error: indexing into a string may panic if the index is within a UTF-8 character
  --> tests/ui/string_slice.rs:7:6
   |
LL |     &"Ölkanne"[1..];
   |      ^^^^^^^^^^^^^^
   |
   = note: `-D clippy::string-slice` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(clippy::string_slice)]`

error: indexing into a string may panic if the index is within a UTF-8 character
  --> tests/ui/string_slice.rs:11:6
   |
LL |     &m[2..5];
   |      ^^^^^^^

error: indexing into a string may panic if the index is within a UTF-8 character
  --> tests/ui/string_slice.rs:14:6
   |
LL |     &s[0..2];
   |      ^^^^^^^

error: indexing into a string may panic if the index is within a UTF-8 character
  --> tests/ui/string_slice.rs:17:6
   |
LL |     &a[0..3];
   |      ^^^^^^^

error: aborting due to 4 previous errors