error: `~const` can only be applied to `#[const_trait]` traits
  --> $DIR/non-const-op-in-closure-in-const.rs:10:51
   |
LL | impl<A, B> const Convert<B> for A where B: ~const From<A> {
   |                                                   ^^^^^^^

error[E0049]: method `to` has 1 const parameter but its trait declaration has 0 const parameters
  --> $DIR/non-const-op-in-closure-in-const.rs:5:1
   |
LL | #[const_trait]
   | ^^^^^^^^^^^^^^ found 1 const parameter
LL | trait Convert<T> {
LL |     fn to(self) -> T;
   |          - expected 0 const parameters

error[E0015]: cannot call non-const fn `<B as From<A>>::from` in constant functions
  --> $DIR/non-const-op-in-closure-in-const.rs:12:9
   |
LL |         B::from(self)
   |         ^^^^^^^^^^^^^
   |
   = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
help: add `#![feature(effects)]` to the crate attributes to enable
   |
LL + #![feature(effects)]
   |

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0015, E0049.
For more information about an error, try `rustc --explain E0015`.