blob: 2ad5e9eca08fd86b7b7663a7ff645375a6358340 [file] [log] [blame]
//! This modules implements a function to resolve a path `foo::bar::baz` to a
//! def, which is used within the name resolution.
//!
//! When name resolution is finished, the result of resolving a path is either
//! `Some(def)` or `None`. However, when we are in process of resolving imports
//! or macros, there's a third possibility:
//!
//! I can't resolve this path right now, but I might be resolve this path
//! later, when more macros are expanded.
//!
//! `ReachedFixedPoint` signals about this.
use either::Either;
use hir_expand::{
Lookup,
mod_path::{ModPath, PathKind},
name::Name,
};
use span::Edition;
use stdx::TupleExt;
use crate::{
AdtId, LocalModuleId, ModuleDefId,
db::DefDatabase,
item_scope::{BUILTIN_SCOPE, ImportOrExternCrate},
item_tree::FieldsShape,
nameres::{
BlockInfo, BuiltinShadowMode, DefMap, LocalDefMap, MacroSubNs, crate_def_map,
sub_namespace_match,
},
per_ns::PerNs,
visibility::{RawVisibility, Visibility},
};
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(super) enum ResolveMode {
Import,
Other,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(super) enum ReachedFixedPoint {
Yes,
No,
}
#[derive(Debug, Clone)]
pub(super) struct ResolvePathResult {
pub(super) resolved_def: PerNs,
/// The index of the last resolved segment, or `None` if the full path has been resolved.
pub(super) segment_index: Option<usize>,
pub(super) reached_fixedpoint: ReachedFixedPoint,
pub(super) prefix_info: ResolvePathResultPrefixInfo,
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub struct ResolvePathResultPrefixInfo {
pub(crate) differing_crate: bool,
/// Path of the form `Enum::Variant` (and not `Variant` alone).
pub enum_variant: bool,
}
impl ResolvePathResult {
fn empty(reached_fixedpoint: ReachedFixedPoint) -> ResolvePathResult {
ResolvePathResult::new(
PerNs::none(),
reached_fixedpoint,
None,
ResolvePathResultPrefixInfo::default(),
)
}
fn new(
resolved_def: PerNs,
reached_fixedpoint: ReachedFixedPoint,
segment_index: Option<usize>,
prefix_info: ResolvePathResultPrefixInfo,
) -> ResolvePathResult {
ResolvePathResult { resolved_def, segment_index, reached_fixedpoint, prefix_info }
}
}
impl PerNs {
pub(super) fn filter_macro(
mut self,
db: &dyn DefDatabase,
expected: Option<MacroSubNs>,
) -> Self {
self.macros = self.macros.filter(|def| {
let this = MacroSubNs::from_id(db, def.def);
sub_namespace_match(Some(this), expected)
});
self
}
}
impl DefMap {
pub(crate) fn resolve_visibility(
&self,
local_def_map: &LocalDefMap,
db: &dyn DefDatabase,
// module to import to
original_module: LocalModuleId,
// pub(path)
// ^^^^ this
visibility: &RawVisibility,
within_impl: bool,
) -> Option<Visibility> {
let mut vis = match visibility {
RawVisibility::Module(path, explicitness) => {
let (result, remaining) = self.resolve_path(
local_def_map,
db,
original_module,
path,
BuiltinShadowMode::Module,
None,
);
if remaining.is_some() {
return None;
}
let types = result.take_types()?;
match types {
ModuleDefId::ModuleId(m) => Visibility::Module(m, *explicitness),
// error: visibility needs to refer to module
_ => {
return None;
}
}
}
RawVisibility::Public => Visibility::Public,
};
// In block expressions, `self` normally refers to the containing non-block module, and
// `super` to its parent (etc.). However, visibilities must only refer to a module in the
// DefMap they're written in, so we restrict them when that happens.
if let Visibility::Module(m, mv) = vis {
// ...unless we're resolving visibility for an associated item in an impl.
