resolve: Partially unify early and late scope-relative ident resolution

compiler/rustc_lint_defs/src/builtin.rs

@@ -1977,7 +1977,7 @@ declare_lint! {
     Warn,
     "detects proc macro derives using inaccessible names from parent modules",
     @future_incompatible = FutureIncompatibleInfo {
-        reference: "issue #50504 <https://github.com/rust-lang/rust/issues/50504>",
+        reference: "issue #83583 <https://github.com/rust-lang/rust/issues/83583>",
         edition: None,
     };
 }

compiler/rustc_resolve/src/diagnostics.rs

@@ -606,7 +606,7 @@ impl<'a> Resolver<'a> {
     /// Lookup typo candidate in scope for a macro or import.
     fn early_lookup_typo_candidate(
         &mut self,
-        scope_set: ScopeSet,
+        scope_set: ScopeSet<'a>,
         parent_scope: &ParentScope<'a>,
         ident: Ident,
         filter_fn: &impl Fn(Res) -> bool,
@@ -662,7 +662,7 @@ impl<'a> Resolver<'a> {
                     let root_module = this.resolve_crate_root(root_ident);
                     this.add_module_candidates(root_module, &mut suggestions, filter_fn);
                 }
-                Scope::Module(module) => {
+                Scope::Module(module, _) => {
                     this.add_module_candidates(module, &mut suggestions, filter_fn);
                 }
                 Scope::RegisteredAttrs => {

compiler/rustc_resolve/src/lib.rs

@@ -25,7 +25,6 @@ use Determinacy::*;
 use rustc_arena::{DroplessArena, TypedArena};
 use rustc_ast::node_id::NodeMap;
 use rustc_ast::ptr::P;
-use rustc_ast::unwrap_or;
 use rustc_ast::visit::{self, Visitor};
 use rustc_ast::{self as ast, NodeId};
 use rustc_ast::{Crate, CRATE_NODE_ID};
@@ -42,7 +41,7 @@ use rustc_hir::def::Namespace::*;
 use rustc_hir::def::{self, CtorOf, DefKind, NonMacroAttrKind, PartialRes};
 use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, CRATE_DEF_INDEX};
 use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
-use rustc_hir::{PrimTy, TraitCandidate};
+use rustc_hir::TraitCandidate;
 use rustc_index::vec::IndexVec;
 use rustc_metadata::creader::{CStore, CrateLoader};
 use rustc_middle::hir::exports::ExportMap;
@@ -108,7 +107,9 @@ enum Scope<'a> {
     DeriveHelpersCompat,
     MacroRules(MacroRulesScopeRef<'a>),
     CrateRoot,
-    Module(Module<'a>),
+    // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
+    // lint if it should be reported.
+    Module(Module<'a>, Option<NodeId>),
     RegisteredAttrs,
     MacroUsePrelude,
     BuiltinAttrs,
@@ -122,13 +123,17 @@ enum Scope<'a> {
 /// with different restrictions when looking up the resolution.
 /// This enum is currently used only for early resolution (imports and macros),
 /// but not for late resolution yet.
-enum ScopeSet {
+#[derive(Clone, Copy)]
+enum ScopeSet<'a> {
     /// All scopes with the given namespace.
     All(Namespace, /*is_import*/ bool),
     /// Crate root, then extern prelude (used for mixed 2015-2018 mode in macros).
     AbsolutePath(Namespace),
     /// All scopes with macro namespace and 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<'a>, Option<NodeId>),
 }
 
 /// Everything you need to know about a name's location to resolve it.
@@ -1466,7 +1471,7 @@ impl<'a> Resolver<'a> {
 
