Rollup merge of rust-lang#32674 - jseyfried:1422_groundwork, r=nikomatsakis

Lay groundwork for RFC 1422  and improve `PrivateItemsInPublicInterfacesVisitor`

This PR lays groundwork for RFC 1422 (cc rust-lang#32409) and improves `PrivateItemsInPublicInterfacesVisitor`. More specifically, it
 - Refactors away `hir::Visibility::inherit_from`, the semantics of which are obsolete.
 - Makes `hir::Visibility` non-`Copy` so that we will be able to add new variants to represent `pub(restricted)` (for example, `Visibility::Restricted(Path)`).
 - Adds a new `Copy` type `ty::Visibility` that represents a visibility value, i.e. a characterization of where an item is accessible. This is able to represent `pub(restricted)` visibilities.
 - Improves `PrivateItemsInPublicInterfacesVisitor` so that it checks for items in an interface that are less visible than the interface. This fixes rust-lang#30079 but doesn't change any other behavior.

r? @nikomatsakis

Author: Manishearth

src/librustc/hir/intravisit.rs

@@ -37,10 +37,10 @@ use std::u32;
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub enum FnKind<'a> {
     /// fn foo() or extern "Abi" fn foo()
-    ItemFn(Name, &'a Generics, Unsafety, Constness, Abi, Visibility, &'a [Attribute]),
+    ItemFn(Name, &'a Generics, Unsafety, Constness, Abi, &'a Visibility, &'a [Attribute]),
 
     /// fn foo(&self)
-    Method(Name, &'a MethodSig, Option<Visibility>, &'a [Attribute]),
+    Method(Name, &'a MethodSig, Option<&'a Visibility>, &'a [Attribute]),
 
     /// |x, y| {}
     Closure(&'a [Attribute]),
@@ -324,7 +324,7 @@ pub fn walk_item<'v, V: Visitor<'v>>(visitor: &mut V, item: &'v Item) {
                                             unsafety,
                                             constness,
                                             abi,
-                                            item.vis,
+                                            &item.vis,
                                             &item.attrs),
                              declaration,
                              body,
@@ -672,7 +672,7 @@ pub fn walk_impl_item<'v, V: Visitor<'v>>(visitor: &mut V, impl_item: &'v ImplIt
         ImplItemKind::Method(ref sig, ref body) => {
             visitor.visit_fn(FnKind::Method(impl_item.name,
                                             sig,
-                                            Some(impl_item.vis),
+                                            Some(&impl_item.vis),
                                             &impl_item.attrs),
                              &sig.decl,
                              body,

src/librustc/hir/map/blocks.rs

@@ -113,7 +113,7 @@ struct ItemFnParts<'a> {
     unsafety: ast::Unsafety,
     constness: ast::Constness,
     abi:      abi::Abi,
-    vis:      ast::Visibility,
+    vis:      &'a ast::Visibility,
     generics: &'a ast::Generics,
     body:     &'a Block,
     id:       NodeId,
@@ -208,7 +208,7 @@ impl<'a> FnLikeNode<'a> {
         M: FnOnce(NodeId,
                   Name,
                   &'a ast::MethodSig,
-                  Option<ast::Visibility>,
+                  Option<&'a ast::Visibility>,
                   &'a ast::Block,
                   Span,
                   &'a [Attribute])
@@ -226,7 +226,7 @@ impl<'a> FnLikeNode<'a> {
                         body: &block,
                         generics: generics,
                         abi: abi,
-                        vis: i.vis,
+                        vis: &i.vis,
                         constness: constness,
                         span: i.span,
                         attrs: &i.attrs,
@@ -242,7 +242,7 @@ impl<'a> FnLikeNode<'a> {
             map::NodeImplItem(ii) => {
                 match ii.node {
                     ast::ImplItemKind::Method(ref sig, ref body) => {
-                        method(ii.id, ii.name, sig, Some(ii.vis), body, ii.span, &ii.attrs)
+                        method(ii.id, ii.name, sig, Some(&ii.vis), body, ii.span, &ii.attrs)
                     }
                     _ => {
                         bug!("impl method FnLikeNode that is not fn-like")

src/librustc/hir/map/mod.rs

@@ -430,7 +430,7 @@ impl<'ast> Map<'ast> {
 
     /// Returns the NodeId of `id`'s nearest module parent, or `id` itself if no
     /// module parent is in this map.
-    fn get_module_parent(&self, id: NodeId) -> NodeId {
+    pub fn get_module_parent(&self, id: NodeId) -> NodeId {
         match self.walk_parent_nodes(id, |node| match *node {
             NodeItem(&Item { node: Item_::ItemMod(_), .. }) => true,
             _ => false,
@@ -440,18 +440,6 @@ impl<'ast> Map<'ast> {
         }
     }
 