if self.block_id() != m.block && !within_impl {
cov_mark::hit!(adjust_vis_in_block_def_map);
vis = Visibility::Module(self.module_id(Self::ROOT), mv);
tracing::debug!("visibility {:?} points outside DefMap, adjusting to {:?}", m, vis);
}
}
Some(vis)
}
// Returns Yes if we are sure that additions to `ItemMap` wouldn't change
// the result.
pub(super) fn resolve_path_fp_with_macro(
&self,
local_def_map: &LocalDefMap,
db: &dyn DefDatabase,
mode: ResolveMode,
// module to import to
mut original_module: LocalModuleId,
path: &ModPath,
shadow: BuiltinShadowMode,
// Pass `MacroSubNs` if we know we're resolving macro names and which kind of macro we're
// resolving them to. Pass `None` otherwise, e.g. when we're resolving import paths.
expected_macro_subns: Option<MacroSubNs>,
) -> ResolvePathResult {
let mut result = self.resolve_path_fp_with_macro_single(
local_def_map,
db,
mode,
original_module,
path,
shadow,
expected_macro_subns,
);
if self.block.is_none() {
// If we're in the root `DefMap`, we can resolve the path directly.
return result;
}
let mut current_map = self;
let mut merge = |new: ResolvePathResult| {
result.resolved_def = result.resolved_def.or(new.resolved_def);
if result.reached_fixedpoint == ReachedFixedPoint::No {
result.reached_fixedpoint = new.reached_fixedpoint;
}
result.prefix_info.differing_crate |= new.prefix_info.differing_crate;
result.prefix_info.enum_variant |= new.prefix_info.enum_variant;
result.segment_index = match (result.segment_index, new.segment_index) {
(Some(idx), None) => Some(idx),
(Some(old), Some(new)) => Some(old.max(new)),
(None, new) => new,
};
};
loop {
match current_map.block {
Some(block) if original_module == Self::ROOT => {
// Block modules "inherit" names from its parent module.
original_module = block.parent.local_id;
current_map = block.parent.def_map(db, current_map.krate);
}
// Proper (non-block) modules, including those in block `DefMap`s, don't.
_ => {
if original_module != Self::ROOT && current_map.block.is_some() {
// A module inside a block. Do not resolve items declared in upper blocks, but we do need to get
// the prelude items (which are not inserted into blocks because they can be overridden there).
original_module = Self::ROOT;
current_map = crate_def_map(db, self.krate);
let new = current_map.resolve_path_fp_in_all_preludes(
local_def_map,
db,
mode,
original_module,
path,
shadow,
);
merge(new);
}
return result;
}
}
let new = current_map.resolve_path_fp_with_macro_single(
local_def_map,
db,
mode,
original_module,
path,
shadow,
expected_macro_subns,
);
merge(new);
}
}
pub(super) fn resolve_path_fp_with_macro_single(
&self,
local_def_map: &LocalDefMap,
db: &dyn DefDatabase,
mode: ResolveMode,
original_module: LocalModuleId,
path: &ModPath,
shadow: BuiltinShadowMode,
expected_macro_subns: Option<MacroSubNs>,
) -> ResolvePathResult {
let mut segments = path.segments().iter().enumerate();
let curr_per_ns = match path.kind {
PathKind::DollarCrate(krate) => {
if krate == self.krate {
cov_mark::hit!(macro_dollar_crate_self);
PerNs::types(self.crate_root().into(), Visibility::Public, None)
} else {
let def_map = crate_def_map(db, krate);
let module = def_map.module_id(Self::ROOT);
cov_mark::hit!(macro_dollar_crate_other);
PerNs::types(module.into(), Visibility::Public, None)
}
}
PathKind::Crate => PerNs::types(self.crate_root().into(), Visibility::Public, None),
// plain import or absolute path in 2015: crate-relative with
// fallback to extern prelude (with the simplification in
// rust-lang/rust#57745)
// FIXME there must be a nicer way to write this condition
PathKind::Plain | PathKind::Abs
if self.data.edition == Edition::Edition2015
&& (path.kind == PathKind::Abs || mode == ResolveMode::Import) =>
{
let (_, segment) = match segments.next() {
Some((idx, segment)) => (idx, segment),
None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
};
tracing::debug!("resolving {:?} in crate root (+ extern prelude)", segment);
self.resolve_name_in_crate_root_or_extern_prelude(
local_def_map,
db,
original_module,
segment,
)
}
PathKind::Plain => {
let (_, segment) = match segments.next() {
Some((idx, segment)) => (idx, segment),
None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
};
// The first segment may be a builtin type. If the path has more
// than one segment, we first try resolving it as a module
// anyway.
