rustc_ast: Do not panic by default when visiting macro calls

Author: petrochenkov

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(&mut self, mac: &mut MacCall) {
+        noop_visit_mac(mac, self);
     }
 
     fn visit_macro_def(&mut self, def: &mut MacroDef) {

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(&mut self, mac: &'ast MacCall) {
+        walk_mac(self, mac)
     }
     fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
         // Nothing to do

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(&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;

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) {

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:

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

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)

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() {

compiler/rustc_expand/src/mbe/transcribe.rs

@@ -27,10 +27,6 @@ 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 (`$(...)`).

compiler/rustc_expand/src/mut_visit/tests.rs

@@ -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`.

compiler/rustc_expand/src/placeholders.rs

@@ -386,8 +386,4 @@ 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.
-    }
 }

compiler/rustc_interface/src/util.rs

@@ -881,12 +881,6 @@ 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)"

compiler/rustc_lint/src/early.rs

@@ -271,14 +271,8 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
     }
 
     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);
-
         run_early_pass!(self, check_mac, mac);
+        ast_visit::walk_mac(self, mac);
     }
 }
 

compiler/rustc_parse/src/parser/pat.rs

@@ -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
                 {

compiler/rustc_passes/src/hir_stats.rs

@@ -338,6 +338,7 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
 
     fn visit_mac(&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) {

src/tools/clippy/clippy_lints/src/non_expressive_names.rs

@@ -149,9 +149,6 @@ impl<'a, 'tcx, 'b> Visitor<'tcx> for SimilarNamesNameVisitor<'a, 'tcx, 'b> {
             _ => walk_pat(self, pat),
         }
     }
-    fn visit_mac(&mut self, _mac: &MacCall) {
-        // do not check macs
-    }
 }
 
 #[must_use]
@@ -356,9 +353,6 @@ impl<'a, 'tcx> Visitor<'tcx> for SimilarNamesLocalVisitor<'a, 'tcx> {
     fn visit_item(&mut self, _: &Item) {
         // do not recurse into inner items
     }
-    fn visit_mac(&mut self, _mac: &MacCall) {
-        // do not check macs
-    }
 }
 
 impl EarlyLintPass for NonExpressiveNames {