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rust/rust/84f09c7144fc419fc42915b406db8e53ab2eca03/./compiler/rustc_resolve/src/ident.rs
blob: 06cc2315851d8c1dcd8eecd87ff870ad5b9dba8e [file]
use std::ops::ControlFlow;
use Determinacy::*;
use Namespace::*;
use rustc_ast::{self as ast, NodeId};
use rustc_errors::ErrorGuaranteed;
use rustc_hir::def::{DefKind, MacroKinds, Namespace, NonMacroAttrKind, PerNS};
use rustc_lint_defs::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK;
use rustc_middle::middle::resolve::PartialRes;
use rustc_middle::{bug, span_bug};
use rustc_session::diagnostics::feature_err;
use rustc_span::edition::Edition;
use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext};
use rustc_span::{Ident, Span, kw, sym};
use smallvec::SmallVec;
use tracing::{debug, instrument};
use crate::diagnostics::{ParamKindInEnumDiscriminant, ParamKindInNonTrivialAnonConst};
use crate::hygiene::Macros20NormalizedSyntaxContext;
use crate::imports::{Import, NameResolution, cycle_detection};
use crate::late::{
ConstantHasGenerics, DiagMetadata, NoConstantGenericsReason, PathSource, Rib, RibKind,
};
use crate::macros::{MacroRulesScope, sub_namespace_match};
use crate::{
AmbiguityError, AmbiguityKind, AmbiguityWarning, BindingKey, CmResolver, Decl, DeclKind,
Determinacy, ExternModule, Finalize, IdentKey, ImportKind, ImportSummary, LateDecl,
LocalModule, Module, ModuleKind, ModuleOrUniformRoot, ParentScope, PathResult, PrivacyError,
Res, ResolutionError, Resolver, Scope, ScopeSet, Segment, Stage, Symbol, Used, diagnostics,
module_to_string,
};
#[derive(Copy, Clone)]
pub enum UsePrelude {
No,
Yes,
}
impl From<UsePrelude> for bool {
fn from(up: UsePrelude) -> bool {
matches!(up, UsePrelude::Yes)
}
}
#[derive(Debug, PartialEq, Clone, Copy)]
enum Shadowing {
Restricted,
Unrestricted,
}
impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
/// A generic scope visitor.
/// Visits scopes in order to resolve some identifier in them or perform other actions.
/// If the callback returns `Some` result, we stop visiting scopes and return it.
pub(crate) fn visit_scopes<'r, T>(
mut self: CmResolver<'r, 'ra, 'tcx>,
scope_set: ScopeSet<'ra>,
parent_scope: &ParentScope<'ra>,
mut ctxt: Macros20NormalizedSyntaxContext,
orig_ident_span: Span,
derive_fallback_lint_id: Option<NodeId>,
mut visitor: impl FnMut(
CmResolver<'_, 'ra, 'tcx>,
Scope<'ra>,
UsePrelude,
Macros20NormalizedSyntaxContext,
) -> ControlFlow<T>,
) -> Option<T> {
// General principles:
// 1. Not controlled (user-defined) names should have higher priority than controlled names
// built into the language or standard library. This way we can add new names into the
// language or standard library without breaking user code.
// 2. "Closed set" below means new names cannot appear after the current resolution attempt.
// Places to search (in order of decreasing priority):
// (Type NS)
// 1. FIXME: Ribs (type parameters), there's no necessary infrastructure yet
// (open set, not controlled).
// 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
// (open, not controlled).
// 3. Extern prelude (open, the open part is from macro expansions, not controlled).
// 4. Tool modules (closed, controlled right now, but not in the future).
// 5. Standard library prelude (de-facto closed, controlled).
// 6. Language prelude (closed, controlled).
// (Value NS)
// 1. FIXME: Ribs (local variables), there's no necessary infrastructure yet
// (open set, not controlled).
// 2. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
// (open, not controlled).
// 3. Standard library prelude (de-facto closed, controlled).
// (Macro NS)
// 1-3. Derive helpers (open, not controlled). All ambiguities with other names
// are currently reported as errors. They should be higher in priority than preludes
// and probably even names in modules according to the "general principles" above. They
// also should be subject to restricted shadowing because are effectively produced by
// derives (you need to resolve the derive first to add helpers into scope), but they
// should be available before the derive is expanded for compatibility.
// It's mess in general, so we are being conservative for now.
// 1-3. `macro_rules` (open, not controlled), loop through `macro_rules` scopes. Have higher
// priority than prelude macros, but create ambiguities with macros in modules.
// 1-3. Names in modules (both normal `mod`ules and blocks), loop through hygienic parents
// (open, not controlled). Have higher priority than prelude macros, but create
// ambiguities with `macro_rules`.
// 4. `macro_use` prelude (open, the open part is from macro expansions, not controlled).
// 4a. User-defined prelude from macro-use
// (open, the open part is from macro expansions, not controlled).
// 4b. "Standard library prelude" part implemented through `macro-use` (closed, controlled).
// 4c. Standard library prelude (de-facto closed, controlled).
// 6. Language prelude: builtin attributes (closed, controlled).
let (ns, macro_kind) = match scope_set {
ScopeSet::All(ns)
| ScopeSet::Module(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::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(),
};
let module_only = matches!(scope_set, ScopeSet::Module(..));
let module_and_extern_prelude = matches!(scope_set, ScopeSet::ModuleAndExternPrelude(..));
let extern_prelude = matches!(scope_set, ScopeSet::ExternPrelude);
let mut scope = match ns {
_ if module_only || module_and_extern_prelude => Scope::ModuleNonGlobs(module, None),
_ if extern_prelude => Scope::ExternPreludeItems,
TypeNS | ValueNS => Scope::ModuleNonGlobs(module, None),
MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
};
let mut use_prelude = !module.no_implicit_prelude;
loop {
let visit = match scope {
// Derive helpers are not in scope when resolving derives in the same container.
Scope::DeriveHelpers(expn_id) => {
!(expn_id == parent_scope.expansion && macro_kind == Some(MacroKind::Derive))
}
Scope::DeriveHelpersCompat => true,
Scope::MacroRules(macro_rules_scope) => {
// Use "path compression" on `macro_rules` scope chains. This is an optimization
// used to avoid long scope chains, see the comments on `MacroRulesScopeRef`.
// As another consequence of this optimization visitors never observe invocation
// scopes for macros that were already expanded.
let mut scope = macro_rules_scope.get();
while let MacroRulesScope::Invocation(invoc_id) = scope {
if let Some(next) = self.output_macro_rules_scopes.get(&invoc_id) {
scope = next.get();
macro_rules_scope.set(scope);
} else {
break;
}
}
true
}
Scope::ModuleNonGlobs(..) | Scope::ModuleGlobs(..) => true,
Scope::MacroUsePrelude => use_prelude || orig_ident_span.is_rust_2015(),
Scope::BuiltinAttrs => true,
Scope::ExternPreludeItems | Scope::ExternPreludeFlags => {
use_prelude || module_and_extern_prelude || extern_prelude
}
Scope::ToolAttributePrelude => use_prelude,
Scope::StdLibPrelude => use_prelude || ns == MacroNS,
Scope::BuiltinTypes => true,
};
if visit {
let use_prelude = if use_prelude { UsePrelude::Yes } else { UsePrelude::No };
if let ControlFlow::Break(break_result) =
visitor(self.reborrow(), scope, use_prelude, ctxt)
{
return Some(break_result);
}
}
scope = match scope {
Scope::DeriveHelpers(LocalExpnId::ROOT) => Scope::DeriveHelpersCompat,
Scope::DeriveHelpers(expn_id) => {
// Derive helpers are not visible to code generated by bang or derive macros.
