only check for automatically_derived on impls, not individual methods

this matches behavior of existing code
b27661eb33/compiler/rustc_passes/src/liveness.rs (L326-L333)
This commit is contained in:
Erik Desjardins 2021-10-02 09:53:51 -04:00
parent eb4ba58572
commit bec5a91450

View File

@ -243,27 +243,16 @@ fn mark_live_symbols(&mut self) {
/// will be ignored for the purposes of dead code analysis (see PR #85200
/// for discussion).
fn should_ignore_item(&self, def_id: DefId) -> bool {
if !self.tcx.has_attr(def_id, sym::automatically_derived)
&& !self
.tcx
.impl_of_method(def_id)
.map_or(false, |impl_id| self.tcx.has_attr(impl_id, sym::automatically_derived))
{
if let Some(impl_of) = self.tcx.impl_of_method(def_id) {
if !self.tcx.has_attr(impl_of, sym::automatically_derived) {
return false;
}
let has_attr = |def_id| self.tcx.has_attr(def_id, sym::rustc_trivial_field_reads);
if let Some(impl_of) = self.tcx.impl_of_method(def_id) {
if let Some(trait_of) = self.tcx.trait_id_of_impl(impl_of) {
if has_attr(trait_of) {
if self.tcx.has_attr(trait_of, sym::rustc_trivial_field_reads) {
return true;
}
}
} else if let Some(trait_of) = self.tcx.trait_of_item(def_id) {
if has_attr(trait_of) {
return true;
}
}
return false;
@ -271,8 +260,7 @@ fn should_ignore_item(&self, def_id: DefId) -> bool {
fn visit_node(&mut self, node: Node<'tcx>) {
if let Some(item_def_id) = match node {
Node::TraitItem(hir::TraitItem { def_id, .. })
| Node::ImplItem(hir::ImplItem { def_id, .. }) => Some(def_id.to_def_id()),
Node::ImplItem(hir::ImplItem { def_id, .. }) => Some(def_id.to_def_id()),
_ => None,
} {
if self.should_ignore_item(item_def_id) {