Make `body_owned_by` return the body directly.

Almost all callers want this anyway, and now we can use it to also return fed bodies

2 files changed, 25 insertions, 7 deletions

diff --git a/compiler/rustc_middle/src/hir/map/mod.rs b/compiler/rustc_middle/src/hir/map/mod.rs
index ff8d2919705..665cd883d44 100644
--- a/compiler/rustc_middle/src/hir/map/mod.rs
+++ b/compiler/rustc_middle/src/hir/map/mod.rs
@@ -1,3 +1,5 @@
+use std::borrow::Cow;
+
 use crate::hir::ModuleItems;
 use crate::middle::debugger_visualizer::DebuggerVisualizerFile;
 use crate::query::LocalCrate;
@@ -254,13 +256,26 @@ impl<'hir> Map<'hir> {
 
     /// Given a `LocalDefId`, returns the `BodyId` associated with it,
     /// if the node is a body owner, otherwise returns `None`.
-    pub fn maybe_body_owned_by(self, id: LocalDefId) -> Option<BodyId> {
-        self.tcx.hir_node_by_def_id(id).body_id()
+    pub fn maybe_body_owned_by(self, id: LocalDefId) -> Option<Cow<'hir, Body<'hir>>> {
+        Some(match self.tcx.def_kind(id) {
+            // Inline consts do not have bodies of their own, so create one to make the follow-up logic simpler.
+            DefKind::InlineConst => {
+                let e = self.expect_expr(self.tcx.local_def_id_to_hir_id(id));
+                Cow::Owned(Body {
+                    params: &[],
+                    value: match e.kind {
+                        ExprKind::ConstBlock(body) => body,
+                        _ => span_bug!(e.span, "InlineConst was not a ConstBlock: {e:#?}"),
+                    },
+                })
+            }
+            _ => Cow::Borrowed(self.body(self.tcx.hir_node_by_def_id(id).body_id()?)),
+        })
     }
 
     /// Given a body owner's id, returns the `BodyId` associated with it.
     #[track_caller]
-    pub fn body_owned_by(self, id: LocalDefId) -> BodyId {
+    pub fn body_owned_by(self, id: LocalDefId) -> Cow<'hir, Body<'hir>> {
         self.maybe_body_owned_by(id).unwrap_or_else(|| {
             let hir_id = self.tcx.local_def_id_to_hir_id(id);
             span_bug!(
diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs
index d39422b2b04..b0c14cdfec9 100644
--- a/compiler/rustc_middle/src/hir/mod.rs
+++ b/compiler/rustc_middle/src/hir/mod.rs
@@ -194,8 +194,7 @@ pub fn provide(providers: &mut Providers) {
     };
     providers.fn_arg_names = |tcx, def_id| {
         let hir = tcx.hir();
-        let hir_id = tcx.local_def_id_to_hir_id(def_id);
-        if let Some(body_id) = hir.maybe_body_owned_by(def_id) {
+        if let Some(body_id) = tcx.hir_node_by_def_id(def_id).body_id() {
             tcx.arena.alloc_from_iter(hir.body_param_names(body_id))
         } else if let Node::TraitItem(&TraitItem {
             kind: TraitItemKind::Fn(_, TraitFn::Required(idents)),
@@ -204,11 +203,15 @@ pub fn provide(providers: &mut Providers) {
         | Node::ForeignItem(&ForeignItem {
             kind: ForeignItemKind::Fn(_, idents, _),
             ..
-        }) = tcx.hir_node(hir_id)
+        }) = tcx.hir_node(tcx.local_def_id_to_hir_id(def_id))
         {
             idents
         } else {
-            span_bug!(hir.span(hir_id), "fn_arg_names: unexpected item {:?}", def_id);
+            span_bug!(
+                hir.span(tcx.local_def_id_to_hir_id(def_id)),
+                "fn_arg_names: unexpected item {:?}",
+                def_id
+            );
         }
     };
     providers.all_local_trait_impls = |tcx, ()| &tcx.resolutions(()).trait_impls;