301 lines
11 KiB
Rust
301 lines
11 KiB
Rust
//! This module is responsible for resolving paths within rules.
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use crate::errors::error;
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use crate::{parsing, SsrError};
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use ide_db::base_db::FilePosition;
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use parsing::Placeholder;
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use rustc_hash::FxHashMap;
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use syntax::{ast, SmolStr, SyntaxKind, SyntaxNode, SyntaxToken};
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pub(crate) struct ResolutionScope<'db> {
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scope: hir::SemanticsScope<'db>,
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node: SyntaxNode,
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}
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pub(crate) struct ResolvedRule {
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pub(crate) pattern: ResolvedPattern,
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pub(crate) template: Option<ResolvedPattern>,
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pub(crate) index: usize,
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}
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pub(crate) struct ResolvedPattern {
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pub(crate) placeholders_by_stand_in: FxHashMap<SmolStr, parsing::Placeholder>,
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pub(crate) node: SyntaxNode,
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// Paths in `node` that we've resolved.
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pub(crate) resolved_paths: FxHashMap<SyntaxNode, ResolvedPath>,
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pub(crate) ufcs_function_calls: FxHashMap<SyntaxNode, UfcsCallInfo>,
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pub(crate) contains_self: bool,
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}
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pub(crate) struct ResolvedPath {
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pub(crate) resolution: hir::PathResolution,
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/// The depth of the ast::Path that was resolved within the pattern.
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pub(crate) depth: u32,
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}
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pub(crate) struct UfcsCallInfo {
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pub(crate) call_expr: ast::CallExpr,
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pub(crate) function: hir::Function,
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pub(crate) qualifier_type: Option<hir::Type>,
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}
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impl ResolvedRule {
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pub(crate) fn new(
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rule: parsing::ParsedRule,
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resolution_scope: &ResolutionScope,
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index: usize,
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) -> Result<ResolvedRule, SsrError> {
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let resolver =
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Resolver { resolution_scope, placeholders_by_stand_in: rule.placeholders_by_stand_in };
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let resolved_template = if let Some(template) = rule.template {
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Some(resolver.resolve_pattern_tree(template)?)
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} else {
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None
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};
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Ok(ResolvedRule {
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pattern: resolver.resolve_pattern_tree(rule.pattern)?,
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template: resolved_template,
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index,
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})
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}
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pub(crate) fn get_placeholder(&self, token: &SyntaxToken) -> Option<&Placeholder> {
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if token.kind() != SyntaxKind::IDENT {
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return None;
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}
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self.pattern.placeholders_by_stand_in.get(token.text())
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}
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}
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struct Resolver<'a, 'db> {
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resolution_scope: &'a ResolutionScope<'db>,
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placeholders_by_stand_in: FxHashMap<SmolStr, parsing::Placeholder>,
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}
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impl Resolver<'_, '_> {
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fn resolve_pattern_tree(&self, pattern: SyntaxNode) -> Result<ResolvedPattern, SsrError> {
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use syntax::ast::AstNode;
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use syntax::{SyntaxElement, T};
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let mut resolved_paths = FxHashMap::default();
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self.resolve(pattern.clone(), 0, &mut resolved_paths)?;
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let ufcs_function_calls = resolved_paths
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.iter()
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.filter_map(|(path_node, resolved)| {
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if let Some(grandparent) = path_node.parent().and_then(|parent| parent.parent()) {
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if let Some(call_expr) = ast::CallExpr::cast(grandparent.clone()) {
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if let hir::PathResolution::AssocItem(hir::AssocItem::Function(function)) =
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resolved.resolution
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{
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let qualifier_type = self.resolution_scope.qualifier_type(path_node);
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return Some((
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grandparent,
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UfcsCallInfo { call_expr, function, qualifier_type },
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));
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}
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}
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}
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None
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})
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.collect();
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let contains_self =
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pattern.descendants_with_tokens().any(|node_or_token| match node_or_token {
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SyntaxElement::Token(t) => t.kind() == T![self],
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_ => false,
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});
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Ok(ResolvedPattern {
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node: pattern,
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resolved_paths,
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placeholders_by_stand_in: self.placeholders_by_stand_in.clone(),
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ufcs_function_calls,
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contains_self,
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})
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}
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fn resolve(
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&self,
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node: SyntaxNode,
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depth: u32,
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resolved_paths: &mut FxHashMap<SyntaxNode, ResolvedPath>,
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) -> Result<(), SsrError> {
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use syntax::ast::AstNode;
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if let Some(path) = ast::Path::cast(node.clone()) {
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if is_self(&path) {
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// Self cannot be resolved like other paths.
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return Ok(());
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}
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// Check if this is an appropriate place in the path to resolve. If the path is
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// something like `a::B::<i32>::c` then we want to resolve `a::B`. If the path contains
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// a placeholder. e.g. `a::$b::c` then we want to resolve `a`.
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if !path_contains_type_arguments(path.qualifier())
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&& !self.path_contains_placeholder(&path)
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{
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let resolution = self
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.resolution_scope
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.resolve_path(&path)
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.ok_or_else(|| error!("Failed to resolve path `{}`", node.text()))?;
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if self.ok_to_use_path_resolution(&resolution) {
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resolved_paths.insert(node, ResolvedPath { resolution, depth });
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return Ok(());
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}
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}
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}
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for node in node.children() {
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self.resolve(node, depth + 1, resolved_paths)?;
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}
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Ok(())
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}
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/// Returns whether `path` contains a placeholder, but ignores any placeholders within type
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/// arguments.