// FIXME: If the next segment doesn't resolve in the module and
// BuiltinShadowMode wasn't Module, then we need to try
// resolving it as a builtin.
let prefer_module =
if path.segments().len() == 1 { shadow } else { BuiltinShadowMode::Module };
tracing::debug!("resolving {:?} in module", segment);
self.resolve_name_in_module(
local_def_map,
db,
original_module,
segment,
prefer_module,
expected_macro_subns,
)
}
PathKind::Super(lvl) => {
let mut local_id = original_module;
let mut ext;
let mut def_map = self;
// Adjust `local_id` to `self`, i.e. the nearest non-block module.
if def_map.module_id(local_id).is_block_module() {
(ext, local_id) = adjust_to_nearest_non_block_module(db, def_map, local_id);
def_map = ext;
}
// Go up the module tree but skip block modules as `super` always refers to the
// nearest non-block module.
for _ in 0..lvl {
// Loop invariant: at the beginning of each loop, `local_id` must refer to a
// non-block module.
if let Some(parent) = def_map.modules[local_id].parent {
local_id = parent;
if def_map.module_id(local_id).is_block_module() {
(ext, local_id) =
adjust_to_nearest_non_block_module(db, def_map, local_id);
def_map = ext;
}
} else {
stdx::always!(def_map.block.is_none());
tracing::debug!("super path in root module");
return ResolvePathResult::empty(ReachedFixedPoint::Yes);
}
}
let module = def_map.module_id(local_id);
stdx::never!(module.is_block_module());
if self.block != def_map.block {
// If we have a different `DefMap` from `self` (the original `DefMap` we started
// with), resolve the remaining path segments in that `DefMap`.
let path =
ModPath::from_segments(PathKind::SELF, path.segments().iter().cloned());
// This is the same crate, so the local def map is the same.
return def_map.resolve_path_fp_with_macro(
local_def_map,
db,
mode,
local_id,
&path,
shadow,
expected_macro_subns,
);
}
PerNs::types(module.into(), Visibility::Public, None)
}
PathKind::Abs => match self.resolve_path_abs(local_def_map, &mut segments, path) {
Either::Left(it) => it,
Either::Right(reached_fixed_point) => {
return ResolvePathResult::empty(reached_fixed_point);
}
},
};
self.resolve_remaining_segments(
db,
mode,
segments,
curr_per_ns,
path,
shadow,
original_module,
)
}
/// Resolves a path only in the preludes, without accounting for item scopes.
