map is internally backed by a pointer (i.e. a "reference type")

core/raw.odin

@@ -20,11 +20,15 @@ Dynamic_Array :: struct {
 	allocator: Allocator,
 }
 
-Map :: struct {
+Map_Internal :: struct {
 	hashes:  [dynamic]int,
 	entries: Dynamic_Array,
 }
 
+Map :: struct {
+	using internal: ^Map_Internal,
+}
+
 make_any :: inline proc(data: rawptr, type_info: ^Type_Info) -> any {
 	return transmute(any)Any{data, type_info};
 }