let expn_data = expn_id.expn_data();
match expn_data.kind {
ExpnKind::Root
| ExpnKind::Macro(MacroKind::Bang | MacroKind::Derive, _) => {
Scope::DeriveHelpersCompat
}
_ => Scope::DeriveHelpers(expn_data.parent.expect_local()),
}
}
Scope::DeriveHelpersCompat => Scope::MacroRules(parent_scope.macro_rules),
Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
MacroRulesScope::Def(binding) => {
Scope::MacroRules(binding.parent_macro_rules_scope)
}
MacroRulesScope::Invocation(invoc_id) => {
Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
}
MacroRulesScope::Empty => Scope::ModuleNonGlobs(module, None),
},
Scope::ModuleNonGlobs(module, lint_id) => Scope::ModuleGlobs(module, lint_id),
Scope::ModuleGlobs(..) if module_only => break,
Scope::ModuleGlobs(..) if module_and_extern_prelude => match ns {
TypeNS => {
ctxt.update_unchecked(|ctxt| ctxt.adjust(ExpnId::root()));
Scope::ExternPreludeItems
}
ValueNS | MacroNS => break,
},
Scope::ModuleGlobs(module, prev_lint_id) => {
use_prelude = !module.no_implicit_prelude;
match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
Some((parent_module, lint_id)) => {
Scope::ModuleNonGlobs(parent_module, lint_id.or(prev_lint_id))
}
None => {
ctxt.update_unchecked(|ctxt| ctxt.adjust(ExpnId::root()));
match ns {
TypeNS => Scope::ExternPreludeItems,
ValueNS => Scope::StdLibPrelude,
MacroNS => Scope::MacroUsePrelude,
}
}
}
}
Scope::MacroUsePrelude => Scope::StdLibPrelude,
Scope::BuiltinAttrs => break, // nowhere else to search
Scope::ExternPreludeItems => Scope::ExternPreludeFlags,
Scope::ExternPreludeFlags if module_and_extern_prelude || extern_prelude => break,
Scope::ExternPreludeFlags => Scope::ToolAttributePrelude,
Scope::ToolAttributePrelude => Scope::StdLibPrelude,
Scope::StdLibPrelude => match ns {
TypeNS => Scope::BuiltinTypes,
ValueNS => break, // nowhere else to search
MacroNS => Scope::BuiltinAttrs,
},
Scope::BuiltinTypes => break, // nowhere else to search
};
}
None
}
fn hygienic_lexical_parent(
&self,
module: Module<'ra>,
ctxt: &mut Macros20NormalizedSyntaxContext,
derive_fallback_lint_id: Option<NodeId>,
) -> Option<(Module<'ra>, Option<NodeId>)> {
if !module.expansion.outer_expn_is_descendant_of(**ctxt) {
let expn_id = ctxt.update_unchecked(|ctxt| ctxt.remove_mark());
return Some((self.expn_def_scope(expn_id), None));
}
if let ModuleKind::Block = module.kind {
return Some((module.parent.unwrap().nearest_item_scope(), None));
}
// We need to support the next case under a deprecation warning
// ```
// struct MyStruct;
// ---- begin: this comes from a proc macro derive
// mod implementation_details {
// // Note that `MyStruct` is not in scope here.
// impl SomeTrait for MyStruct { ... }
// }
// ---- 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()
&& let Some(parent) = module.parent
// Inner module is inside the macro
&& module.expansion != parent.expansion
// Parent module is outside of the macro
&& module.expansion.is_descendant_of(parent.expansion)
// The macro is a proc macro derive
&& let Some(def_id) = module.expansion.expn_data().macro_def_id
{
let ext = self.get_macro_by_def_id(def_id);
if ext.builtin_name.is_none()
&& ext.macro_kinds() == MacroKinds::DERIVE
&& parent.expansion.outer_expn_is_descendant_of(**ctxt)
{
return Some((parent, derive_fallback_lint_id));
}
}
None
}
/// This resolves the identifier `ident` in the namespace `ns` in the current lexical scope.
/// More specifically, we proceed up the hierarchy of scopes and return the binding for
/// `ident` in the first scope that defines it (or None if no scopes define it).
///
/// A block's items are above its local variables in the scope hierarchy, regardless of where
/// the items are defined in the block. For example,
/// ```rust
/// fn f() {
/// g(); // Since there are no local variables in scope yet, this resolves to the item.
/// let g = || {};
/// fn g() {}
/// g(); // This resolves to the local variable `g` since it shadows the item.
/// }
/// ```
///
/// Invariant: This must only be called during main resolution, not during
/// import resolution.
#[instrument(level = "debug", skip(self, ribs))]
pub(crate) fn resolve_ident_in_lexical_scope(
&mut self,
mut ident: Ident,
ns: Namespace,
parent_scope: &ParentScope<'ra>,
finalize: Option<Finalize>,
ribs: &[Rib<'ra>],
ignore_decl: Option<Decl<'ra>>,
diag_metadata: Option<&DiagMetadata<'_>>,
) -> Option<LateDecl<'ra>> {
let orig_ident = ident;
let (general_span, normalized_span) = if ident.name == kw::SelfUpper {
// FIXME(jseyfried) improve `Self` hygiene
let empty_span = ident.span.with_ctxt(SyntaxContext::root());
(empty_span, empty_span)
} else if ns == TypeNS {
let normalized_span = ident.span.normalize_to_macros_2_0();
(normalized_span, normalized_span)
} else {
(ident.span.normalize_to_macro_rules(), ident.span.normalize_to_macros_2_0())
};
ident.span = general_span;
let normalized_ident = Ident { span: normalized_span, ..ident };
// Walk backwards up the ribs in scope.
for (i, rib) in ribs.iter().enumerate().rev() {
debug!("walk rib\n{:?}", rib.bindings);
// Use the rib kind to determine whether we are resolving parameters
// (macro 2.0 hygiene) or local variables (`macro_rules` hygiene).
let rib_ident = if rib.kind.contains_params() { normalized_ident } else { ident };
if let Some((original_rib_ident_def, res)) = rib.bindings.get_key_value(&rib_ident) {
// The ident resolves to a type parameter or local variable.
return Some(LateDecl::RibDef(self.validate_res_from_ribs(
i,
rib_ident,
*res,
finalize.map(|_| general_span),
*original_rib_ident_def,
ribs,
diag_metadata,
)));
} else if let RibKind::Block(Some(module)) = rib.kind
&& let Ok(binding) = self.cm_mut().resolve_ident_in_scope_set(
ident,
ScopeSet::Module(ns, module.to_module()),
parent_scope,
finalize.map(|finalize| Finalize { used: Used::Scope, ..finalize }),
ignore_decl,
None,
)
{
// The ident resolves to an item in a block.
return Some(LateDecl::Decl(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: module.to_module(), ..*parent_scope };
let finalize = finalize.map(|f| Finalize { stage: Stage::Late, ..f });
return self
.cm_mut()
.resolve_ident_in_scope_set(
orig_ident,
ScopeSet::All(ns),
parent_scope,
finalize,
ignore_decl,
None,
)
.ok()
.map(LateDecl::Decl);
}
if let RibKind::MacroDefinition(def) = rib.kind
&& def == self.macro_def(ident.span.ctxt())
{
// If an invocation of this macro created `ident`, give up on `ident`
// and switch to `ident`'s source from the macro definition.
ident.span.remove_mark();
}
}
unreachable!()
}
/// Resolve an identifier in the specified set of scopes.
pub(crate) fn resolve_ident_in_scope_set<'r>(
self: CmResolver<'r, 'ra, 'tcx>,
orig_ident: Ident,
scope_set: ScopeSet<'ra>,
parent_scope: &ParentScope<'ra>,
finalize: Option<Finalize>,
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
) -> Result<Decl<'ra>, Determinacy> {
self.resolve_ident_in_scope_set_inner(
IdentKey::new(orig_ident),
orig_ident.span,
scope_set,
parent_scope,
finalize,
ignore_decl,
ignore_import,
)
}
fn resolve_ident_in_scope_set_inner<'r>(
self: CmResolver<'r, 'ra, 'tcx>,
ident: IdentKey,
orig_ident_span: Span,
scope_set: ScopeSet<'ra>,
parent_scope: &ParentScope<'ra>,
finalize: Option<Finalize>,
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
) -> Result<Decl<'ra>, Determinacy> {
// Make sure `self`, `super` etc produce an error when passed to here.
if ident.name.is_path_segment_keyword() {
return Err(Determinacy::Determined);
}
let (ns, macro_kind) = match scope_set {
ScopeSet::All(ns)
| ScopeSet::Module(ns, _)
| ScopeSet::ModuleAndExternPrelude(ns, _) => (ns, None),
ScopeSet::ExternPrelude => (TypeNS, None),
ScopeSet::Macro(macro_kind) => (MacroNS, Some(macro_kind)),
};
let derive_fallback_lint_id = match finalize {
Some(Finalize { node_id, stage: Stage::Late, .. }) => Some(node_id),
_ => None,
};
// This is *the* result, resolution from the scope closest to the resolved identifier.
// However, sometimes this result is "weak" because it comes from a glob import or
// a macro expansion, and in this case it cannot shadow names from outer scopes, e.g.
