Auto merge of #28715 - petrochenkov:visit, r=nrc

Some minor parts of AST and HIR were not visited by the `visit::walk_xxx` methods - some identifiers, lifetimes, loop labels, attributes of exported macros - but nothing as serious as in, for example, #28364.
\+ Added a convenience macro for visiting lists (including Options)
\+ Removed some pre-Deref-coersions `&**` noise from visitors

r? @nrc

src/librustc/front/map/mod.rs

@@ -912,12 +912,12 @@ impl<'ast> Visitor<'ast> for NodeCollector<'ast> {
         self.parent_node = parent_node;
     }
 
-    fn visit_lifetime_ref(&mut self, lifetime: &'ast Lifetime) {
+    fn visit_lifetime(&mut self, lifetime: &'ast Lifetime) {
         self.insert(lifetime.id, NodeLifetime(lifetime));
     }
 
     fn visit_lifetime_def(&mut self, def: &'ast LifetimeDef) {
-        self.visit_lifetime_ref(&def.lifetime);
+        self.visit_lifetime(&def.lifetime);
     }
 }
 

src/librustc/lint/context.rs

@@ -745,12 +745,8 @@ impl<'a, 'tcx, 'v> hir_visit::Visitor<'v> for LateContext<'a, 'tcx> {
         });
     }
 
-    fn visit_opt_lifetime_ref(&mut self, sp: Span, lt: &Option<hir::Lifetime>) {
-        run_lints!(self, check_opt_lifetime_ref, late_passes, sp, lt);
-    }
-
-    fn visit_lifetime_ref(&mut self, lt: &hir::Lifetime) {
-        run_lints!(self, check_lifetime_ref, late_passes, lt);
+    fn visit_lifetime(&mut self, lt: &hir::Lifetime) {
+        run_lints!(self, check_lifetime, late_passes, lt);
     }
 
     fn visit_lifetime_def(&mut self, lt: &hir::LifetimeDef) {
@@ -898,12 +894,8 @@ impl<'a, 'v> ast_visit::Visitor<'v> for EarlyContext<'a> {
         });
     }
 
-    fn visit_opt_lifetime_ref(&mut self, sp: Span, lt: &Option<ast::Lifetime>) {
-        run_lints!(self, check_opt_lifetime_ref, early_passes, sp, lt);
-    }
-
-    fn visit_lifetime_ref(&mut self, lt: &ast::Lifetime) {
-        run_lints!(self, check_lifetime_ref, early_passes, lt);
+    fn visit_lifetime(&mut self, lt: &ast::Lifetime) {
+        run_lints!(self, check_lifetime, early_passes, lt);
     }
 
     fn visit_lifetime_def(&mut self, lt: &ast::LifetimeDef) {

src/librustc/lint/mod.rs

@@ -156,8 +156,7 @@ pub trait LateLintPass: LintPass {
     fn check_struct_field(&mut self, _: &LateContext, _: &hir::StructField) { }
     fn check_variant(&mut self, _: &LateContext, _: &hir::Variant, _: &hir::Generics) { }
     fn check_variant_post(&mut self, _: &LateContext, _: &hir::Variant, _: &hir::Generics) { }
-    fn check_opt_lifetime_ref(&mut self, _: &LateContext, _: Span, _: &Option<hir::Lifetime>) { }
-    fn check_lifetime_ref(&mut self, _: &LateContext, _: &hir::Lifetime) { }
+    fn check_lifetime(&mut self, _: &LateContext, _: &hir::Lifetime) { }
     fn check_lifetime_def(&mut self, _: &LateContext, _: &hir::LifetimeDef) { }
     fn check_explicit_self(&mut self, _: &LateContext, _: &hir::ExplicitSelf) { }
     fn check_path(&mut self, _: &LateContext, _: &hir::Path, _: ast::NodeId) { }
@@ -199,11 +198,7 @@ pub trait EarlyLintPass: LintPass {
     fn check_struct_field(&mut self, _: &EarlyContext, _: &ast::StructField) { }
     fn check_variant(&mut self, _: &EarlyContext, _: &ast::Variant, _: &ast::Generics) { }
     fn check_variant_post(&mut self, _: &EarlyContext, _: &ast::Variant, _: &ast::Generics) { }
-    fn check_opt_lifetime_ref(&mut self,
-                              _: &EarlyContext,
-                              _: Span,
-                              _: &Option<ast::Lifetime>) { }
-    fn check_lifetime_ref(&mut self, _: &EarlyContext, _: &ast::Lifetime) { }
+    fn check_lifetime(&mut self, _: &EarlyContext, _: &ast::Lifetime) { }
     fn check_lifetime_def(&mut self, _: &EarlyContext, _: &ast::LifetimeDef) { }
     fn check_explicit_self(&mut self, _: &EarlyContext, _: &ast::ExplicitSelf) { }
     fn check_path(&mut self, _: &EarlyContext, _: &ast::Path, _: ast::NodeId) { }

