Remove path_span argument to the visit_path_segment methods.

The `visit_path_segment` method of both the AST and HIR visitors has a
`path_span` argument that isn't necessary. This commit removes it.

There are two very small and inconsequential functional changes.

- One call to `NodeCollector::insert` now is passed a path segment
  identifier span instead of a full path span. This span is only used in
a panic message printed in the case of an internal compiler bug.

- Likewise, one call to `LifetimeCollectVisitor::record_elided_anchor`
  now uses a path segment identifier span instead of a full path span.
  This span is used to make some `'_` lifetimes.

Author: nnethercote

compiler/rustc_ast/src/visit.rs

@@ -201,11 +201,11 @@ pub trait Visitor<'ast>: Sized {
     fn visit_use_tree(&mut self, use_tree: &'ast UseTree, id: NodeId, _nested: bool) {
         walk_use_tree(self, use_tree, id)
     }
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
-        walk_path_segment(self, path_span, path_segment)
+    fn visit_path_segment(&mut self, path_segment: &'ast PathSegment) {
+        walk_path_segment(self, path_segment)
     }
-    fn visit_generic_args(&mut self, path_span: Span, generic_args: &'ast GenericArgs) {
-        walk_generic_args(self, path_span, generic_args)
+    fn visit_generic_args(&mut self, generic_args: &'ast GenericArgs) {
+        walk_generic_args(self, generic_args)
     }
     fn visit_generic_arg(&mut self, generic_arg: &'ast GenericArg) {
         walk_generic_arg(self, generic_arg)
@@ -435,7 +435,7 @@ pub fn walk_ty<'a, V: Visitor<'a>>(visitor: &mut V, typ: &'a Ty) {
 
 pub fn walk_path<'a, V: Visitor<'a>>(visitor: &mut V, path: &'a Path) {
     for segment in &path.segments {
-        visitor.visit_path_segment(path.span, segment);
+        visitor.visit_path_segment(segment);
     }
 }
 
@@ -457,18 +457,14 @@ pub fn walk_use_tree<'a, V: Visitor<'a>>(visitor: &mut V, use_tree: &'a UseTree,
     }
 }
 
-pub fn walk_path_segment<'a, V: Visitor<'a>>(
-    visitor: &mut V,
-    path_span: Span,
-    segment: &'a PathSegment,
-) {
+pub fn walk_path_segment<'a, V: Visitor<'a>>(visitor: &mut V, segment: &'a PathSegment) {
     visitor.visit_ident(segment.ident);
     if let Some(ref args) = segment.args {
-        visitor.visit_generic_args(path_span, args);
+        visitor.visit_generic_args(args);
     }
 }
 
-pub fn walk_generic_args<'a, V>(visitor: &mut V, _path_span: Span, generic_args: &'a GenericArgs)
+pub fn walk_generic_args<'a, V>(visitor: &mut V, generic_args: &'a GenericArgs)
 where
     V: Visitor<'a>,
 {
@@ -502,7 +498,7 @@ where
 pub fn walk_assoc_constraint<'a, V: Visitor<'a>>(visitor: &mut V, constraint: &'a AssocConstraint) {
     visitor.visit_ident(constraint.ident);
     if let Some(ref gen_args) = constraint.gen_args {
-        visitor.visit_generic_args(gen_args.span(), gen_args);
+        visitor.visit_generic_args(gen_args);
     }
     match constraint.kind {
         AssocConstraintKind::Equality { ref term } => match term {
@@ -800,7 +796,7 @@ pub fn walk_expr<'a, V: Visitor<'a>>(visitor: &mut V, expression: &'a Expr) {
             walk_list!(visitor, visit_expr, arguments);
         }
         ExprKind::MethodCall(ref segment, ref receiver, ref arguments, _span) => {
-            visitor.visit_path_segment(expression.span, segment);
+            visitor.visit_path_segment(segment);
             visitor.visit_expr(receiver);
             walk_list!(visitor, visit_expr, arguments);
         }