-    pub fn private_item_is_visible_from(&self, item: NodeId, block: NodeId) -> bool {
-        // A private item is visible from everything in its nearest module parent.
-        let visibility = self.get_module_parent(item);
-        let mut block_ancestor = self.get_module_parent(block);
-        loop {
-            if block_ancestor == visibility { return true }
-            let block_ancestor_parent = self.get_module_parent(block_ancestor);
-            if block_ancestor_parent == block_ancestor { return false }
-            block_ancestor = block_ancestor_parent;
-        }
-    }
-
     /// Returns the nearest enclosing scope. A scope is an item or block.
     /// FIXME it is not clear to me that all items qualify as scopes - statics
     /// and associated types probably shouldn't, for example. Behaviour in this

src/librustc/hir/mod.rs

@@ -1431,21 +1431,12 @@ pub struct PolyTraitRef {
     pub span: Span,
 }
 
-#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug, Copy)]
+#[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub enum Visibility {
     Public,
     Inherited,
 }
 
-impl Visibility {
-    pub fn inherit_from(&self, parent_visibility: Visibility) -> Visibility {
-        match self {
-            &Inherited => parent_visibility,
-            &Public => *self,
-        }
-    }
-}
-
 #[derive(Clone, PartialEq, Eq, RustcEncodable, RustcDecodable, Hash, Debug)]
 pub struct StructField {
     pub span: Span,

src/librustc/hir/print.rs

@@ -294,7 +294,7 @@ pub fn fun_to_string(decl: &hir::FnDecl,
                    Some(name),
                    generics,
                    opt_explicit_self,
-                   hir::Inherited)?;
+                   &hir::Inherited)?;
         s.end()?; // Close the head box
         s.end() // Close the outer box
     })
@@ -322,8 +322,8 @@ pub fn arg_to_string(arg: &hir::Arg) -> String {
     to_string(|s| s.print_arg(arg, false))
 }
 
-pub fn visibility_qualified(vis: hir::Visibility, s: &str) -> String {
-    match vis {
+pub fn visibility_qualified(vis: &hir::Visibility, s: &str) -> String {
+    match *vis {
         hir::Public => format!("pub {}", s),
         hir::Inherited => s.to_string(),
     }
@@ -573,13 +573,13 @@ impl<'a> State<'a> {
                               Some(item.name),
                               generics,
                               None,
-                              item.vis)?;
+                              &item.vis)?;
                 self.end()?; // end head-ibox
                 word(&mut self.s, ";")?;
                 self.end() // end the outer fn box
             }
             hir::ForeignItemStatic(ref t, m) => {
-                self.head(&visibility_qualified(item.vis, "static"))?;
+                self.head(&visibility_qualified(&item.vis, "static"))?;
                 if m {
                     self.word_space("mut")?;
                 }
@@ -597,7 +597,7 @@ impl<'a> State<'a> {
                               name: ast::Name,
                               ty: &hir::Ty,
                               default: Option<&hir::Expr>,
-                              vis: hir::Visibility)
+                              vis: &hir::Visibility)
                               -> io::Result<()> {
         word(&mut self.s, &visibility_qualified(vis, ""))?;
         self.word_space("const")?;
@@ -648,7 +648,7 @@ impl<'a> State<'a> {
         self.ann.pre(self, NodeItem(item))?;
         match item.node {
             hir::ItemExternCrate(ref optional_path) => {
-                self.head(&visibility_qualified(item.vis, "extern crate"))?;
+                self.head(&visibility_qualified(&item.vis, "extern crate"))?;
                 if let Some(p) = *optional_path {
                     let val = p.as_str();
                     if val.contains("-") {
@@ -666,14 +666,14 @@ impl<'a> State<'a> {
                 self.end()?; // end outer head-block
             }
             hir::ItemUse(ref vp) => {
-                self.head(&visibility_qualified(item.vis, "use"))?;
+                self.head(&visibility_qualified(&item.vis, "use"))?;
                 self.print_view_path(&vp)?;
                 word(&mut self.s, ";")?;
                 self.end()?; // end inner head-block
                 self.end()?; // end outer head-block
             }
             hir::ItemStatic(ref ty, m, ref expr) => {
-                self.head(&visibility_qualified(item.vis, "static"))?;
+                self.head(&visibility_qualified(&item.vis, "static"))?;
                 if m == hir::MutMutable {
                     self.word_space("mut")?;
                 }
@@ -689,7 +689,7 @@ impl<'a> State<'a> {
                 self.end()?; // end the outer cbox
             }
             hir::ItemConst(ref ty, ref expr) => {
-                self.head(&visibility_qualified(item.vis, "const"))?;
+                self.head(&visibility_qualified(&item.vis, "const"))?;
                 self.print_name(item.name)?;
                 self.word_space(":")?;
                 self.print_type(&ty)?;
@@ -710,12 +710,12 @@ impl<'a> State<'a> {
                               Some(item.name),
                               typarams,
                               None,
-                              item.vis)?;
+                              &item.vis)?;
                 word(&mut self.s, " ")?;
                 self.print_block_with_attrs(&body, &item.attrs)?;
             }
             hir::ItemMod(ref _mod) => {
-                self.head(&visibility_qualified(item.vis, "mod"))?;
+                self.head(&visibility_qualified(&item.vis, "mod"))?;
                 self.print_name(item.name)?;
                 self.nbsp()?;
                 self.bopen()?;
@@ -732,7 +732,7 @@ impl<'a> State<'a> {
             hir::ItemTy(ref ty, ref params) => {
                 self.ibox(indent_unit)?;
                 self.ibox(0)?;
-                self.word_nbsp(&visibility_qualified(item.vis, "type"))?;
+                self.word_nbsp(&visibility_qualified(&item.vis, "type"))?;
                 self.print_name(item.name)?;
                 self.print_generics(params)?;
                 self.end()?; // end the inner ibox
@@ -745,16 +745,16 @@ impl<'a> State<'a> {
                 self.end()?; // end the outer ibox
             }
             hir::ItemEnum(ref enum_definition, ref params) => {
-                self.print_enum_def(enum_definition, params, item.name, item.span, item.vis)?;
+                self.print_enum_def(enum_definition, params, item.name, item.span, &item.vis)?;
             }
             hir::ItemStruct(ref struct_def, ref generics) => {
-                self.head(&visibility_qualified(item.vis, "struct"))?;
+                self.head(&visibility_qualified(&item.vis, "struct"))?;
                 self.print_struct(struct_def, generics, item.name, item.span, true)?;
             }
 