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fn path_contains_placeholder(&self, path: &ast::Path) -> bool {
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if let Some(segment) = path.segment() {
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if let Some(name_ref) = segment.name_ref() {
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if self.placeholders_by_stand_in.contains_key(name_ref.text().as_str()) {
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return true;
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}
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}
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}
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if let Some(qualifier) = path.qualifier() {
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return self.path_contains_placeholder(&qualifier);
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}
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false
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}
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fn ok_to_use_path_resolution(&self, resolution: &hir::PathResolution) -> bool {
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match resolution {
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hir::PathResolution::AssocItem(hir::AssocItem::Function(function)) => {
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if function.self_param(self.resolution_scope.scope.db).is_some() {
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// If we don't use this path resolution, then we won't be able to match method
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// calls. e.g. `Foo::bar($s)` should match `x.bar()`.
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true
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} else {
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cov_mark::hit!(replace_associated_trait_default_function_call);
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false
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}
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}
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hir::PathResolution::AssocItem(_) => {
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// Not a function. Could be a constant or an associated type.
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cov_mark::hit!(replace_associated_trait_constant);
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false
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}
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_ => true,
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}
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}
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}
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impl<'db> ResolutionScope<'db> {
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pub(crate) fn new(
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sema: &hir::Semantics<'db, ide_db::RootDatabase>,
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resolve_context: FilePosition,
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) -> ResolutionScope<'db> {
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use syntax::ast::AstNode;
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let file = sema.parse(resolve_context.file_id);
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// Find a node at the requested position, falling back to the whole file.
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let node = file
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.syntax()
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.token_at_offset(resolve_context.offset)
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.left_biased()
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.and_then(|token| token.parent())
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.unwrap_or_else(|| file.syntax().clone());
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let node = pick_node_for_resolution(node);
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let scope = sema.scope(&node);
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ResolutionScope { scope, node }
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}
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/// Returns the function in which SSR was invoked, if any.
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pub(crate) fn current_function(&self) -> Option<SyntaxNode> {
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self.node.ancestors().find(|node| node.kind() == SyntaxKind::FN)
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}
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fn resolve_path(&self, path: &ast::Path) -> Option<hir::PathResolution> {
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// First try resolving the whole path. This will work for things like
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// `std::collections::HashMap`, but will fail for things like
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// `std::collections::HashMap::new`.
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if let Some(resolution) = self.scope.speculative_resolve(path) {
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return Some(resolution);
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}
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// Resolution failed, try resolving the qualifier (e.g. `std::collections::HashMap` and if
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// that succeeds, then iterate through the candidates on the resolved type with the provided
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// name.
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let resolved_qualifier = self.scope.speculative_resolve(&path.qualifier()?)?;
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if let hir::PathResolution::Def(hir::ModuleDef::Adt(adt)) = resolved_qualifier {
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let name = path.segment()?.name_ref()?;
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adt.ty(self.scope.db).iterate_path_candidates(
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self.scope.db,
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self.scope.module()?.krate(),
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&self.scope.traits_in_scope(),
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None,
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|_ty, assoc_item| {
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let item_name = assoc_item.name(self.scope.db)?;
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if item_name.to_string().as_str() == name.text() {
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Some(hir::PathResolution::AssocItem(assoc_item))
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} else {
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None
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}
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},
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)
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} else {
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None
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}
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}
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fn qualifier_type(&self, path: &SyntaxNode) -> Option<hir::Type> {
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use syntax::ast::AstNode;
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if let Some(path) = ast::Path::cast(path.clone()) {
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if let Some(qualifier) = path.qualifier() {
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if let Some(resolved_qualifier) = self.resolve_path(&qualifier) {
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if let hir::PathResolution::Def(hir::ModuleDef::Adt(adt)) = resolved_qualifier {
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return Some(adt.ty(self.scope.db));
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}
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}
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}
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}
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None
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}
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}
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fn is_self(path: &ast::Path) -> bool {
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path.segment().map(|segment| segment.self_token().is_some()).unwrap_or(false)
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}
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/// Returns a suitable node for resolving paths in the current scope. If we create a scope based on
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/// a statement node, then we can't resolve local variables that were defined in the current scope
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/// (only in parent scopes). So we find another node, ideally a child of the statement where local
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/// variable resolution is permitted.
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fn pick_node_for_resolution(node: SyntaxNode) -> SyntaxNode {
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match node.kind() {
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SyntaxKind::EXPR_STMT => {
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if let Some(n) = node.first_child() {
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cov_mark::hit!(cursor_after_semicolon);
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return n;
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}
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}
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SyntaxKind::LET_STMT | SyntaxKind::IDENT_PAT => {
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if let Some(next) = node.next_sibling() {
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return pick_node_for_resolution(next);
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}
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}
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SyntaxKind::NAME => {
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if let Some(parent) = node.parent() {
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return pick_node_for_resolution(parent);
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}
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}
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_ => {}
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}
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node
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}
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/// Returns whether `path` or any of its qualifiers contains type arguments.
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fn path_contains_type_arguments(path: Option<ast::Path>) -> bool {
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if let Some(path) = path {
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if let Some(segment) = path.segment() {
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if segment.generic_arg_list().is_some() {
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cov_mark::hit!(type_arguments_within_path);
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return true;
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}
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}
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return path_contains_type_arguments(path.qualifier());
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}
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false
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}
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