Rollup merge of #78710 - petrochenkov:macvisit, r=davidtwco

rustc_ast: Do not panic by default when visiting macro calls

Panicking by default made sense when we didn't have HIR or MIR and everything worked on AST, but now all AST visitors run early and majority of them have to deal with macro calls, often by ignoring them.

The second commit renames `visit_mac` to `visit_mac_call`, the corresponding structures were renamed earlier in https://github.com/rust-lang/rust/pull/69589.

16 files changed, 27 insertions, 85 deletions

diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index 517717eebd9..7b85d28568b 100644
--- a/compiler/rustc_ast/src/mut_visit.rs
+++ b/compiler/rustc_ast/src/mut_visit.rs
@@ -210,11 +210,8 @@ pub trait MutVisitor: Sized {
         noop_visit_local(l, self);
     }
 
-    fn visit_mac(&mut self, _mac: &mut MacCall) {
-        panic!("visit_mac disabled by default");
-        // N.B., see note about macros above. If you really want a visitor that
-        // works on macros, use this definition in your trait impl:
-        //   mut_visit::noop_visit_mac(_mac, self);
+    fn visit_mac_call(&mut self, mac: &mut MacCall) {
+        noop_visit_mac(mac, self);
     }
 
     fn visit_macro_def(&mut self, def: &mut MacroDef) {
@@ -494,7 +491,7 @@ pub fn noop_visit_ty<T: MutVisitor>(ty: &mut P<Ty>, vis: &mut T) {
             vis.visit_id(id);
             visit_vec(bounds, |bound| vis.visit_param_bound(bound));
         }
-        TyKind::MacCall(mac) => vis.visit_mac(mac),
+        TyKind::MacCall(mac) => vis.visit_mac_call(mac),
     }
     vis.visit_span(span);
     visit_lazy_tts(tokens, vis);
@@ -962,7 +959,7 @@ pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
             vis.visit_generics(generics);
             visit_bounds(bounds, vis);
         }
-        ItemKind::MacCall(m) => vis.visit_mac(m),
+        ItemKind::MacCall(m) => vis.visit_mac_call(m),
         ItemKind::MacroDef(def) => vis.visit_macro_def(def),
     }
 }
@@ -991,7 +988,7 @@ pub fn noop_flat_map_assoc_item<T: MutVisitor>(
             visit_bounds(bounds, visitor);
             visit_opt(ty, |ty| visitor.visit_ty(ty));
         }
-        AssocItemKind::MacCall(mac) => visitor.visit_mac(mac),
+        AssocItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
     }
     visitor.visit_span(span);
     visit_lazy_tts(tokens, visitor);
@@ -1081,7 +1078,7 @@ pub fn noop_flat_map_foreign_item<T: MutVisitor>(
             visit_bounds(bounds, visitor);
             visit_opt(ty, |ty| visitor.visit_ty(ty));
         }
-        ForeignItemKind::MacCall(mac) => visitor.visit_mac(mac),
+        ForeignItemKind::MacCall(mac) => visitor.visit_mac_call(mac),
     }
     visitor.visit_span(span);
     visit_lazy_tts(tokens, visitor);
@@ -1121,7 +1118,7 @@ pub fn noop_visit_pat<T: MutVisitor>(pat: &mut P<Pat>, vis: &mut T) {
             visit_vec(elems, |elem| vis.visit_pat(elem))
         }
         PatKind::Paren(inner) => vis.visit_pat(inner),
-        PatKind::MacCall(mac) => vis.visit_mac(mac),