             hir::ItemDefaultImpl(unsafety, ref trait_ref) => {
                 self.head("")?;
-                self.print_visibility(item.vis)?;
+                self.print_visibility(&item.vis)?;
                 self.print_unsafety(unsafety)?;
                 self.word_nbsp("impl")?;
                 self.print_trait_ref(trait_ref)?;
@@ -771,7 +771,7 @@ impl<'a> State<'a> {
                           ref ty,
                           ref impl_items) => {
                 self.head("")?;
-                self.print_visibility(item.vis)?;
+                self.print_visibility(&item.vis)?;
                 self.print_unsafety(unsafety)?;
                 self.word_nbsp("impl")?;
 
@@ -809,7 +809,7 @@ impl<'a> State<'a> {
             }
             hir::ItemTrait(unsafety, ref generics, ref bounds, ref trait_items) => {
                 self.head("")?;
-                self.print_visibility(item.vis)?;
+                self.print_visibility(&item.vis)?;
                 self.print_unsafety(unsafety)?;
                 self.word_nbsp("trait")?;
                 self.print_name(item.name)?;
@@ -867,7 +867,7 @@ impl<'a> State<'a> {
                           generics: &hir::Generics,
                           name: ast::Name,
                           span: codemap::Span,
-                          visibility: hir::Visibility)
+                          visibility: &hir::Visibility)
                           -> io::Result<()> {
         self.head(&visibility_qualified(visibility, "enum"))?;
         self.print_name(name)?;
@@ -895,8 +895,8 @@ impl<'a> State<'a> {
         self.bclose(span)
     }
 
