error[E0015]: cannot convert `std::ops::Range<i32>` into an iterator in constants
  --> $DIR/const-for.rs:5:14
   |
LL |     for _ in 0..5 {}
   |              ^^^^
   |
note: impl defined here, but it is not `const`
  --> $SRC_DIR/core/src/iter/traits/collect.rs:LL:COL
   = note: calls in constants are limited to constant functions, tuple structs and tuple variants
   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable

error[E0015]: cannot call non-const fn `<std::ops::Range<i32> as Iterator>::next` in constants
  --> $DIR/const-for.rs:5:14
   |
LL |     for _ in 0..5 {}
   |              ^^^^
   |
   = note: calls in constants are limited to constant functions, tuple structs and tuple variants
   = help: add `#![feature(const_trait_impl)]` to the crate attributes to enable

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0015`.