+        PatKind::MacCall(mac) => vis.visit_mac_call(mac),
     }
     vis.visit_span(span);
     visit_lazy_tts(tokens, vis);
@@ -1287,7 +1284,7 @@ pub fn noop_visit_expr<T: MutVisitor>(
             }
             visit_vec(inputs, |(_c, expr)| vis.visit_expr(expr));
         }
-        ExprKind::MacCall(mac) => vis.visit_mac(mac),
+        ExprKind::MacCall(mac) => vis.visit_mac_call(mac),
         ExprKind::Struct(path, fields, expr) => {
             vis.visit_path(path);
             fields.flat_map_in_place(|field| vis.flat_map_field(field));
@@ -1350,7 +1347,7 @@ pub fn noop_flat_map_stmt_kind<T: MutVisitor>(
         StmtKind::Empty => smallvec![StmtKind::Empty],
         StmtKind::MacCall(mut mac) => {
             let MacCallStmt { mac: mac_, style: _, attrs } = mac.deref_mut();
-            vis.visit_mac(mac_);
+            vis.visit_mac_call(mac_);
             visit_thin_attrs(attrs, vis);
             smallvec![StmtKind::MacCall(mac)]
         }
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 2ab6667ac3c..8751f09cfcb 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -176,13 +176,8 @@ pub trait Visitor<'ast>: Sized {
     fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
         walk_lifetime(self, lifetime)
     }
-    fn visit_mac(&mut self, _mac: &'ast MacCall) {
-        panic!("visit_mac disabled by default");
-        // N.B., see note about macros above.
-        // if you really want a visitor that
-        // works on macros, use this
-        // definition in your trait impl:
-        // visit::walk_mac(self, _mac)
+    fn visit_mac_call(&mut self, mac: &'ast MacCall) {
+        walk_mac(self, mac)
     }
     fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
         // Nothing to do
@@ -346,7 +341,7 @@ pub fn walk_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a Item) {
             visitor.visit_generics(generics);
             walk_list!(visitor, visit_param_bound, bounds);
         }
-        ItemKind::MacCall(ref mac) => visitor.visit_mac(mac),
+        ItemKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
         ItemKind::MacroDef(ref ts) => visitor.visit_mac_def(ts, item.id),
     }
     walk_list!(visitor, visit_attribute, &item.attrs);
@@ -414,7 +409,7 @@ pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
         }
         TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
         TyKind::Infer | TyKind::ImplicitSelf | TyKind::Err => {}
-        TyKind::MacCall(ref mac) => visitor.visit_mac(mac),
+        TyKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
         TyKind::Never | TyKind::CVarArgs => {}
     }
 }
@@ -532,7 +527,7 @@ pub fn walk_pat<'a, V: Visitor<'a>>(visitor: &mut V, pattern: &'a Pat) {
         PatKind::Tuple(ref elems) | PatKind::Slice(ref elems) | PatKind::Or(ref elems) => {
             walk_list!(visitor, visit_pat, elems);
         }
-        PatKind::MacCall(ref mac) => visitor.visit_mac(mac),
+        PatKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
     }
 }
 
