error: expected a literal
  --> $DIR/issue-106837.rs:5:13
   |
LL |     concat!(-"hello");
   |             ^^^^^^^^
   |
   = note: only literals (like `"foo"`, `-42` and `3.14`) can be passed to `concat!()`

error: expected a literal
  --> $DIR/issue-106837.rs:8:13
   |
LL |     concat!(--1);
   |             ^^^
   |
   = note: only literals (like `"foo"`, `-42` and `3.14`) can be passed to `concat!()`

error: aborting due to 2 previous errors