Rollup merge of #145401 - estebank:remove-useless-iter, r=compiler-errors

cleanup: Remove useless `[T].iter().last()`

Author: Kobzol

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -1741,7 +1741,7 @@ fn deny_equality_constraints(
  .map(|segment| segment.ident.name)
  .zip(poly.trait_ref.path.segments.iter().map(|segment| segment.ident.name))
  .all(|(a, b)| a == b)
- && let Some(potential_assoc) = full_path.segments.iter().last()
+ && let Some(potential_assoc) = full_path.segments.last()
  {
  suggest(poly, potential_assoc, predicate);
  }

compiler/rustc_macros/src/diagnostics/utils.rs

@@ -146,7 +146,7 @@ impl<'ty> FieldInnerTy<'ty> {
  };
 
  let path = &ty_path.path;
- let ty = path.segments.iter().last().unwrap();
+ let ty = path.segments.last().unwrap();
  let syn::PathArguments::AngleBracketed(bracketed) = &ty.arguments else {
  panic!("expected bracketed generic arguments");
  };