Rollup merge of rust-lang#145597 - petrochenkov:nolateset, r=b-naber

resolve: Remove `ScopeSet::Late`

It's better to decouple the late/early stage from scope set, because in rust-lang#144131 (comment) we'll need the stage for `ScopeSet::Module` as well.

See individual commits for the refactoring details.
r? ``@b-naber``

Author: jhpratt

compiler/rustc_resolve/src/diagnostics.rs

@@ -1020,11 +1020,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         &mut self,
         suggestions: &mut Vec<TypoSuggestion>,
         scope_set: ScopeSet<'ra>,
-        parent_scope: &ParentScope<'ra>,
+        ps: &ParentScope<'ra>,
         ctxt: SyntaxContext,
         filter_fn: &impl Fn(Res) -> bool,
     ) {
-        self.cm().visit_scopes(scope_set, parent_scope, ctxt, |this, scope, use_prelude, _| {
+        self.cm().visit_scopes(scope_set, ps, ctxt, None, |this, scope, use_prelude, _| {
             match scope {
                 Scope::DeriveHelpers(expn_id) => {
                     let res = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
@@ -1557,7 +1557,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             });
         }
         for ns in [Namespace::MacroNS, Namespace::TypeNS, Namespace::ValueNS] {
-            let Ok(binding) = self.cm().early_resolve_ident_in_lexical_scope(
+            let Ok(binding) = self.cm().resolve_ident_in_scope_set(
                 ident,
                 ScopeSet::All(ns),
                 parent_scope,
@@ -2371,7 +2371,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     }
                 } else {
                     self.cm()
-                        .early_resolve_ident_in_lexical_scope(
+                        .resolve_ident_in_scope_set(
                             ident,
                             ScopeSet::All(ns_to_try),
                             parent_scope,
@@ -2474,7 +2474,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     },
                 )
             });
-            if let Ok(binding) = self.cm().early_resolve_ident_in_lexical_scope(
+            if let Ok(binding) = self.cm().resolve_ident_in_scope_set(
                 ident,
                 ScopeSet::All(ValueNS),
                 parent_scope,

compiler/rustc_resolve/src/ident.rs

@@ -19,7 +19,7 @@ use crate::{
     AmbiguityError, AmbiguityErrorMisc, AmbiguityKind, BindingKey, CmResolver, Determinacy,
     Finalize, ImportKind, LexicalScopeBinding, Module, ModuleKind, ModuleOrUniformRoot,
     NameBinding, NameBindingKind, ParentScope, PathResult, PrivacyError, Res, ResolutionError,
-    Resolver, Scope, ScopeSet, Segment, Used, Weak, errors,
+    Resolver, Scope, ScopeSet, Segment, Stage, Used, Weak, errors,
 };
 
 #[derive(Copy, Clone)]
@@ -49,6 +49,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         scope_set: ScopeSet<'ra>,
         parent_scope: &ParentScope<'ra>,
         ctxt: SyntaxContext,
+        derive_fallback_lint_id: Option<NodeId>,
         mut visitor: impl FnMut(
             &mut CmResolver<'r, 'ra, 'tcx>,
             Scope<'ra>,
@@ -99,15 +100,13 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 
         let rust_2015 = ctxt.edition().is_rust_2015();
         let (ns, macro_kind) = match scope_set {
-            ScopeSet::All(ns)
-            | ScopeSet::ModuleAndExternPrelude(ns, _)
-            | ScopeSet::Late(ns, ..) => (ns, None),
+            ScopeSet::All(ns) | ScopeSet::ModuleAndExternPrelude(ns, _) => (ns, None),
             ScopeSet::ExternPrelude => (TypeNS, None),
             ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind)),
         };
         let module = match scope_set {
             // Start with the specified module.
-            ScopeSet::Late(_, module, _) | ScopeSet::ModuleAndExternPrelude(_, module) => module,
+            ScopeSet::ModuleAndExternPrelude(_, module) => module,
             // Jump out of trait or enum modules, they do not act as scopes.
             _ => parent_scope.module.nearest_item_scope(),
         };
@@ -193,10 +192,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 },
                 Scope::Module(module, prev_lint_id) => {
                     use_prelude = !module.no_implicit_prelude;
-                    let derive_fallback_lint_id = match scope_set {
-                        ScopeSet::Late(.., lint_id) => lint_id,
-                        _ => None,
-                    };
                     match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
                         Some((parent_module, lint_id)) => {
                             Scope::Module(parent_module, lint_id.or(prev_lint_id))
@@ -349,11 +344,13 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 return Some(LexicalScopeBinding::Item(binding));
             } else if let RibKind::Module(module) = rib.kind {
                 // Encountered a module item, abandon ribs and look into that module and preludes.
+                let parent_scope = &ParentScope { module, ..*parent_scope };
+                let finalize = finalize.map(|f| Finalize { stage: Stage::Late, ..f });
                 return self
                     .cm()
-                    .early_resolve_ident_in_lexical_scope(
+                    .resolve_ident_in_scope_set(
                         orig_ident,
-                        ScopeSet::Late(ns, module, finalize.map(|finalize| finalize.node_id)),
+                        ScopeSet::All(ns),
                         parent_scope,
                         finalize,
                         finalize.is_some(),
@@ -376,13 +373,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         unreachable!()
     }
 
