServer {
 
-const double mouse_accel_max = 3.5;
-const double mouse_accel_min = 0.5;
-const unsigned scroll_step_size_min = 1;
+constexpr double mouse_accel_max = 3.5;
+constexpr double mouse_accel_min = 0.5;
+constexpr unsigned scroll_step_size_min = 1;
 
 class Screen {
 public: