• Parse opt-out ?const trait bounds (#767)
• Parse const generics in method generic arguments (#816, thanks @yodaldevoid)
• Parse trait bounds on type alias items (#821)
• Parse const generics on impl blocks (#822)
• Fix precedence of attributes on binary expressions to match rustc (#823)
• Remove parsing of extern:: paths which were removed from nightly in January 2019 (#825, rust-lang/rust#57572)
• Add Punctuated::clear, analogous to Vec::clear (#828)