compiler/rustc_ast_lowering/src/index.rs

@@ -245,9 +245,9 @@ impl<'a, 'hir> Visitor<'hir> for NodeCollector<'a, 'hir> {
         });
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'hir PathSegment<'hir>) {
-        self.insert(path_span, path_segment.hir_id, Node::PathSegment(path_segment));
-        intravisit::walk_path_segment(self, path_span, path_segment);
+    fn visit_path_segment(&mut self, path_segment: &'hir PathSegment<'hir>) {
+        self.insert(path_segment.ident.span, path_segment.hir_id, Node::PathSegment(path_segment));
+        intravisit::walk_path_segment(self, path_segment);
     }
 
     fn visit_ty(&mut self, ty: &'hir Ty<'hir>) {

compiler/rustc_ast_lowering/src/lifetime_collector.rs

@@ -63,9 +63,9 @@ impl<'ast> Visitor<'ast> for LifetimeCollectVisitor<'ast> {
         self.record_lifetime_use(*lifetime);
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'ast PathSegment) {
-        self.record_elided_anchor(path_segment.id, path_span);
-        visit::walk_path_segment(self, path_span, path_segment);
+    fn visit_path_segment(&mut self, path_segment: &'ast PathSegment) {
+        self.record_elided_anchor(path_segment.id, path_segment.ident.span);
+        visit::walk_path_segment(self, path_segment);
     }
 
     fn visit_poly_trait_ref(&mut self, t: &'ast PolyTraitRef) {

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -223,11 +223,9 @@ impl<'a> AstValidator<'a> {
                 for (i, segment) in path.segments.iter().enumerate() {
                     // Allow `impl Trait` iff we're on the final path segment
                     if i == path.segments.len() - 1 {
-                        self.visit_path_segment(path.span, segment);
+                        self.visit_path_segment(segment);
                     } else {
-                        self.with_banned_impl_trait(|this| {
-                            this.visit_path_segment(path.span, segment)
-                        });
+                        self.with_banned_impl_trait(|this| this.visit_path_segment(segment));
                     }
                 }
             }
@@ -1293,7 +1291,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
     }
 
     // Mirrors `visit::walk_generic_args`, but tracks relevant state.
-    fn visit_generic_args(&mut self, _: Span, generic_args: &'a GenericArgs) {
+    fn visit_generic_args(&mut self, generic_args: &'a GenericArgs) {
         match *generic_args {
             GenericArgs::AngleBracketed(ref data) => {
                 self.check_generic_args_before_constraints(data);

compiler/rustc_ast_passes/src/node_count.rs

@@ -115,9 +115,9 @@ impl<'ast> Visitor<'ast> for NodeCounter {
         self.count += 1;
         walk_use_tree(self, use_tree, id)
     }
-    fn visit_generic_args(&mut self, path_span: Span, generic_args: &GenericArgs) {
+    fn visit_generic_args(&mut self, generic_args: &GenericArgs) {
         self.count += 1;
-        walk_generic_args(self, path_span, generic_args)
+        walk_generic_args(self, generic_args)
     }
     fn visit_assoc_constraint(&mut self, constraint: &AssocConstraint) {
         self.count += 1;

compiler/rustc_hir/src/intravisit.rs

@@ -420,17 +420,18 @@ pub trait Visitor<'v>: Sized {
     fn visit_lifetime(&mut self, lifetime: &'v Lifetime) {
         walk_lifetime(self, lifetime)
     }
-    fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, span: Span) {
-        walk_qpath(self, qpath, id, span)
+    // The span is that of the surrounding type/pattern/expr/whatever.
+    fn visit_qpath(&mut self, qpath: &'v QPath<'v>, id: HirId, _span: Span) {
+        walk_qpath(self, qpath, id)
     }
     fn visit_path(&mut self, path: &'v Path<'v>, _id: HirId) {
         walk_path(self, path)
     }
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v PathSegment<'v>) {
-        walk_path_segment(self, path_span, path_segment)
+    fn visit_path_segment(&mut self, path_segment: &'v PathSegment<'v>) {
+        walk_path_segment(self, path_segment)
     }
-    fn visit_generic_args(&mut self, path_span: Span, generic_args: &'v GenericArgs<'v>) {
-        walk_generic_args(self, path_span, generic_args)
+    fn visit_generic_args(&mut self, generic_args: &'v GenericArgs<'v>) {
+        walk_generic_args(self, generic_args)
     }
     fn visit_assoc_type_binding(&mut self, type_binding: &'v TypeBinding<'v>) {
         walk_assoc_type_binding(self, type_binding)
@@ -693,48 +694,35 @@ pub fn walk_inf<'v, V: Visitor<'v>>(visitor: &mut V, inf: &'v InferArg) {
     visitor.visit_id(inf.hir_id);
 }
 
