diff --git a/Source/Core/Common/FilesystemWatcher.cpp b/Source/Core/Common/FilesystemWatcher.cpp
index 646e2467ed..94970232b2 100644
--- a/Source/Core/Common/FilesystemWatcher.cpp
+++ b/Source/Core/Common/FilesystemWatcher.cpp
@@ -31,13 +31,13 @@ void FilesystemWatcher::Watch(const std::string& path)
 
       if (e.effect_type == wtr::event::effect_type::create)
       {
-        const auto path = WithUnifiedPathSeparators(watched_path);
-        PathAdded(path);
+        const auto unified_path = WithUnifiedPathSeparators(watched_path);
+        PathAdded(unified_path);
       }
       else if (e.effect_type == wtr::event::effect_type::modify)
       {
-        const auto path = WithUnifiedPathSeparators(watched_path);
-        PathModified(path);
+        const auto unified_path = WithUnifiedPathSeparators(watched_path);
+        PathModified(unified_path);
       }
       else if (e.effect_type == wtr::event::effect_type::rename)
       {
@@ -53,8 +53,8 @@ void FilesystemWatcher::Watch(const std::string& path)
       }
       else if (e.effect_type == wtr::event::effect_type::destroy)
       {
-        const auto path = WithUnifiedPathSeparators(watched_path);
-        PathDeleted(path);
+        const auto unified_path = WithUnifiedPathSeparators(watched_path);
+        PathDeleted(unified_path);
       }
     });
   }
diff --git a/Source/Core/Core/ARDecrypt.cpp b/Source/Core/Core/ARDecrypt.cpp
index 46ca74d159..98f49cfc41 100644
--- a/Source/Core/Core/ARDecrypt.cpp
+++ b/Source/Core/Core/ARDecrypt.cpp
@@ -459,7 +459,7 @@ static int alphatobin(u32* dst, const std::vector<std::string>& alpha, int size)
 
 void DecryptARCode(std::vector<std::string> vCodes, std::vector<AREntry>* ops)
 {
-  std::array<u32, 1200> uCodes;
+  std::array<u32, 1200> uCodes{};
 
   for (std::string& s : vCodes)
   {
diff --git a/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp b/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp
index 3b308891c6..0394ae9236 100644
--- a/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp
+++ b/Source/Core/Core/HW/WiimoteEmu/Speaker.cpp
@@ -67,7 +67,7 @@ void SpeakerLogic::SpeakerData(const u8* data, int length, float speaker_pan)
 
   // Potentially 40 resulting samples.
   std::array<s16, WiimoteCommon::OutputReportSpeakerData::DATA_SIZE * 2> samples;
-  assert(length * 2 <= samples.size());
+  assert(length * 2 <= static_cast<int>(samples.size()));
 
   unsigned int sample_rate_dividend, sample_length;
   u8 volume_divisor;
diff --git a/Source/Core/Core/IOS/Network/IP/Top.cpp b/Source/Core/Core/IOS/Network/IP/Top.cpp
index 08008f97b7..c99f3d0511 100644
--- a/Source/Core/Core/IOS/Network/IP/Top.cpp
+++ b/Source/Core/Core/IOS/Network/IP/Top.cpp
@@ -256,7 +256,7 @@ static std::vector<InterfaceRouting> GetSystemInterfaceRouting()
   }
 
   // read response
-  int msg_len = 0;
+  unsigned int msg_len = 0;
   msg_buffer.fill(0);
 
   do
@@ -270,9 +270,10 @@ static std::vector<InterfaceRouting> GetSystemInterfaceRouting()
     }
 
     nl_msg = reinterpret_cast<nlmsghdr*>(buf_ptr);
-    if (NLMSG_OK(nl_msg, read_len) == 0)
+    if (NLMSG_OK(nl_msg, static_cast<unsigned int>(read_len)) == 0)
     {
-      ERROR_LOG_FMT(IOS_NET, "Received netlink error response ({})", NLMSG_OK(nl_msg, read_len));
+      ERROR_LOG_FMT(IOS_NET, "Received netlink error response ({})",
+                    NLMSG_OK(nl_msg, static_cast<unsigned int>(read_len)));
       return {};
     }
 