// mod m { ... } // solution in outer scope
// {
// use prefix::*; // imports another `m` - innermost solution
// // weak, cannot shadow the outer `m`, need to report ambiguity error
// m::mac!();
// }
// So we have to save the innermost solution and continue searching in outer scopes
// to detect potential ambiguities.
let mut innermost_results: SmallVec<[(Decl<'_>, Scope<'_>); 2]> = SmallVec::new();
let mut determinacy = Determinacy::Determined;
// Go through all the scopes and try to resolve the name.
let break_result = self.visit_scopes(
scope_set,
parent_scope,
ident.ctxt,
orig_ident_span,
derive_fallback_lint_id,
|mut this, scope, use_prelude, ctxt| {
let ident = IdentKey { name: ident.name, ctxt };
let res = match this.reborrow().resolve_ident_in_scope(
ident,
orig_ident_span,
ns,
scope,
use_prelude,
scope_set,
parent_scope,
// Shadowed decls don't need to be marked as used or non-speculatively loaded.
if innermost_results.is_empty() { finalize } else { None },
ignore_decl,
ignore_import,
) {
Ok(decl) => Ok(decl),
// We can break with an error at this step, it means we cannot determine the
// resolution right now, but we must block and wait until we can, instead of
// considering outer scopes. Although there's no need to do that if we already
// have a better solution.
Err(ControlFlow::Break(determinacy)) if innermost_results.is_empty() => {
return ControlFlow::Break(Err(determinacy));
}
Err(determinacy) => Err(determinacy.into_value()),
};
match res {
Ok(decl) if sub_namespace_match(decl.macro_kinds(), macro_kind) => {
// 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.
let import = match finalize {
None | Some(Finalize { stage: Stage::Late, .. }) => {
return ControlFlow::Break(Ok(decl));
}
Some(Finalize { import, .. }) => import,
};
this.get_mut().maybe_push_glob_vs_glob_vis_ambiguity(
ident,
orig_ident_span,
decl,
import,
);
if let Some(&(innermost_decl, _)) = innermost_results.first() {
// Found another solution, if the first one was "weak", report an error.
if this.get_mut().maybe_push_ambiguity(
ident,
orig_ident_span,
ns,
scope_set,
parent_scope,
decl,
scope,
&innermost_results,
import,
) {
// No need to search for more potential ambiguities, one is enough.
return ControlFlow::Break(Ok(innermost_decl));
}
}
innermost_results.push((decl, scope));
}
Ok(_) | Err(Determinacy::Determined) => {}
Err(Determinacy::Undetermined) => determinacy = Determinacy::Undetermined,
}
ControlFlow::Continue(())
},
);
// Scope visiting returned some result early.
if let Some(break_result) = break_result {
return break_result;
}
// Scope visiting walked all the scopes and maybe found something in one of them.
match innermost_results.first() {
Some(&(decl, ..)) => Ok(decl),
None => Err(determinacy),
}
}
fn resolve_ident_in_scope<'r>(
mut self: CmResolver<'r, 'ra, 'tcx>,
ident: IdentKey,
orig_ident_span: Span,
ns: Namespace,
scope: Scope<'ra>,
use_prelude: UsePrelude,
scope_set: ScopeSet<'ra>,
parent_scope: &ParentScope<'ra>,
finalize: Option<Finalize>,
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
) -> Result<Decl<'ra>, ControlFlow<Determinacy, Determinacy>> {
let ret = match scope {
Scope::DeriveHelpers(expn_id) => {
if let Some(decl) = self
.helper_attrs
.get(&expn_id)
.and_then(|attrs| attrs.iter().rfind(|(i, ..)| ident == *i).map(|(.., d)| *d))
{
Ok(decl)
} else {
Err(Determinacy::Determined)
}
}
Scope::DeriveHelpersCompat => {
let mut result = Err(Determinacy::Determined);
for derive in parent_scope.derives {
let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
match self.reborrow().resolve_derive_macro_path(
derive,
parent_scope,
false,
ignore_import,
) {
Ok((Some(ext), _)) => {
if ext.helper_attrs.contains(&ident.name) {
let decl = self.arenas.new_pub_def_decl(
Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat),
derive.span,
LocalExpnId::ROOT,
);
result = Ok(decl);
break;
}
}
Ok(_) | Err(Determinacy::Determined) => {}
Err(Determinacy::Undetermined) => result = Err(Determinacy::Undetermined),
}
}
result
}
Scope::MacroRules(macro_rules_scope) => match macro_rules_scope.get() {
MacroRulesScope::Def(macro_rules_def) if ident == macro_rules_def.ident => {
Ok(macro_rules_def.decl)
}
MacroRulesScope::Invocation(_) => Err(Determinacy::Undetermined),
_ => Err(Determinacy::Determined),
},
Scope::ModuleNonGlobs(module, derive_fallback_lint_id) => {
let (adjusted_parent_scope, adjusted_finalize) = if matches!(
scope_set,
ScopeSet::Module(..) | ScopeSet::ModuleAndExternPrelude(..)
) {
(parent_scope, finalize)
} else {
(
&ParentScope { module, ..*parent_scope },
finalize.map(|f| Finalize { used: Used::Scope, ..f }),
)
};
let shadowing = if matches!(scope_set, ScopeSet::Module(..)) {
Shadowing::Unrestricted
} else {
Shadowing::Restricted
};
let decl = if module.is_local() {
self.reborrow().resolve_ident_in_local_module_non_globs_unadjusted(
module.expect_local(),
ident,
orig_ident_span,
ns,
adjusted_parent_scope,
shadowing,
adjusted_finalize,
ignore_decl,
ignore_import,
)
} else {
self.reborrow().resolve_ident_in_extern_module_non_globs_unadjusted(
module.expect_extern(),
ident,
orig_ident_span,
ns,
adjusted_parent_scope,
shadowing,
adjusted_finalize,
ignore_decl,
)
};
match decl {
Ok(decl) => {
if let Some(lint_id) = derive_fallback_lint_id {
self.get_mut().lint_buffer.buffer_lint(
PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
lint_id,
orig_ident_span,
diagnostics::ProcMacroDeriveResolutionFallback {
span: orig_ident_span,
ns_descr: ns.descr(),
ident: ident.name,
},
);
}
Ok(decl)
}
Err(ControlFlow::Continue(determinacy)) => Err(determinacy),
Err(ControlFlow::Break(..)) => return decl,
}
}
Scope::ModuleGlobs(module, _) if !module.is_local() => {
// Fast path: external module decoding only creates non-glob declarations.
Err(Determined)
}
Scope::ModuleGlobs(module, derive_fallback_lint_id) => {
let (adjusted_parent_scope, adjusted_finalize) = if matches!(
scope_set,
ScopeSet::Module(..) | ScopeSet::ModuleAndExternPrelude(..)
