resolve: Avoid double normalization in resolve_ident_in_module

Author: petrochenkov

compiler/rustc_resolve/src/ident.rs

@@ -905,7 +905,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     pub(crate) fn resolve_ident_in_module<'r>(
         self: CmResolver<'r, 'ra, 'tcx>,
         module: ModuleOrUniformRoot<'ra>,
-        mut ident: Ident,
+        ident: Ident,
         ns: Namespace,
         parent_scope: &ParentScope<'ra>,
         finalize: Option<Finalize>,
@@ -914,15 +914,14 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     ) -> Result<Decl<'ra>, Determinacy> {
         match module {
             ModuleOrUniformRoot::Module(module) => {
-                let tmp_parent_scope;
-                let mut adjusted_parent_scope = parent_scope;
-                if let Some(def) = ident.span.normalize_to_macros_2_0_and_adjust(module.expansion) {
-                    tmp_parent_scope =
-                        ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
-                    adjusted_parent_scope = &tmp_parent_scope;
-                }
-                self.resolve_ident_in_scope_set(
-                    ident,
+                let (ident_key, def) = IdentKey::new_adjusted(ident, module.expansion);
+                let adjusted_parent_scope = match def {
+                    Some(def) => ParentScope { module: self.expn_def_scope(def), ..*parent_scope },
+                    None => *parent_scope,
+                };
+                self.resolve_ident_in_scope_set_inner(
+                    ident_key,
+                    ident.span,
                     ScopeSet::Module(ns, module),
                     &adjusted_parent_scope,
                     finalize,
@@ -942,9 +941,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 if ns != TypeNS {
                     Err(Determined)
                 } else {
-                    ident.span.normalize_to_macros_2_0_and_adjust(ExpnId::root());
-                    self.resolve_ident_in_scope_set(
-                        ident,
+                    self.resolve_ident_in_scope_set_inner(
+                        IdentKey::new_adjusted(ident, ExpnId::root()).0,
+                        ident.span,
                         ScopeSet::ExternPrelude,
                         parent_scope,
                         finalize,

compiler/rustc_resolve/src/lib.rs

@@ -575,6 +575,12 @@ impl IdentKey {
         IdentKey { name: ident.name, ctxt: Macros20NormalizedSyntaxContext::new(ident.span.ctxt()) }
     }
 
+    #[inline]
+    fn new_adjusted(ident: Ident, expn_id: ExpnId) -> (IdentKey, Option<ExpnId>) {
+        let (ctxt, def) = Macros20NormalizedSyntaxContext::new_adjusted(ident.span.ctxt(), expn_id);
+        (IdentKey { name: ident.name, ctxt }, def)
+    }
+
     #[inline]
     fn with_root_ctxt(name: Symbol) -> Self {
         let ctxt = Macros20NormalizedSyntaxContext::new_unchecked(SyntaxContext::root());
@@ -2724,7 +2730,7 @@ mod ref_mut {
 }
 
 mod hygiene {
-    use rustc_span::SyntaxContext;
+    use rustc_span::{ExpnId, SyntaxContext};
 
     /// A newtype around `SyntaxContext` that can only keep contexts produced by
     /// [SyntaxContext::normalize_to_macros_2_0].
@@ -2737,6 +2743,15 @@ mod hygiene {
             Macros20NormalizedSyntaxContext(ctxt.normalize_to_macros_2_0())
         }
 
+        #[inline]
+        pub(crate) fn new_adjusted(
+            mut ctxt: SyntaxContext,
+            expn_id: ExpnId,
+        ) -> (Macros20NormalizedSyntaxContext, Option<ExpnId>) {
+            let def = ctxt.normalize_to_macros_2_0_and_adjust(expn_id);
+            (Macros20NormalizedSyntaxContext(ctxt), def)
+        }
+
         #[inline]
         pub(crate) fn new_unchecked(ctxt: SyntaxContext) -> Macros20NormalizedSyntaxContext {
             debug_assert_eq!(ctxt, ctxt.normalize_to_macros_2_0());

compiler/rustc_span/src/hygiene.rs

@@ -804,7 +804,7 @@ impl SyntaxContext {
 
     /// Like `SyntaxContext::adjust`, but also normalizes `self` to macros 2.0.
     #[inline]
-    pub(crate) fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
+    pub fn normalize_to_macros_2_0_and_adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId> {
         HygieneData::with(|data| {
             *self = data.normalize_to_macros_2_0(*self);
             data.adjust(self, expn_id)