error[E0393]: the type parameter `R` must be explicitly specified
  --> $DIR/canonicalize-fresh-infer-vars-issue-103626.rs:10:17
   |
LL | trait FromResidual<R = <Self as Try>::Residual> {
   | ----------------------------------------------- type parameter `R` must be specified for this
...
LL |     let b: &dyn FromResidual = &();
   |                 ^^^^^^^^^^^^
   |
   = note: because the parameter default references `Self`, the parameter must be specified on the object type
help: set the type parameter to the desired type
   |
LL |     let b: &dyn FromResidual<R> = &();
   |                             +++

error[E0038]: the trait `FromResidual` is not dyn compatible
  --> $DIR/canonicalize-fresh-infer-vars-issue-103626.rs:10:32
   |
LL |     let b: &dyn FromResidual = &();
   |                                ^^^ `FromResidual` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/canonicalize-fresh-infer-vars-issue-103626.rs:2:8
   |
LL | trait FromResidual<R = <Self as Try>::Residual> {
   |       ------------ this trait is not dyn compatible...
LL |     fn from_residual(residual: R) -> Self;
   |        ^^^^^^^^^^^^^ ...because associated function `from_residual` has no `self` parameter
   = note: required for the cast from `&()` to `&dyn FromResidual<{type error}>`
help: consider turning `from_residual` into a method by giving it a `&self` argument
   |
LL |     fn from_residual(&self, residual: R) -> Self;
   |                      ++++++
help: alternatively, consider constraining `from_residual` so it does not apply to trait objects
   |
LL |     fn from_residual(residual: R) -> Self where Self: Sized;
   |                                           +++++++++++++++++

error[E0038]: the trait `FromResidual` is not dyn compatible
  --> $DIR/canonicalize-fresh-infer-vars-issue-103626.rs:10:12
   |
LL |     let b: &dyn FromResidual = &();
   |            ^^^^^^^^^^^^^^^^^ `FromResidual` is not dyn compatible
   |
note: for a trait to be dyn compatible it needs to allow building a vtable
      for more information, visit <https://doc.rust-lang.org/reference/items/traits.html#dyn-compatibility>
  --> $DIR/canonicalize-fresh-infer-vars-issue-103626.rs:2:8
   |
LL | trait FromResidual<R = <Self as Try>::Residual> {
   |       ------------ this trait is not dyn compatible...
LL |     fn from_residual(residual: R) -> Self;
   |        ^^^^^^^^^^^^^ ...because associated function `from_residual` has no `self` parameter
help: consider turning `from_residual` into a method by giving it a `&self` argument
   |
LL |     fn from_residual(&self, residual: R) -> Self;
   |                      ++++++
help: alternatively, consider constraining `from_residual` so it does not apply to trait objects
   |
LL |     fn from_residual(residual: R) -> Self where Self: Sized;
   |                                           +++++++++++++++++

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0038, E0393.
For more information about an error, try `rustc --explain E0038`.