-    pub fn print_visibility(&mut self, vis: hir::Visibility) -> io::Result<()> {
-        match vis {
+    pub fn print_visibility(&mut self, vis: &hir::Visibility) -> io::Result<()> {
+        match *vis {
             hir::Public => self.word_nbsp("pub"),
             hir::Inherited => Ok(()),
         }
@@ -915,7 +915,7 @@ impl<'a> State<'a> {
             if struct_def.is_tuple() {
                 self.popen()?;
                 self.commasep(Inconsistent, struct_def.fields(), |s, field| {
-                    s.print_visibility(field.vis)?;
+                    s.print_visibility(&field.vis)?;
                     s.maybe_print_comment(field.span.lo)?;
                     s.print_type(&field.ty)
                 })?;
@@ -937,7 +937,7 @@ impl<'a> State<'a> {
                 self.hardbreak_if_not_bol()?;
                 self.maybe_print_comment(field.span.lo)?;
                 self.print_outer_attributes(&field.attrs)?;
-                self.print_visibility(field.vis)?;
+                self.print_visibility(&field.vis)?;
                 self.print_name(field.name)?;
                 self.word_nbsp(":")?;
                 self.print_type(&field.ty)?;
@@ -964,7 +964,7 @@ impl<'a> State<'a> {
     pub fn print_method_sig(&mut self,
                             name: ast::Name,
                             m: &hir::MethodSig,
-                            vis: hir::Visibility)
+                            vis: &hir::Visibility)
                             -> io::Result<()> {
         self.print_fn(&m.decl,
                       m.unsafety,
@@ -986,13 +986,13 @@ impl<'a> State<'a> {
                 self.print_associated_const(ti.name,
                                             &ty,
                                             default.as_ref().map(|expr| &**expr),
-                                            hir::Inherited)?;
+                                            &hir::Inherited)?;
             }
             hir::MethodTraitItem(ref sig, ref body) => {
                 if body.is_some() {
                     self.head("")?;
                 }
-                self.print_method_sig(ti.name, sig, hir::Inherited)?;
+                self.print_method_sig(ti.name, sig, &hir::Inherited)?;
                 if let Some(ref body) = *body {
                     self.nbsp()?;
                     self.print_block_with_attrs(body, &ti.attrs)?;
@@ -1021,11 +1021,11 @@ impl<'a> State<'a> {
 
         match ii.node {
             hir::ImplItemKind::Const(ref ty, ref expr) => {
-                self.print_associated_const(ii.name, &ty, Some(&expr), ii.vis)?;
+                self.print_associated_const(ii.name, &ty, Some(&expr), &ii.vis)?;
             }
             hir::ImplItemKind::Method(ref sig, ref body) => {
                 self.head("")?;
-                self.print_method_sig(ii.name, sig, ii.vis)?;
+                self.print_method_sig(ii.name, sig, &ii.vis)?;
                 self.nbsp()?;
                 self.print_block_with_attrs(body, &ii.attrs)?;
             }
@@ -1910,7 +1910,7 @@ impl<'a> State<'a> {
                     name: Option<ast::Name>,
                     generics: &hir::Generics,
                     opt_explicit_self: Option<&hir::ExplicitSelf_>,
-                    vis: hir::Visibility)
+                    vis: &hir::Visibility)
                     -> io::Result<()> {
         self.print_fn_header_info(unsafety, constness, abi, vis)?;
 
@@ -2267,7 +2267,7 @@ impl<'a> State<'a> {
                       name,
                       &generics,
                       opt_explicit_self,
-                      hir::Inherited)?;
+                      &hir::Inherited)?;
         self.end()
     }
 
@@ -2347,7 +2347,7 @@ impl<'a> State<'a> {
                                 unsafety: hir::Unsafety,
                                 constness: hir::Constness,
                                 abi: Abi,
-                                vis: hir::Visibility)
+                                vis: &hir::Visibility)
                                 -> io::Result<()> {
         word(&mut self.s, &visibility_qualified(vis, ""))?;
         self.print_unsafety(unsafety)?;

src/librustc/middle/cstore.rs

@@ -116,7 +116,7 @@ pub const LOCAL_CRATE: ast::CrateNum = 0;
 pub struct ChildItem {
     pub def: DefLike,
     pub name: ast::Name,
-    pub vis: hir::Visibility
+    pub vis: ty::Visibility,
 }
 
 pub enum FoundAst<'ast> {
@@ -157,7 +157,7 @@ pub trait CrateStore<'tcx> : Any {
     // item info
     fn stability(&self, def: DefId) -> Option<attr::Stability>;
     fn deprecation(&self, def: DefId) -> Option<attr::Deprecation>;
-    fn visibility(&self, def: DefId) -> hir::Visibility;
+    fn visibility(&self, def: DefId) -> ty::Visibility;
     fn closure_kind(&self, tcx: &TyCtxt<'tcx>, def_id: DefId)
                     -> ty::ClosureKind;
     fn closure_ty(&self, tcx: &TyCtxt<'tcx>, def_id: DefId)
@@ -334,7 +334,7 @@ impl<'tcx> CrateStore<'tcx> for DummyCrateStore {
     // item info
     fn stability(&self, def: DefId) -> Option<attr::Stability> { bug!("stability") }
     fn deprecation(&self, def: DefId) -> Option<attr::Deprecation> { bug!("deprecation") }
-    fn visibility(&self, def: DefId) -> hir::Visibility { bug!("visibility") }
+    fn visibility(&self, def: DefId) -> ty::Visibility { bug!("visibility") }
     fn closure_kind(&self, tcx: &TyCtxt<'tcx>, def_id: DefId)
                     -> ty::ClosureKind  { bug!("closure_kind") }
     fn closure_ty(&self, tcx: &TyCtxt<'tcx>, def_id: DefId)