error: type parameter goes unused in function definition
       --> src/backtrace.rs:399:15
        |
    399 |     fn _assert<T: Send + Sync>() {}
        |               ^^^^^^^^^^^^^^^^
        |
        = help: consider removing the parameter
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters
        = note: `-D clippy::extra-unused-type-parameters` implied by `-D clippy::all`

    error: type parameter goes unused in function definition
     --> tests/test_autotrait.rs:5:19
      |
    5 |     fn assert_send<T: Send>() {}
      |                   ^^^^^^^^^
      |
      = help: consider removing the parameter
      = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters

    error: type parameter goes unused in function definition
      --> tests/test_autotrait.rs:11:19
       |
    11 |     fn assert_sync<T: Sync>() {}
       |                   ^^^^^^^^^
       |
       = help: consider removing the parameter
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters

    error: type parameter goes unused in function definition
       --> tests/test_ensure.rs:353:10
        |
    353 |     fn g<T, const I: isize>() {}
        |          ^^
        |
        = help: consider removing the parameter
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters

    error: type parameter goes unused in function definition
      --> tests/test_repr.rs:20:14
       |
    20 |     fn assert<E: Unpin + Send + Sync + 'static>() {}
       |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
       |
       = help: consider removing the parameter
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#extra_unused_type_parameters

Support const block syntax in ensure! macro

    error: non-binding `let` without a type annotation
       --> src/error.rs:618:5
        |
    618 |     let _ = target;
        |     ^^^^^^^^^^^^^^^
        |
        = help: consider adding a type annotation or removing the `let` keyword
        = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_untyped
        = note: `-D clippy::let-underscore-untyped` implied by `-D clippy::pedantic`

    error: non-binding `let` without a type annotation
      --> tests/test_backtrace.rs:12:5
       |
    12 |     let _ = error.backtrace();
       |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
       |
       = help: consider adding a type annotation or removing the `let` keyword
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_untyped
       = note: `-D clippy::let-underscore-untyped` implied by `-D clippy::pedantic`

    error: non-binding `let` without a type annotation
      --> tests/test_ensure.rs:35:9
       |
    35 |         let _ = rhs;
       |         ^^^^^^^^^^^^
       |
       = help: consider adding a type annotation or removing the `let` keyword
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#let_underscore_untyped
       = note: `-D clippy::let-underscore-untyped` implied by `-D clippy::pedantic`

Update to syn 2