Match constructor first in Constructor methods
Match constructor first in Constructor methods

This makes it easier to add new non-standard constructors, and this also
ensures that we don't forget cases when adding a new constructor.

aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust