Conflicting error messages for HRTB in impl Trait

[JustAPerson]

Rust declares the lifetime 'a is both undeclared and that it is a shadowing declaration

#[derive(Debug)]
struct Ctx<'d> {
    phantom: std::marker::PhantomData<&'d ()>   
}
fn map<'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
    data.into_iter().inspect(|t| println!("{:?}", ctx))
}

My more complicated example is trying to use the &'c mut Ctx<'d> reference in one of the closures passed to Iterator::map() so I need to somehow incorporate the lifetime 'c into the return type.

Instead I get this confusing error:

error[E0261]: use of undeclared lifetime name `'a`
 --> src/lib.rs:5:95
  |
5 | fn map<'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
  |                                                                                               ^^ undeclared lifetime

error[E0496]: lifetime name `'a` shadows a lifetime name that is already in scope
 --> src/lib.rs:5:69
  |
5 | fn map<'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
  |                                                                     ^^                        -- first declared here
  |                                                                     |
  |                                                                     lifetime 'a already in scope

error[E0261]: use of undeclared lifetime name `'a`
 --> src/lib.rs:5:108
  |
5 | fn map<'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
  |                                                                                                            ^^ undeclared lifetime

error: aborting due to 3 previous errors

You'll notice the help text of the first error says "undeclared lifetime" but the help of the second says "first declared here" and then gives a bogus "already in scope" hint.

[estebank]

Current output:

error[E0261]: use of undeclared lifetime name `'a`
 --> src/lib.rs:6:108
  |
6 | fn map<'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
  |        - help: consider introducing lifetime `'a` here: `'a,`                                              ^^ undeclared lifetime

error[E0261]: use of undeclared lifetime name `'a`
 --> src/lib.rs:6:95
  |
6 | fn map<'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
  |        - help: consider introducing lifetime `'a` here: `'a,`                                 ^^ undeclared lifetime

After applying suggestion:

error[E0496]: lifetime name `'a` shadows a lifetime name that is already in scope
 --> src/lib.rs:6:73
  |
6 | fn map<'a, 'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
  |        -- first declared here                                           ^^ lifetime `'a` already in scope

error[E0700]: hidden type for `impl Iterator<Item = ()> + 'a` captures lifetime that does not appear in bounds
 --> src/lib.rs:7:5
  |
6 | fn map<'a, 'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a where 'c: 'a {
  |                --                                              ------------------------------------- opaque type defined here
  |                |
  |                hidden type `Inspect<std::vec::IntoIter<()>, {closure@src/lib.rs:7:30: 7:33}>` captures the lifetime `'d` as defined here
7 |     data.into_iter().inspect(|t| println!("{:?}", ctx))
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  |
help: to declare that `impl Iterator<Item = ()> + 'a` captures `'d`, you can add an explicit `'d` lifetime bound
  |
6 | fn map<'a, 'c, 'd: 'c>(ctx: &'c mut Ctx<'d>, data: Vec<()>) -> impl for<'a> Iterator<Item = ()> + 'a + 'd where 'c: 'a {
  |                                                                                                      ++++

error[E0373]: closure may outlive the current function, but it borrows `ctx`, which is owned by the current function
 --> src/lib.rs:7:30
  |
7 |     data.into_iter().inspect(|t| println!("{:?}", ctx))
  |                              ^^^                  --- `ctx` is borrowed here
  |                              |
  |                              may outlive borrowed value `ctx`
  |
note: closure is returned here
 --> src/lib.rs:7:5
  |
7 |     data.into_iter().inspect(|t| println!("{:?}", ctx))
  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
help: to force the closure to take ownership of `ctx` (and any other referenced variables), use the `move` keyword
  |
7 |     data.into_iter().inspect(move |t| println!("{:?}", ctx))
  |                              ++++