Compiling playground v0.0.1 (/playground) error: expected one of `:`, `@`, or `|`, found `)` --> src/lib.rs:1:28 | 1 | fn foo<'a>(_: impl 'a Sized) {} | ^ expected one of `:`, `@`, or `|` | = note: anonymous parameters are removed in the 2018 edition (see RFC 1685) help: if this is a parameter name, give it a type | 1 | fn foo<'a>(_: impl 'a Sized: TypeName) {} | ++++++++++ help: if this is a type, explicitly ignore the parameter name | 1 | fn foo<'a>(_: impl 'a _: Sized) {} | ++ error: expected one of `)`, `+`, or `,`, found `Sized` --> src/lib.rs:1:23 | 1 | fn foo<'a>(_: impl 'a Sized) {} | -^^^^^ expected one of `)`, `+`, or `,` | | | help: missing `,` error: at least one trait must be specified --> src/lib.rs:1:15 | 1 | fn foo<'a>(_: impl 'a Sized) {} | ^^^^^^^ error: could not compile `playground` due to 3 previous errors 

 Compiling playground v0.0.1 (/playground) error: expected `+` between lifetime and trait --> src/lib.rs:1:22 | 1 | fn foo<'a>(_: impl 'a + Sized) {} | ^ | | | help: missing `+` | error: could not compile `playground` due to 1 previous errors