error: expected identifier, found keyword `unsafe`
  --> $DIR/double-unsafe-attributes.rs:1:10
   |
LL | #[unsafe(unsafe(no_mangle))]
   |          ^^^^^^ expected identifier, found keyword
   |
help: escape `unsafe` to use it as an identifier
   |
LL | #[unsafe(r#unsafe(no_mangle))]
   |          ++

error: `r#unsafe` is not an unsafe attribute
  --> $DIR/double-unsafe-attributes.rs:1:3
   |
LL | #[unsafe(unsafe(no_mangle))]
   |   ^^^^^^ this is not an unsafe attribute
   |
   = note: extraneous unsafe is not allowed in attributes

error: cannot find attribute `r#unsafe` in this scope
  --> $DIR/double-unsafe-attributes.rs:1:10
   |
LL | #[unsafe(unsafe(no_mangle))]
   |          ^^^^^^

error: aborting due to 3 previous errors