) {
(parent_scope, finalize)
} else {
(
&ParentScope { module, ..*parent_scope },
finalize.map(|f| Finalize { used: Used::Scope, ..f }),
)
};
let binding = self.reborrow().resolve_ident_in_module_globs_unadjusted(
module.expect_local(),
ident,
orig_ident_span,
ns,
adjusted_parent_scope,
if matches!(scope_set, ScopeSet::Module(..)) {
Shadowing::Unrestricted
} else {
Shadowing::Restricted
},
adjusted_finalize,
ignore_decl,
ignore_import,
);
match binding {
Ok(binding) => {
if let Some(lint_id) = derive_fallback_lint_id {
self.get_mut().lint_buffer.buffer_lint(
PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
lint_id,
orig_ident_span,
diagnostics::ProcMacroDeriveResolutionFallback {
span: orig_ident_span,
ns_descr: ns.descr(),
ident: ident.name,
},
);
}
Ok(binding)
}
Err(ControlFlow::Continue(determinacy)) => Err(determinacy),
Err(ControlFlow::Break(..)) => return binding,
}
}
Scope::MacroUsePrelude => match self.macro_use_prelude.get(&ident.name).cloned() {
Some(decl) => Ok(decl),
None => {
Err(Determinacy::determined(!self.graph_root.has_unexpanded_invocations(&self)))
}
},
Scope::BuiltinAttrs => match self.builtin_attr_decls.get(&ident.name) {
Some(decl) => Ok(*decl),
None => Err(Determinacy::Determined),
},
Scope::ExternPreludeItems => {
match self.reborrow().extern_prelude_get_item(
ident,
orig_ident_span,
finalize.is_some(),
) {
Some(decl) => Ok(decl),
None => Err(Determinacy::determined(
!self.graph_root.has_unexpanded_invocations(&self),
)),
}
}
Scope::ExternPreludeFlags => {
match self.extern_prelude_get_flag(ident, orig_ident_span, finalize.is_some()) {
Some(decl) => Ok(decl),
None => Err(Determinacy::Determined),
}
}
Scope::ToolAttributePrelude => match self.registered_attr_tool_decls.get(&ident) {
Some(decl) => Ok(*decl),
None => Err(Determinacy::Determined),
},
Scope::StdLibPrelude => {
let mut result = Err(Determinacy::Determined);
if let Some(prelude) = self.prelude
&& let Ok(decl) = self.reborrow().resolve_ident_in_scope_set_inner(
ident,
orig_ident_span,
ScopeSet::Module(ns, prelude),
parent_scope,
None,
ignore_decl,
ignore_import,
)
&& (matches!(use_prelude, UsePrelude::Yes) || self.is_builtin_macro(decl.res()))
{
result = Ok(decl)
}
result
}
Scope::BuiltinTypes => match self.builtin_type_decls.get(&ident.name) {
Some(decl) => {
if matches!(ident.name, sym::f16)
&& !self.features.f16()
&& !orig_ident_span.allows_unstable(sym::f16)
&& finalize.is_some()
{
feature_err(
self.tcx.sess,
sym::f16,
orig_ident_span,
"the type `f16` is unstable",
)
.emit();
}
if matches!(ident.name, sym::f128)
&& !self.features.f128()
&& !orig_ident_span.allows_unstable(sym::f128)
&& finalize.is_some()
{
feature_err(
self.tcx.sess,
sym::f128,
orig_ident_span,
"the type `f128` is unstable",
)
.emit();
}
Ok(*decl)
}
None => Err(Determinacy::Determined),
},
};
ret.map_err(ControlFlow::Continue)
}
fn maybe_push_glob_vs_glob_vis_ambiguity(
&mut self,
ident: IdentKey,
orig_ident_span: Span,
decl: Decl<'ra>,
import: Option<ImportSummary>,
) {
let Some(import) = import else { return };
let vis1 = self.import_decl_vis(decl, import);
let vis2 = self.import_decl_vis_ext(decl, import, true);
if vis1 != vis2 {
self.ambiguity_errors.push(AmbiguityError {
kind: AmbiguityKind::GlobVsGlob,
ambig_vis: Some((vis1, vis2)),
ident: ident.orig(orig_ident_span),
b1: decl.ambiguity_vis_max.get().unwrap_or(decl),
b2: decl.ambiguity_vis_min.get().unwrap_or(decl),
scope1: Scope::ModuleGlobs(decl.parent_module.unwrap(), None),
scope2: Scope::ModuleGlobs(decl.parent_module.unwrap(), None),
warning: Some(AmbiguityWarning::GlobImport),
});
}
}
fn maybe_push_ambiguity(
&mut self,
ident: IdentKey,
orig_ident_span: Span,
ns: Namespace,
scope_set: ScopeSet<'ra>,
parent_scope: &ParentScope<'ra>,
decl: Decl<'ra>,
scope: Scope<'ra>,
innermost_results: &[(Decl<'ra>, Scope<'ra>)],
import: Option<ImportSummary>,
) -> bool {
let (innermost_decl, innermost_scope) = innermost_results[0];
let (res, innermost_res) = (decl.res(), innermost_decl.res());
let ambig_vis = if res != innermost_res {
None
} else if let Some(import) = import
&& let vis1 = self.import_decl_vis(decl, import)
&& let vis2 = self.import_decl_vis(innermost_decl, import)
&& vis1 != vis2
{
Some((vis1, vis2))
} else {
return false;
};
// FIXME: Use `scope` instead of `res` to detect built-in attrs and derive helpers,
// it will exclude imports, make slightly more code legal, and will require lang approval.
let module_only = matches!(scope_set, ScopeSet::Module(..));
let is_builtin = |res| matches!(res, Res::NonMacroAttr(NonMacroAttrKind::Builtin(..)));
let derive_helper = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelper);
let derive_helper_compat = Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat);
let ambiguity_error_kind = if is_builtin(innermost_res) || is_builtin(res) {
Some(AmbiguityKind::BuiltinAttr)
} else if innermost_res == derive_helper_compat {
Some(AmbiguityKind::DeriveHelper)
} else if res == derive_helper_compat && innermost_res != derive_helper {
span_bug!(orig_ident_span, "impossible inner resolution kind")
} else if matches!(innermost_scope, Scope::MacroRules(_))
&& matches!(scope, Scope::ModuleNonGlobs(..) | Scope::ModuleGlobs(..))
&& !self.disambiguate_macro_rules_vs_modularized(innermost_decl, decl)
{
Some(AmbiguityKind::MacroRulesVsModularized)
} else if matches!(scope, Scope::MacroRules(_))
&& matches!(innermost_scope, Scope::ModuleNonGlobs(..) | Scope::ModuleGlobs(..))
{
// should be impossible because of visitation order in
// visit_scopes
//
// we visit all macro_rules scopes (e.g. textual scope macros)
// before we visit any modules (e.g. path-based scope macros)
span_bug!(
orig_ident_span,
"ambiguous scoped macro resolutions with path-based \
scope resolution as first candidate"
)
} else if innermost_decl.is_glob_import() {
Some(AmbiguityKind::GlobVsOuter)
} else if !module_only && innermost_decl.may_appear_after(parent_scope.expansion, decl) {
Some(AmbiguityKind::MoreExpandedVsOuter)
} else if innermost_decl.expansion != LocalExpnId::ROOT
&& (!module_only || ns == MacroNS)
&& let Scope::ModuleGlobs(m1, _) = scope
&& let Scope::ModuleNonGlobs(m2, _) = innermost_scope
&& m1 == m2
{
// FIXME: this error is too conservative and technically unnecessary now when module
// scope is split into two scopes, at least when not resolving in `ScopeSet::Module`,
// remove it with lang team approval.
Some(AmbiguityKind::GlobVsExpanded)
} else {
None
};
if let Some(kind) = ambiguity_error_kind {
// Skip ambiguity errors for extern flag bindings "overridden"
// by extern item bindings.
// FIXME: Remove with lang team approval.
let issue_145575_hack = matches!(scope, Scope::ExternPreludeFlags)
&& innermost_results[1..]
.iter()
.any(|(b, s)| matches!(s, Scope::ExternPreludeItems) && *b != innermost_decl);
// Skip ambiguity errors for nonglob module bindings "overridden"
// by glob module bindings in the same module.
// FIXME: Remove with lang team approval.
let issue_149681_hack = match scope {
Scope::ModuleGlobs(m1, _)
if innermost_results[1..]
.iter()
.any(|(_, s)| matches!(*s, Scope::ModuleNonGlobs(m2, _) if m1 == m2)) =>
{
true
}
_ => false,
};
if issue_145575_hack || issue_149681_hack {
self.issue_145575_hack_applied = true;
} else {
// Turn ambiguity errors for core vs std panic into warnings.
// FIXME: Remove with lang team approval.
