error[E0369]: cannot add `&str` to `&str`
  --> $DIR/issue-39018.rs:2:22
   |
LL |     let x = "Hello " + "World!";
   |             -------- ^ -------- &str
   |             |        |
   |             |        `+` cannot be used to concatenate two `&str` strings
   |             &str
   |
   = note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
   |
LL |     let x = "Hello ".to_owned() + "World!";
   |                     +++++++++++

error[E0369]: cannot add `World` to `World`
  --> $DIR/issue-39018.rs:8:26
   |
LL |     let y = World::Hello + World::Goodbye;
   |             ------------ ^ -------------- World
   |             |
   |             World
   |
note: an implementation of `Add<_>` might be missing for `World`
  --> $DIR/issue-39018.rs:15:1
   |
LL | enum World {
   | ^^^^^^^^^^ must implement `Add<_>`
note: the following trait must be implemented
  --> $SRC_DIR/core/src/ops/arith.rs:LL:COL
   |
LL | pub trait Add<Rhs = Self> {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0369]: cannot add `String` to `&str`
  --> $DIR/issue-39018.rs:11:22
   |
LL |     let x = "Hello " + "World!".to_owned();
   |             -------- ^ ------------------- String
   |             |        |
   |             |        `+` cannot be used to concatenate a `&str` with a `String`
   |             &str
   |
help: create an owned `String` on the left and add a borrow on the right
   |
LL |     let x = "Hello ".to_owned() + &"World!".to_owned();
   |                     +++++++++++   +

error[E0369]: cannot add `&String` to `&String`
  --> $DIR/issue-39018.rs:26:16
   |
LL |     let _ = &a + &b;
   |             -- ^ -- &String
   |             |  |
   |             |  `+` cannot be used to concatenate two `&str` strings
   |             &String
   |
   = note: string concatenation requires an owned `String` on the left
help: remove the borrow to obtain an owned `String`
   |
LL -     let _ = &a + &b;
LL +     let _ = a + &b;
   |

error[E0369]: cannot add `String` to `&String`
  --> $DIR/issue-39018.rs:27:16
   |
LL |     let _ = &a + b;
   |             -- ^ - String
   |             |  |
   |             |  `+` cannot be used to concatenate a `&str` with a `String`
   |             &String
   |
help: remove the borrow on the left and add one on the right
   |
LL -     let _ = &a + b;
LL +     let _ = a + &b;
   |

error[E0308]: mismatched types
  --> $DIR/issue-39018.rs:29:17
   |
LL |     let _ = a + b;
   |                 ^
   |                 |
   |                 expected `&str`, found struct `String`
   |                 help: consider borrowing here: `&b`

error[E0369]: cannot add `String` to `&String`
  --> $DIR/issue-39018.rs:30:15
   |
LL |     let _ = e + b;
   |             - ^ - String
   |             | |
   |             | `+` cannot be used to concatenate a `&str` with a `String`
   |             &String
   |
help: create an owned `String` on the left and add a borrow on the right
   |
LL |     let _ = e.to_owned() + &b;
   |              +++++++++++   +

error[E0369]: cannot add `&String` to `&String`
  --> $DIR/issue-39018.rs:31:15
   |
LL |     let _ = e + &b;
   |             - ^ -- &String
   |             | |
   |             | `+` cannot be used to concatenate two `&str` strings
   |             &String
   |
   = note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
   |
LL |     let _ = e.to_owned() + &b;
   |              +++++++++++

error[E0369]: cannot add `&str` to `&String`
  --> $DIR/issue-39018.rs:32:15
   |
LL |     let _ = e + d;
   |             - ^ - &str
   |             | |
   |             | `+` cannot be used to concatenate two `&str` strings
   |             &String
   |
   = note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
   |
LL |     let _ = e.to_owned() + d;
   |              +++++++++++

error[E0369]: cannot add `&&str` to `&String`
  --> $DIR/issue-39018.rs:33:15
   |
LL |     let _ = e + &d;
   |             - ^ -- &&str
   |             | |
   |             | `+` cannot be used to concatenate two `&str` strings
   |             &String
   |
   = note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
   |
LL |     let _ = e.to_owned() + &d;
   |              +++++++++++

error[E0369]: cannot add `&&str` to `&&str`
  --> $DIR/issue-39018.rs:34:16
   |
LL |     let _ = &c + &d;
   |             -- ^ -- &&str
   |             |
   |             &&str

error[E0369]: cannot add `&str` to `&&str`
  --> $DIR/issue-39018.rs:35:16
   |
LL |     let _ = &c + d;
   |             -- ^ - &str
   |             |
   |             &&str

error[E0369]: cannot add `&&str` to `&str`
  --> $DIR/issue-39018.rs:36:15
   |
LL |     let _ = c + &d;
   |             - ^ -- &&str
   |             | |
   |             | `+` cannot be used to concatenate two `&str` strings
   |             &str
   |
   = note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
   |
LL |     let _ = c.to_owned() + &d;
   |              +++++++++++

error[E0369]: cannot add `&str` to `&str`
  --> $DIR/issue-39018.rs:37:15
   |
LL |     let _ = c + d;
   |             - ^ - &str
   |             | |
   |             | `+` cannot be used to concatenate two `&str` strings
   |             &str
   |
   = note: string concatenation requires an owned `String` on the left
help: create an owned `String` from a string reference
   |
LL |     let _ = c.to_owned() + d;
   |              +++++++++++

error: aborting due to 14 previous errors

Some errors have detailed explanations: E0308, E0369.
For more information about an error, try `rustc --explain E0308`.