         self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
             match scope {
-                Scope::Module(module) => {
+                Scope::Module(module, _) => {
                     this.traits_in_module(module, assoc_item, &mut found_traits);
                 }
                 Scope::StdLibPrelude => {
@@ -1630,7 +1635,7 @@ impl<'a> Resolver<'a> {
     /// If the callback returns `Some` result, we stop visiting scopes and return it.
     fn visit_scopes<T>(
         &mut self,
-        scope_set: ScopeSet,
+        scope_set: ScopeSet<'a>,
         parent_scope: &ParentScope<'a>,
         ctxt: SyntaxContext,
         mut visitor: impl FnMut(
@@ -1686,12 +1691,17 @@ impl<'a> Resolver<'a> {
             ScopeSet::All(ns, _) => (ns, None, false),
             ScopeSet::AbsolutePath(ns) => (ns, None, true),
             ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
+            ScopeSet::Late(ns, ..) => (ns, None, false),
         };
+        let module = match scope_set {
+            // Start with the specified module.
+            ScopeSet::Late(_, module, _) => module,
             // Jump out of trait or enum modules, they do not act as scopes.
-        let module = parent_scope.module.nearest_item_scope();
+            _ => parent_scope.module.nearest_item_scope(),
+        };
         let mut scope = match ns {
             _ if is_absolute_path => Scope::CrateRoot,
-            TypeNS | ValueNS => Scope::Module(module),
+            TypeNS | ValueNS => Scope::Module(module, None),
             MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
         };
         let mut ctxt = ctxt.normalize_to_macros_2_0();
@@ -1756,7 +1766,7 @@ impl<'a> Resolver<'a> {
                     MacroRulesScope::Invocation(invoc_id) => {
                         Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
                     }
-                    MacroRulesScope::Empty => Scope::Module(module),
+                    MacroRulesScope::Empty => Scope::Module(module, None),
                 },
                 Scope::CrateRoot => match ns {
                     TypeNS => {
@@ -1765,10 +1775,16 @@ impl<'a> Resolver<'a> {
                     }
                     ValueNS | MacroNS => break,
                 },
-                Scope::Module(module) => {
+                Scope::Module(module, prev_lint_id) => {
                     use_prelude = !module.no_implicit_prelude;
-                    match self.hygienic_lexical_parent(module, &mut ctxt) {
+                    let derive_fallback_lint_id = match scope_set {
-                        Some(parent_module) => Scope::Module(parent_module),
+                        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))
+                        }
                         None => {
                             ctxt.adjust(ExpnId::root());
                             match ns {
@@ -1824,6 +1840,7 @@ impl<'a> Resolver<'a> {
         ribs: &[Rib<'a>],
     ) -> Option<LexicalScopeBinding<'a>> {
         assert!(ns == TypeNS || ns == ValueNS);
+        let orig_ident = ident;
         if ident.name == kw::Empty {
             return Some(LexicalScopeBinding::Res(Res::Err));
         }
@@ -1873,6 +1890,11 @@ impl<'a> Resolver<'a> {
                 _ => continue,
             };
 
+            match module.kind {
+                ModuleKind::Block(..) => {} // We can see through blocks
+                _ => break,
+            }
+
             let item = self.resolve_ident_in_module_unadjusted(
                 ModuleOrUniformRoot::Module(module),
                 ident,
@@ -1885,123 +1907,32 @@ impl<'a> Resolver<'a> {
                 // The ident resolves to an item.
                 return Some(LexicalScopeBinding::Item(binding));
             }
-
-            match module.kind {
-                ModuleKind::Block(..) => {} // We can see through blocks
-                _ => break,
-            }
         }
 