@@ -557,7 +552,7 @@ pub fn walk_foreign_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a ForeignI
             walk_list!(visitor, visit_ty, ty);
         }
         ForeignItemKind::MacCall(mac) => {
-            visitor.visit_mac(mac);
+            visitor.visit_mac_call(mac);
         }
     }
 }
@@ -662,7 +657,7 @@ pub fn walk_assoc_item<'a, V: Visitor<'a>>(visitor: &mut V, item: &'a AssocItem,
             walk_list!(visitor, visit_ty, ty);
         }
         AssocItemKind::MacCall(mac) => {
-            visitor.visit_mac(mac);
+            visitor.visit_mac_call(mac);
         }
     }
 }
@@ -692,7 +687,7 @@ pub fn walk_stmt<'a, V: Visitor<'a>>(visitor: &mut V, statement: &'a Stmt) {
         StmtKind::Empty => {}
         StmtKind::MacCall(ref mac) => {
             let MacCallStmt { ref mac, style: _, ref attrs } = **mac;
-            visitor.visit_mac(mac);
+            visitor.visit_mac_call(mac);
             for attr in attrs.iter() {
                 visitor.visit_attribute(attr);
             }
@@ -823,7 +818,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
         ExprKind::Ret(ref optional_expression) => {
             walk_list!(visitor, visit_expr, optional_expression);
         }
-        ExprKind::MacCall(ref mac) => visitor.visit_mac(mac),
+        ExprKind::MacCall(ref mac) => visitor.visit_mac_call(mac),
         ExprKind::Paren(ref subexpression) => visitor.visit_expr(subexpression),
         ExprKind::InlineAsm(ref ia) => {
             for (op, _) in &ia.operands {
diff --git a/compiler/rustc_ast_passes/src/node_count.rs b/compiler/rustc_ast_passes/src/node_count.rs
index 706dca2b7f4..6efc78c8842 100644
--- a/compiler/rustc_ast_passes/src/node_count.rs
+++ b/compiler/rustc_ast_passes/src/node_count.rs
@@ -114,9 +114,9 @@ impl<'ast> Visitor<'ast> for NodeCounter {
         self.count += 1;
         walk_lifetime(self, lifetime)
     }
-    fn visit_mac(&mut self, _mac: &MacCall) {
+    fn visit_mac_call(&mut self, mac: &MacCall) {
         self.count += 1;
-        walk_mac(self, _mac)
+        walk_mac(self, mac)
     }
     fn visit_path(&mut self, path: &Path, _id: NodeId) {
         self.count += 1;
diff --git a/compiler/rustc_ast_passes/src/show_span.rs b/compiler/rustc_ast_passes/src/show_span.rs
index 053aba86222..6cef26a13e6 100644
--- a/compiler/rustc_ast_passes/src/show_span.rs
+++ b/compiler/rustc_ast_passes/src/show_span.rs
@@ -54,10 +54,6 @@ impl<'a> Visitor<'a> for ShowSpanVisitor<'a> {
         }
         visit::walk_ty(self, t);
     }
-
-    fn visit_mac(&mut self, mac: &'a ast::MacCall) {
-        visit::walk_mac(self, mac);
-    }
 }
 
 pub fn run(span_diagnostic: &rustc_errors::Handler, mode: &str, krate: &ast::Crate) {
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
index 2e52d2a3923..0642edff6b6 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
@@ -358,7 +358,7 @@ fn find_type_parameters(
             visit::walk_ty(self, ty)
         }
 
-        fn visit_mac(&mut self, mac: &ast::MacCall) {
+        fn visit_mac_call(&mut self, mac: &ast::MacCall) {
             self.cx.span_err(mac.span(), "`derive` cannot be used on items with type macros");
         }
     }
diff --git a/compiler/rustc_builtin_macros/src/proc_macro_harness.rs b/compiler/rustc_builtin_macros/src/proc_macro_harness.rs
index c6ab3faf568..4e91436199a 100644
--- a/compiler/rustc_builtin_macros/src/proc_macro_harness.rs
+++ b/compiler/rustc_builtin_macros/src/proc_macro_harness.rs
@@ -344,10 +344,6 @@ impl<'a> Visitor<'a> for CollectProcMacros<'a> {
         visit::walk_item(self, item);
         self.in_root = prev_in_root;
     }
-
-    fn visit_mac(&mut self, mac: &'a ast::MacCall) {
-        visit::walk_mac(self, mac)
-    }
 }
 
 // Creates a new module which looks like:
diff --git a/compiler/rustc_builtin_macros/src/test_harness.rs b/compiler/rustc_builtin_macros/src/test_harness.rs
index da74f0aeaa1..e68b626e22d 100644
--- a/compiler/rustc_builtin_macros/src/test_harness.rs
+++ b/compiler/rustc_builtin_macros/src/test_harness.rs
@@ -130,10 +130,6 @@ impl<'a> MutVisitor for TestHarnessGenerator<'a> {
         }
         smallvec![P(item)]
     }
-
-    fn visit_mac(&mut self, _mac: &mut ast::MacCall) {
-        // Do nothing.
-    }
 }
 
