This is one scary looking error message:
SSIS error 0x00084005 "the parameter type cannot be deduced because a single expression contains two untyped parameters @x and @P1"
It's terrifying enough to make you think maybe you should quit your SSIS development career altogether. But wait... What's this? Perhaps you're getting this message for the same bone-headed reason I was. In my case a better error message would have been:
SSIS error 0x00084005 "Hey, you forgot to declare your variables in the SELECT statement"
Whoops! Looks like cut and paste was the problem 🙂 Here's to hoping all your problems are as easy to solve as this!