Auto merge of #120393 - Urgau:rfc3373-non-local-defs, r=WaffleLapkin

Implement RFC 3373: Avoid non-local definitions in functions

This PR implements [RFC 3373: Avoid non-local definitions in functions](#120363).

Author: bors

Cargo.lock

@@ -4101,6 +4101,7 @@ dependencies = [
  "rustc_target",
  "rustc_trait_selection",
  "rustc_type_ir",
+ "smallvec",
  "tracing",
  "unicode-security",
 ]

compiler/rustc_hir_analysis/src/coherence/inherent_impls_overlap.rs

@@ -24,6 +24,11 @@ struct InherentOverlapChecker<'tcx> {
     tcx: TyCtxt<'tcx>,
 }
 
+rustc_index::newtype_index! {
+    #[orderable]
+    pub struct RegionId {}
+}
+
 impl<'tcx> InherentOverlapChecker<'tcx> {
     /// Checks whether any associated items in impls 1 and 2 share the same identifier and
     /// namespace.
@@ -205,11 +210,6 @@ impl<'tcx> InherentOverlapChecker<'tcx> {
             // This is advantageous to running the algorithm over the
             // entire graph when there are many connected regions.
 
-            rustc_index::newtype_index! {
-                #[orderable]
-                pub struct RegionId {}
-            }
-
             struct ConnectedRegion {
                 idents: SmallVec<[Symbol; 8]>,
                 impl_blocks: FxHashSet<usize>,