Rollup merge of #34207 - petrochenkov:nohyg, r=jseyfried

Remove last traces of identifier hygiene from HIR

https://github.com/rust-lang/rust/pull/34095/commits/e783a0a5e39d5ae2fa147508197d09a51530fae8 removed the [last](https://github.com/rust-lang/rust/pull/33654#discussion_r63415218) [use](https://github.com/rust-lang/rust/pull/33654#discussion_r63416284) of hygiene at post-resolve compilation stages, so we can avoid renaming during lowering to HIR and just keep original names.

r? @nrc

7 files changed, 13 insertions, 42 deletions

diff --git a/src/librustc/hir/lowering.rs b/src/librustc/hir/lowering.rs
index 69cf5baa26f..393045bf93e 100644
--- a/src/librustc/hir/lowering.rs
+++ b/src/librustc/hir/lowering.rs
@@ -51,10 +51,9 @@ use std::collections::BTreeMap;
 use std::iter;
 use syntax::ast::*;
 use syntax::attr::{ThinAttributes, ThinAttributesExt};
-use syntax::ext::mtwt;
 use syntax::ptr::P;
 use syntax::codemap::{respan, Spanned, Span};
-use syntax::parse::token::{self, keywords};
+use syntax::parse::token;
 use syntax::std_inject;
 use syntax::visit::{self, Visitor};
 
@@ -184,16 +183,8 @@ impl<'a> LoweringContext<'a> {
         result
     }
 
-    fn lower_ident(&mut self, ident: Ident) -> Name {
-        if ident.name != keywords::Invalid.name() {
-            mtwt::resolve(ident)
-        } else {
-            ident.name
-        }
-    }
-
     fn lower_opt_sp_ident(&mut self, o_id: Option<Spanned<Ident>>) -> Option<Spanned<Name>> {
-        o_id.map(|sp_ident| respan(sp_ident.span, self.lower_ident(sp_ident.node)))
+        o_id.map(|sp_ident| respan(sp_ident.span, sp_ident.node.name))
     }
 
     fn lower_attrs(&mut self, attrs: &Vec<Attribute>) -> hir::HirVec<Attribute> {
@@ -338,18 +329,14 @@ impl<'a> LoweringContext<'a> {
         }
     }
 
-    fn lower_path_full(&mut self, p: &Path, rename: bool) -> hir::Path {
+    fn lower_path(&mut self, p: &Path) -> hir::Path {
         hir::Path {
             global: p.global,
             segments: p.segments
                        .iter()
                        .map(|&PathSegment { identifier, ref parameters }| {
                            hir::PathSegment {
-                               name: if rename {
-                                   self.lower_ident(identifier)
-                               } else {
-                                   identifier.name
-                               },
+                               name: identifier.name,
                                parameters: self.lower_path_parameters(parameters),
                            }
                        })
@@ -358,10 +345,6 @@ impl<'a> LoweringContext<'a> {
         }
     }
 
-    fn lower_path(&mut self, p: &Path) -> hir::Path {
-        self.lower_path_full(p, false)
-    }
-
     fn lower_path_parameters(&mut self, path_parameters: &PathParameters) -> hir::PathParameters {
         match *path_parameters {
             PathParameters::AngleBracketed(ref data) =>
@@ -870,8 +853,7 @@ impl<'a> LoweringContext<'a> {
                             // `None` can occur in body-less function signatures
                             None | Some(Def::Local(..)) => {
                                 hir::PatKind::Binding(this.lower_binding_mode(binding_mode),
-                                                      respan(pth1.span,
-                                                             this.lower_ident(pth1.node)),
+                                                      respan(pth1.span, pth1.node.name),
                                                       sub.as_ref().map(|x| this.lower_pat(x)))
                             }
                             _ => hir::PatKind::Path(hir::Path::from_name(pth1.span, pth1.node.name))
@@ -1238,12 +1220,7 @@ impl<'a> LoweringContext<'a> {
                             position: position,
                         }
                     });
-                    // Only local variables are renamed
-                    let rename = match self.resolver.get_resolution(e.id).map(|d| d.base_def) {
-                        Some(Def::Local(..)) | Some(Def::Upvar(..)) => true,
-                        _ => false,
-                    };
-                    hir::ExprPath(hir_qself, self.lower_path_full(path, rename))
+                    hir::ExprPath(hir_qself, self.lower_path(path))
                 }
                 ExprKind::Break(opt_ident) => hir::ExprBreak(self.lower_opt_sp_ident(opt_ident)),
                 ExprKind::Again(opt_ident) => hir::ExprAgain(self.lower_opt_sp_ident(opt_ident)),
diff --git a/src/librustc/hir/mod.rs b/src/librustc/hir/mod.rs
index c36c88c7990..8faa1cc1174 100644
--- a/src/librustc/hir/mod.rs
+++ b/src/librustc/hir/mod.rs
@@ -1138,7 +1138,7 @@ pub type ExplicitSelf = Spanned<SelfKind>;
 impl Arg {
     pub fn to_self(&self) -> Option<ExplicitSelf> {
         if let PatKind::Binding(BindByValue(mutbl), name, _) = self.pat.node {
-            if name.node.unhygienize() == keywords::SelfValue.name() {
+            if name.node == keywords::SelfValue.name() {
                 return match self.ty.node {
                     TyInfer => Some(respan(self.pat.span, SelfKind::Value(mutbl))),
                     TyRptr(lt, MutTy{ref ty, mutbl}) if ty.node == TyInfer => {
@@ -1154,7 +1154,7 @@ impl Arg {
 
