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:

<cfset z = {name='r',age=34}> <cfset somefunc(data=z)>

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:

<cfset somefunc(data={name='r',age=34})>

I also tried the simpler form:

<cfset somefunc({name='r',age=34})>

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!)