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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_db::FilePosition;
use ra_syntax::{ast, SmolStr, SyntaxKind, SyntaxNode, SyntaxToken};
use rustc_hash::{FxHashMap, FxHashSet};
use test_utils::mark;
pub(crate) struct ResolutionScope<'db> {
scope: hir::SemanticsScope<'db>,
hygiene: hir::Hygiene,
}
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) ufcs_function_calls: FxHashMap<SyntaxNode, hir::Function>,
}
pub(crate) struct ResolvedPath {
pub(crate) resolution: hir::PathResolution,
/// The depth of the ast::Path that was resolved within the pattern.
pub(crate) depth: u32,
}
impl ResolvedRule {
pub(crate) fn new(
rule: parsing::ParsedRule,
resolution_scope: &ResolutionScope,
index: usize,
) -> Result<ResolvedRule, SsrError> {
let resolver =
Resolver { resolution_scope, 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> {
resolution_scope: &'a ResolutionScope<'db>,
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)?;
let ufcs_function_calls = resolved_paths
.iter()
.filter_map(|(path_node, resolved)| {
if let Some(grandparent) = path_node.parent().and_then(|parent| parent.parent()) {
if grandparent.kind() == SyntaxKind::CALL_EXPR {
if let hir::PathResolution::AssocItem(hir::AssocItem::Function(function)) =
&resolved.resolution
{
return Some((grandparent, *function));
}
}
}
None
})
.collect();
Ok(ResolvedPattern {
node: pattern,
resolved_paths,
placeholders_by_stand_in: self.placeholders_by_stand_in.clone(),
ufcs_function_calls,
})
}
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
.resolution_scope
.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
}
}
impl<'db> ResolutionScope<'db> {
pub(crate) fn new(
sema: &hir::Semantics<'db, ra_ide_db::RootDatabase>,
lookup_context: FilePosition,
) -> ResolutionScope<'db> {
use ra_syntax::ast::AstNode;
let file = sema.parse(lookup_context.file_id);
// Find a node at the requested position, falling back to the whole file.
let node = file
.syntax()
.token_at_offset(lookup_context.offset)
.left_biased()
.map(|token| token.parent())
.unwrap_or_else(|| file.syntax().clone());
let node = pick_node_for_resolution(node);
let scope = sema.scope(&node);
ResolutionScope {
scope,
hygiene: hir::Hygiene::new(sema.db, lookup_context.file_id.into()),
}
}
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 a suitable node for resolving paths in the current scope. If we create a scope based on
/// a statement node, then we can't resolve local variables that were defined in the current scope
/// (only in parent scopes). So we find another node, ideally a child of the statement where local
/// variable resolution is permitted.
fn pick_node_for_resolution(node: SyntaxNode) -> SyntaxNode {
match node.kind() {
SyntaxKind::EXPR_STMT => {
if let Some(n) = node.first_child() {
mark::hit!(cursor_after_semicolon);
return n;
}
}
SyntaxKind::LET_STMT | SyntaxKind::BIND_PAT => {
if let Some(next) = node.next_sibling() {
return pick_node_for_resolution(next);
}
}
SyntaxKind::NAME => {
if let Some(parent) = node.parent() {
return pick_node_for_resolution(parent);
}
}
_ => {}
}
node
}
/// 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
}
|
