Disallow `using` on an enum declaration.

core/sys/windows/kernel32.odin

@@ -474,10 +474,12 @@ foreign kernel32 {
 }
 
 
-using MEMORY_RESOURCE_NOTIFICATION_TYPE :: enum c_int {
+MEMORY_RESOURCE_NOTIFICATION_TYPE :: enum c_int {
 	LowMemoryResourceNotification,
 	HighMemoryResourceNotification,
 }
+LowMemoryResourceNotification  :: MEMORY_RESOURCE_NOTIFICATION_TYPE.LowMemoryResourceNotification;
+HighMemoryResourceNotification :: MEMORY_RESOURCE_NOTIFICATION_TYPE.HighMemoryResourceNotification;
 
 
 foreign kernel32 {
@@ -598,12 +600,16 @@ foreign kernel32 {
 	) -> BOOL ---;
 }
 
-using OFFER_PRIORITY :: enum c_int {
+OFFER_PRIORITY :: enum c_int {
 	VmOfferPriorityVeryLow = 1,
 	VmOfferPriorityLow,
 	VmOfferPriorityBelowNormal,
 	VmOfferPriorityNormal,
 }
+VmOfferPriorityVeryLow     :: OFFER_PRIORITY.VmOfferPriorityVeryLow;
+VmOfferPriorityLow         :: OFFER_PRIORITY.VmOfferPriorityLow;
+VmOfferPriorityBelowNormal :: OFFER_PRIORITY.VmOfferPriorityBelowNormal;
+VmOfferPriorityNormal      :: OFFER_PRIORITY.VmOfferPriorityNormal;
 
 foreign kernel32 {
 	OfferVirtualMemory :: proc(
@@ -638,9 +644,11 @@ foreign kernel32 {
 	) -> HANDLE ---;
 }
 
-using WIN32_MEMORY_INFORMATION_CLASS :: enum c_int {
+WIN32_MEMORY_INFORMATION_CLASS :: enum c_int {
 	MemoryRegionInfo,
 }
+MemoryRegionInfo :: WIN32_MEMORY_INFORMATION_CLASS.MemoryRegionInfo;
+
 WIN32_MEMORY_REGION_INFORMATION :: struct {
 	AllocationBase: PVOID,
 	AllocationProtect: ULONG,

examples/demo/demo.odin

@@ -778,16 +778,6 @@ using_statement :: proc() {
 
 		// Note: using’d fields can still be referred by name.
 	}
-	{ // using on an enum declaration
-
-		using Foo :: enum {A, B, C};
-
-		f0 := A;
-		f1 := B;
-		f2 := C;
-		fmt.println(f0, f1, f2);
-		fmt.println(len(Foo));
-	}
 }
 
 
@@ -1337,7 +1327,7 @@ bit_set_type :: proc() {
 	fmt.println("\n# bit_set type");
 
 	{
-		using Day :: enum {
+		Day :: enum {
 			Sunday,
 			Monday,
 			Tuesday,
@@ -1348,20 +1338,20 @@ bit_set_type :: proc() {
 		};
 
 		Days :: distinct bit_set[Day];
-		WEEKEND :: Days{Sunday, Saturday};
+		WEEKEND :: Days{.Sunday, .Saturday};
 
 		d: Days;
-		d = {Sunday, Monday};
+		d = {.Sunday, .Monday};
 		e := d + WEEKEND;
-		e += {Monday};
+		e += {.Monday};
 		fmt.println(d, e);
 
-		ok := Saturday in e; // `in` is only allowed for `map` and `bit_set` types
+		ok := .Saturday in e; // `in` is only allowed for `map` and `bit_set` types
 		fmt.println(ok);
-		if Saturday in e {
+		if .Saturday in e {
 			fmt.println("Saturday in", e);
 		}
-		X :: Saturday in WEEKEND; // Constant evaluation
+		X :: .Saturday in WEEKEND; // Constant evaluation
 		fmt.println(X);
 		fmt.println("Cardinality:", card(e));
 	}

src/check_decl.cpp

@@ -294,6 +294,8 @@ void check_type_decl(CheckerContext *ctx, Entity *e, Ast *init_expr, Type *def)
 
 	// using decl
 	if (decl->is_using) {
+		warning(init_expr, "'using' an enum declaration is not allowed, prefer using implicit selector expressions e.g. '.A'");
+		#if 0
 		// NOTE(bill): Must be an enum declaration
 		if (te->kind == Ast_EnumType) {
 			Scope *parent = e->scope;
@@ -317,6 +319,7 @@ void check_type_decl(CheckerContext *ctx, Entity *e, Ast *init_expr, Type *def)
 				}
 			}
 		}
+		#endif
 	}
 }