let is_issue_147319_hack = orig_ident_span.edition() <= Edition::Edition2024
&& matches!(ident.name, sym::panic)
&& matches!(scope, Scope::StdLibPrelude)
&& matches!(innermost_scope, Scope::ModuleGlobs(_, _))
&& ((self.is_specific_builtin_macro(res, sym::std_panic)
&& self.is_specific_builtin_macro(innermost_res, sym::core_panic))
|| (self.is_specific_builtin_macro(res, sym::core_panic)
&& self.is_specific_builtin_macro(innermost_res, sym::std_panic)));
let warning = if ambig_vis.is_some() {
Some(AmbiguityWarning::GlobImport)
} else if is_issue_147319_hack {
Some(AmbiguityWarning::PanicImport)
} else {
None
};
self.ambiguity_errors.push(AmbiguityError {
kind,
ambig_vis,
ident: ident.orig(orig_ident_span),
b1: innermost_decl,
b2: decl,
scope1: innermost_scope,
scope2: scope,
warning,
});
return true;
}
}
false
}
#[instrument(level = "debug", skip(self))]
pub(crate) fn maybe_resolve_ident_in_module<'r>(
self: CmResolver<'r, 'ra, 'tcx>,
module: ModuleOrUniformRoot<'ra>,
ident: Ident,
ns: Namespace,
parent_scope: &ParentScope<'ra>,
ignore_import: Option<Import<'ra>>,
) -> Result<Decl<'ra>, Determinacy> {
self.resolve_ident_in_module(module, ident, ns, parent_scope, None, None, ignore_import)
}
fn resolve_super_in_module(
&self,
ident: Ident,
module: Option<Module<'ra>>,
parent_scope: &ParentScope<'ra>,
) -> Option<Module<'ra>> {
let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
module
.unwrap_or_else(|| self.resolve_self(&mut ctxt, parent_scope.module))
.parent
.map(|parent| self.resolve_self(&mut ctxt, parent))
}
pub(crate) fn path_root_is_crate_root(&self, ident: Ident) -> bool {
ident.name == kw::PathRoot && ident.span.is_rust_2015() && self.tcx.sess.is_rust_2015()
}
#[instrument(level = "debug", skip(self))]
pub(crate) fn resolve_ident_in_module<'r>(
self: CmResolver<'r, 'ra, 'tcx>,
module: ModuleOrUniformRoot<'ra>,
ident: Ident,
ns: Namespace,
parent_scope: &ParentScope<'ra>,
finalize: Option<Finalize>,
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
) -> Result<Decl<'ra>, Determinacy> {
match module {
ModuleOrUniformRoot::Module(module) => {
if ns == TypeNS {
if ident.name == kw::SelfLower {
return Ok(module.self_decl.unwrap());
}
if ident.name == kw::Super
&& let Some(module) =
self.resolve_super_in_module(ident, Some(module), parent_scope)
{
return Ok(module.self_decl.unwrap());
}
}
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,
ignore_decl,
ignore_import,
)
}
ModuleOrUniformRoot::OpenModule(sym) => {
if ns != TypeNS {
Err(Determined)
} else {
if ident.name == kw::SelfLower {
let res = Res::OpenMod(sym);
return Ok(self.arenas.new_pub_def_decl(
res,
ident.span,
LocalExpnId::ROOT,
));
}
let open_ns_name = format!("{}::{}", sym.as_str(), ident.name);
let ns_ident = IdentKey::with_root_ctxt(Symbol::intern(&open_ns_name));
match self.extern_prelude_get_flag(ns_ident, ident.span, finalize.is_some()) {
Some(decl) => Ok(decl),
None => Err(Determined),
}
}
}
ModuleOrUniformRoot::ModuleAndExternPrelude(module) => self.resolve_ident_in_scope_set(
ident,
ScopeSet::ModuleAndExternPrelude(ns, module),
parent_scope,
finalize,
ignore_decl,
ignore_import,
),
ModuleOrUniformRoot::ExternPrelude => {
if ns != TypeNS {
Err(Determined)
} else {
self.resolve_ident_in_scope_set_inner(
IdentKey::new_adjusted(ident, ExpnId::root()).0,
ident.span,
ScopeSet::ExternPrelude,
parent_scope,
finalize,
ignore_decl,
ignore_import,
)
}
}
ModuleOrUniformRoot::CurrentScope => {
if ns == TypeNS {
if ident.name == kw::SelfLower {
let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
let module = self.resolve_self(&mut ctxt, parent_scope.module);
return Ok(module.self_decl.unwrap());
}
if ident.name == kw::Super
&& let Some(module) =
self.resolve_super_in_module(ident, None, parent_scope)
{
return Ok(module.self_decl.unwrap());
}
if ident.name == kw::Crate
|| ident.name == kw::DollarCrate
|| self.path_root_is_crate_root(ident)
{
let module = self.resolve_crate_root(ident);
return Ok(module.self_decl.unwrap());
}
}
self.resolve_ident_in_scope_set(
ident,
ScopeSet::All(ns),
parent_scope,
finalize,
ignore_decl,
ignore_import,
)
}
}
}
/// Attempts to resolve `ident` in namespace `ns` of non-glob bindings in an external `module`.
fn resolve_ident_in_extern_module_non_globs_unadjusted<'r>(
mut self: CmResolver<'r, 'ra, 'tcx>,
module: ExternModule<'ra>,
ident: IdentKey,
orig_ident_span: Span,
ns: Namespace,
parent_scope: &ParentScope<'ra>,
shadowing: Shadowing,
finalize: Option<Finalize>,
// This binding should be ignored during in-module resolution, so that we don't get
// "self-confirming" import resolutions during import validation and checking.
ignore_decl: Option<Decl<'ra>>,
) -> Result<Decl<'ra>, ControlFlow<Determinacy, Determinacy>> {
let key = BindingKey::new(ident, ns);
let resolution =
&*self.resolution(module.to_module(), key).ok_or(ControlFlow::Continue(Determined))?;
let binding = resolution.non_glob_decl.filter(|b| Some(*b) != ignore_decl);
if let Some(finalize) = finalize {
return self.get_mut().finalize_module_binding(
ident,
orig_ident_span,
binding,
parent_scope,
finalize,
shadowing,
);
}
// Items and single imports are not shadowable, if we have one, then it's determined.
if let Some(binding) = binding {
let accessible = self.is_accessible_from(binding.vis(), parent_scope.module);
return if accessible { Ok(binding) } else { Err(ControlFlow::Break(Determined)) };
}
Err(ControlFlow::Continue(Determined))
}
/// Attempts to resolve `ident` in namespace `ns` of non-glob bindings in a local `module`.
fn resolve_ident_in_local_module_non_globs_unadjusted<'r>(
mut self: CmResolver<'r, 'ra, 'tcx>,
module: LocalModule<'ra>,
ident: IdentKey,
orig_ident_span: Span,
ns: Namespace,
parent_scope: &ParentScope<'ra>,
shadowing: Shadowing,
finalize: Option<Finalize>,
// This binding should be ignored during in-module resolution, so that we don't get
// "self-confirming" import resolutions during import validation and checking.
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
) -> Result<Decl<'ra>, ControlFlow<Determinacy, Determinacy>> {
let key = BindingKey::new(ident, ns);
let resolution = self.resolution(module.to_module(), key);
let binding =
resolution.as_ref().and_then(|r| r.non_glob_decl).filter(|b| Some(*b) != ignore_decl);
if let Some(finalize) = finalize {
// finalize implies that the module is fully expanded
assert!(!module.has_unexpanded_invocations(&self));
return self.get_mut().finalize_module_binding(
ident,
orig_ident_span,
binding,
parent_scope,
finalize,
shadowing,
);
}
// Items and single imports are not shadowable, if we have one, then it's determined.
if let Some(binding) = binding {
let accessible = self.is_accessible_from(binding.vis(), parent_scope.module);
return if accessible { Ok(binding) } else { Err(ControlFlow::Break(Determined)) };
}
if let Some(resolution) = resolution {
// We need to detect resolution cycles to avoid infinite recursion. The guard ensures
// the resolution is removed when this resolve call ends.
let _cycle_guard = cycle_detection::enter_cycle_detector(module, key)
.map_err(|_| ControlFlow::Continue(Determined))?;
// Check if one of single imports can still define the name, block if it can.
if self.reborrow().single_import_can_define_name(
&resolution,
None,
ns,
ignore_import,
ignore_decl,
parent_scope,
) {
return Err(ControlFlow::Break(Undetermined));
}
}
// Check if one of unexpanded macros can still define the name.
if module.has_unexpanded_invocations(&self) {
return Err(ControlFlow::Continue(Undetermined));
}
// No resolution and no one else can define the name - determinate error.
Err(ControlFlow::Continue(Determined))
}
/// Attempts to resolve `ident` in namespace `ns` of glob bindings in `module`.
fn resolve_ident_in_module_globs_unadjusted<'r>(
mut self: CmResolver<'r, 'ra, 'tcx>,
module: LocalModule<'ra>,
ident: IdentKey,
orig_ident_span: Span,
ns: Namespace,
parent_scope: &ParentScope<'ra>,
shadowing: Shadowing,
finalize: Option<Finalize>,
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
) -> Result<Decl<'ra>, ControlFlow<Determinacy, Determinacy>> {
let key = BindingKey::new(ident, ns);
let resolution = self.resolution(module.to_module(), key);
let binding =
resolution.as_ref().and_then(|r| r.glob_decl).filter(|b| Some(*b) != ignore_decl);
if let Some(finalize) = finalize {
// finalize implies that the module is fully expanded
assert!(!module.has_unexpanded_invocations(&self));
return self.get_mut().finalize_module_binding(
ident,
orig_ident_span,
binding,
parent_scope,
finalize,
shadowing,
);
}
// We need to detect resolution cycles to avoid infinite recursion. The guard ensures
// the resolution is removed when this resolve call ends.
let _cycle_guard = cycle_detection::enter_cycle_detector(module, key)
.map_err(|_| ControlFlow::Continue(Determined))?;
// Check if one of single imports can still define the name,
// if it can then our result is not determined and can be invalidated.
if let Some(resolution) = resolution {
if self.reborrow().single_import_can_define_name(
&resolution,
binding,
ns,
ignore_import,
ignore_decl,
parent_scope,
) {
return Err(ControlFlow::Break(Undetermined));
}
}
// So we have a resolution that's from a glob import. This resolution is determined
// if it cannot be shadowed by some new item/import expanded from a macro.
// This happens either if there are no unexpanded macros, or expanded names cannot
// shadow globs (that happens in macro namespace or with restricted shadowing).
//
// Additionally, any macro in any module can plant names in the root module if it creates
// `macro_export` macros, so the root module effectively has unresolved invocations if any
// module has unresolved invocations.
