error: argument 1 is required to be a constant
  --> $DIR/rustc-args-required-const.rs:24:5
   |
LL |     foo(a);
   |     ^^^^^^

error: argument 2 is required to be a constant
  --> $DIR/rustc-args-required-const.rs:26:5
   |
LL |     bar(a, a);
   |     ^^^^^^^^^

error: aborting due to 2 previous errors