src/librustc/metadata/creader.rs

@@ -481,6 +481,12 @@ impl<'a> CrateReader<'a> {
                 };
                 let span = mk_sp(lo, p.last_span.hi);
                 p.abort_if_errors();
+
+                // Mark the attrs as used
+                for attr in &attrs {
+                    attr::mark_used(attr);
+                }
+
                 macros.push(ast::MacroDef {
                     ident: ast::Ident::with_empty_ctxt(name),
                     attrs: attrs,

src/librustc/middle/region.rs

@@ -705,7 +705,7 @@ fn resolve_block(visitor: &mut RegionResolutionVisitor, blk: &hir::Block) {
             }
             visitor.visit_stmt(&**statement)
         }
-        visit::walk_expr_opt(visitor, &blk.expr)
+        walk_list!(visitor, visit_expr, &blk.expr);
     }
 
     visitor.cx = prev_cx;

src/librustc/middle/resolve_lifetime.rs

@@ -195,7 +195,6 @@ impl<'a, 'v> Visitor<'v> for LifetimeContext<'a> {
     fn visit_ty(&mut self, ty: &hir::Ty) {
         match ty.node {
             hir::TyBareFn(ref c) => {
-                visit::walk_lifetime_decls_helper(self, &c.lifetimes);
                 self.with(LateScope(&c.lifetimes, self.scope), |old_scope, this| {
                     // a bare fn has no bounds, so everything
                     // contained within is scoped within its binder.
@@ -245,7 +244,7 @@ impl<'a, 'v> Visitor<'v> for LifetimeContext<'a> {
                   |_, this| visit::walk_block(this, b));
     }
 
-    fn visit_lifetime_ref(&mut self, lifetime_ref: &hir::Lifetime) {
+    fn visit_lifetime(&mut self, lifetime_ref: &hir::Lifetime) {
         if lifetime_ref.name == special_idents::static_lifetime.name {
             self.insert_lifetime(lifetime_ref, DefStaticRegion);
             return;
@@ -255,7 +254,7 @@ impl<'a, 'v> Visitor<'v> for LifetimeContext<'a> {
 
     fn visit_generics(&mut self, generics: &hir::Generics) {
         for ty_param in generics.ty_params.iter() {
-            visit::walk_ty_param_bounds_helper(self, &ty_param.bounds);
+            walk_list!(self, visit_ty_param_bound, &ty_param.bounds);
             match ty_param.default {
                 Some(ref ty) => self.visit_ty(&**ty),
                 None => {}
@@ -273,22 +272,22 @@ impl<'a, 'v> Visitor<'v> for LifetimeContext<'a> {
                                                |old_scope, this| {
                             this.check_lifetime_defs(old_scope, bound_lifetimes);
                             this.visit_ty(&**bounded_ty);
-                            visit::walk_ty_param_bounds_helper(this, bounds);
+                            walk_list!(this, visit_ty_param_bound, bounds);
                         });
                         self.trait_ref_hack = false;
                         result
                     } else {
                         self.visit_ty(&**bounded_ty);
-                        visit::walk_ty_param_bounds_helper(self, bounds);
+                        walk_list!(self, visit_ty_param_bound, bounds);
                     }
                 }
                 &hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate{ref lifetime,
                                                                                 ref bounds,
                                                                                 .. }) => {
 
