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|
//! 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 hir_expand::name::Name;
use ra_db::Edition;
use test_utils::tested_by;
use crate::{
db::DefDatabase,
nameres::{BuiltinShadowMode, CrateDefMap},
path::{Path, PathKind},
per_ns::PerNs,
AdtId, EnumVariantId, LocalModuleId, ModuleDefId, ModuleId,
};
#[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,
pub(super) segment_index: Option<usize>,
pub(super) reached_fixedpoint: ReachedFixedPoint,
}
impl ResolvePathResult {
fn empty(reached_fixedpoint: ReachedFixedPoint) -> ResolvePathResult {
ResolvePathResult::with(PerNs::none(), reached_fixedpoint, None)
}
fn with(
resolved_def: PerNs,
reached_fixedpoint: ReachedFixedPoint,
segment_index: Option<usize>,
) -> ResolvePathResult {
ResolvePathResult { resolved_def, reached_fixedpoint, segment_index }
}
}
impl CrateDefMap {
pub(super) fn resolve_name_in_extern_prelude(&self, name: &Name) -> PerNs {
self.extern_prelude.get(name).map_or(PerNs::none(), |&it| PerNs::types(it))
}
// Returns Yes if we are sure that additions to `ItemMap` wouldn't change
// the result.
pub(super) fn resolve_path_fp_with_macro(
&self,
db: &impl DefDatabase,
mode: ResolveMode,
original_module: LocalModuleId,
path: &Path,
shadow: BuiltinShadowMode,
) -> ResolvePathResult {
let mut segments = path.segments.iter().enumerate().peekable();
let mut curr_per_ns: PerNs = match path.kind {
PathKind::DollarCrate(krate) => {
if krate == self.krate {
tested_by!(macro_dollar_crate_self);
PerNs::types(ModuleId { krate: self.krate, local_id: self.root }.into())
} else {
let def_map = db.crate_def_map(krate);
let module = ModuleId { krate, local_id: def_map.root };
tested_by!(macro_dollar_crate_other);
PerNs::types(module.into())
}
}
PathKind::Crate => {
PerNs::types(ModuleId { krate: self.krate, local_id: self.root }.into())
}
PathKind::Self_ => {
PerNs::types(ModuleId { krate: self.krate, local_id: original_module }.into())
}
// 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.edition == Edition::Edition2015
&& (path.kind == PathKind::Abs || mode == ResolveMode::Import) =>
{
let segment = match segments.next() {
Some((_, segment)) => segment,
None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
};
log::debug!("resolving {:?} in crate root (+ extern prelude)", segment);
self.resolve_name_in_crate_root_or_extern_prelude(
&segment.name,
prefer_module(&mut segments, shadow),
)
}
PathKind::Plain => {
let segment = match segments.next() {
Some((_, segment)) => segment,
None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
};
log::debug!("resolving {:?} in module", segment);
self.resolve_name_in_module(
db,
original_module,
&segment.name,
prefer_module(&mut segments, shadow),
)
}
PathKind::Super => {
if let Some(p) = self.modules[original_module].parent {
PerNs::types(ModuleId { krate: self.krate, local_id: p }.into())
} else {
log::debug!("super path in root module");
return ResolvePathResult::empty(ReachedFixedPoint::Yes);
}
}
PathKind::Abs => {
// 2018-style absolute path -- only extern prelude
let segment = match segments.next() {
Some((_, segment)) => segment,
None => return ResolvePathResult::empty(ReachedFixedPoint::Yes),
};
if let Some(def) = self.extern_prelude.get(&segment.name) {
log::debug!("absolute path {:?} resolved to crate {:?}", path, def);
PerNs::types(*def)
} else {
return ResolvePathResult::empty(ReachedFixedPoint::No); // extern crate declarations can add to the extern prelude
}
}
PathKind::Type(_) => {
