mark lua error functions as noreturn

Author: IanE9

CvGameCoreDLL_Expansion2/Lua/CvLuaPlayer.cpp

@@ -1473,7 +1473,6 @@ static DomainTypes LuaToTradeDomain(lua_State* L, int index)
 		return eDomain;
 	default:
 		luaL_error(L, "Invalid trade domain index %d", iDomain);
-		UNREACHABLE();
 	}
 }
 
@@ -9391,7 +9390,6 @@ int CvLuaPlayer::lGetPlayerColors(lua_State* L)
 	if(pkPlayerColor == NULL)
 	{
 		luaL_error(L, "Could not find player color at row %d", eColor);
-		return 0;
 	}
 
 	const ColorTypes ePrimaryColor	 = (ColorTypes)pkPlayerColor->GetColorTypePrimary();
@@ -9401,15 +9399,13 @@ int CvLuaPlayer::lGetPlayerColors(lua_State* L)
 	if(pkPrimaryColor == NULL)
 	{
 		luaL_error(L, "Could not find primary color at row %d", ePrimaryColor);
-		return 0;
 	}
 	const CvColorA& kPrimaryColor = pkPrimaryColor->GetColor();
 
 	CvColorInfo* pkSecondaryColor = GC.GetColorInfo(eSecondaryColor);
 	if(pkSecondaryColor == NULL)
 	{
 		luaL_error(L, "Could not find secondary color at row %d", eSecondaryColor);
-		return 0;
 	}
 	const CvColorA& kSecondaryColor = pkSecondaryColor->GetColor();
 
@@ -9529,7 +9525,6 @@ int CvLuaPlayer::lGetIncomingUnitType(lua_State* L)
 			else
 			{
 				luaL_error(L, "Player index %d is not a valid major civilization index.", static_cast<lua_Integer>(eFromPlayer));
-				return 0;
 			}
 		}
 	}
@@ -9558,7 +9553,6 @@ int CvLuaPlayer::lGetIncomingUnitCountdown(lua_State* L)
 			else
 			{
 				luaL_error(L, "Player index %d is not a valid major civilization index.", static_cast<lua_Integer>(eFromPlayer));
-				return 0;
 			}
 		}
 	}

ThirdPartyLibs/Lua51/include/lauxlib.h

@@ -66,7 +66,7 @@ LUALIB_API int   (luaL_newmetatable) (lua_State *L, const char *tname);
 LUALIB_API void *(luaL_checkudata) (lua_State *L, int ud, const char *tname);
 
 LUALIB_API void (luaL_where) (lua_State *L, int lvl);
-LUALIB_API int (luaL_error) (lua_State *L, const char *fmt, ...);
+LUALIB_API LUA_NORETURN int (luaL_error) (lua_State *L, const char *fmt, ...);
 
 LUALIB_API int (luaL_checkoption) (lua_State *L, int narg, const char *def,
                                    const char *const lst[]);

ThirdPartyLibs/Lua51/include/lua.h

@@ -15,6 +15,17 @@
 
 #include "luaconf.h"
 
+// Added for Vox Populi.
+// 
+// Certain Lua functions are documented as not returning and it's desirable
+// that be reflected in the function declarations so that the compiler is
+// able to recognize unreachable code.
+#ifdef _MSC_VER
+#define LUA_NORETURN __declspec(noreturn)
+#else
+#define LUA_NORETURN [[noreturn]]
+#endif // _MSC_VER
+
 
 #define LUA_VERSION	"Lua 5.1"
 #define LUA_RELEASE	"Lua 5.1.4"
@@ -234,7 +245,7 @@ LUA_API int (lua_gc) (lua_State *L, int what, int data);
 ** miscellaneous functions
 */
 
-LUA_API int   (lua_error) (lua_State *L);
+LUA_API LUA_NORETURN int   (lua_error) (lua_State *L);
 
 LUA_API int   (lua_next) (lua_State *L, int idx);