五年锈病

   Compiling error-messages v0.1.0 (file:///Users/usr/src/rust/error-messages)
src/lib.rs:6:5: 6:12 error: the trait `core::marker::Sized` is not implemented for the type `std::io::Write` [E0277]
src/lib.rs:6     generic(w);
                 ^~~~~~~
src/lib.rs:6:5: 6:12 note: `std::io::Write` does not have a constant size known at compile-time
src/lib.rs:6     generic(w);
                 ^~~~~~~
error: aborting due to previous error
Could not compile `error-messages`.

To learn more, run the command again with --verbose.

   Compiling error-messages v0.1.0 (/Users/ep/src/rust/error-messages)
error[E0277]: the size for values of type `dyn std::io::Write` cannot be known at compilation time
 --> src/lib.rs:6:13
  |
6 |     generic(w);
  |             ^ doesn't have a size known at compile-time
...
9 | fn generic<W: Write>(_w: &W) {}
  |    ------- -       - help: consider relaxing the implicit `Sized` restriction: `+  ?Sized`
  |            |
  |            required by this bound in `generic`
  |
  = help: the trait `std::marker::Sized` is not implemented for `dyn std::io::Write`
  = note: to learn more, visit <https://doc.rust-lang.org/book/ch19-04-advanced-types.html#dynamically-sized-types-and-the-sized-trait>

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.
error: could not compile `error-messages`.

To learn more, run the command again with --verbose.

   Compiling error-messages v0.1.0 (file:///Users/ep/src/rust/error-messages)
src/lib.rs:3:24: 3:43 error: the trait `core::ops::FnMut<(char,)>` is not implemented for the type `collections::string::String` [E0277]
src/lib.rs:3     println!("{:?}", s.find("".to_owned()));
                                    ^~~~~~~~~~~~~~~~~~~
note: in expansion of format_args!
<std macros>:2:25: 2:56 note: expansion site
<std macros>:1:1: 2:62 note: in expansion of print!
<std macros>:3:1: 3:54 note: expansion site
<std macros>:1:1: 3:58 note: in expansion of println!
src/lib.rs:3:5: 3:45 note: expansion site
src/lib.rs:3:24: 3:43 error: the trait `core::ops::FnOnce<(char,)>` is not implemented for the type `collections::string::String` [E0277]
src/lib.rs:3     println!("{:?}", s.find("".to_owned()));
                                    ^~~~~~~~~~~~~~~~~~~
note: in expansion of format_args!
<std macros>:2:25: 2:56 note: expansion site
<std macros>:1:1: 2:62 note: in expansion of print!
<std macros>:3:1: 3:54 note: expansion site
<std macros>:1:1: 3:58 note: in expansion of println!
src/lib.rs:3:5: 3:45 note: expansion site
error: aborting due to 2 previous errors
Could not compile `error-messages`.

To learn more, run the command again with --verbose.

   Compiling error-messages v0.1.0 (/Users/ep/src/rust/error-messages)
error[E0277]: expected a `std::ops::FnMut<(char,)>` closure, found `std::string::String`
 --> src/lib.rs:3:29
  |
3 |     println!("{:?}", s.find("".to_owned()));
  |                             ^^^^^^^^^^^^^
  |                             |
  |                             expected an implementor of trait `std::str::pattern::Pattern<'_>`
  |                             help: consider borrowing here: `&"".to_owned()`
  |
  = note: the trait bound `std::string::String: std::str::pattern::Pattern<'_>` is not satisfied
  = note: required because of the requirements on the impl of `std::str::pattern::Pattern<'_>` for `std::string::String`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.
error: could not compile `error-messages`.

To learn more, run the command again with --verbose.

   Compiling error-messages v0.1.0 (file:///Users/ep/src/rust/error-messages)
src/lib.rs:5:23: 5:24 error: cannot borrow `x` as immutable because it is also borrowed as mutable
src/lib.rs:5     println!("{} {}", x, y);
                                   ^
note: in expansion of format_args!
<std macros>:2:25: 2:56 note: expansion site
<std macros>:1:1: 2:62 note: in expansion of print!
<std macros>:3:1: 3:54 note: expansion site
<std macros>:1:1: 3:58 note: in expansion of println!
src/lib.rs:5:5: 5:29 note: expansion site
src/lib.rs:3:18: 3:19 note: previous borrow of `x` occurs here; the mutable borrow prevents subsequent moves, borrows, or modification of `x` until the borrow ends
src/lib.rs:3     let y = &mut x;
                              ^
src/lib.rs:6:2: 6:2 note: previous borrow ends here
src/lib.rs:1 fn main() {
src/lib.rs:2     let mut x = 7;
src/lib.rs:3     let y = &mut x;
src/lib.rs:4
src/lib.rs:5     println!("{} {}", x, y);
src/lib.rs:6 }
             ^
error: aborting due to previous error
Could not compile `error-messages`.

To learn more, run the command again with --verbose.

   Compiling error-messages v0.1.0 (/Users/ep/src/rust/error-messages)
error[E0502]: cannot borrow `x` as immutable because it is also borrowed as mutable
 --> src/lib.rs:5:23
  |
3 |     let y = &mut x;
  |             ------ mutable borrow occurs here
4 |
5 |     println!("{} {}", x, y);
  |                       ^  - mutable borrow later used here
  |                       |
  |                       immutable borrow occurs here

error: aborting due to previous error

For more information about this error, try `rustc --explain E0502`.
error: could not compile `error-messages`.

To learn more, run the command again with --verbose.