-    /// Resolve an identifier in lexical scope.
-    /// This is a variation of `fn resolve_ident_in_lexical_scope` that can be run during
-    /// expansion and import resolution (perhaps they can be merged in the future).
-    /// The function is used for resolving initial segments of macro paths (e.g., `foo` in
-    /// `foo::bar!();` or `foo!();`) and also for import paths on 2018 edition.
+    /// Resolve an identifier in the specified set of scopes.
     #[instrument(level = "debug", skip(self))]
-    pub(crate) fn early_resolve_ident_in_lexical_scope<'r>(
+    pub(crate) fn resolve_ident_in_scope_set<'r>(
         self: CmResolver<'r, 'ra, 'tcx>,
         orig_ident: Ident,
         scope_set: ScopeSet<'ra>,
@@ -411,9 +404,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
 
         let (ns, macro_kind) = match scope_set {
-            ScopeSet::All(ns)
-            | ScopeSet::ModuleAndExternPrelude(ns, _)
-            | ScopeSet::Late(ns, ..) => (ns, None),
+            ScopeSet::All(ns) | ScopeSet::ModuleAndExternPrelude(ns, _) => (ns, None),
             ScopeSet::ExternPrelude => (TypeNS, None),
             ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind)),
         };
@@ -437,10 +428,15 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         }
 
         // Go through all the scopes and try to resolve the name.
+        let derive_fallback_lint_id = match finalize {
+            Some(Finalize { node_id, stage: Stage::Late, .. }) => Some(node_id),
+            _ => None,
+        };
         let break_result = self.visit_scopes(
             scope_set,
             parent_scope,
             orig_ident.span.ctxt(),
+            derive_fallback_lint_id,
             |this, scope, use_prelude, ctxt| {
                 let ident = Ident::new(orig_ident.name, orig_ident.span.with_ctxt(ctxt));
                 let result = match scope {
@@ -510,11 +506,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                             ident,
                             ns,
                             adjusted_parent_scope,
-                            if matches!(scope_set, ScopeSet::Late(..)) {
-                                Shadowing::Unrestricted
-                            } else {
-                                Shadowing::Restricted
-                            },
+                            Shadowing::Restricted,
                             adjusted_finalize,
                             ignore_binding,
                             ignore_import,
@@ -643,7 +635,11 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                             return None;
                         }
 
-                        if finalize.is_none() || matches!(scope_set, ScopeSet::Late(..)) {
+                        // Below we report various ambiguity errors.
+                        // We do not need to report them if we are either in speculative resolution,
+                        // or in late resolution when everything is already imported and expanded
+                        // and no ambiguities exist.
+                        if matches!(finalize, None | Some(Finalize { stage: Stage::Late, .. })) {
                             return Some(Ok(binding));
                         }
 
