From 3237b3886c8d1bd19b78eda6040e2c55e5332a82 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Tue, 3 Nov 2020 20:26:17 +0300
Subject: [PATCH] rustc_ast: Do not panic by default when visiting macro calls

---
 compiler/rustc_ast/src/mut_visit.rs                      | 7 ++-----
 compiler/rustc_ast/src/visit.rs                          | 9 ++-------
 compiler/rustc_ast_passes/src/node_count.rs              | 4 ++--
 compiler/rustc_ast_passes/src/show_span.rs               | 4 ----
 compiler/rustc_builtin_macros/src/proc_macro_harness.rs  | 4 ----
 compiler/rustc_builtin_macros/src/test_harness.rs        | 8 --------
 compiler/rustc_expand/src/config.rs                      | 5 -----
 compiler/rustc_expand/src/expand.rs                      | 2 --
 compiler/rustc_expand/src/mbe/transcribe.rs              | 4 ----
 compiler/rustc_expand/src/mut_visit/tests.rs             | 3 ---
 compiler/rustc_expand/src/placeholders.rs                | 4 ----
 compiler/rustc_interface/src/util.rs                     | 6 ------
 compiler/rustc_lint/src/early.rs                         | 8 +-------
 compiler/rustc_parse/src/parser/pat.rs                   | 4 ----
 compiler/rustc_passes/src/hir_stats.rs                   | 1 +
 .../clippy/clippy_lints/src/non_expressive_names.rs      | 6 ------
 16 files changed, 8 insertions(+), 71 deletions(-)

diff --git a/compiler/rustc_ast/src/mut_visit.rs b/compiler/rustc_ast/src/mut_visit.rs
index fe9ad58c9ac..d99337ee06e 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(&mut self, mac: &mut MacCall) {
+        noop_visit_mac(mac, self);
     }
 
     fn visit_macro_def(&mut self, def: &mut MacroDef) {
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 2ab6667ac3c..1b8026bf439 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(&mut self, mac: &'ast MacCall) {
+        walk_mac(self, mac)
     }
     fn visit_mac_def(&mut self, _mac: &'ast MacroDef, _id: NodeId) {
         // Nothing to do
diff --git a/compiler/rustc_ast_passes/src/node_count.rs b/compiler/rustc_ast_passes/src/node_count.rs
index 706dca2b7f4..773b81d771c 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(&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/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 3e5762ab992..9ac3550d223 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..70eb7e22835 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/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 (`$(...)`).
diff --git a/compiler/rustc_expand/src/mut_visit/tests.rs b/compiler/rustc_expand/src/mut_visit/tests.rs
index 9e65fc2eca7..568618fa8df 100644
--- a/compiler/rustc_expand/src/mut_visit/tests.rs
+++ b/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`.
diff --git a/compiler/rustc_expand/src/placeholders.rs b/compiler/rustc_expand/src/placeholders.rs
index 0cffca17271..552a4c899dd 100644
--- a/compiler/rustc_expand/src/placeholders.rs
+++ b/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.
-    }
 }
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index 46a6c5861d5..f406578f997 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/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)"
diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
index 9aeeb627792..ba5b60bd535 100644
--- a/compiler/rustc_lint/src/early.rs
+++ b/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);
     }
 }
 
diff --git a/compiler/rustc_parse/src/parser/pat.rs b/compiler/rustc_parse/src/parser/pat.rs
index 196790a0ab3..c06b012d8c0 100644
--- a/compiler/rustc_parse/src/parser/pat.rs
+++ b/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
                 {
diff --git a/compiler/rustc_passes/src/hir_stats.rs b/compiler/rustc_passes/src/hir_stats.rs
index 9537321026e..697b48718b2 100644
--- a/compiler/rustc_passes/src/hir_stats.rs
+++ b/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) {
diff --git a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs b/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
index 603440c0f83..6b56380edf8 100644
--- a/src/tools/clippy/clippy_lints/src/non_expressive_names.rs
+++ b/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 {