delegation: Fix hygiene for `self`

And fix diagnostics for `self` from a macro.

2 files changed, 28 insertions, 20 deletions

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index b0adc3775f6..fa711d932b6 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -3281,17 +3281,19 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
         }
         self.visit_path(&delegation.path, delegation.id);
         if let Some(body) = &delegation.body {
-            // `PatBoundCtx` is not necessary in this context
-            let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
-
-            let span = delegation.path.segments.last().unwrap().ident.span;
-            self.fresh_binding(
-                Ident::new(kw::SelfLower, span),
-                delegation.id,
-                PatternSource::FnParam,
-                &mut bindings,
-            );
-            self.visit_block(body);
+            self.with_rib(ValueNS, RibKind::FnOrCoroutine, |this| {
+                // `PatBoundCtx` is not necessary in this context
+                let mut bindings = smallvec![(PatBoundCtx::Product, Default::default())];
+
+                let span = delegation.path.segments.last().unwrap().ident.span;
+                this.fresh_binding(
+                    Ident::new(kw::SelfLower, span),
+                    delegation.id,
+                    PatternSource::FnParam,
+                    &mut bindings,
+                );
+                this.visit_block(body);
+            });
         }
     }
 
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index 9eeb0da7ed2..be24755d4c5 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -1021,12 +1021,14 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
             },
         );
         let is_assoc_fn = self.self_type_is_available();
+        let self_from_macro = "a `self` parameter, but a macro invocation can only \
+                               access identifiers it receives from parameters";
         if let Some((fn_kind, span)) = &self.diag_metadata.current_function {
             // The current function has a `self` parameter, but we were unable to resolve
             // a reference to `self`. This can only happen if the `self` identifier we
             // are resolving came from a different hygiene context.
             if fn_kind.decl().inputs.get(0).is_some_and(|p| p.is_self()) {
-                err.span_label(*span, "this function has a `self` parameter, but a macro invocation can only access identifiers it receives from parameters");
+                err.span_label(*span, format!("this function has {self_from_macro}"));
             } else {
                 let doesnt = if is_assoc_fn {
                     let (span, sugg) = fn_kind
@@ -1068,14 +1070,18 @@ impl<'a: 'ast, 'ast, 'tcx> LateResolutionVisitor<'a, '_, 'ast, 'tcx> {
                 }
             }
         } else if let Some(item_kind) = self.diag_metadata.current_item {
-            err.span_label(
-                item_kind.ident.span,
-                format!(
-                    "`self` not allowed in {} {}",
-                    item_kind.kind.article(),
-                    item_kind.kind.descr()
-                ),
-            );
+            if matches!(item_kind.kind, ItemKind::Delegation(..)) {
+                err.span_label(item_kind.span, format!("delegation supports {self_from_macro}"));
+            } else {
+                err.span_label(
+                    item_kind.ident.span,
+                    format!(
+                        "`self` not allowed in {} {}",
+                        item_kind.kind.article(),
+                        item_kind.kind.descr()
+                    ),
+                );
+            }
         }
         true
     }