Auto merge of #52555 - petrochenkov:mresfact, r=alexcrichton

resolve: Some renaming, refactoring and comments

Commits are self-descriptive.
The only functional change is 34bf2f5 that tightens shadowing rules for macro paths (makes the second and third cases in `test/ui/imports/glob-shadowing.rs` an error).

Author: bors

src/liballoc/collections/btree/node.rs

@@ -103,7 +103,7 @@ impl<K, V> LeafNode<K, V> {
     }
 
     fn is_shared_root(&self) -> bool {
-        self as *const _ == &EMPTY_ROOT_NODE as *const _ as *const LeafNode<K, V>
+        ptr::eq(self, &EMPTY_ROOT_NODE as *const _ as *const _)
     }
 }
 

src/librustc/lint/mod.rs

@@ -39,7 +39,7 @@ use hir::intravisit;
 use hir;
 use lint::builtin::BuiltinLintDiagnostics;
 use session::{Session, DiagnosticMessageId};
-use std::hash;
+use std::{hash, ptr};
 use syntax::ast;
 use syntax::codemap::{MultiSpan, ExpnFormat};
 use syntax::edition::Edition;
@@ -354,7 +354,7 @@ pub struct LintId {
 
 impl PartialEq for LintId {
     fn eq(&self, other: &LintId) -> bool {
-        (self.lint as *const Lint) == (other.lint as *const Lint)
+        ptr::eq(self.lint, other.lint)
     }
 }
 

src/librustc/ty/mod.rs

@@ -47,7 +47,7 @@ use std::ops::Deref;
 use rustc_data_structures::sync::{self, Lrc, ParallelIterator, par_iter};
 use std::slice;
 use std::vec::IntoIter;
-use std::mem;
+use std::{mem, ptr};
 use syntax::ast::{self, DUMMY_NODE_ID, Name, Ident, NodeId};
 use syntax::attr;
 use syntax::ext::hygiene::Mark;
@@ -527,8 +527,7 @@ impl<'tcx> PartialOrd for TyS<'tcx> {
 impl<'tcx> PartialEq for TyS<'tcx> {
     #[inline]
     fn eq(&self, other: &TyS<'tcx>) -> bool {
-        // (self as *const _) == (other as *const _)
-        (self as *const TyS<'tcx>) == (other as *const TyS<'tcx>)
+        ptr::eq(self, other)
     }
 }
 impl<'tcx> Eq for TyS<'tcx> {}
@@ -678,7 +677,7 @@ impl<T> PartialOrd for Slice<T> where T: PartialOrd {
 impl<T: PartialEq> PartialEq for Slice<T> {
     #[inline]
     fn eq(&self, other: &Slice<T>) -> bool {
-        (self as *const _) == (other as *const _)
+        ptr::eq(self, other)
     }
 }
 impl<T: Eq> Eq for Slice<T> {}
@@ -1730,7 +1729,7 @@ impl Ord for AdtDef {
 impl PartialEq for AdtDef {
     // AdtDef are always interned and this is part of TyS equality
     #[inline]
-    fn eq(&self, other: &Self) -> bool { self as *const _ == other as *const _ }
+    fn eq(&self, other: &Self) -> bool { ptr::eq(self, other) }
 }
 
 impl Eq for AdtDef {}

src/librustc/ty/query/job.rs

@@ -20,7 +20,7 @@ use ty::query::plumbing::CycleError;
 use ty::context::TyCtxt;
 use errors::Diagnostic;
 use std::process;
-use std::fmt;
+use std::{fmt, ptr};
 use std::collections::HashSet;
 #[cfg(parallel_queries)]
 use {
@@ -124,7 +124,7 @@ impl<'tcx> QueryJob<'tcx> {
         while let Some(job) = current_job {
             cycle.insert(0, job.info.clone());
 
-            if &*job as *const _ == self as *const _ {
+            if ptr::eq(&*job, self) {
                 // This is the end of the cycle
                 // The span entry we included was for the usage
                 // of the cycle itself, and not part of the cycle

src/librustc_data_structures/lib.rs

@@ -56,29 +56,30 @@ extern crate rustc_cratesio_shim;
 
 pub use rustc_serialize::hex::ToHex;
 
-pub mod array_vec;
 pub mod accumulate_vec;
-pub mod small_vec;
+pub mod array_vec;
 pub mod base_n;
 pub mod bitslice;
 pub mod bitvec;
+pub mod flock;
+pub mod fx;
+pub mod graph;
 pub mod indexed_set;
 pub mod indexed_vec;
 pub mod obligation_forest;
+pub mod owning_ref;
+pub mod ptr_key;
 pub mod sip128;
+pub mod small_vec;
 pub mod snapshot_map;
 pub use ena::snapshot_vec;
+pub mod sorted_map;
 pub mod stable_hasher;
-pub mod transitive_relation;
-pub use ena::unify;
-pub mod fx;
-pub mod tuple_slice;
-pub mod graph;
-pub mod flock;
 pub mod sync;
-pub mod owning_ref;
 pub mod tiny_list;
-pub mod sorted_map;
+pub mod transitive_relation;
+pub mod tuple_slice;
+pub use ena::unify;
 pub mod work_queue;
 