// However, it causes resolution/expansion to stuck too often (#53144), so, to make
// progress, we have to ignore those potential unresolved invocations from other modules
// and prohibit access to macro-expanded `macro_export` macros instead (unless restricted
// shadowing is enabled, see `macro_expanded_macro_export_errors`).
if let Some(binding) = binding {
return if binding.determined(&self)
|| ns == MacroNS
|| shadowing == Shadowing::Restricted
{
let accessible = self.is_accessible_from(binding.vis(), parent_scope.module);
if accessible { Ok(binding) } else { Err(ControlFlow::Break(Determined)) }
} else {
Err(ControlFlow::Break(Undetermined))
};
}
// 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 `resolve_ident_in_scope_set` to continue search in outer
// scopes we return `Undetermined` with `ControlFlow::Continue`.
// Check if one of unexpanded macros can still define the name,
// if it can then our "no resolution" result is not determined and can be invalidated.
if module.has_unexpanded_invocations(&self) {
return Err(ControlFlow::Continue(Undetermined));
}
// Check if one of glob imports can still define the name,
// if it can then our "no resolution" result is not determined and can be invalidated.
for glob_import in module.globs.borrow_checked(&self).iter() {
if ignore_import == Some(*glob_import) {
continue;
}
if !self.is_accessible_from(glob_import.vis, parent_scope.module) {
continue;
}
let module = match glob_import.imported_module.get() {
Some(ModuleOrUniformRoot::Module(module)) => module,
Some(_) => continue,
None => return Err(ControlFlow::Continue(Undetermined)),
};
let tmp_parent_scope;
let (mut adjusted_parent_scope, mut adjusted_ident) = (parent_scope, ident);
match adjusted_ident
.ctxt
.update_unchecked(|ctxt| ctxt.glob_adjust(module.expansion, glob_import.span))
{
Some(Some(def)) => {
tmp_parent_scope =
ParentScope { module: self.expn_def_scope(def), ..*parent_scope };
adjusted_parent_scope = &tmp_parent_scope;
}
Some(None) => {}
None => continue,
};
let result = self.reborrow().resolve_ident_in_scope_set_inner(
adjusted_ident,
orig_ident_span,
ScopeSet::Module(ns, module),
adjusted_parent_scope,
None,
ignore_decl,
ignore_import,
);
match result {
Err(Determined) => continue,
Ok(binding)
if !self.is_accessible_from(binding.vis(), glob_import.parent_scope.module) =>
{
continue;
}
Ok(_) | Err(Undetermined) => return Err(ControlFlow::Continue(Undetermined)),
}
}
// No resolution and no one else can define the name - determinate error.
Err(ControlFlow::Continue(Determined))
}
fn finalize_module_binding(
&mut self,
ident: IdentKey,
orig_ident_span: Span,
binding: Option<Decl<'ra>>,
parent_scope: &ParentScope<'ra>,
finalize: Finalize,
shadowing: Shadowing,
) -> Result<Decl<'ra>, ControlFlow<Determinacy, Determinacy>> {
let Finalize { path_span, report_private, used, root_span, .. } = finalize;
let Some(binding) = binding else {
return Err(ControlFlow::Continue(Determined));
};
let ident = ident.orig(orig_ident_span);
if !self.is_accessible_from(binding.vis(), parent_scope.module) {
if report_private {
self.privacy_errors.push(PrivacyError {
ident,
decl: binding,
dedup_span: path_span,
outermost_res: None,
source: None,
parent_scope: *parent_scope,
single_nested: path_span != root_span,
});
} else {
return Err(ControlFlow::Break(Determined));
}
}
if shadowing == Shadowing::Unrestricted
&& binding.expansion != LocalExpnId::ROOT
&& let DeclKind::Import { import, .. } = binding.kind
&& matches!(import.kind, ImportKind::MacroExport)
{
self.macro_expanded_macro_export_errors.insert((path_span, binding.span));
}
self.record_use(ident, binding, used);
return Ok(binding);
}
// Checks if a single import can define the `Ident` corresponding to `binding`.
// This is used to check whether we can definitively accept a glob as a resolution.
fn single_import_can_define_name<'r>(
mut self: CmResolver<'r, 'ra, 'tcx>,
resolution: &NameResolution<'ra>,
binding: Option<Decl<'ra>>,
ns: Namespace,
ignore_import: Option<Import<'ra>>,
ignore_decl: Option<Decl<'ra>>,
parent_scope: &ParentScope<'ra>,
) -> bool {
for single_import in &resolution.single_imports {
if let Some(decl) = resolution.non_glob_decl
&& let DeclKind::Import { import, .. } = decl.kind
&& import == *single_import
{
// Single import has already defined the name and we are aware of it,
// no need to block the globs.
continue;
}
if ignore_import == Some(*single_import) {
continue;
}
if !self.is_accessible_from(single_import.vis, parent_scope.module) {
continue;
}
if let Some(ignored) = ignore_decl
&& let DeclKind::Import { import, .. } = ignored.kind
&& import == *single_import
{
continue;
}
let Some(module) = single_import.imported_module.get() else {
return true;
};
let ImportKind::Single { source, target, decls, .. } = &single_import.kind else {
unreachable!();
};
if source != target {
if decls.iter().all(|d| d.get().decl().is_none()) {
return true;
} else if decls[ns].get().decl().is_none() && binding.is_some() {
return true;
}
}
match self.reborrow().resolve_ident_in_module(
module,
*source,
ns,
&single_import.parent_scope,
None,
ignore_decl,
None,
) {
Err(Determined) => continue,
Ok(binding)
if !self
.is_accessible_from(binding.vis(), single_import.parent_scope.module) =>
{
continue;
}
Ok(_) | Err(Undetermined) => return true,
}
}
false
}
/// Validate a local resolution (from ribs).
#[instrument(level = "debug", skip(self, all_ribs))]
fn validate_res_from_ribs(
&self,
rib_index: usize,
rib_ident: Ident,
res: Res,
finalize: Option<Span>,
original_rib_ident_def: Ident,
all_ribs: &[Rib<'ra>],
diag_metadata: Option<&DiagMetadata<'_>>,
) -> Res {
debug!("validate_res_from_ribs({:?})", res);
let ribs = &all_ribs[rib_index + 1..];
// An invalid forward use of a generic parameter from a previous default
// or in a const param ty.
if let RibKind::ForwardGenericParamBan(reason) = all_ribs[rib_index].kind {
if let Some(span) = finalize {
let res_error = if rib_ident.name == kw::SelfUpper {
ResolutionError::ForwardDeclaredSelf(reason)
} else {
ResolutionError::ForwardDeclaredGenericParam(rib_ident.name, reason)
};
self.report_error(span, res_error);
}
assert_eq!(res, Res::Err);
return Res::Err;
}
match res {
Res::Local(_) => {
use ResolutionError::*;
let mut res_err = None;
for rib in ribs {
match rib.kind {
RibKind::Normal
| RibKind::Block(..)
| RibKind::FnOrCoroutine
| RibKind::Module(..)
| RibKind::MacroDefinition(..)
| RibKind::ForwardGenericParamBan(_) => {
// Nothing to do. Continue.
}
RibKind::Item(..) | RibKind::AssocItem => {
// This was an attempt to access an upvar inside a
// named function item. This is not allowed, so we
// report an error.
if let Some(span) = finalize {
// We don't immediately trigger a resolve error, because
// we want certain other resolution errors (namely those
// emitted for `ConstantItemRibKind` below) to take
// precedence.
res_err = Some((span, CannotCaptureDynamicEnvironmentInFnItem));
}
}
RibKind::ConstantItem(_, item, requires_type) => {
// Still doesn't deal with upvars
if let Some(span) = finalize {
let (span, resolution_error) = match item {
None if rib_ident.name == kw::SelfLower => {
(span, LowercaseSelf)
}
None => {
// If we have a `let name = expr;`, we have the span for
// `name` and use that to see if it is followed by a type
// specifier. If not, then we know we need to suggest
// `const name: Ty = expr;`. This is a heuristic, it will
// break down in the presence of macros.
let sm = self.tcx.sess.source_map();
let type_span = match sm
.span_followed_by(original_rib_ident_def.span, ":")
{
None => {
Some(original_rib_ident_def.span.shrink_to_hi())
}
Some(_) => None,
};
(
rib_ident.span,
AttemptToUseNonConstantValueInConstant {
ident: original_rib_ident_def,
suggestion: "const",
current: "let",
type_span,
requires_type,
},
)
}
Some((ident, kind)) => (
span,
AttemptToUseNonConstantValueInConstant {
ident,
suggestion: "let",
current: kind.as_str(),
type_span: None,
requires_type,
},
),
};
self.report_error(span, resolution_error);
}
return Res::Err;
}
RibKind::ConstParamTy => {
if let Some(span) = finalize {
self.report_error(
span,
ParamInTyOfConstParam { name: rib_ident.name },
);
}
return Res::Err;
}
RibKind::InlineAsmSym => {
if let Some(span) = finalize {
self.report_error(span, InvalidAsmSym);
}
return Res::Err;
}
}
}
if let Some((span, res_err)) = res_err {
self.report_error(span, res_err);
return Res::Err;
}
}
Res::Def(DefKind::TyParam, _) | Res::SelfTyParam { .. } | Res::SelfTyAlias { .. } => {
for rib in ribs {
let (has_generic_params, def_kind) = match rib.kind {
RibKind::Normal
| RibKind::Block(..)