 // Beware, this is duplicated in librustc_passes/entry.rs (with
@@ -201,10 +197,6 @@ impl<'a> MutVisitor for EntryPointCleaner<'a> {
 
         smallvec![item]
     }
-
-    fn visit_mac(&mut self, _mac: &mut ast::MacCall) {
-        // Do nothing.
-    }
 }
 
 /// Crawl over the crate, inserting test reexports and the test main function
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index c124ab64218..a07dd8ede8b 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -547,11 +547,6 @@ impl<'a> MutVisitor for StripUnconfigured<'a> {
         noop_flat_map_assoc_item(configure!(self, item), self)
     }
 
-    fn visit_mac(&mut self, _mac: &mut ast::MacCall) {
-        // Don't configure interpolated AST (cf. issue #34171).
-        // Interpolated AST will get configured once the surrounding tokens are parsed.
-    }
-
     fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
         self.configure_pat(pat);
         noop_visit_pat(pat, self)
diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
index f6959591b56..8c7a4f06838 100644
--- a/compiler/rustc_expand/src/expand.rs
+++ b/compiler/rustc_expand/src/expand.rs
@@ -850,8 +850,6 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
 
                 visit::walk_item(self, item);
             }
-
-            fn visit_mac(&mut self, _: &'ast ast::MacCall) {}
         }
 
         if !self.cx.ecfg.proc_macro_hygiene() {
diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs
index 629e0e702b6..dde65d998d8 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/compiler/rustc_expand/src/mbe/transcribe.rs
@@ -5,7 +5,6 @@ use crate::mbe::macro_parser::{MatchedNonterminal, MatchedSeq, NamedMatch};
 use rustc_ast::mut_visit::{self, MutVisitor};
 use rustc_ast::token::{self, NtTT, Token};
 use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree, TreeAndSpacing};
-use rustc_ast::MacCall;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
 use rustc_errors::{pluralize, PResult};
@@ -27,10 +26,6 @@ impl MutVisitor for Marker {
     fn visit_span(&mut self, span: &mut Span) {
         *span = span.apply_mark(self.0, self.1)
     }
-
-    fn visit_mac(&mut self, mac: &mut MacCall) {
-        mut_visit::noop_visit_mac(mac, self)
-    }
 }
 
 /// An iterator over the token trees in a delimited token tree (`{ ... }`) or a sequence (`$(...)`).
diff --git a/compiler/rustc_expand/src/mut_visit/tests.rs b/compiler/rustc_expand/src/mut_visit/tests.rs
index 9e65fc2eca7..be0300bad98 100644
--- a/compiler/rustc_expand/src/mut_visit/tests.rs
+++ b/compiler/rustc_expand/src/mut_visit/tests.rs
@@ -1,7 +1,7 @@
 use crate::tests::{matches_codepattern, string_to_crate};
 
 use rustc_ast as ast;
-use rustc_ast::mut_visit::{self, MutVisitor};
+use rustc_ast::mut_visit::MutVisitor;
 use rustc_ast_pretty::pprust;
 use rustc_span::symbol::Ident;
 use rustc_span::with_default_session_globals;
@@ -21,9 +21,6 @@ impl MutVisitor for ToZzIdentMutVisitor {
     fn visit_ident(&mut self, ident: &mut Ident) {
         *ident = Ident::from_str("zz");
     }
-    fn visit_mac(&mut self, mac: &mut ast::MacCall) {
-        mut_visit::noop_visit_mac(mac, self)
-    }
 }
 