@@ -811,7 +807,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             ModuleOrUniformRoot::Module(module) => module,
             ModuleOrUniformRoot::ModuleAndExternPrelude(module) => {
                 assert_eq!(shadowing, Shadowing::Unrestricted);
-                let binding = self.early_resolve_ident_in_lexical_scope(
+                let binding = self.resolve_ident_in_scope_set(
                     ident,
                     ScopeSet::ModuleAndExternPrelude(ns, module),
                     parent_scope,
@@ -827,7 +823,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 return if ns != TypeNS {
                     Err((Determined, Weak::No))
                 } else {
-                    let binding = self.early_resolve_ident_in_lexical_scope(
+                    let binding = self.resolve_ident_in_scope_set(
                         ident,
                         ScopeSet::ExternPrelude,
                         parent_scope,
@@ -852,7 +848,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     }
                 }
 
-                let binding = self.early_resolve_ident_in_lexical_scope(
+                let binding = self.resolve_ident_in_scope_set(
                     ident,
                     ScopeSet::All(ns),
                     parent_scope,
@@ -945,7 +941,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // Now we are in situation when new item/import can appear only from a glob or a macro
         // expansion. With restricted shadowing names from globs and macro expansions cannot
         // shadow names from outer scopes, so we can freely fallback from module search to search
-        // in outer scopes. For `early_resolve_ident_in_lexical_scope` to continue search in outer
+        // in outer scopes. For `resolve_ident_in_scope_set` to continue search in outer
         // scopes we return `Undetermined` with `Weak::Yes`.
 
         // Check if one of unexpanded macros can still define the name,
@@ -1040,6 +1036,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // Forbid expanded shadowing to avoid time travel.
         if let Some(shadowed_glob) = shadowed_glob
             && shadowing == Shadowing::Restricted
+            && finalize.stage == Stage::Early
             && binding.expansion != LocalExpnId::ROOT
             && binding.res() != shadowed_glob.res()
         {
@@ -1635,7 +1632,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     _ => Err(Determinacy::determined(finalize.is_some())),
                 }
             } else {
-                self.reborrow().early_resolve_ident_in_lexical_scope(
+                self.reborrow().resolve_ident_in_scope_set(
                     ident,
                     ScopeSet::All(ns),
                     parent_scope,

compiler/rustc_resolve/src/imports.rs

@@ -1446,7 +1446,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                     return;
                 }
 
-                match this.cm().early_resolve_ident_in_lexical_scope(
+                match this.cm().resolve_ident_in_scope_set(
                     target,
                     ScopeSet::All(ns),
                     &import.parent_scope,

compiler/rustc_resolve/src/late/diagnostics.rs

@@ -38,8 +38,8 @@ use crate::late::{
 };
 use crate::ty::fast_reject::SimplifiedType;
 use crate::{
-    Module, ModuleKind, ModuleOrUniformRoot, PathResult, PathSource, Resolver, ScopeSet, Segment,
-    errors, path_names_to_string,
+    Module, ModuleKind, ModuleOrUniformRoot, ParentScope, PathResult, PathSource, Resolver,
+    ScopeSet, Segment, errors, path_names_to_string,
 };
 
 type Res = def::Res<ast::NodeId>;
@@ -2460,10 +2460,11 @@ impl<'ast, 'ra, 'tcx> LateResolutionVisitor<'_, 'ast, 'ra, 'tcx> {
                     self.r.add_module_candidates(module, &mut names, &filter_fn, Some(ctxt));
                 } else if let RibKind::Module(module) = rib.kind {
                     // Encountered a module item, abandon ribs and look into that module and preludes.
+                    let parent_scope = &ParentScope { module, ..self.parent_scope };
                     self.r.add_scope_set_candidates(
                         &mut names,
-                        ScopeSet::Late(ns, module, None),
-                        &self.parent_scope,
+                        ScopeSet::All(ns),
+                        parent_scope,
                         ctxt,
                         filter_fn,
                     );

compiler/rustc_resolve/src/lib.rs

@@ -156,11 +156,8 @@ enum ScopeSet<'ra> {
     ModuleAndExternPrelude(Namespace, Module<'ra>),
     /// Just two extern prelude scopes.
     ExternPrelude,
-    /// All scopes with macro namespace and the given macro kind restriction.
+    /// Same as `All(MacroNS)`, but with the given macro kind restriction.
     Macro(MacroKind),
-    /// All scopes with the given namespace, used for partially performing late resolution.
-    /// The node id enables lints and is used for reporting them.
-    Late(Namespace, Module<'ra>, Option<NodeId>),
 }
 