-                    self.visit_lifetime_ref(lifetime);
+                    self.visit_lifetime(lifetime);
                     for bound in bounds {
-                        self.visit_lifetime_ref(bound);
+                        self.visit_lifetime(bound);
                     }
                 }
                 &hir::WherePredicate::EqPredicate(hir::WhereEqPredicate{ id,
@@ -799,23 +798,23 @@ fn early_bound_lifetime_names(generics: &hir::Generics) -> Vec<ast::Name> {
             FreeLifetimeCollector { early_bound: &mut early_bound,
                                     late_bound: &mut late_bound };
         for ty_param in generics.ty_params.iter() {
-            visit::walk_ty_param_bounds_helper(&mut collector, &ty_param.bounds);
+            walk_list!(&mut collector, visit_ty_param_bound, &ty_param.bounds);
         }
         for predicate in &generics.where_clause.predicates {
             match predicate {
                 &hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate{ref bounds,
                                                                               ref bounded_ty,
                                                                               ..}) => {
                     collector.visit_ty(&**bounded_ty);
-                    visit::walk_ty_param_bounds_helper(&mut collector, bounds);
+                    walk_list!(&mut collector, visit_ty_param_bound, bounds);
                 }
                 &hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate{ref lifetime,
                                                                                 ref bounds,
                                                                                 ..}) => {
-                    collector.visit_lifetime_ref(lifetime);
+                    collector.visit_lifetime(lifetime);
 
                     for bound in bounds {
-                        collector.visit_lifetime_ref(bound);
+                        collector.visit_lifetime(bound);
                     }
                 }
                 &hir::WherePredicate::EqPredicate(_) => unimplemented!()
@@ -843,7 +842,7 @@ fn early_bound_lifetime_names(generics: &hir::Generics) -> Vec<ast::Name> {
     }
 
     impl<'a, 'v> Visitor<'v> for FreeLifetimeCollector<'a> {
-        fn visit_lifetime_ref(&mut self, lifetime_ref: &hir::Lifetime) {
+        fn visit_lifetime(&mut self, lifetime_ref: &hir::Lifetime) {
             shuffle(self.early_bound, self.late_bound,
                     lifetime_ref.name);
         }

src/librustc_back/svh.rs

@@ -177,7 +177,7 @@ mod svh_visitor {
         SawIdent(token::InternedString),
         SawStructDef(token::InternedString),
 
-        SawLifetimeRef(token::InternedString),
+        SawLifetime(token::InternedString),
         SawLifetimeDef(token::InternedString),
 
         SawMod,
@@ -193,7 +193,6 @@ mod svh_visitor {
         SawVariant,
         SawExplicitSelf,
         SawPath,
-        SawOptLifetimeRef,
         SawBlock,
         SawPat,
         SawLocal,
@@ -316,17 +315,6 @@ mod svh_visitor {
             visit::walk_variant(self, v, g)
         }
 
-        fn visit_opt_lifetime_ref(&mut self, _: Span, l: &Option<Lifetime>) {
-            SawOptLifetimeRef.hash(self.st);
-            // (This is a strange method in the visitor trait, in that
-            // it does not expose a walk function to do the subroutine
-            // calls.)
-            match *l {
-                Some(ref l) => self.visit_lifetime_ref(l),
-                None => ()
-            }
-        }
-
         // All of the remaining methods just record (in the hash
         // SipHasher) that the visitor saw that particular variant
         // (with its payload), and continue walking as the default
@@ -345,8 +333,8 @@ mod svh_visitor {
             SawIdent(name.as_str()).hash(self.st);
         }
 
-        fn visit_lifetime_ref(&mut self, l: &Lifetime) {
-            SawLifetimeRef(l.name.as_str()).hash(self.st);
+        fn visit_lifetime(&mut self, l: &Lifetime) {
+            SawLifetime(l.name.as_str()).hash(self.st);
         }
 
         fn visit_lifetime_def(&mut self, l: &LifetimeDef) {

src/librustc_front/hir.rs

@@ -1054,6 +1054,13 @@ impl PathListItem_ {
         }
     }
 
+    pub fn name(&self) -> Option<Name> {
+        match *self {
+            PathListIdent { name, .. } => Some(name),
+            PathListMod { .. } => None,
+        }
+    }
+
     pub fn rename(&self) -> Option<Name> {
         match *self {
             PathListIdent { rename, .. } | PathListMod { rename, .. } => rename

src/librustc_front/util.rs

@@ -303,12 +303,12 @@ impl<'a, 'v, O: ast_util::IdVisitingOperation> Visitor<'v> for IdVisitor<'a, O>
         visit::walk_impl_item(self, ii);
     }
 
-    fn visit_lifetime_ref(&mut self, lifetime: &Lifetime) {
+    fn visit_lifetime(&mut self, lifetime: &Lifetime) {
         self.operation.visit_id(lifetime.id);
     }
 
     fn visit_lifetime_def(&mut self, def: &LifetimeDef) {
-        self.visit_lifetime_ref(&def.lifetime);
+        self.visit_lifetime(&def.lifetime);
     }
 
     fn visit_trait_ref(&mut self, trait_ref: &TraitRef) {