 // Maybe add to `expand.rs`.
diff --git a/compiler/rustc_expand/src/placeholders.rs b/compiler/rustc_expand/src/placeholders.rs
index e413564fb3f..f0e5826f403 100644
--- a/compiler/rustc_expand/src/placeholders.rs
+++ b/compiler/rustc_expand/src/placeholders.rs
@@ -385,8 +385,4 @@ impl<'a, 'b> MutVisitor for PlaceholderExpander<'a, 'b> {
             |item| !matches!(item.kind, ast::ItemKind::MacCall(_) if !self.cx.ecfg.keep_macs),
         );
     }
-
-    fn visit_mac(&mut self, _mac: &mut ast::MacCall) {
-        // Do nothing.
-    }
 }
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index 3ed7d20ae45..d9ec6d51cdf 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -880,12 +880,6 @@ impl<'a> MutVisitor for ReplaceBodyWithLoop<'a, '_> {
             })
         }
     }
-
-    // in general the pretty printer processes unexpanded code, so
-    // we override the default `visit_mac` method which panics.
-    fn visit_mac(&mut self, mac: &mut ast::MacCall) {
-        noop_visit_mac(mac, self)
-    }
 }
 
 /// Returns a version string such as "rustc 1.46.0 (04488afe3 2020-08-24)"
diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
index 9aeeb627792..08c147ec3ac 100644
--- a/compiler/rustc_lint/src/early.rs
+++ b/compiler/rustc_lint/src/early.rs
@@ -270,15 +270,9 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
         self.check_id(id);
     }
 
-    fn visit_mac(&mut self, mac: &'a ast::MacCall) {
-        // FIXME(#54110): So, this setup isn't really right. I think
-        // that (a) the librustc_ast visitor ought to be doing this as
-        // part of `walk_mac`, and (b) we should be calling
-        // `visit_path`, *but* that would require a `NodeId`, and I
-        // want to get #53686 fixed quickly. -nmatsakis
-        ast_visit::walk_path(self, &mac.path);
-
+    fn visit_mac_call(&mut self, mac: &'a ast::MacCall) {
         run_early_pass!(self, check_mac, mac);
+        ast_visit::walk_mac(self, mac);
     }
 }
 
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 196790a0ab3..ee9a6dca5ad 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/compiler/rustc_parse/src/parser/pat.rs
@@ -1,6 +1,6 @@
 use super::{Parser, PathStyle};
 use crate::{maybe_recover_from_interpolated_ty_qpath, maybe_whole};
-use rustc_ast::mut_visit::{noop_visit_mac, noop_visit_pat, MutVisitor};
+use rustc_ast::mut_visit::{noop_visit_pat, MutVisitor};
 use rustc_ast::ptr::P;
 use rustc_ast::token;
 use rustc_ast::{self as ast, AttrVec, Attribute, FieldPat, MacCall, Pat, PatKind, RangeEnd};
@@ -570,10 +570,6 @@ impl<'a> Parser<'a> {
     fn make_all_value_bindings_mutable(pat: &mut P<Pat>) -> bool {
         struct AddMut(bool);
         impl MutVisitor for AddMut {
-            fn visit_mac(&mut self, mac: &mut MacCall) {
-                noop_visit_mac(mac, self);
-            }
-
             fn visit_pat(&mut self, pat: &mut P<Pat>) {
                 if let PatKind::Ident(BindingMode::ByValue(m @ Mutability::Not), ..) = &mut pat.kind
                 {
diff --git a/compiler/rustc_passes/src/hir_stats.rs b/compiler/rustc_passes/src/hir_stats.rs
index 9537321026e..1d02c9aa637 100644
--- a/compiler/rustc_passes/src/hir_stats.rs
+++ b/compiler/rustc_passes/src/hir_stats.rs
@@ -336,8 +336,9 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
         ast_visit::walk_lifetime(self, lifetime)
     }
 
-    fn visit_mac(&mut self, mac: &'v ast::MacCall) {
+    fn visit_mac_call(&mut self, mac: &'v ast::MacCall) {
         self.record("MacCall", Id::None, mac);
+        ast_visit::walk_mac(self, mac)
     }
 
     fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v ast::PathSegment) {