2018-Specific Changes

The following is a summary of changes that only apply to code compiled withthe 2018 edition compared to the 2015 edition.

• Path changes:
  • Paths in use declarations work the same as other paths.
  • Paths starting with :: must be followed with an external crate.
  • Paths in pub(in path) visibility modifiers must start with crate,self, or super.
• Anonymous trait function parameters are not allowed.
  • Trait function parameters may use any irrefutable pattern when thefunction has a body.
• dyn is a strict keyword, in 2015 it is a weak keyword.
• async, await, and try are reserved keywords.
• The following lints are now deny by default:
  • tyvar_behind_raw_pointer

Cargo

• If there is a target definition in a Cargo.toml manifest, it no longerautomatically disables automatic discovery of other targets.
• Target paths of the form src/{target_name}.rs are no longer inferred fortargets where the path field is not set.
• cargo install for the current directory is no longer allowed, you mustspecify cargo install —path . to install the current package.