     pub fn is_self(&self) -> bool {
         if let PatKind::Binding(_, name, _) = self.pat.node {
-            name.node.unhygienize() == keywords::SelfValue.name()
+            name.node == keywords::SelfValue.name()
         } else {
             false
         }
diff --git a/src/librustc/middle/resolve_lifetime.rs b/src/librustc/middle/resolve_lifetime.rs
index dcc84fb0439..78d9f5c9b7c 100644
--- a/src/librustc/middle/resolve_lifetime.rs
+++ b/src/librustc/middle/resolve_lifetime.rs
@@ -456,8 +456,7 @@ fn extract_labels(ctxt: &mut LifetimeContext, b: &hir::Block) {
     fn expression_label(ex: &hir::Expr) -> Option<(ast::Name, Span)> {
         match ex.node {
             hir::ExprWhile(_, _, Some(label)) |
-            hir::ExprLoop(_, Some(label)) => Some((label.node.unhygienize(),
-                                                   label.span)),
+            hir::ExprLoop(_, Some(label)) => Some((label.node, label.span)),
             _ => None,
         }
     }
diff --git a/src/librustc_const_eval/check_match.rs b/src/librustc_const_eval/check_match.rs
index f183736b9ed..dbca15ffd34 100644
--- a/src/librustc_const_eval/check_match.rs
+++ b/src/librustc_const_eval/check_match.rs
@@ -247,8 +247,7 @@ fn check_for_bindings_named_the_same_as_variants(cx: &MatchCheckCtxt, pat: &Pat)
             if let ty::TyEnum(edef, _) = pat_ty.sty {
                 if let Def::Local(..) = cx.tcx.expect_def(p.id) {
                     if edef.variants.iter().any(|variant|
-                        variant.name == name.node.unhygienize()
-                            && variant.kind() == VariantKind::Unit
+                        variant.name == name.node && variant.kind() == VariantKind::Unit
                     ) {
                         let ty_path = cx.tcx.item_path_str(edef.did);
                         let mut err = struct_span_warn!(cx.tcx.sess, p.span, E0170,
diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index 2bd2997566e..3ceca9218bd 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -163,7 +163,7 @@ impl LateLintPass for NonShorthandFieldPatterns {
                     continue;
                 }
                 if let PatKind::Binding(_, ident, None) = fieldpat.node.pat.node {
-                    if ident.node.unhygienize() == fieldpat.node.name {
+                    if ident.node == fieldpat.node.name {
                         cx.span_lint(NON_SHORTHAND_FIELD_PATTERNS, fieldpat.span,
                                      &format!("the `{}:` in this pattern is redundant and can \
                                               be removed", ident.node))
diff --git a/src/librustc_trans/debuginfo/create_scope_map.rs b/src/librustc_trans/debuginfo/create_scope_map.rs
index f1d9e2c5a57..33bdccbf067 100644
--- a/src/librustc_trans/debuginfo/create_scope_map.rs
+++ b/src/librustc_trans/debuginfo/create_scope_map.rs
@@ -51,7 +51,7 @@ pub fn create_scope_map(cx: &CrateContext,
     for arg in args {
         pat_util::pat_bindings(&arg.pat, |_, node_id, _, path1| {
             scope_stack.push(ScopeStackEntry { scope_metadata: fn_metadata,
-                                               name: Some(path1.node.unhygienize()) });
+                                               name: Some(path1.node) });
             scope_map.insert(node_id, fn_metadata);
         })
     }
@@ -260,7 +260,7 @@ fn walk_pattern(cx: &CrateContext,
             // N.B.: this comparison must be UNhygienic... because
             // gdb knows nothing about the context, so any two
             // variables with the same name will cause the problem.
-            let name = path1.node.unhygienize();
+            let name = path1.node;
             let need_new_scope = scope_stack
                 .iter()
                 .any(|entry| entry.name == Some(name));
diff --git a/src/libsyntax/ast.rs b/src/libsyntax/ast.rs
index 40c98206c16..8537fcc221c 100644
--- a/src/libsyntax/ast.rs
+++ b/src/libsyntax/ast.rs
@@ -60,10 +60,6 @@ impl Name {
     pub fn as_str(self) -> token::InternedString {
         token::InternedString::new_from_name(self)
     }
-
-    pub fn unhygienize(self) -> Name {
-        token::intern(&self.as_str())
-    }
 }
 
 impl fmt::Debug for Name {