Update `core:odin` for `union #shared_nil`

core/odin/ast/ast.odin

@@ -708,13 +708,19 @@ Struct_Type :: struct {
 	name_count:    int,
 }
 
+Union_Type_Kind :: enum u8 {
+	Normal,
+	maybe,
+	no_nil,
+	shared_nil,
+}
+
 Union_Type :: struct {
 	using node: Expr,
 	tok_pos:       tokenizer.Pos,
 	poly_params:   ^Field_List,
 	align:         ^Expr,
-	is_maybe:      bool,
-	is_no_nil:     bool,
+	kind:          Union_Type_Kind,
 	where_token:   tokenizer.Token,
 	where_clauses: []^Expr,
 	variants:      []^Expr,

core/odin/parser/parser.odin

@@ -2630,8 +2630,9 @@ parse_operand :: proc(p: ^Parser, lhs: bool) -> ^ast.Expr {
 		tok := expect_token(p, .Union)
 		poly_params: ^ast.Field_List
 		align:       ^ast.Expr
-		is_maybe:    bool
-		is_no_nil:   bool
+		is_maybe:      bool
+		is_no_nil:     bool
+		is_shared_nil: bool
 
 		if allow_token(p, .Open_Paren) {
 			param_count: int
@@ -2663,12 +2664,34 @@ parse_operand :: proc(p: ^Parser, lhs: bool) -> ^ast.Expr {
 					error(p, tag.pos, "duplicate union tag '#%s'", tag.text)
 				}
 				is_no_nil = true
+			case "shared_nil":
+				if is_shared_nil {
+					error(p, tag.pos, "duplicate union tag '#%s'", tag.text)
+				}
+				is_shared_nil = true
 			case:
 				error(p, tag.pos, "invalid union tag '#%s", tag.text)
 			}
 		}
 		p.expr_level = prev_level
 
+		if is_no_nil && is_maybe {
+			error(p, p.curr_tok.pos, "#maybe and #no_nil cannot be applied together");
+		}
+		if is_no_nil && is_shared_nil {
+			error(p, p.curr_tok.pos, "#shared_nil and #no_nil cannot be applied together");
+		}
+		if is_shared_nil && is_maybe {
+			error(p, p.curr_tok.pos, "#maybe and #shared_nil cannot be applied together");
+		}
+
+		union_kind := ast.Union_Type_Kind.Normal
+		switch {
+		case is_maybe:      union_kind = .maybe
+		case is_no_nil:     union_kind = .no_nil
+		case is_shared_nil: union_kind = .shared_nil
+		}
+
 		where_token: tokenizer.Token
 		where_clauses: []^ast.Expr
 
@@ -2699,14 +2722,15 @@ parse_operand :: proc(p: ^Parser, lhs: bool) -> ^ast.Expr {
 
 		close := expect_closing_brace_of_field_list(p)
 
+
+
 		ut := ast.new(ast.Union_Type, tok.pos, end_pos(close))
 		ut.poly_params   = poly_params
 		ut.variants      = variants[:]
 		ut.align         = align
 		ut.where_token   = where_token
 		ut.where_clauses = where_clauses
-		ut.is_maybe      = is_maybe
-		ut.is_no_nil     = is_no_nil
+		ut.kind          = union_kind
 
 		return ut
 

core/odin/printer/visit.odin

@@ -1046,8 +1046,11 @@ visit_expr :: proc(p: ^Printer, expr: ^ast.Expr, options := List_Options{}) {
 
 		push_poly_params(p, v.poly_params)
 
-		if v.is_maybe {
-			push_ident_token(p, "#maybe", 1)
+		switch v.kind {
+		case .Normal:
+		case .maybe:      push_ident_token(p, "#maybe", 1)
+		case .no_nil:     push_ident_token(p, "#no_nil", 1)
+		case .shared_nil: push_ident_token(p, "#shared_nil", 1)
 		}
 
 		push_where_clauses(p, v.where_clauses)