-        ident = normalized_ident;
+        self.early_resolve_ident_in_lexical_scope(
-        let mut poisoned = None;
+            orig_ident,
-        loop {
+            ScopeSet::Late(ns, module, record_used_id),
-            let mut span_data = ident.span.data();
+            parent_scope,
-            let opt_module = if let Some(node_id) = record_used_id {
+            record_used,
-                self.hygienic_lexical_parent_with_compatibility_fallback(
-                    module,
-                    &mut span_data.ctxt,
-                    node_id,
-                    &mut poisoned,
-                )
-            } else {
-                self.hygienic_lexical_parent(module, &mut span_data.ctxt)
-            };
-            ident.span = span_data.span();
-            module = unwrap_or!(opt_module, break);
-            let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
-            let result = self.resolve_ident_in_module_unadjusted(
-                ModuleOrUniformRoot::Module(module),
-                ident,
-                ns,
-                adjusted_parent_scope,
             record_used,
             path_span,
-            );
+        )
-
+        .ok()
-            match result {
+        .map(LexicalScopeBinding::Item)
-                Ok(binding) => {
-                    if let Some(node_id) = poisoned {
-                        self.lint_buffer.buffer_lint_with_diagnostic(
-                            lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
-                            node_id,
-                            ident.span,
-                            &format!("cannot find {} `{}` in this scope", ns.descr(), ident),
-                            BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(ident.span),
-                        );
-                    }
-                    return Some(LexicalScopeBinding::Item(binding));
-                }
-                Err(Determined) => continue,
-                Err(Undetermined) => {
-                    span_bug!(ident.span, "undetermined resolution during main resolution pass")
-                }
-            }
-        }
-
-        if !module.no_implicit_prelude {
-            ident.span.adjust(ExpnId::root());
-            if ns == TypeNS {
-                if let Some(binding) = self.extern_prelude_get(ident, !record_used) {
-                    return Some(LexicalScopeBinding::Item(binding));
-                }
-                if let Some(ident) = self.registered_tools.get(&ident) {
-                    let binding =
-                        (Res::ToolMod, ty::Visibility::Public, ident.span, ExpnId::root())
-                            .to_name_binding(self.arenas);
-                    return Some(LexicalScopeBinding::Item(binding));
-                }
-            }
-            if let Some(prelude) = self.prelude {
-                if let Ok(binding) = self.resolve_ident_in_module_unadjusted(
-                    ModuleOrUniformRoot::Module(prelude),
-                    ident,
-                    ns,
-                    parent_scope,
-                    false,
-                    path_span,
-                ) {
-                    return Some(LexicalScopeBinding::Item(binding));
-                }
-            }
-        }
-
-        if ns == TypeNS {
-            if let Some(prim_ty) = PrimTy::from_name(ident.name) {
-                let binding =
-                    (Res::PrimTy(prim_ty), ty::Visibility::Public, DUMMY_SP, ExpnId::root())
-                        .to_name_binding(self.arenas);
-                return Some(LexicalScopeBinding::Item(binding));
-            }
-        }
-
-        None
     }
 
     fn hygienic_lexical_parent(
         &mut self,
         module: Module<'a>,
         ctxt: &mut SyntaxContext,
-    ) -> Option<Module<'a>> {
+        derive_fallback_lint_id: Option<NodeId>,
+    ) -> Option<(Module<'a>, Option<NodeId>)> {
         if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
-            return Some(self.macro_def_scope(ctxt.remove_mark()));
+            return Some((self.macro_def_scope(ctxt.remove_mark()), None));
         }
 
         if let ModuleKind::Block(..) = module.kind {
-            return Some(module.parent.unwrap().nearest_item_scope());
+            return Some((module.parent.unwrap().nearest_item_scope(), None));
-        }
-
-        None
-    }
-
-    fn hygienic_lexical_parent_with_compatibility_fallback(
-        &mut self,
-        module: Module<'a>,
-        ctxt: &mut SyntaxContext,
-        node_id: NodeId,
-        poisoned: &mut Option<NodeId>,
-    ) -> Option<Module<'a>> {
-        if let module @ Some(..) = self.hygienic_lexical_parent(module, ctxt) {
-            return module;
         }
 
         // We need to support the next case under a deprecation warning
@@ -2015,6 +1946,7 @@ impl<'a> Resolver<'a> {
         // ---- end
         // ```
         // So we have to fall back to the module's parent during lexical resolution in this case.
+        if derive_fallback_lint_id.is_some() {
             if let Some(parent) = module.parent {
                 // Inner module is inside the macro, parent module is outside of the macro.
                 if module.expansion != parent.expansion
@@ -2027,8 +1959,8 @@ impl<'a> Resolver<'a> {
                             && ext.macro_kind() == MacroKind::Derive
                             && parent.expansion.outer_expn_is_descendant_of(*ctxt)
                         {
-                        *poisoned = Some(node_id);
+                            return Some((parent, derive_fallback_lint_id));
-                        return module.parent;
+                        }
                     }
                 }
             }