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp
index 465d0257af..20a86c0389 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp
@@ -176,7 +176,10 @@ Arm64GPRCache::GuestRegInfo Arm64GPRCache::GetGuestCR(size_t preg)
 
 Arm64GPRCache::GuestRegInfo Arm64GPRCache::GetGuestByIndex(size_t index)
 {
-  if (index >= GUEST_GPR_OFFSET && index < GUEST_GPR_OFFSET + GUEST_GPR_COUNT)
+  // We do not need to test for `index >= GUEST_GPR_OFFSET` because
+  // GUEST_GPR_OFFSET is always 0. This otherwise raises a warning.
+  static_assert(GUEST_GPR_OFFSET == 0);
+  if (index < GUEST_GPR_OFFSET + GUEST_GPR_COUNT)
     return GetGuestGPR(index - GUEST_GPR_OFFSET);
   if (index >= GUEST_CR_OFFSET && index < GUEST_CR_OFFSET + GUEST_CR_COUNT)
     return GetGuestCR(index - GUEST_CR_OFFSET);
diff --git a/Source/Core/Core/State.h b/Source/Core/Core/State.h
index 1e4ba0029b..4b100b214c 100644
--- a/Source/Core/Core/State.h
+++ b/Source/Core/Core/State.h
@@ -107,7 +107,7 @@ void SaveAs(Core::System& system, const std::string& filename, bool wait = false
 void LoadAs(Core::System& system, const std::string& filename);
 
 void SaveToBuffer(Core::System& system, Common::UniqueBuffer<u8>& buffer);
-void LoadFromBuffer(Core::System& system, const Common::UniqueBuffer<u8>& buffer);
+void LoadFromBuffer(Core::System& system, Common::UniqueBuffer<u8>& buffer);
 
 void LoadLastSaved(Core::System& system, int i = 1);
 void SaveFirstSaved(Core::System& system);
diff --git a/Source/Core/DolphinQt/CheatSearchWidget.cpp b/Source/Core/DolphinQt/CheatSearchWidget.cpp
index bbd8675f3e..c18e8cb6a6 100644
--- a/Source/Core/DolphinQt/CheatSearchWidget.cpp
+++ b/Source/Core/DolphinQt/CheatSearchWidget.cpp
@@ -531,7 +531,7 @@ void CheatSearchWidget::GenerateARCodes()
     return;
 
   bool had_success = false;
-  bool had_error = false;
+  bool had_multiple_errors = false;
   std::optional<Cheats::GenerateActionReplayCodeErrorCode> error_code;
 
   for (auto* const item : m_address_table->selectedItems())
@@ -546,23 +546,24 @@ void CheatSearchWidget::GenerateARCodes()
     else
     {
       const auto new_error_code = result.Error();
-      if (!had_error)
+      if (!error_code.has_value())
       {
         error_code = new_error_code;
       }
       else if (error_code != new_error_code)
       {
-        // If we have a different error code signify multiple errors with an empty optional<>.
-        error_code.reset();
+        had_multiple_errors = true;
       }
-
-      had_error = true;
     }
   }
 
-  if (had_error)
+  if (error_code.has_value())
   {
-    if (error_code.has_value())
+    if (had_multiple_errors)
+    {
+      m_info_label_1->setText(tr("Multiple errors occurred while generating AR codes."));
+    }
+    else
     {
       switch (*error_code)
       {
@@ -577,10 +578,6 @@ void CheatSearchWidget::GenerateARCodes()
         break;
       }
     }
-    else
-    {
-      m_info_label_1->setText(tr("Multiple errors while generating AR codes."));
-    }
   }
   else if (had_success)
   {
diff --git a/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp b/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp
index ef6989ad9b..11c98ee883 100644
--- a/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp
+++ b/Source/Core/DolphinQt/Config/WiimoteControllersWidget.cpp
@@ -309,8 +309,15 @@ void WiimoteControllersWidget::OnBluetoothPassthroughDeviceChanged(int index)
     return;
   }
 
