I'm thinking this is something folks have blogged about before, but I just ran into it today. When using array and struct implicit creation, you cannot use the syntax directly in a udf/method call. Let me explain. Consider this example:

In this example I use shorthand notation to creation a structure. I then pass it to somefunc as an argument named data. This works just fine. But this version, which should be the same, will give you a syntax error:

I also tried the simpler form:

Which also failed. It looks like you can only use the implicit creation in cfset statements. (Which is certainly ok, I'm just happy we have this shortcut!)