| RibKind::FnOrCoroutine
| RibKind::Module(..)
| RibKind::MacroDefinition(..)
| RibKind::InlineAsmSym
| RibKind::AssocItem
| RibKind::ForwardGenericParamBan(_) => {
// Nothing to do. Continue.
continue;
}
RibKind::ConstParamTy => {
let adt_enabled = self.features.min_adt_const_params()
|| self.features.adt_const_params();
let is_self = matches!(res, Res::SelfTyAlias { .. });
// We check whether Self depends on generics parameters in `fn type_of`
if self.features.generic_const_parameter_types()
|| (adt_enabled && is_self)
{
continue;
} else {
if let Some(span) = finalize {
if matches!(res, Res::SelfTyAlias { .. }) {
self.report_error(span, ResolutionError::SelfInConstParam);
} else {
self.report_error(
span,
ResolutionError::ParamInTyOfConstParam {
name: rib_ident.name,
},
);
}
}
return Res::Err;
}
}
RibKind::ConstantItem(trivial, _, _) => {
if let ConstantHasGenerics::No(cause) = trivial
&& !matches!(res, Res::SelfTyAlias { .. })
{
if let Some(span) = finalize {
let error = match cause {
NoConstantGenericsReason::IsEnumDiscriminant => {
ResolutionError::ParamInEnumDiscriminant {
name: rib_ident.name,
param_kind: ParamKindInEnumDiscriminant::Type,
}
}
NoConstantGenericsReason::NonTrivialConstArg => {
ResolutionError::ParamInNonTrivialAnonConst {
is_gca: self.features.generic_const_args(),
name: rib_ident.name,
param_kind: ParamKindInNonTrivialAnonConst::Type,
}
}
};
let _: ErrorGuaranteed = self.report_error(span, error);
}
return Res::Err;
}
continue;
}
// This was an attempt to use a type parameter outside its scope.
RibKind::Item(has_generic_params, def_kind) => {
(has_generic_params, def_kind)
}
};
if let Some(span) = finalize {
let item = if let Some(diag_metadata) = diag_metadata
&& let Some(current_item) = diag_metadata.current_item
{
let label_span = current_item
.kind
.ident()
.map(|i| i.span)
.unwrap_or(current_item.span);
Some((label_span, current_item.span, current_item.kind.clone()))
} else {
None
};
self.report_error(
span,
ResolutionError::GenericParamsFromOuterItem {
outer_res: res,
has_generic_params,
def_kind,
inner_item: item,
current_self_ty: diag_metadata
.and_then(|m| m.current_self_type.as_ref())
.and_then(|ty| {
self.tcx.sess.source_map().span_to_snippet(ty.span).ok()
}),
},
);
}
return Res::Err;
}
}
Res::Def(DefKind::ConstParam, _) => {
for rib in ribs {
let (has_generic_params, def_kind) = match rib.kind {
RibKind::Normal
| RibKind::Block(..)
| RibKind::FnOrCoroutine
| RibKind::Module(..)
| RibKind::MacroDefinition(..)
| RibKind::InlineAsmSym
| RibKind::AssocItem
| RibKind::ForwardGenericParamBan(_) => continue,
RibKind::ConstParamTy => {
if !self.features.generic_const_parameter_types() {
if let Some(span) = finalize {
self.report_error(
span,
ResolutionError::ParamInTyOfConstParam {
name: rib_ident.name,
},
);
}
return Res::Err;
} else {
continue;
}
}
RibKind::ConstantItem(trivial, _, _) => {
if let ConstantHasGenerics::No(cause) = trivial {
if let Some(span) = finalize {
let error = match cause {
NoConstantGenericsReason::IsEnumDiscriminant => {
ResolutionError::ParamInEnumDiscriminant {
name: rib_ident.name,
param_kind: ParamKindInEnumDiscriminant::Const,
}
}
NoConstantGenericsReason::NonTrivialConstArg => {
ResolutionError::ParamInNonTrivialAnonConst {
is_gca: self.features.generic_const_args(),
name: rib_ident.name,
param_kind: ParamKindInNonTrivialAnonConst::Const {
name: rib_ident.name,
},
}
}
};
self.report_error(span, error);
}
return Res::Err;
}
continue;
}
RibKind::Item(has_generic_params, def_kind) => {
(has_generic_params, def_kind)
}
};
// This was an attempt to use a const parameter outside its scope.
if let Some(span) = finalize {
let item = if let Some(diag_metadata) = diag_metadata
&& let Some(current_item) = diag_metadata.current_item
{
let label_span = current_item
.kind
.ident()
.map(|i| i.span)
.unwrap_or(current_item.span);
Some((label_span, current_item.span, current_item.kind.clone()))
} else {
None
};
self.report_error(
span,
ResolutionError::GenericParamsFromOuterItem {
outer_res: res,
has_generic_params,
def_kind,
inner_item: item,
current_self_ty: diag_metadata
.and_then(|m| m.current_self_type.as_ref())
.and_then(|ty| {
self.tcx.sess.source_map().span_to_snippet(ty.span).ok()
}),
},
);
}
return Res::Err;
}
}
_ => {}
}
res
}
#[instrument(level = "debug", skip(self))]
pub(crate) fn maybe_resolve_path<'r>(
self: CmResolver<'r, 'ra, 'tcx>,
path: &[Segment],
opt_ns: Option<Namespace>, // `None` indicates a module path in import
parent_scope: &ParentScope<'ra>,
ignore_import: Option<Import<'ra>>,
) -> PathResult<'ra> {
self.resolve_path_with_ribs(
path,
opt_ns,
parent_scope,
None,
None,
None,
None,
ignore_import,
None,
)
}
#[instrument(level = "debug", skip(self))]
pub(crate) fn resolve_path<'r>(
self: CmResolver<'r, 'ra, 'tcx>,
path: &[Segment],
opt_ns: Option<Namespace>, // `None` indicates a module path in import
parent_scope: &ParentScope<'ra>,
finalize: Option<Finalize>,
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
) -> PathResult<'ra> {
self.resolve_path_with_ribs(
path,
opt_ns,
parent_scope,
None,
finalize,
None,
ignore_decl,
ignore_import,
None,
)
}
pub(crate) fn resolve_path_with_ribs<'r>(
mut self: CmResolver<'r, 'ra, 'tcx>,
path: &[Segment],
opt_ns: Option<Namespace>, // `None` indicates a module path in import
parent_scope: &ParentScope<'ra>,
source: Option<PathSource<'_, '_, '_>>,
finalize: Option<Finalize>,
ribs: Option<&PerNS<Vec<Rib<'ra>>>>,
ignore_decl: Option<Decl<'ra>>,
ignore_import: Option<Import<'ra>>,
diag_metadata: Option<&DiagMetadata<'_>>,
) -> PathResult<'ra> {
let mut module = None;
let mut module_had_parse_errors = !self.mods_with_parse_errors.is_empty()
&& self
.mods_with_parse_errors
.contains(&parent_scope.module.nearest_parent_mod().to_def_id());
let mut allow_super = true;
let mut second_binding = None;
// We'll provide more context to the privacy errors later, up to `len`.