-  auto device_info =
-      m_bluetooth_adapters->itemData(index).value<LibUSBBluetoothAdapter::BluetoothDeviceInfo>();
+  const QVariant item_data = m_bluetooth_adapters->itemData(index);
+
+  if (!item_data.isValid() || !item_data.canConvert<LibUSBBluetoothAdapter::BluetoothDeviceInfo>())
+  {
+    ERROR_LOG_FMT(COMMON, "Invalid Bluetooth device info selected in WiimoteControllersWidget");
+    return;
+  }
+
+  const auto& device_info = item_data.value<LibUSBBluetoothAdapter::BluetoothDeviceInfo>();
 
   Config::SetBaseOrCurrent(Config::MAIN_BLUETOOTH_PASSTHROUGH_PID, device_info.pid);
   Config::SetBaseOrCurrent(Config::MAIN_BLUETOOTH_PASSTHROUGH_VID, device_info.vid);
diff --git a/Source/Core/InputCommon/ControllerInterface/SDL/SDLGamepad.cpp b/Source/Core/InputCommon/ControllerInterface/SDL/SDLGamepad.cpp
index 345bef00a3..38358999b7 100644
--- a/Source/Core/InputCommon/ControllerInterface/SDL/SDLGamepad.cpp
+++ b/Source/Core/InputCommon/ControllerInterface/SDL/SDLGamepad.cpp
@@ -13,7 +13,7 @@
 namespace ciface::SDL
 {
 
-bool IsTriggerAxis(int index)
+static bool IsTriggerAxis(int index)
 {
   // First 4 axes are for the analog sticks, the rest are for the triggers
   return index >= 4;
diff --git a/Source/Core/VideoBackends/Metal/MRCHelpers.h b/Source/Core/VideoBackends/Metal/MRCHelpers.h
index 1da2e0c8d1..839b24cf60 100644
--- a/Source/Core/VideoBackends/Metal/MRCHelpers.h
+++ b/Source/Core/VideoBackends/Metal/MRCHelpers.h
@@ -20,7 +20,7 @@ template <typename T>
 class MRCOwned
 {
   T ptr;
-  MRCOwned(T ptr) : ptr(ptr) {}
+  MRCOwned(T raw_ptr) : ptr(raw_ptr) {}
 
 public:
   MRCOwned() : ptr(nullptr) {}
diff --git a/Source/Core/VideoBackends/Metal/MTLStateTracker.mm b/Source/Core/VideoBackends/Metal/MTLStateTracker.mm
index c2cd685a82..755da35249 100644
--- a/Source/Core/VideoBackends/Metal/MTLStateTracker.mm
+++ b/Source/Core/VideoBackends/Metal/MTLStateTracker.mm
@@ -32,7 +32,7 @@ struct Metal::StateTracker::Backref
 {
   std::mutex mtx;
   StateTracker* state_tracker;
-  explicit Backref(StateTracker* state_tracker) : state_tracker(state_tracker) {}
+  explicit Backref(StateTracker* tracker) : state_tracker(tracker) {}
 };
 
 struct Metal::StateTracker::PerfQueryTracker
diff --git a/Source/UnitTests/Common/SPSCQueueTest.cpp b/Source/UnitTests/Common/SPSCQueueTest.cpp
index 13848bd95f..ddc57c8d1a 100644
--- a/Source/UnitTests/Common/SPSCQueueTest.cpp
+++ b/Source/UnitTests/Common/SPSCQueueTest.cpp
@@ -32,7 +32,7 @@ TEST(SPSCQueue, Simple)
   EXPECT_EQ(1000u, q.Size());
   for (u32 i = 0; i < 1000; ++i)
   {
-    u32 v2;
+    u32 v2 = 0;
     q.Pop(v2);
     EXPECT_EQ(i, v2);
   }
diff --git a/Source/UnitTests/Common/StringUtilTest.cpp b/Source/UnitTests/Common/StringUtilTest.cpp
index 5c21610a13..2be462a1b5 100644
--- a/Source/UnitTests/Common/StringUtilTest.cpp
+++ b/Source/UnitTests/Common/StringUtilTest.cpp
@@ -57,7 +57,7 @@ static void DoRoundTripTest(const std::vector<T>& data)
   for (const T& e : data)
   {
     const std::string s = ValueToString(e);
-    T out;
+    T out = T();
     EXPECT_TRUE(TryParse(s, &out));
     EXPECT_EQ(e, out);
   }