pub(super) fn resolve_path_fp_in_all_preludes(
&self,
local_def_map: &LocalDefMap,
db: &dyn DefDatabase,
mode: ResolveMode,
original_module: LocalModuleId,
path: &ModPath,
shadow: BuiltinShadowMode,
) -> ResolvePathResult {
let mut segments = path.segments().iter().enumerate();
let curr_per_ns = match path.kind {
// plain import or absolute path in 2015: crate-relative with
// fallback to extern prelude (with the simplification in
// rust-lang/rust#57745)
// FIXME there must be a nicer way to write this condition
PathKind::Plain | PathKind::Abs
if self.data.edition == Edition::Edition2015
&& (path.kind == PathKind::Abs || mode == ResolveMode::Import) =>
{
let (_, segment) = match segments.next() {
Some((idx, segment)) => (idx, segment),
None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
};
tracing::debug!("resolving {:?} in crate root (+ extern prelude)", segment);
self.resolve_name_in_extern_prelude(local_def_map, segment)
}
PathKind::Plain => {
let (_, segment) = match segments.next() {
Some((idx, segment)) => (idx, segment),
None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
};
tracing::debug!("resolving {:?} in module", segment);
self.resolve_name_in_all_preludes(local_def_map, db, segment)
}
PathKind::Abs => match self.resolve_path_abs(local_def_map, &mut segments, path) {
Either::Left(it) => it,
Either::Right(reached_fixed_point) => {
return ResolvePathResult::empty(reached_fixed_point);
}
},
PathKind::DollarCrate(_) | PathKind::Crate | PathKind::Super(_) => {
return ResolvePathResult::empty(ReachedFixedPoint::Yes);
}
};
self.resolve_remaining_segments(
db,
mode,
segments,
curr_per_ns,
path,
shadow,
original_module,
)
}
/// 2018-style absolute path -- only extern prelude
fn resolve_path_abs<'a>(
&self,
local_def_map: &LocalDefMap,
segments: &mut impl Iterator<Item = (usize, &'a Name)>,
path: &ModPath,
) -> Either<PerNs, ReachedFixedPoint> {
let segment = match segments.next() {
Some((_, segment)) => segment,
None => return Either::Right(ReachedFixedPoint::Yes),
};
if let Some(&(def, extern_crate)) = local_def_map.extern_prelude.get(segment) {
tracing::debug!("absolute path {:?} resolved to crate {:?}", path, def);
Either::Left(PerNs::types(
def.into(),
Visibility::Public,
extern_crate.map(ImportOrExternCrate::ExternCrate),
))
} else {
Either::Right(ReachedFixedPoint::No) // extern crate declarations can add to the extern prelude
}
}
fn resolve_remaining_segments<'a>(
&self,
db: &dyn DefDatabase,
mode: ResolveMode,
mut segments: impl Iterator<Item = (usize, &'a Name)>,
mut curr_per_ns: PerNs,
path: &ModPath,
shadow: BuiltinShadowMode,
original_module: LocalModuleId,
) -> ResolvePathResult {
while let Some((i, segment)) = segments.next() {
let curr = match curr_per_ns.take_types_full() {
Some(r) => r,
None => {
// we still have path segments left, but the path so far
// didn't resolve in the types namespace => no resolution
// (don't break here because `curr_per_ns` might contain
// something in the value namespace, and it would be wrong
// to return that)
return ResolvePathResult::empty(ReachedFixedPoint::No);
}
};
// resolve segment in curr
curr_per_ns = match curr.def {
ModuleDefId::ModuleId(module) => {
if module.krate != self.krate {
let path = ModPath::from_segments(
PathKind::SELF,
path.segments()[i..].iter().cloned(),
);
tracing::debug!("resolving {:?} in other crate", path);
let defp_map = module.def_map(db);
// Macro sub-namespaces only matter when resolving single-segment paths
// because `macro_use` and other preludes should be taken into account. At
// this point, we know we're resolving a multi-segment path so macro kind
// expectation is discarded.
let resolution = defp_map.resolve_path_fp_with_macro(
LocalDefMap::EMPTY,
db,
mode,
module.local_id,
&path,
shadow,
None,
);
return ResolvePathResult::new(
resolution.resolved_def,
ReachedFixedPoint::Yes,
resolution.segment_index.map(|s| s + i),
ResolvePathResultPrefixInfo {
differing_crate: true,
enum_variant: resolution.prefix_info.enum_variant,
},
);
}
let def_map;
let module_data = if module.block == self.block_id() {
&self[module.local_id]
} else {
def_map = module.def_map(db);
&def_map[module.local_id]
};
// Since it is a qualified path here, it should not contains legacy macros
module_data.scope.get(segment)
}
ModuleDefId::AdtId(AdtId::EnumId(e)) => {
// enum variant
cov_mark::hit!(can_import_enum_variant);
let res =
db.enum_variants(e).variants.iter().find(|(_, name)| name == segment).map(
|&(variant, _)| {
let item_tree_id = variant.lookup(db).id;
match item_tree_id.item_tree(db)[item_tree_id.value].shape {
FieldsShape::Record => {
PerNs::types(variant.into(), Visibility::Public, None)
}
FieldsShape::Tuple | FieldsShape::Unit => PerNs::both(
variant.into(),
variant.into(),
Visibility::Public,
None,
),
}
},
);
// FIXME: Need to filter visibility here and below? Not sure.
return match res {
Some(res) => {
if segments.next().is_some() {
// Enum variants are in value namespace, segments left => no resolution.