let privacy_errors_len = self.privacy_errors.len();
fn record_segment_res<'r, 'ra, 'tcx>(
mut this: CmResolver<'r, 'ra, 'tcx>,
finalize: Option<Finalize>,
res: Res,
id: Option<NodeId>,
) {
if finalize.is_some()
&& let Some(id) = id
&& !this.partial_res_map.contains_key(&id)
{
assert!(id != ast::DUMMY_NODE_ID, "Trying to resolve dummy id");
this.get_mut().record_partial_res(id, PartialRes::new(res));
}
}
for (segment_idx, &Segment { ident, id, .. }) in path.iter().enumerate() {
debug!("resolve_path ident {} {:?} {:?}", segment_idx, ident, id);
let is_last = segment_idx + 1 == path.len();
let ns = if is_last { opt_ns.unwrap_or(TypeNS) } else { TypeNS };
let name = ident.name;
allow_super &= ns == TypeNS && (name == kw::SelfLower || name == kw::Super);
if ns == TypeNS {
if allow_super && name == kw::Super {
let parent = if segment_idx == 0 {
self.resolve_super_in_module(ident, None, parent_scope)
} else if let Some(ModuleOrUniformRoot::Module(module)) = module {
self.resolve_super_in_module(ident, Some(module), parent_scope)
} else {
None
};
if let Some(parent) = parent {
module = Some(ModuleOrUniformRoot::Module(parent));
continue;
}
let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
let current_module = self.resolve_self(&mut ctxt, parent_scope.module);
let current_module_path = module_to_string(current_module)
.map_or_else(|| "crate".to_string(), |path| format!("crate::{path}"));
return PathResult::failed(
ident,
false,
finalize.is_some(),
module_had_parse_errors,
module,
|| {
(
format!(
"too many leading `super` keywords within `{current_module_path}`"
),
"this `super` would go above the crate root".to_string(),
None,
None,
None,
)
},
);
}
if segment_idx == 0 {
if name == kw::SelfLower {
let mut ctxt = ident.span.ctxt().normalize_to_macros_2_0();
let self_mod = self.resolve_self(&mut ctxt, parent_scope.module);
if let Some(res) = self_mod.res() {
record_segment_res(self.reborrow(), finalize, res, id);
}
module = Some(ModuleOrUniformRoot::Module(self_mod));
continue;
}
if name == kw::PathRoot && ident.span.at_least_rust_2018() {
module = Some(ModuleOrUniformRoot::ExternPrelude);
continue;
}
if name == kw::PathRoot
&& ident.span.is_rust_2015()
&& self.tcx.sess.at_least_rust_2018()
{
// `::a::b` from 2015 macro on 2018 global edition
let crate_root = self.resolve_crate_root(ident);
module = Some(ModuleOrUniformRoot::ModuleAndExternPrelude(crate_root));
continue;
}
if name == kw::PathRoot || name == kw::Crate || name == kw::DollarCrate {
// `::a::b`, `crate::a::b` or `$crate::a::b`
let crate_root = self.resolve_crate_root(ident);
if let Some(res) = crate_root.res() {
record_segment_res(self.reborrow(), finalize, res, id);
}
module = Some(ModuleOrUniformRoot::Module(crate_root));
continue;
}
}
}
let allow_trailing_self = is_last && name == kw::SelfLower;
// Report special messages for path segment keywords in wrong positions.
if ident.is_path_segment_keyword() && segment_idx != 0 && !allow_trailing_self {
return PathResult::failed(
ident,
false,
finalize.is_some(),
module_had_parse_errors,
module,
|| {
let name_str = if name == kw::PathRoot {
"the crate root".to_string()
} else {
format!("`{name}`")
};
let (message, label) = if segment_idx == 1
&& path[0].ident.name == kw::PathRoot
{
(
format!("global paths cannot start with {name_str}"),
"cannot start with this".to_string(),
)
} else if name == kw::SelfLower {
(
format!(
"`self` in paths can only be used in start position or last position"
),
"can only be used in path start position or last position"
.to_string(),
)
} else {
(
format!("{name_str} in paths can only be used in start position"),
"can only be used in path start position".to_string(),
)
};
(message, label, None, None, None)
},
);
}
let binding = if let Some(module) = module {
self.reborrow().resolve_ident_in_module(
module,
ident,
ns,
parent_scope,
finalize,
ignore_decl,
ignore_import,
)
} else if let Some(ribs) = ribs
&& let Some(TypeNS | ValueNS) = opt_ns
{
assert!(ignore_import.is_none());
match self.get_mut().resolve_ident_in_lexical_scope(
ident,
ns,
parent_scope,
finalize,
&ribs[ns],
ignore_decl,
diag_metadata,
) {
// we found a locally-imported or available item/module
Some(LateDecl::Decl(binding)) => Ok(binding),
// we found a local variable or type param
Some(LateDecl::RibDef(res)) => {
record_segment_res(self.reborrow(), finalize, res, id);
return PathResult::NonModule(PartialRes::with_unresolved_segments(
res,
path.len() - 1,
));
}
_ => Err(Determinacy::determined(finalize.is_some())),
}
} else {
self.reborrow().resolve_ident_in_scope_set(
ident,
ScopeSet::All(ns),
parent_scope,
finalize,
ignore_decl,
ignore_import,
)
};
match binding {
Ok(binding) => {
if segment_idx == 1 {
second_binding = Some(binding);
}
let res = binding.res();
// Mark every privacy error in this path with the res to the last element. This allows us
// to detect the item the user cares about and either find an alternative import, or tell
// the user it is not accessible.
if finalize.is_some() {
for error in &mut self.get_mut().privacy_errors[privacy_errors_len..] {
error.outermost_res = Some((res, ident));
error.source = match source {
Some(PathSource::Struct(Some(expr)))
| Some(PathSource::Expr(Some(expr))) => Some(expr.clone()),
_ => None,
};
}
}
let maybe_assoc = opt_ns != Some(MacroNS) && PathSource::Type.is_expected(res);
if let Res::OpenMod(sym) = binding.res() {
module = Some(ModuleOrUniformRoot::OpenModule(sym));
record_segment_res(self.reborrow(), finalize, res, id);
} else if let Some(def_id) = binding.res().module_like_def_id() {
if self.mods_with_parse_errors.contains(&def_id) {
module_had_parse_errors = true;
}
module = Some(ModuleOrUniformRoot::Module(self.expect_module(def_id)));
record_segment_res(self.reborrow(), finalize, res, id);
} else if res == Res::ToolMod && !is_last && opt_ns.is_some() {
if binding.is_import() {
self.dcx().emit_err(diagnostics::ToolModuleImported {
span: ident.span,
import: binding.span,
});
}
let res = Res::NonMacroAttr(NonMacroAttrKind::Tool);
return PathResult::NonModule(PartialRes::new(res));
} else if res == Res::Err {
return PathResult::NonModule(PartialRes::new(Res::Err));
} else if opt_ns.is_some() && (is_last || maybe_assoc) {
if let Some(finalize) = finalize {
self.get_mut().lint_if_path_starts_with_module(
finalize,
path,
second_binding,
);
}
record_segment_res(self.reborrow(), finalize, res, id);
return PathResult::NonModule(PartialRes::with_unresolved_segments(
res,
path.len() - segment_idx - 1,
));
} else {
return PathResult::failed(
ident,
is_last,
finalize.is_some(),
module_had_parse_errors,
module,
|| {
let import_inherent_item_error_flag =
self.features.import_trait_associated_functions()
&& matches!(
res,
Res::Def(
DefKind::Struct
| DefKind::Enum
| DefKind::Union
| DefKind::ForeignTy,
_
)
);
// Show a different error message for items that can have associated items.
let label = format!(
"`{ident}` is {} {}, not a module{}",
res.article(),
res.descr(),
if import_inherent_item_error_flag {
" or a trait"
} else {
""
}
);
let scope = match &path[..segment_idx] {
[.., prev] => {
if prev.ident.name == kw::PathRoot {
format!("the crate root")
} else {
format!("`{}`", prev.ident)
}
}
_ => format!("this scope"),
};
// FIXME: reword, as the reason we expected a module is because of
// the following path segment.
let message = format!("cannot find module `{ident}` in {scope}");
let note = if import_inherent_item_error_flag {
Some(
"cannot import inherent associated items, only trait associated items".to_string(),
)
} else {
None
};
(message, label, None, note, None)
},
);
}
}
Err(Undetermined) if finalize.is_none() => return PathResult::Indeterminate,
Err(Determined | Undetermined) => {
if let Some(ModuleOrUniformRoot::Module(module)) = module
&& opt_ns.is_some()
&& !module.is_normal()
{
return PathResult::NonModule(PartialRes::with_unresolved_segments(
module.res().unwrap(),
path.len() - segment_idx,
));
}
let mut this = self.reborrow();
return PathResult::failed(
ident,
is_last,
finalize.is_some(),
module_had_parse_errors,
module,
|| {
let (message, label, suggestion, help) =
this.get_mut().report_path_resolution_error(
path,
opt_ns,
parent_scope,
ribs,
ignore_decl,
ignore_import,
module,
segment_idx,
ident,
diag_metadata,
);
(message, label, suggestion, None, help)
},
);
}
}
}
if let Some(finalize) = finalize {
self.get_mut().lint_if_path_starts_with_module(finalize, path, second_binding);
}
PathResult::Module(match module {
Some(module) => module,
None if path.is_empty() => ModuleOrUniformRoot::CurrentScope,
_ => bug!("resolve_path: non-empty path `{:?}` has no module", path),
})
}
}