-pub fn walk_qpath<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    qpath: &'v QPath<'v>,
-    id: HirId,
-    span: Span,
-) {
+pub fn walk_qpath<'v, V: Visitor<'v>>(visitor: &mut V, qpath: &'v QPath<'v>, id: HirId) {
     match *qpath {
         QPath::Resolved(ref maybe_qself, ref path) => {
             walk_list!(visitor, visit_ty, maybe_qself);
             visitor.visit_path(path, id)
         }
         QPath::TypeRelative(ref qself, ref segment) => {
             visitor.visit_ty(qself);
-            visitor.visit_path_segment(span, segment);
+            visitor.visit_path_segment(segment);
         }
         QPath::LangItem(..) => {}
     }
 }
 
 pub fn walk_path<'v, V: Visitor<'v>>(visitor: &mut V, path: &'v Path<'v>) {
     for segment in path.segments {
-        visitor.visit_path_segment(path.span, segment);
+        visitor.visit_path_segment(segment);
     }
 }
 
-pub fn walk_path_segment<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    path_span: Span,
-    segment: &'v PathSegment<'v>,
-) {
+pub fn walk_path_segment<'v, V: Visitor<'v>>(visitor: &mut V, segment: &'v PathSegment<'v>) {
     visitor.visit_ident(segment.ident);
     visitor.visit_id(segment.hir_id);
     if let Some(ref args) = segment.args {
-        visitor.visit_generic_args(path_span, args);
+        visitor.visit_generic_args(args);
     }
 }
 
-pub fn walk_generic_args<'v, V: Visitor<'v>>(
-    visitor: &mut V,
-    _path_span: Span,
-    generic_args: &'v GenericArgs<'v>,
-) {
+pub fn walk_generic_args<'v, V: Visitor<'v>>(visitor: &mut V, generic_args: &'v GenericArgs<'v>) {
     walk_list!(visitor, visit_generic_arg, generic_args.args);
     walk_list!(visitor, visit_assoc_type_binding, generic_args.bindings);
 }
@@ -745,7 +733,7 @@ pub fn walk_assoc_type_binding<'v, V: Visitor<'v>>(
 ) {
     visitor.visit_id(type_binding.hir_id);
     visitor.visit_ident(type_binding.ident);
-    visitor.visit_generic_args(type_binding.span, type_binding.gen_args);
+    visitor.visit_generic_args(type_binding.gen_args);
     match type_binding.kind {
         TypeBindingKind::Equality { ref term } => match term {
             Term::Ty(ref ty) => visitor.visit_ty(ty),
@@ -822,9 +810,9 @@ pub fn walk_param_bound<'v, V: Visitor<'v>>(visitor: &mut V, bound: &'v GenericB
         GenericBound::Trait(ref typ, modifier) => {
             visitor.visit_poly_trait_ref(typ, modifier);
         }
-        GenericBound::LangItemTrait(_, span, hir_id, args) => {
+        GenericBound::LangItemTrait(_, _span, hir_id, args) => {
             visitor.visit_id(hir_id);
-            visitor.visit_generic_args(span, args);
+            visitor.visit_generic_args(args);
         }
         GenericBound::Outlives(ref lifetime) => visitor.visit_lifetime(lifetime),
     }
@@ -1095,7 +1083,7 @@ pub fn walk_expr<'v, V: Visitor<'v>>(visitor: &mut V, expression: &'v Expr<'v>)
             walk_list!(visitor, visit_expr, arguments);
         }
         ExprKind::MethodCall(ref segment, receiver, arguments, _) => {
-            visitor.visit_path_segment(expression.span, segment);
+            visitor.visit_path_segment(segment);
             visitor.visit_expr(receiver);
             walk_list!(visitor, visit_expr, arguments);
         }