compiler/rustc_resolve/src/macros.rs

@@ -24,7 +24,8 @@ use rustc_hir::def_id;
 use rustc_hir::PrimTy;
 use rustc_middle::middle::stability;
 use rustc_middle::ty;
-use rustc_session::lint::builtin::{LEGACY_DERIVE_HELPERS, SOFT_UNSTABLE, UNUSED_MACROS};
+use rustc_session::lint::builtin::{LEGACY_DERIVE_HELPERS, PROC_MACRO_DERIVE_RESOLUTION_FALLBACK};
+use rustc_session::lint::builtin::{SOFT_UNSTABLE, UNUSED_MACROS};
 use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_session::parse::feature_err;
 use rustc_session::Session;
@@ -642,7 +643,7 @@ impl<'a> Resolver<'a> {
     crate fn early_resolve_ident_in_lexical_scope(
         &mut self,
         orig_ident: Ident,
-        scope_set: ScopeSet,
+        scope_set: ScopeSet<'a>,
         parent_scope: &ParentScope<'a>,
         record_used: bool,
         force: bool,
@@ -669,6 +670,7 @@ impl<'a> Resolver<'a> {
             ScopeSet::All(ns, is_import) => (ns, None, is_import),
             ScopeSet::AbsolutePath(ns) => (ns, None, false),
             ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind), false),
+            ScopeSet::Late(ns, ..) => (ns, None, false),
         };
 
         // This is *the* result, resolution from the scope closest to the resolved identifier.
@@ -777,19 +779,34 @@ impl<'a> Resolver<'a> {
                             Err((Determinacy::Determined, _)) => Err(Determinacy::Determined),
                         }
                     }
-                    Scope::Module(module) => {
+                    Scope::Module(module, derive_fallback_lint_id) => {
                         let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
                         let binding = this.resolve_ident_in_module_unadjusted_ext(
                             ModuleOrUniformRoot::Module(module),
                             ident,
                             ns,
                             adjusted_parent_scope,
-                            true,
+                            !matches!(scope_set, ScopeSet::Late(..)),
                             record_used,
                             path_span,
                         );
                         match binding {
                             Ok(binding) => {
+                                if let Some(lint_id) = derive_fallback_lint_id {
+                                    this.lint_buffer.buffer_lint_with_diagnostic(
+                                        PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
+                                        lint_id,
+                                        orig_ident.span,
+                                        &format!(
+                                            "cannot find {} `{}` in this scope",
+                                            ns.descr(),
+                                            ident
+                                        ),
+                                        BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(
+                                            orig_ident.span,
+                                        ),
+                                    );
+                                }
                                 let misc_flags = if ptr::eq(module, this.graph_root) {
                                     Flags::MISC_SUGGEST_CRATE
                                 } else if module.is_normal() {
@@ -873,7 +890,7 @@ impl<'a> Resolver<'a> {
                     Ok((binding, flags))
                         if sub_namespace_match(binding.macro_kind(), macro_kind) =>
                     {
-                        if !record_used {
+                        if !record_used || matches!(scope_set, ScopeSet::Late(..)) {
                             return Some(Ok(binding));
                         }
 

src/test/ui/proc-macro/generate-mod.stderr

@@ -46,7 +46,8 @@ LL | #[derive(generate_mod::CheckDerive)]
    |
    = note: `#[warn(proc_macro_derive_resolution_fallback)]` on by default
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #50504 <https://github.com/rust-lang/rust/issues/50504>
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: this warning originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 warning: cannot find type `OuterDerive` in this scope
   --> $DIR/generate-mod.rs:16:10
@@ -55,7 +56,8 @@ LL | #[derive(generate_mod::CheckDerive)]
    |          ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #50504 <https://github.com/rust-lang/rust/issues/50504>
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: this warning originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 warning: cannot find type `FromOutside` in this scope
   --> $DIR/generate-mod.rs:23:14
@@ -64,7 +66,8 @@ LL |     #[derive(generate_mod::CheckDerive)]
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #50504 <https://github.com/rust-lang/rust/issues/50504>
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: this warning originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 warning: cannot find type `OuterDerive` in this scope
   --> $DIR/generate-mod.rs:23:14
@@ -73,7 +76,8 @@ LL |     #[derive(generate_mod::CheckDerive)]
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
-   = note: for more information, see issue #50504 <https://github.com/rust-lang/rust/issues/50504>
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: this warning originates in a derive macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to 4 previous errors; 4 warnings emitted