diff options
| -rw-r--r-- | compiler/rustc_ast_lowering/src/lib.rs | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs index 901284f3c19..a82225850c4 100644 --- a/compiler/rustc_ast_lowering/src/lib.rs +++ b/compiler/rustc_ast_lowering/src/lib.rs @@ -1809,21 +1809,30 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> { debug!(?captures); - self.with_hir_id_owner(opaque_ty_node_id, |this| { - let lifetimes_in_bounds = - lifetime_collector::lifetimes_in_ret_ty(&this.resolver, output); - debug!(?lifetimes_in_bounds); + // We only want to capture the lifetimes that appear in the bounds. So visit the bounds to + // find out exactly which ones those are. + // in fn return position, like the `fn test<'a>() -> impl Debug + 'a` example, + // we only keep the lifetimes that appear in the `impl Debug` itself: + let lifetimes_to_remap = lifetime_collector::lifetimes_in_ret_ty(&self.resolver, output); + debug!(?lifetimes_to_remap); + self.with_hir_id_owner(opaque_ty_node_id, |this| { + // If this opaque type is only capturing a subset of the lifetimes (those that appear + // in bounds), then create the new lifetime parameters required and create a mapping + // from the old `'a` (on the function) to the new `'a` (on the opaque type). captures.extend( this.create_lifetime_defs( opaque_ty_def_id, - &lifetimes_in_bounds, + &lifetimes_to_remap, &mut new_remapping, ) .into_iter() .map(|(new_node_id, lifetime)| (new_node_id, lifetime, None)), ); + debug!(?captures); + debug!(?new_remapping); + // Install the remapping from old to new (if any): this.with_remapping(new_remapping, |this| { // We have to be careful to get elision right here. The // idea is that we create a lifetime parameter for each |