rust/tests/ui/consts/const-fn-cycle.stderr at 55bfcb8c850cbd73ff703da56e1aad8c29f2dee4 · oli-obk/rust · GitHub

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error[E0391]: cycle detected when computing type of `<impl at $DIR/const-fn-cycle.rs:12:1: 12:21>::many::{opaque#0}`
  --> $DIR/const-fn-cycle.rs:20:47
   |
LL |     pub const fn many<'s>(&'s self) -> Parser<impl for<'a> Fn(&'a str) -> Vec<T> + 's> {
   |                                               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
note: ...which requires borrow-checking `<impl at $DIR/const-fn-cycle.rs:12:1: 12:21>::many`...
  --> $DIR/const-fn-cycle.rs:20:5
   |
LL |     pub const fn many<'s>(&'s self) -> Parser<impl for<'a> Fn(&'a str) -> Vec<T> + 's> {
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires promoting constants in MIR for `<impl at $DIR/const-fn-cycle.rs:12:1: 12:21>::many`...
  --> $DIR/const-fn-cycle.rs:20:5
   |
LL |     pub const fn many<'s>(&'s self) -> Parser<impl for<'a> Fn(&'a str) -> Vec<T> + 's> {
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: ...which requires const checking `<impl at $DIR/const-fn-cycle.rs:12:1: 12:21>::many`...
  --> $DIR/const-fn-cycle.rs:20:5
   |
LL |     pub const fn many<'s>(&'s self) -> Parser<impl for<'a> Fn(&'a str) -> Vec<T> + 's> {
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = note: ...which requires computing whether `Parser<<impl at $DIR/const-fn-cycle.rs:12:1: 12:21>::many::{opaque#0}>` is freeze...
   = note: ...which requires evaluating trait selection obligation `Parser<<impl at $DIR/const-fn-cycle.rs:12:1: 12:21>::many::{opaque#0}>: core::marker::Freeze`...
   = note: ...which again requires computing type of `<impl at $DIR/const-fn-cycle.rs:12:1: 12:21>::many::{opaque#0}`, completing the cycle
note: cycle used when checking item types in top-level module
  --> $DIR/const-fn-cycle.rs:1:1
   |
LL | / /// Discovered in https://github.com/rust-lang/rust/issues/112602.
LL | | /// This caused a cycle error, which made no sense.
LL | | /// Removing the `const` part of the `many` function would make the
LL | | /// test pass again.
...  |
LL | |     println!("Hello, world!");
LL | | }
   | |_^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0391`.