ResolvePathResult::empty(ReachedFixedPoint::No)
} else {
ResolvePathResult::new(
res,
ReachedFixedPoint::Yes,
None,
ResolvePathResultPrefixInfo {
enum_variant: true,
..ResolvePathResultPrefixInfo::default()
},
)
}
}
None => ResolvePathResult::new(
PerNs::types(e.into(), curr.vis, curr.import),
ReachedFixedPoint::Yes,
Some(i),
ResolvePathResultPrefixInfo::default(),
),
};
}
def @ ModuleDefId::TraitId(t) if mode == ResolveMode::Import => {
// FIXME: Implement this correctly
// We can't actually call `trait_items`, the reason being that if macro calls
// occur, they will call back into the def map which we might be computing right
// now resulting in a cycle.
// To properly implement this, trait item collection needs to be done in def map
// collection...
let item =
if true { None } else { db.trait_items(t).assoc_item_by_name(segment) };
return match item {
Some(item) => ResolvePathResult::new(
match item {
crate::AssocItemId::FunctionId(function_id) => PerNs::values(
function_id.into(),
curr.vis,
curr.import.and_then(|it| it.import_or_glob()),
),
crate::AssocItemId::ConstId(const_id) => PerNs::values(
const_id.into(),
curr.vis,
curr.import.and_then(|it| it.import_or_glob()),
),
crate::AssocItemId::TypeAliasId(type_alias_id) => {
PerNs::types(type_alias_id.into(), curr.vis, curr.import)
}
},
ReachedFixedPoint::Yes,
segments.next().map(TupleExt::head),
ResolvePathResultPrefixInfo::default(),
),
None => ResolvePathResult::new(
PerNs::types(def, curr.vis, curr.import),
ReachedFixedPoint::Yes,
Some(i),
ResolvePathResultPrefixInfo::default(),
),
};
}
s => {
// could be an inherent method call in UFCS form
// (`Struct::method`), or some other kind of associated item
tracing::debug!(
"path segment {:?} resolved to non-module {:?}, but is not last",
segment,
curr,
);
return ResolvePathResult::new(
PerNs::types(s, curr.vis, curr.import),
ReachedFixedPoint::Yes,
Some(i),
ResolvePathResultPrefixInfo::default(),
);
}
};
curr_per_ns = curr_per_ns
.filter_visibility(|vis| vis.is_visible_from_def_map(db, self, original_module));
}
ResolvePathResult::new(
curr_per_ns,
ReachedFixedPoint::Yes,
None,
ResolvePathResultPrefixInfo::default(),
)
}
fn resolve_name_in_module(
&self,
local_def_map: &LocalDefMap,
db: &dyn DefDatabase,
module: LocalModuleId,
name: &Name,
shadow: BuiltinShadowMode,
expected_macro_subns: Option<MacroSubNs>,
) -> PerNs {
// Resolve in:
// - legacy scope of macro
// - current module / scope
// - extern prelude / macro_use prelude
// - std prelude
let from_legacy_macro = self[module]
.scope
.get_legacy_macro(name)
// FIXME: shadowing
.and_then(|it| it.last())
.copied()
.filter(|&id| {
sub_namespace_match(Some(MacroSubNs::from_id(db, id)), expected_macro_subns)
})
.map_or_else(PerNs::none, |m| PerNs::macros(m, Visibility::Public, None));
let from_scope = self[module].scope.get(name).filter_macro(db, expected_macro_subns);
let from_builtin = match self.block {
Some(_) => {
// Only resolve to builtins in the root `DefMap`.
