Do not insert impl_trait_in_bindings opaque definitions twice.
Do not insert impl_trait_in_bindings opaque definitions twice.

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