// This is handled in `infer::infer_path_expr`
// The result returned here does not matter
return ResolvePathResult::empty(ReachedFixedPoint::Yes);
}
};
while let Some((i, segment)) = segments.next() {
let curr = match curr_per_ns.take_types() {
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 {
ModuleDefId::ModuleId(module) => {
if module.krate != self.krate {
let path =
Path { segments: path.segments[i..].to_vec(), kind: PathKind::Self_ };
log::debug!("resolving {:?} in other crate", path);
let defp_map = db.crate_def_map(module.krate);
let (def, s) = defp_map.resolve_path(db, module.local_id, &path, shadow);
return ResolvePathResult::with(
def,
ReachedFixedPoint::Yes,
s.map(|s| s + i),
);
}
// Since it is a qualified path here, it should not contains legacy macros
match self[module.local_id]
.scope
.get(&segment.name, prefer_module(&mut segments, shadow))
{
Some(res) => res.def,
_ => {
log::debug!("path segment {:?} not found", segment.name);
return ResolvePathResult::empty(ReachedFixedPoint::No);
}
}
}
ModuleDefId::AdtId(AdtId::EnumId(e)) => {
// enum variant
tested_by!(can_import_enum_variant);
let enum_data = db.enum_data(e);
match enum_data.variant(&segment.name) {
Some(local_id) => {
let variant = EnumVariantId { parent: e, local_id };
PerNs::both(variant.into(), variant.into())
}
None => {
return ResolvePathResult::with(
PerNs::types(e.into()),
ReachedFixedPoint::Yes,
Some(i),
);
}
}
}
s => {
// could be an inherent method call in UFCS form
// (`Struct::method`), or some other kind of associated item
log::debug!(
"path segment {:?} resolved to non-module {:?}, but is not last",
segment.name,
curr,
);
return ResolvePathResult::with(
PerNs::types(s),
ReachedFixedPoint::Yes,
Some(i),
);
}
};
}
return ResolvePathResult::with(curr_per_ns, ReachedFixedPoint::Yes, None);
// if it is not the last segment, we prefer builtin as module
fn prefer_module<I>(
segments: &mut std::iter::Peekable<I>,
shadow: BuiltinShadowMode,
) -> BuiltinShadowMode
where
I: Iterator,
{
if segments.peek().is_some() {
BuiltinShadowMode::Module
} else {
shadow
}
}
}
fn resolve_name_in_module(
&self,
db: &impl DefDatabase,
module: LocalModuleId,
name: &Name,
shadow: BuiltinShadowMode,
) -> PerNs {
// Resolve in:
// - legacy scope of macro
// - current module / scope
// - extern prelude
// - std prelude
let from_legacy_macro =
self[module].scope.get_legacy_macro(name).map_or_else(PerNs::none, PerNs::macros);
let from_scope =
self[module].scope.get(name, shadow).map_or_else(PerNs::none, |res| res.def);
let from_extern_prelude =
self.extern_prelude.get(name).map_or(PerNs::none(), |&it| PerNs::types(it));
let from_prelude = self.resolve_in_prelude(db, name, shadow);
from_legacy_macro.or(from_scope).or(from_extern_prelude).or(from_prelude)
}
fn resolve_name_in_crate_root_or_extern_prelude(
&self,
name: &Name,
shadow: BuiltinShadowMode,
) -> PerNs {
let from_crate_root =
self[self.root].scope.get(name, shadow).map_or_else(PerNs::none, |res| res.def);
let from_extern_prelude = self.resolve_name_in_extern_prelude(name);
from_crate_root.or(from_extern_prelude)
}
fn resolve_in_prelude(
&self,
db: &impl DefDatabase,
name: &Name,
shadow: BuiltinShadowMode,
) -> PerNs {
if let Some(prelude) = self.prelude {
let keep;
let def_map = if prelude.krate == self.krate {
self
} else {
// Extend lifetime
keep = db.crate_def_map(prelude.krate);
&keep
};
def_map[prelude.local_id]
.scope
.get(name, shadow)
.map_or_else(PerNs::none, |res| res.def)
} else {
PerNs::none()
}
}
}
|