 pub struct OnDrop<F: Fn()>(pub F);

src/librustc_data_structures/ptr_key.rs

@@ -0,0 +1,45 @@
+// Copyright 2018 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::{hash, ptr};
+use std::ops::Deref;
+
+/// A wrapper around reference that compares and hashes like a pointer.
+/// Can be used as a key in sets/maps indexed by pointers to avoid `unsafe`.
+#[derive(Debug)]
+pub struct PtrKey<'a, T: 'a>(pub &'a T);
+
+impl<'a, T> Clone for PtrKey<'a, T> {
+    fn clone(&self) -> Self { *self }
+}
+
+impl<'a, T> Copy for PtrKey<'a, T> {}
+
+impl<'a, T> PartialEq for PtrKey<'a, T> {
+    fn eq(&self, rhs: &Self) -> bool {
+        ptr::eq(self.0, rhs.0)
+    }
+}
+
+impl<'a, T> Eq for PtrKey<'a, T> {}
+
+impl<'a, T> hash::Hash for PtrKey<'a, T> {
+    fn hash<H: hash::Hasher>(&self, hasher: &mut H) {
+        (self.0 as *const T).hash(hasher)
+    }
+}
+
+impl<'a, T> Deref for PtrKey<'a, T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        self.0
+    }
+}

src/librustc_resolve/build_reduced_graph.rs

@@ -651,7 +651,7 @@ impl<'a> Resolver<'a> {
                            binding: &'a NameBinding<'a>,
                            span: Span,
                            allow_shadowing: bool) {
-        if self.global_macros.insert(name, binding).is_some() && !allow_shadowing {
+        if self.macro_prelude.insert(name, binding).is_some() && !allow_shadowing {
             let msg = format!("`{}` is already in scope", name);
             let note =
                 "macro-expanded `#[macro_use]`s may not shadow existing macros (see RFC 1560)";
@@ -704,8 +704,7 @@ impl<'a> Resolver<'a> {
         } else {
             for (name, span) in legacy_imports.imports {
                 let ident = Ident::with_empty_ctxt(name);
-                let result = self.resolve_ident_in_module(module, ident, MacroNS,
-                                                          false, false, span);
+                let result = self.resolve_ident_in_module(module, ident, MacroNS, false, span);
                 if let Ok(binding) = result {
                     let directive = macro_use_directive(span);
                     self.potentially_unused_imports.push(directive);

src/librustc_resolve/lib.rs

@@ -1393,7 +1393,7 @@ pub struct Resolver<'a> {
 
     crate_loader: &'a mut dyn CrateLoader,
     macro_names: FxHashSet<Ident>,
-    global_macros: FxHashMap<Name, &'a NameBinding<'a>>,
+    macro_prelude: FxHashMap<Name, &'a NameBinding<'a>>,
     pub all_macros: FxHashMap<Name, Def>,
     lexical_macro_resolutions: Vec<(Ident, &'a Cell<LegacyScope<'a>>)>,
     macro_map: FxHashMap<DefId, Lrc<SyntaxExtension>>,
@@ -1715,7 +1715,7 @@ impl<'a> Resolver<'a> {
 
             crate_loader,
             macro_names: FxHashSet(),
-            global_macros: FxHashMap(),
+            macro_prelude: FxHashMap(),
             all_macros: FxHashMap(),
             lexical_macro_resolutions: Vec::new(),
             macro_map: FxHashMap(),
@@ -2002,7 +2002,6 @@ impl<'a> Resolver<'a> {
                                module: Module<'a>,
                                mut ident: Ident,
                                ns: Namespace,
-                               ignore_unresolved_invocations: bool,
                                record_used: bool,
                                span: Span)
                                -> Result<&'a NameBinding<'a>, Determinacy> {
@@ -2012,7 +2011,7 @@ impl<'a> Resolver<'a> {
             self.current_module = self.macro_def_scope(def);
         }
         let result = self.resolve_ident_in_module_unadjusted(
-            module, ident, ns, ignore_unresolved_invocations, record_used, span,
+            module, ident, ns, false, record_used, span,
         );
         self.current_module = orig_current_module;
         result
@@ -2518,7 +2517,7 @@ impl<'a> Resolver<'a> {
         // If there is a TraitRef in scope for an impl, then the method must be in the
         // trait.
         if let Some((module, _)) = self.current_trait_ref {
-            if self.resolve_ident_in_module(module, ident, ns, false, false, span).is_err() {
+            if self.resolve_ident_in_module(module, ident, ns, false, span).is_err() {
                 let path = &self.current_trait_ref.as_ref().unwrap().1.path;
                 resolve_error(self, span, err(ident.name, &path_names_to_string(path)));
             }
@@ -3225,7 +3224,7 @@ impl<'a> Resolver<'a> {
                 };
             }
         }
-        let is_global = self.global_macros.get(&path[0].name).cloned()
+        let is_global = self.macro_prelude.get(&path[0].name).cloned()
             .map(|binding| binding.get_macro(self).kind() == MacroKind::Bang).unwrap_or(false);
         if primary_ns != MacroNS && (is_global ||
                                      self.macro_names.contains(&path[0].modern())) {
@@ -3468,7 +3467,7 @@ impl<'a> Resolver<'a> {
             }
 