 /// Everything you need to know about a name's location to resolve it.
@@ -1888,7 +1885,8 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             }
         }
 
-        self.cm().visit_scopes(ScopeSet::All(TypeNS), parent_scope, ctxt, |this, scope, _, _| {
+        let scope_set = ScopeSet::All(TypeNS);
+        self.cm().visit_scopes(scope_set, parent_scope, ctxt, None, |this, scope, _, _| {
             match scope {
                 Scope::Module(module, _) => {
                     this.get_mut().traits_in_module(module, assoc_item, &mut found_traits);
@@ -2455,6 +2453,17 @@ fn module_to_string(mut module: Module<'_>) -> Option<String> {
     Some(names_to_string(names.iter().rev().copied()))
 }
 
+#[derive(Copy, Clone, PartialEq, Debug)]
+enum Stage {
+    /// Resolving an import or a macro.
+    /// Used when macro expansion is either not yet finished, or we are finalizing its results.
+    /// Used by default as a more restrictive variant that can produce additional errors.
+    Early,
+    /// Resolving something in late resolution when all imports are resolved
+    /// and all macros are expanded.
+    Late,
+}
+
 #[derive(Copy, Clone, Debug)]
 struct Finalize {
     /// Node ID for linting.
@@ -2467,9 +2476,11 @@ struct Finalize {
     root_span: Span,
     /// Whether to report privacy errors or silently return "no resolution" for them,
     /// similarly to speculative resolution.
-    report_private: bool,
+    report_private: bool = true,
     /// Tracks whether an item is used in scope or used relatively to a module.
-    used: Used,
+    used: Used = Used::Other,
+    /// Finalizing early or late resolution.
+    stage: Stage = Stage::Early,
 }
 
 impl Finalize {
@@ -2478,7 +2489,7 @@ impl Finalize {
     }
 
     fn with_root_span(node_id: NodeId, path_span: Span, root_span: Span) -> Finalize {
-        Finalize { node_id, path_span, root_span, report_private: true, used: Used::Other }
+        Finalize { node_id, path_span, root_span, .. }
     }
 }
 

compiler/rustc_resolve/src/macros.rs

@@ -789,7 +789,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             self.prohibit_imported_non_macro_attrs(None, res.ok(), path_span);
             res
         } else {
-            let binding = self.reborrow().early_resolve_ident_in_lexical_scope(
+            let binding = self.reborrow().resolve_ident_in_scope_set(
                 path[0].ident,
                 ScopeSet::Macro(kind),
                 parent_scope,
@@ -951,7 +951,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         // FIXME: Should be an output of Speculative Resolution.
         let macro_resolutions = self.single_segment_macro_resolutions.take();
         for (ident, kind, parent_scope, initial_binding, sugg_span) in macro_resolutions {
-            match self.cm().early_resolve_ident_in_lexical_scope(
+            match self.cm().resolve_ident_in_scope_set(
                 ident,
                 ScopeSet::Macro(kind),
                 &parent_scope,
@@ -1006,7 +1006,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 
         let builtin_attrs = mem::take(&mut self.builtin_attrs);
         for (ident, parent_scope) in builtin_attrs {
-            let _ = self.cm().early_resolve_ident_in_lexical_scope(
+            let _ = self.cm().resolve_ident_in_scope_set(
                 ident,
                 ScopeSet::Macro(MacroKind::Attr),
                 &parent_scope,
@@ -1112,7 +1112,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             // If such resolution is successful and gives the same result
             // (e.g. if the macro is re-imported), then silence the lint.
             let no_macro_rules = self.arenas.alloc_macro_rules_scope(MacroRulesScope::Empty);
-            let fallback_binding = self.reborrow().early_resolve_ident_in_lexical_scope(
+            let fallback_binding = self.reborrow().resolve_ident_in_scope_set(
                 path.segments[0].ident,
                 ScopeSet::Macro(MacroKind::Bang),
                 &ParentScope { macro_rules: no_macro_rules, ..*parent_scope },