Switch to a bitflags `MacroKinds` to support macros with more than one kind

Review everything that uses `MacroKind`, and switch anything that could
refer to more than one kind to use `MacroKinds`.

Add a new `SyntaxExtensionKind::MacroRules` for `macro_rules!` macros,
using the concrete `MacroRulesMacroExpander` type, and have it track
which kinds it can handle. Eliminate the separate optional `attr_ext`,
now that a `SyntaxExtension` can handle multiple macro kinds.

This also avoids the need to downcast when calling methods on
`MacroRulesMacroExpander`, such as `get_unused_rule`.

Integrate macro kind checking into name resolution's
`sub_namespace_match`, so that we only find a macro if it's the right
type, and eliminate the special-case hack for attributes.

1 files changed, 4 insertions, 5 deletions

diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index aca251da71d..c8cab5a0fe9 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -19,14 +19,13 @@ use rustc_errors::{
 };
 use rustc_hir as hir;
 use rustc_hir::def::Namespace::{self, *};
-use rustc_hir::def::{self, CtorKind, CtorOf, DefKind};
+use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, MacroKinds};
 use rustc_hir::def_id::{CRATE_DEF_ID, DefId};
 use rustc_hir::{MissingLifetimeKind, PrimTy};
 use rustc_middle::ty;
 use rustc_session::{Session, lint};
 use rustc_span::edit_distance::{edit_distance, find_best_match_for_name};
 use rustc_span::edition::Edition;
-use rustc_span::hygiene::MacroKind;
 use rustc_span::{DUMMY_SP, Ident, Span, Symbol, kw, sym};
 use thin_vec::ThinVec;
 use tracing::debug;
@@ -1850,12 +1849,12 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
 
         match (res, source) {
             (
-                Res::Def(DefKind::Macro(MacroKind::Bang), def_id),
+                Res::Def(DefKind::Macro(kinds), def_id),
                 PathSource::Expr(Some(Expr {
                     kind: ExprKind::Index(..) | ExprKind::Call(..), ..
                 }))
                 | PathSource::Struct(_),
-            ) => {
+            ) if kinds.contains(MacroKinds::BANG) => {
                 // Don't suggest macro if it's unstable.
                 let suggestable = def_id.is_local()
                     || self.r.tcx.lookup_stability(def_id).is_none_or(|s| s.is_stable());
@@ -1880,7 +1879,7 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                     err.note("if you want the `try` keyword, you need Rust 2018 or later");
                 }
             }
-            (Res::Def(DefKind::Macro(MacroKind::Bang), _), _) => {
+            (Res::Def(DefKind::Macro(kinds), _), _) if kinds.contains(MacroKinds::BANG) => {
                 err.span_label(span, fallback_label.to_string());
             }
             (Res::Def(DefKind::TyAlias, def_id), PathSource::Trait(_)) => {