rust: pin-init: internal: init: provide span for slot projection

When initializing a field, pin-init first projects the full slot to a slot
of the field, then initialize it by invoking a method. Currently the span
location is not explicitly set, so the error message points to the full
macro invocation.

Improve it by provide a span, so Rust will point to the specific fields
causing the error when type check fails.

Old error message:

    error[E0308]: mismatched types
     --> tests/ui/compile-fail/init/field_value_wrong_type.rs:8:28
      |
    8 |     let _ = init!(Foo { a: () });
      |             ---------------^^---
      |             |              |
      |             |              expected `usize`, found `()`
      |             arguments to this method are incorrect

New error message:

    error[E0308]: mismatched types
     --> tests/ui/compile-fail/init/field_value_wrong_type.rs:8:28
      |
    8 |     let _ = init!(Foo { a: () });
      |                         ---^^
      |                         |  |
      |                         |  expected `usize`, found `()`
      |                         arguments to this method are incorrect

Link: https://patch.msgid.link/20260916-dev-hygiene-v1-3-dfb6ae2588ba@garyguo.net
Signed-off-by: Gary Guo <gary@garyguo.net>

0 files changed, 0 insertions, 0 deletions