Auto merge of #103902 - vincenzopalazzo:macros/obligation_rulesv2, r=oli-obk

use `LocalDefId` instead of `HirId` in trait resolution to simplify the obligation clause resolution

This commit introduces a refactoring suggested by `@lcnr` to simplify the obligation clause resolution.

This is just the first PR that introduces a type of refactoring, but others PRs will follow this to introduce name changing to change from the variable name from `body_id` to something else.

Fixes https://github.com/rust-lang/rust/issues/104827

Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>

`@rustbot` r? `@lcnr`

2 files changed, 7 insertions, 5 deletions

diff --git a/compiler/rustc_middle/src/traits/mod.rs b/compiler/rustc_middle/src/traits/mod.rs
index d00b26a5a3d..f6fae8ab552 100644
--- a/compiler/rustc_middle/src/traits/mod.rs
+++ b/compiler/rustc_middle/src/traits/mod.rs
@@ -18,7 +18,8 @@ use crate::ty::{self, AdtKind, Ty, TyCtxt};
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{Applicability, Diagnostic};
 use rustc_hir as hir;
-use rustc_hir::def_id::{DefId, LocalDefId};
+use rustc_hir::def_id::DefId;
+use rustc_span::def_id::{LocalDefId, CRATE_DEF_ID};
 use rustc_span::symbol::Symbol;
 use rustc_span::{Span, DUMMY_SP};
 use smallvec::SmallVec;
@@ -99,7 +100,7 @@ pub struct ObligationCause<'tcx> {
     /// (in particular, closures can add new assumptions). See the
     /// field `region_obligations` of the `FulfillmentContext` for more
     /// information.
-    pub body_id: hir::HirId,
+    pub body_id: LocalDefId,
 
     code: InternedObligationCauseCode<'tcx>,
 }
@@ -120,13 +121,13 @@ impl<'tcx> ObligationCause<'tcx> {
     #[inline]
     pub fn new(
         span: Span,
-        body_id: hir::HirId,
+        body_id: LocalDefId,
         code: ObligationCauseCode<'tcx>,
     ) -> ObligationCause<'tcx> {
         ObligationCause { span, body_id, code: code.into() }
     }
 
-    pub fn misc(span: Span, body_id: hir::HirId) -> ObligationCause<'tcx> {
+    pub fn misc(span: Span, body_id: LocalDefId) -> ObligationCause<'tcx> {
         ObligationCause::new(span, body_id, MiscObligation)
     }
 
@@ -137,7 +138,7 @@ impl<'tcx> ObligationCause<'tcx> {
 
     #[inline(always)]
     pub fn dummy_with_span(span: Span) -> ObligationCause<'tcx> {
-        ObligationCause { span, body_id: hir::CRATE_HIR_ID, code: Default::default() }
+        ObligationCause { span, body_id: CRATE_DEF_ID, code: Default::default() }
     }
 
     pub fn span(&self) -> Span {
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index f83bceca3b5..4af29fcbfb5 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -2437,6 +2437,7 @@ impl<'tcx> TyCtxt<'tcx> {
         ident
     }
 
+    // FIXME(vincenzoapalzzo): move the HirId to a LocalDefId
     pub fn adjust_ident_and_get_scope(
         self,
         mut ident: Ident,