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//! This module is responsible for resolving paths within rules.
use crate::errors::error;
use crate::{parsing, SsrError};
use parsing::Placeholder;
use ra_syntax::{ast, SmolStr, SyntaxKind, SyntaxNode, SyntaxToken};
use rustc_hash::{FxHashMap, FxHashSet};
use test_utils::mark;
pub(crate) struct ResolvedRule {
pub(crate) pattern: ResolvedPattern,
pub(crate) template: Option<ResolvedPattern>,
pub(crate) index: usize,
}
pub(crate) struct ResolvedPattern {
pub(crate) placeholders_by_stand_in: FxHashMap<SmolStr, parsing::Placeholder>,
pub(crate) node: SyntaxNode,
// Paths in `node` that we've resolved.
pub(crate) resolved_paths: FxHashMap<SyntaxNode, ResolvedPath>,
}
pub(crate) struct ResolvedPath {
pub(crate) resolution: hir::PathResolution,
pub(crate) depth: u32,
}
impl ResolvedRule {
pub(crate) fn new(
rule: parsing::ParsedRule,
scope: &hir::SemanticsScope,
hygiene: &hir::Hygiene,
index: usize,
) -> Result<ResolvedRule, SsrError> {
let resolver =
Resolver { scope, hygiene, placeholders_by_stand_in: rule.placeholders_by_stand_in };
let resolved_template = if let Some(template) = rule.template {
Some(resolver.resolve_pattern_tree(template)?)
} else {
None
};
Ok(ResolvedRule {
pattern: resolver.resolve_pattern_tree(rule.pattern)?,
template: resolved_template,
index,
})
}
pub(crate) fn get_placeholder(&self, token: &SyntaxToken) -> Option<&Placeholder> {
if token.kind() != SyntaxKind::IDENT {
return None;
}
self.pattern.placeholders_by_stand_in.get(token.text())
}
}
struct Resolver<'a, 'db> {
scope: &'a hir::SemanticsScope<'db>,
hygiene: &'a hir::Hygiene,
placeholders_by_stand_in: FxHashMap<SmolStr, parsing::Placeholder>,
}
impl Resolver<'_, '_> {
fn resolve_pattern_tree(&self, pattern: SyntaxNode) -> Result<ResolvedPattern, SsrError> {
let mut resolved_paths = FxHashMap::default();
self.resolve(pattern.clone(), 0, &mut resolved_paths)?;
Ok(ResolvedPattern {
node: pattern,
resolved_paths,
placeholders_by_stand_in: self.placeholders_by_stand_in.clone(),
})
}
fn resolve(
&self,
node: SyntaxNode,
depth: u32,
resolved_paths: &mut FxHashMap<SyntaxNode, ResolvedPath>,
) -> Result<(), SsrError> {
use ra_syntax::ast::AstNode;
if let Some(path) = ast::Path::cast(node.clone()) {
// Check if this is an appropriate place in the path to resolve. If the path is
// something like `a::B::<i32>::c` then we want to resolve `a::B`. If the path contains
// a placeholder. e.g. `a::$b::c` then we want to resolve `a`.
if !path_contains_type_arguments(path.qualifier())
&& !self.path_contains_placeholder(&path)
{
let resolution = self
.resolve_path(&path)
.ok_or_else(|| error!("Failed to resolve path `{}`", node.text()))?;
resolved_paths.insert(node, ResolvedPath { resolution, depth });
return Ok(());
}
}
for node in node.children() {
self.resolve(node, depth + 1, resolved_paths)?;
}
Ok(())
}
/// Returns whether `path` contains a placeholder, but ignores any placeholders within type
/// arguments.
fn path_contains_placeholder(&self, path: &ast::Path) -> bool {
if let Some(segment) = path.segment() {
if let Some(name_ref) = segment.name_ref() {
if self.placeholders_by_stand_in.contains_key(name_ref.text()) {
return true;
}
}
}
if let Some(qualifier) = path.qualifier() {
return self.path_contains_placeholder(&qualifier);
}
false
}
fn resolve_path(&self, path: &ast::Path) -> Option<hir::PathResolution> {
let hir_path = hir::Path::from_src(path.clone(), self.hygiene)?;
// First try resolving the whole path. This will work for things like
// `std::collections::HashMap`, but will fail for things like
// `std::collections::HashMap::new`.
if let Some(resolution) = self.scope.resolve_hir_path(&hir_path) {
return Some(resolution);
}
// Resolution failed, try resolving the qualifier (e.g. `std::collections::HashMap` and if
// that succeeds, then iterate through the candidates on the resolved type with the provided
// name.
let resolved_qualifier = self.scope.resolve_hir_path_qualifier(&hir_path.qualifier()?)?;
if let hir::PathResolution::Def(hir::ModuleDef::Adt(adt)) = resolved_qualifier {
adt.ty(self.scope.db).iterate_path_candidates(
self.scope.db,
self.scope.module()?.krate(),
&FxHashSet::default(),
Some(hir_path.segments().last()?.name),
|_ty, assoc_item| Some(hir::PathResolution::AssocItem(assoc_item)),
)
} else {
None
}
}
}
/// Returns whether `path` or any of its qualifiers contains type arguments.
fn path_contains_type_arguments(path: Option<ast::Path>) -> bool {
if let Some(path) = path {
if let Some(segment) = path.segment() {
if segment.type_arg_list().is_some() {
mark::hit!(type_arguments_within_path);
return true;
}
}
return path_contains_type_arguments(path.qualifier());
}
false
}
|
