diff --git a/source/dyaml/token.d b/source/dyaml/token.d
index 6ec259b..2625df2 100644
--- a/source/dyaml/token.d
+++ b/source/dyaml/token.d
@@ -77,6 +77,8 @@ struct Token
     /// Get string representation of the token ID.
     @property string idString() @safe pure const {return id.to!string;}
 }
+static assert(Token.sizeof <= 32, "Token has unexpected size");
+
 
 @safe pure nothrow @nogc: