diff --git a/CMakeLists.txt b/CMakeLists.txt
index cd3cdcb..dff74bd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -217,6 +217,8 @@ elseif(MSVC)
 
 	add_compile_options(/W4)
 	add_compile_options(/we4840) # treat as error when passing a class to a vararg-function (probably printf-like)
+	# treat several kinds of truncating int<->pointer conversions as errors (for more 64bit-safety)
+	add_compile_options(/we4306 /we4311 /we4312 /we4302)
 	add_compile_options(/wd4100) # unreferenced formal parameter
 	add_compile_options(/wd4127) # conditional expression is constant
 	add_compile_options(/wd4244) # possible loss of data
diff --git a/framework/CVarSystem.h b/framework/CVarSystem.h
index 1f1bd31..e0ae01c 100644
--- a/framework/CVarSystem.h
+++ b/framework/CVarSystem.h
@@ -182,6 +182,8 @@ private:
 	static idCVar *			staticVars;
 };
 
+static idCVar const * const staticCVarsInvalid = (const idCVar*)(uintptr_t)0xFFFFFFFF;
+
 ID_INLINE idCVar::idCVar( const char *name, const char *value, int flags, const char *description,
 							argCompletion_t valueCompletion ) {
 	if ( !valueCompletion && ( flags & CVAR_BOOL ) ) {
@@ -293,7 +295,7 @@ ID_INLINE void idCVar::Init( const char *name, const char *value, int flags, con
 	this->integerValue = 0;
 	this->floatValue = 0.0f;
 	this->internalVar = this;
-	if ( staticVars != (idCVar *)0xFFFFFFFF ) {
+	if ( staticVars != staticCVarsInvalid ) {
 		this->next = staticVars;
 		staticVars = this;
 	} else {
@@ -302,11 +304,11 @@ ID_INLINE void idCVar::Init( const char *name, const char *value, int flags, con
 }
 
 ID_INLINE void idCVar::RegisterStaticVars( void ) {
-	if ( staticVars != (idCVar *)0xFFFFFFFF ) {
+	if ( staticVars != staticCVarsInvalid ) {
 		for ( idCVar *cvar = staticVars; cvar; cvar = cvar->next ) {
 			cvarSystem->Register( cvar );
 		}
-		staticVars = (idCVar *)0xFFFFFFFF;
+		staticVars = (idCVar *)staticCVarsInvalid;
 	}
 }