- did a test compile as C++20 and fixed all warnings that got emitted.

src/common/engine/renderstyle.h

@@ -39,10 +39,7 @@
 #undef OPAQUE
 #endif
 
-enum
-{
-	OPAQUE = 65536,
-};
+constexpr int OPAQUE = 65536;
 
 enum ETexMode
 {

src/console/c_notifybuffer.cpp

@@ -64,7 +64,7 @@ CUSTOM_CVAR(Int, con_scaletext, 0, CVAR_ARCHIVE)		// Scale notify text at high r
 	if (self < 0) self = 0;
 }
 
-enum { NOTIFYFADETIME = 6 };
+constexpr int NOTIFYFADETIME = 6;
 
 CUSTOM_CVAR(Int, con_notifylines, 4, CVAR_GLOBALCONFIG | CVAR_ARCHIVE)
 {

src/doomdef.h

@@ -57,15 +57,15 @@ typedef enum
 #endif
 #endif
 
+// State updates, number of tics / second.
+constexpr int TICRATE = 35;
+
 // Global constants that were defines.
 enum
 {
 	// The maximum number of players, multiplayer/networking.
 	MAXPLAYERS = 8,
 
-	// State updates, number of tics / second.
-	TICRATE = 35,
-
 	// Amount of damage done by a telefrag.
 	TELEFRAG_DAMAGE = 1000000
 };

src/gamedata/p_blockmap.h

@@ -43,10 +43,7 @@ struct FBlockmap
 
 	// mapblocks are used to check movement
 	// against lines and things
-	enum
-	{
-		MAPBLOCKUNITS = 128
-	};
+	static constexpr int MAPBLOCKUNITS = 128;
 
 	inline int GetBlockX(double xpos)
 	{

src/rendering/swrenderer/things/r_playersprite.h

@@ -92,8 +92,8 @@ namespace swrenderer
 	private:
 		void RenderSprite(DPSprite *pspr, AActor *owner, float bobx, float boby, double wx, double wy, double ticfrac, int lightlevel, FDynamicColormap *basecolormap, bool foggy);
 
-		enum { BASEXCENTER = 160 };
-		enum { BASEYCENTER = 100 };
+		static constexpr int BASEXCENTER = 160;
+		static constexpr int BASEYCENTER = 100;
 
 		TArray<HWAccelPlayerSprite> AcceleratedSprites;
 		sector_t tempsec;

src/utility/nodebuilder/nodebuild.h

@@ -173,8 +173,8 @@ class FNodeBuilder
 		fixed64_t MinX, MinY, MaxX, MaxY;
 		int BlocksWide, BlocksTall;
 
-		enum { BLOCK_SHIFT = 8 + FRACBITS };
-		enum { BLOCK_SIZE = 1 << BLOCK_SHIFT };
+		static constexpr int BLOCK_SHIFT = 8 + FRACBITS;
+		static constexpr int BLOCK_SIZE = 1 << BLOCK_SHIFT;
 
 		int InsertVertex (FPrivVert &vert);
 		inline int GetBlock (fixed64_t x, fixed64_t y)