diff --git a/src/common/rendering/gl/gl_shader.h b/src/common/rendering/gl/gl_shader.h
index 33381b6dc9..4f7debda38 100644
--- a/src/common/rendering/gl/gl_shader.h
+++ b/src/common/rendering/gl/gl_shader.h
@@ -340,7 +340,7 @@ public:
 	FShader *Get(unsigned int eff, bool alphateston)
 	{
 		// indices 0-2 match the warping modes, 3 no texture, the following are custom
-		if (!alphateston && eff < SHADER_NoTexture)
+		if (!alphateston && eff < SHADER_NoTexture && mCompileState == -1)
 		{
 			return mMaterialShadersNAT[eff];	// Non-alphatest shaders are only created for default, warp1+2 and brightmap. The rest won't get used anyway
 		}
diff --git a/src/common/textures/bitmap.cpp b/src/common/textures/bitmap.cpp
index f944f2782d..b685b03252 100644
--- a/src/common/textures/bitmap.cpp
+++ b/src/common/textures/bitmap.cpp
@@ -403,7 +403,6 @@ void FBitmap::CopyPixelDataRGB(int originx, int originy, const uint8_t *patch, i
 	}
 }
 
-
 template<class TDest, class TBlend> 
 void iCopyPaletted(uint8_t *buffer, const uint8_t * patch, int srcwidth, int srcheight, int Pitch,
 					int step_x, int step_y, int rotate, const PalEntry * palette, FCopyInfo *inf)
diff --git a/src/common/textures/formats/startuptexture.cpp b/src/common/textures/formats/startuptexture.cpp
index 1d17fb91c1..098d45d50e 100644
--- a/src/common/textures/formats/startuptexture.cpp
+++ b/src/common/textures/formats/startuptexture.cpp
@@ -322,7 +322,7 @@ int FNotchTexture::CopyPixels(FBitmap *bmp, int conversion)
 	const uint8_t *source = (const uint8_t *)lump.GetMem();
 
 	auto Work = (uint32_t*)bmp->GetPixels();
-	for(int i=0; i * Width * Height / 2; i++)
+	for(int i = 0; i < Width * Height / 2; i++)
 	{
 		Work[i * 2] = startuppalette32[source[i] >> 4];
 		Work[i * 2 + 1] = startuppalette32[source[i] & 15];
diff --git a/src/gamedata/a_weapons.cpp b/src/gamedata/a_weapons.cpp
index c8918a95c8..fa527d7708 100644
--- a/src/gamedata/a_weapons.cpp
+++ b/src/gamedata/a_weapons.cpp
@@ -208,20 +208,6 @@ void FWeaponSlot::Sort()
 	}
 }
 
-//===========================================================================
-//
-// FWeaponSlots - Copy Constructor
-//
-//===========================================================================
-
-FWeaponSlots::FWeaponSlots(const FWeaponSlots &other)
-{
-	for (int i = 0; i < NUM_WEAPON_SLOTS; ++i)
-	{
-		Slots[i] = other.Slots[i];
-	}
-}
-
 //===========================================================================
 //
 // FWeaponSlots :: Clear
diff --git a/src/gamedata/a_weapons.h b/src/gamedata/a_weapons.h
index 786990223f..1ef6d6cc19 100644
--- a/src/gamedata/a_weapons.h
+++ b/src/gamedata/a_weapons.h
@@ -51,7 +51,7 @@ enum ESlotDef
 struct FWeaponSlots
 {
 	FWeaponSlots() { Clear(); }
-	FWeaponSlots(const FWeaponSlots &other);
+	FWeaponSlots(const FWeaponSlots &other) = default;
 
 private:
 	FWeaponSlot Slots[NUM_WEAPON_SLOTS];
diff --git a/src/gamedata/d_dehacked.cpp b/src/gamedata/d_dehacked.cpp
index 8e6fdfea65..e41e1a3360 100644
--- a/src/gamedata/d_dehacked.cpp
+++ b/src/gamedata/d_dehacked.cpp
@@ -1270,7 +1270,7 @@ static int PatchThing (int thingy)
 				di->Amount = -1;
 				info->GetInfo()->DropItems = di;
 			}
-			else if (val == -1)
+			else if ((int)val == -1)
 			{
 				info->GetInfo()->DropItems = nullptr;
 			}
diff --git a/src/playsim/fragglescript/t_script.h b/src/playsim/fragglescript/t_script.h
index fbe88db9a0..94770645b7 100644
--- a/src/playsim/fragglescript/t_script.h
+++ b/src/playsim/fragglescript/t_script.h
@@ -101,12 +101,7 @@ struct svalue_t
 		value.i = 0;
 	}
 
-	svalue_t(const svalue_t & other)
-	{
-		type = other.type;
-		string = other.string;
-		value = other.value;
-	}
+	svalue_t(const svalue_t & other) = default;
 
 	void setInt(int ip)
 	{
diff --git a/src/rendering/swrenderer/r_swcolormaps.cpp b/src/rendering/swrenderer/r_swcolormaps.cpp
index 0ce48fe5f0..4bebd92e04 100644
--- a/src/rendering/swrenderer/r_swcolormaps.cpp
+++ b/src/rendering/swrenderer/r_swcolormaps.cpp
@@ -45,7 +45,6 @@
 #include "c_dispatch.h"
 #include "sc_man.h"
 #include "v_text.h"
-#include "st_start.h"
 #include "doomstat.h"
 #include "v_palette.h"
 #include "colormatcher.h"
diff --git a/src/rendering/swrenderer/scene/r_portal.cpp b/src/rendering/swrenderer/scene/r_portal.cpp
index 17f962b908..2e94df39d3 100644
--- a/src/rendering/swrenderer/scene/r_portal.cpp
+++ b/src/rendering/swrenderer/scene/r_portal.cpp
@@ -46,7 +46,6 @@
 #include "v_palette.h"
 #include "po_man.h"
 #include "p_effect.h"
-#include "st_start.h"
 #include "v_font.h"
 #include "r_data/colormaps.h"
 #include "p_maputl.h"