PerNs::none()
}
None => BUILTIN_SCOPE.get(name).copied().unwrap_or_else(PerNs::none),
};
let from_scope_or_builtin = match shadow {
BuiltinShadowMode::Module => from_scope.or(from_builtin),
BuiltinShadowMode::Other => match from_scope.take_types() {
Some(ModuleDefId::ModuleId(_)) => from_builtin.or(from_scope),
Some(_) | None => from_scope.or(from_builtin),
},
};
let extern_prelude = || {
if self.block.is_some() && module == DefMap::ROOT {
// Don't resolve extern prelude in pseudo-modules of blocks, because
// they might been shadowed by local names.
return PerNs::none();
}
self.resolve_name_in_extern_prelude(local_def_map, name)
};
let macro_use_prelude = || self.resolve_in_macro_use_prelude(name);
let prelude = || {
if self.block.is_some() && module == DefMap::ROOT {
return PerNs::none();
}
self.resolve_in_prelude(db, name)
};
from_legacy_macro
.or(from_scope_or_builtin)
.or_else(extern_prelude)
.or_else(macro_use_prelude)
.or_else(prelude)
}
fn resolve_name_in_all_preludes(
&self,
local_def_map: &LocalDefMap,
db: &dyn DefDatabase,
name: &Name,
) -> PerNs {
// Resolve in:
// - extern prelude / macro_use prelude
// - std prelude
let extern_prelude = self.resolve_name_in_extern_prelude(local_def_map, name);
let macro_use_prelude = || self.resolve_in_macro_use_prelude(name);
let prelude = || self.resolve_in_prelude(db, name);
extern_prelude.or_else(macro_use_prelude).or_else(prelude)
}
fn resolve_name_in_extern_prelude(&self, local_def_map: &LocalDefMap, name: &Name) -> PerNs {
local_def_map.extern_prelude.get(name).map_or(PerNs::none(), |&(it, extern_crate)| {
PerNs::types(
it.into(),
Visibility::Public,
extern_crate.map(ImportOrExternCrate::ExternCrate),
)
})
}
fn resolve_in_macro_use_prelude(&self, name: &Name) -> PerNs {
self.macro_use_prelude.get(name).map_or(PerNs::none(), |&(it, extern_crate)| {
PerNs::macros(
it,
Visibility::Public,
extern_crate.map(ImportOrExternCrate::ExternCrate),
)
})
}
fn resolve_name_in_crate_root_or_extern_prelude(
&self,
local_def_map: &LocalDefMap,
db: &dyn DefDatabase,
module: LocalModuleId,
name: &Name,
) -> PerNs {
let from_crate_root = match self.block {
Some(_) => {
let def_map = self.crate_root().def_map(db);
def_map[Self::ROOT].scope.get(name)
}
None => self[Self::ROOT].scope.get(name),
};
let from_extern_prelude = || {
if self.block.is_some() && module == DefMap::ROOT {
// Don't resolve extern prelude in pseudo-module of a block.
return PerNs::none();
}
self.resolve_name_in_extern_prelude(local_def_map, name)
};
from_crate_root.or_else(from_extern_prelude)
}
fn resolve_in_prelude(&self, db: &dyn DefDatabase, name: &Name) -> PerNs {
if let Some((prelude, _use)) = self.prelude {
let keep;
let def_map = if prelude.krate == self.krate {
self
} else {
// Extend lifetime
keep = prelude.def_map(db);
keep
};
def_map[prelude.local_id].scope.get(name)
} else {
PerNs::none()
}
}
}
/// Given a block module, returns its nearest non-block module and the `DefMap` it belongs to.
fn adjust_to_nearest_non_block_module<'db>(
db: &'db dyn DefDatabase,
def_map: &'db DefMap,
mut local_id: LocalModuleId,
) -> (&'db DefMap, LocalModuleId) {
// INVARIANT: `local_id` in `def_map` must be a block module.
stdx::always!(def_map.module_id(local_id).is_block_module());
// This needs to be a local variable due to our mighty lifetime.
let mut def_map = def_map;
loop {
let BlockInfo { parent, .. } = def_map.block.expect("block module without parent module");
def_map = parent.def_map(db, def_map.krate);
local_id = parent.local_id;
if !parent.is_block_module() {
return (def_map, local_id);
}
}
}