error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:16:13
   |
LL |     let x = concat!();
   |             ^^^^^^^^^ help: replace with: `""`
   |
   = note: `-D clippy::useless-concat` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::useless_concat)]`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:17:13
   |
LL |     let x = concat!('c');
   |             ^^^^^^^^^^^^ help: replace with: `"c"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:18:13
   |
LL |     let x = concat!('"');
   |             ^^^^^^^^^^^^ help: replace with: `"\""`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:19:13
   |
LL |     let x = concat!(true);
   |             ^^^^^^^^^^^^^ help: replace with: `"true"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:20:13
   |
LL |     let x = concat!(1f32);
   |             ^^^^^^^^^^^^^ help: replace with: `"1"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:21:13
   |
LL |     let x = concat!(1.0000f32);
   |             ^^^^^^^^^^^^^^^^^^ help: replace with: `"1.0000"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:22:13
   |
LL |     let x = concat!(1_f32);
   |             ^^^^^^^^^^^^^^ help: replace with: `"1"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:23:13
   |
LL |     let x = concat!(1_);
   |             ^^^^^^^^^^^ help: replace with: `"1"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:24:13
   |
LL |     let x = concat!(1.0000_f32);
   |             ^^^^^^^^^^^^^^^^^^^ help: replace with: `"1.0000"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:25:13
   |
LL |     let x = concat!(1.0000_);
   |             ^^^^^^^^^^^^^^^^ help: replace with: `"1.0000"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:26:13
   |
LL |     let x = concat!("a\u{1f600}\n");
   |             ^^^^^^^^^^^^^^^^^^^^^^^ help: replace with: `"a😀\n"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:27:13
   |
LL |     let x = concat!(r##"a"##);
   |             ^^^^^^^^^^^^^^^^^ help: replace with: `"a"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:28:13
   |
LL |     let x = concat!(1);
   |             ^^^^^^^^^^ help: replace with: `"1"`

error: unneeded use of `concat!` macro
  --> tests/ui/useless_concat.rs:29:23
   |
LL |     println!("b: {}", concat!("a"));
   |                       ^^^^^^^^^^^^ help: replace with: `"a"`

error: aborting due to 14 previous errors