             let binding = if let Some(module) = module {
-                self.resolve_ident_in_module(module, ident, ns, false, record_used, path_span)
+                self.resolve_ident_in_module(module, ident, ns, record_used, path_span)
             } else if opt_ns == Some(MacroNS) {
                 self.resolve_lexical_macro_path_segment(ident, ns, record_used, path_span)
                     .map(MacroBinding::binding)
@@ -3762,7 +3761,7 @@ impl<'a> Resolver<'a> {
         // Look for associated items in the current trait.
         if let Some((module, _)) = self.current_trait_ref {
             if let Ok(binding) =
-                    self.resolve_ident_in_module(module, ident, ns, false, false, module.span) {
+                    self.resolve_ident_in_module(module, ident, ns, false, module.span) {
                 let def = binding.def();
                 if filter_fn(def) {
                     return Some(if self.has_self.contains(&def.def_id()) {
@@ -4075,7 +4074,7 @@ impl<'a> Resolver<'a> {
         let mut found_traits = Vec::new();
         // Look for the current trait.
         if let Some((module, _)) = self.current_trait_ref {
-            if self.resolve_ident_in_module(module, ident, ns, false, false, module.span).is_ok() {
+            if self.resolve_ident_in_module(module, ident, ns, false, module.span).is_ok() {
                 let def_id = module.def_id().unwrap();
                 found_traits.push(TraitCandidate { def_id: def_id, import_id: None });
             }

src/librustc_resolve/macros.rs

@@ -220,7 +220,7 @@ impl<'a> base::Resolver for Resolver<'a> {
             vis: ty::Visibility::Invisible,
             expansion: Mark::root(),
         });
-        self.global_macros.insert(ident.name, binding);
+        self.macro_prelude.insert(ident.name, binding);
     }
 
     fn resolve_imports(&mut self) {
@@ -238,7 +238,7 @@ impl<'a> base::Resolver for Resolver<'a> {
                 attr::mark_known(&attrs[i]);
             }
 
-            match self.global_macros.get(&name).cloned() {
+            match self.macro_prelude.get(&name).cloned() {
                 Some(binding) => match *binding.get_macro(self) {
                     MultiModifier(..) | MultiDecorator(..) | SyntaxExtension::AttrProcMacro(..) => {
                         return Some(attrs.remove(i))
@@ -274,7 +274,7 @@ impl<'a> base::Resolver for Resolver<'a> {
                     }
                     let trait_name = traits[j].segments[0].ident.name;
                     let legacy_name = Symbol::intern(&format!("derive_{}", trait_name));
-                    if !self.global_macros.contains_key(&legacy_name) {
+                    if !self.macro_prelude.contains_key(&legacy_name) {
                         continue
                     }
                     let span = traits.remove(j).span;
@@ -565,7 +565,7 @@ impl<'a> Resolver<'a> {
                     module, ident, ns, true, record_used, path_span,
                 ).map(MacroBinding::Modern)
             } else {
-                self.global_macros.get(&ident.name).cloned().ok_or(determinacy)
+                self.macro_prelude.get(&ident.name).cloned().ok_or(determinacy)
                     .map(MacroBinding::Global)
             };
             self.current_module = orig_current_module;
@@ -588,8 +588,7 @@ impl<'a> Resolver<'a> {
                             return potential_illegal_shadower;
                         }
                     }
-                    if binding.expansion != Mark::root() ||
-                       (binding.is_glob_import() && module.unwrap().def().is_some()) {
+                    if binding.is_glob_import() || binding.expansion != Mark::root() {
                         potential_illegal_shadower = result;
                     } else {
                         return result;
@@ -652,7 +651,7 @@ impl<'a> Resolver<'a> {
 
         let binding = if let Some(binding) = binding {
             MacroBinding::Legacy(binding)
-        } else if let Some(binding) = self.global_macros.get(&ident.name).cloned() {
+        } else if let Some(binding) = self.macro_prelude.get(&ident.name).cloned() {
             if !self.use_extern_macros {
                 self.record_use(ident, MacroNS, binding, DUMMY_SP);
             }
@@ -762,8 +761,8 @@ impl<'a> Resolver<'a> {
         // Then check global macros.
         }.or_else(|| {
             // FIXME: get_macro needs an &mut Resolver, can we do it without cloning?
-            let global_macros = self.global_macros.clone();
-            let names = global_macros.iter().filter_map(|(name, binding)| {
+            let macro_prelude = self.macro_prelude.clone();
+            let names = macro_prelude.iter().filter_map(|(name, binding)| {
                 if binding.get_macro(self).kind() == kind {
                     Some(name)
                 } else {