diff --git a/Source/Core/Core/PowerPC/JitCommon/JitBackpatch.cpp b/Source/Core/Core/PowerPC/JitCommon/JitBackpatch.cpp
index 03963dc5dd..5039996c43 100644
--- a/Source/Core/Core/PowerPC/JitCommon/JitBackpatch.cpp
+++ b/Source/Core/Core/PowerPC/JitCommon/JitBackpatch.cpp
@@ -109,7 +109,7 @@ bool Jitx86Base::BackPatch(u32 emAddress, SContext* ctx)
 			if (codePtr[totalSize] != 0xc1 || codePtr[totalSize + 2] != 0x10)
 			{
 				PanicAlert("BackPatch: didn't find expected shift %p", codePtr);
-				return nullptr;
+				return false;
 			}
 			info.signExtend = (codePtr[totalSize + 1] & 0x10) != 0;
 			totalSize += 3;
@@ -168,7 +168,7 @@ bool Jitx86Base::BackPatch(u32 emAddress, SContext* ctx)
 		if (it3 == pcAtLoc.end())
 		{
 			PanicAlert("BackPatch: no pc entry for address %p", codePtr);
-			return nullptr;
+			return false;
 		}
 
 		u32 pc = it3->second;
diff --git a/Source/Core/VideoBackends/OGL/GLInterface/GLX.h b/Source/Core/VideoBackends/OGL/GLInterface/GLX.h
index 7b6f8ac8f0..56630475ec 100644
--- a/Source/Core/VideoBackends/OGL/GLInterface/GLX.h
+++ b/Source/Core/VideoBackends/OGL/GLInterface/GLX.h
@@ -23,7 +23,7 @@ public:
 	void SwapInterval(int Interval) override;
 	void Swap() override;
 	void* GetFuncAddress(const std::string& name) override;
-	bool Create(void *window_handle);
+	bool Create(void *window_handle) override;
 	bool MakeCurrent() override;
 	bool ClearCurrent() override;
 	void Shutdown() override;
diff --git a/Source/Core/VideoCommon/OpcodeDecoding.cpp b/Source/Core/VideoCommon/OpcodeDecoding.cpp
index 20a8f2eac9..4b258e7127 100644
--- a/Source/Core/VideoCommon/OpcodeDecoding.cpp
+++ b/Source/Core/VideoCommon/OpcodeDecoding.cpp
@@ -33,7 +33,7 @@
 
 
 bool g_bRecordFifoData = false;
-bool g_bFifoErrorSeen = false;
+static bool s_bFifoErrorSeen = false;
 
 static u32 InterpretDisplayList(u32 address, u32 size)
 {
@@ -125,7 +125,7 @@ static void UnknownOpcode(u8 cmd_byte, void *buffer, bool preprocess)
 
 void OpcodeDecoder_Init()
 {
-	g_bFifoErrorSeen = false;
+	s_bFifoErrorSeen = false;
 }
 
 
@@ -291,10 +291,10 @@ u8* OpcodeDecoder_Run(DataReader src, u32* cycles, bool in_display_list)
 			}
 			else
 			{
-				if (!g_bFifoErrorSeen)
+				if (!s_bFifoErrorSeen)
 					UnknownOpcode(cmd_byte, opcodeStart, is_preprocess);
 				ERROR_LOG(VIDEO, "FIFO: Unknown Opcode(0x%02x @ %p, preprocessing = %s)", cmd_byte, opcodeStart, is_preprocess ? "yes" : "no");
-				g_bFifoErrorSeen = true;
+				s_bFifoErrorSeen = true;
 				totalCycles += 1;
 			}
 			break;
diff --git a/Source/UnitTests/Core/MMIOTest.cpp b/Source/UnitTests/Core/MMIOTest.cpp
index 7285157c34..9da0dee684 100644
--- a/Source/UnitTests/Core/MMIOTest.cpp
+++ b/Source/UnitTests/Core/MMIOTest.cpp
@@ -108,12 +108,12 @@ TEST_F(MappingTest, ReadWriteComplex)
 
 	m_mapping->Register(0x0C001234,
 		MMIO::ComplexRead<u8>([&read_called](u32 addr) {
-			EXPECT_EQ(0x0C001234, addr);
+			EXPECT_EQ(0x0C001234u, addr);
 			read_called = true;
 			return 0x12;
 		}),
 		MMIO::ComplexWrite<u8>([&write_called](u32 addr, u8 val) {
-			EXPECT_EQ(0x0C001234, addr);
+			EXPECT_EQ(0x0C001234u, addr);
 			EXPECT_EQ(0x34, val);
 			write_called = true;
 		})