compiler/rustc_lint/src/builtin.rs

@@ -1467,7 +1467,7 @@ impl TypeAliasBounds {
                 if TypeAliasBounds::is_type_variable_assoc(qpath) {
                     self.err.span_help(span, fluent::lint::builtin_type_alias_bounds_help);
                 }
-                intravisit::walk_qpath(self, qpath, id, span)
+                intravisit::walk_qpath(self, qpath, id)
             }
         }
 

compiler/rustc_lint/src/early.rs

@@ -266,9 +266,9 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
         ast_visit::walk_path(self, p);
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, s: &'a ast::PathSegment) {
+    fn visit_path_segment(&mut self, s: &'a ast::PathSegment) {
         self.check_id(s.id);
-        ast_visit::walk_path_segment(self, path_span, s);
+        ast_visit::walk_path_segment(self, s);
     }
 
     fn visit_attribute(&mut self, attr: &'a ast::Attribute) {

compiler/rustc_passes/src/hir_stats.rs

@@ -447,14 +447,14 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
         hir_visit::walk_path(self, path)
     }
 
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v hir::PathSegment<'v>) {
+    fn visit_path_segment(&mut self, path_segment: &'v hir::PathSegment<'v>) {
         self.record("PathSegment", Id::None, path_segment);
-        hir_visit::walk_path_segment(self, path_span, path_segment)
+        hir_visit::walk_path_segment(self, path_segment)
     }
 
-    fn visit_generic_args(&mut self, sp: Span, ga: &'v hir::GenericArgs<'v>) {
+    fn visit_generic_args(&mut self, ga: &'v hir::GenericArgs<'v>) {
         self.record("GenericArgs", Id::None, ga);
-        hir_visit::walk_generic_args(self, sp, ga)
+        hir_visit::walk_generic_args(self, ga)
     }
 
     fn visit_assoc_type_binding(&mut self, type_binding: &'v hir::TypeBinding<'v>) {
@@ -652,21 +652,21 @@ impl<'v> ast_visit::Visitor<'v> for StatCollector<'v> {
     // one non-inline use (in `ast::Path::segments`). The latter case is more
     // common than the former case, so we implement this visitor and tolerate
     // the double counting in the former case.
-    fn visit_path_segment(&mut self, path_span: Span, path_segment: &'v ast::PathSegment) {
+    fn visit_path_segment(&mut self, path_segment: &'v ast::PathSegment) {
         self.record("PathSegment", Id::None, path_segment);
-        ast_visit::walk_path_segment(self, path_span, path_segment)
+        ast_visit::walk_path_segment(self, path_segment)
     }
 
     // `GenericArgs` has one inline use (in `ast::AssocConstraint::gen_args`) and one
     // non-inline use (in `ast::PathSegment::args`). The latter case is more
     // common, so we implement `visit_generic_args` and tolerate the double
     // counting in the former case.
-    fn visit_generic_args(&mut self, sp: Span, g: &'v ast::GenericArgs) {
+    fn visit_generic_args(&mut self, g: &'v ast::GenericArgs) {
         record_variants!(
             (self, g, g, Id::None, ast, GenericArgs, GenericArgs),
             [AngleBracketed, Parenthesized]
         );
-        ast_visit::walk_generic_args(self, sp, g)
+        ast_visit::walk_generic_args(self, g)
     }
 
     fn visit_attribute(&mut self, attr: &'v ast::Attribute) {

compiler/rustc_privacy/src/lib.rs

@@ -1315,7 +1315,7 @@ impl<'tcx> Visitor<'tcx> for TypePrivacyVisitor<'tcx> {
             }
         }
 
-        intravisit::walk_qpath(self, qpath, id, span);
+        intravisit::walk_qpath(self, qpath, id);
     }
 
     // Check types of patterns.