[ty] Optimize "workspace symbols" retrieval

Basically, this splits the implementation into two pieces:
the first piece does the traversal and finds *all* symbols
across the workspace. The second piece does filtering based
on a user provided query string. Only the first piece is
cached by Salsa.

This brings warm "workspace symbols" requests down from
500-600ms to 100-200ms.

Cargo.lock

@@ -4245,12 +4245,14 @@ dependencies = [
  "itertools 0.14.0",
  "regex",
  "ruff_db",
+ "ruff_memory_usage",
  "ruff_python_ast",
  "ruff_python_parser",
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash",
+ "salsa",
  "smallvec",
  "tracing",
  "ty_project",

crates/ty_ide/Cargo.toml

@@ -13,6 +13,7 @@ license = { workspace = true }
 [dependencies]
 bitflags = { workspace = true }
 ruff_db = { workspace = true }
+ruff_memory_usage = { workspace = true }
 ruff_python_ast = { workspace = true }
 ruff_python_parser = { workspace = true }
 ruff_python_trivia = { workspace = true }
@@ -24,6 +25,7 @@ ty_project = { workspace = true, features = ["testing"] }
 itertools = { workspace = true }
 regex = { workspace = true }
 rustc-hash = { workspace = true }
+salsa = { workspace = true, features = ["compact_str"] }
 smallvec = { workspace = true }
 tracing = { workspace = true }
 

crates/ty_ide/src/document_symbols.rs

@@ -8,7 +8,7 @@ pub fn document_symbols_with_options(
     file: File,
     options: &SymbolsOptions,
 ) -> Vec<SymbolInfo> {
-    symbols_for_file(db, file, options)
+    symbols_for_file(db, file, options).cloned().collect()
 }
 
 /// Get all document symbols for a file (hierarchical by default).

crates/ty_ide/src/symbols.rs

@@ -125,47 +125,64 @@ impl SymbolKind {
     }
 }
 
-pub(crate) fn symbols_for_file(
-    db: &dyn Db,
+pub(crate) fn symbols_for_file<'db>(
+    db: &'db dyn Db,
     file: File,
     options: &SymbolsOptions,
-) -> Vec<SymbolInfo> {
+) -> impl Iterator<Item = &'db SymbolInfo> {
     assert!(
         !options.hierarchical || options.query_string.is_none(),
         "Cannot use hierarchical mode with a query string"
     );
 
+    let ingredient = SymbolsOptionsWithoutQuery {
+        hierarchical: options.hierarchical,
+        global_only: options.global_only,
+    };
+    symbols_for_file_inner(db, file, ingredient)
+        .iter()
+        .filter(|symbol| {
+            let Some(ref query) = options.query_string else {
+                return true;
+            };
+            query.is_match(symbol)
+        })
+}
+
+#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+struct SymbolsOptionsWithoutQuery {
+    hierarchical: bool,
+    global_only: bool,
+}
+
+#[salsa::tracked(returns(deref))]
+fn symbols_for_file_inner<'db>(
+    db: &'db dyn Db,
+    file: File,
+    options: SymbolsOptionsWithoutQuery,
+) -> Vec<SymbolInfo> {
     let parsed = parsed_module(db, file);
     let module = parsed.load(db);
 
-    let mut visitor = SymbolVisitor::new(options);
+    let mut visitor = SymbolVisitor {
+        symbols: vec![],
+        symbol_stack: vec![],
+        in_function: false,
+        options,
+    };
     visitor.visit_body(&module.syntax().body);
-    let mut symbols = visitor.symbols;
-    if let Some(ref query) = options.query_string {
-        symbols.retain(|symbol| query.is_match(symbol));
-    }
-    symbols
+    visitor.symbols
 }
 
-struct SymbolVisitor<'a> {
+struct SymbolVisitor {
     symbols: Vec<SymbolInfo>,
     symbol_stack: Vec<SymbolInfo>,
     /// Track if we're currently inside a function (to exclude local variables)
     in_function: bool,
-    /// Options controlling symbol collection
-    options: &'a SymbolsOptions,
-}
-
-impl<'a> SymbolVisitor<'a> {
-    fn new(options: &'a SymbolsOptions) -> Self {
-        Self {
-            symbols: Vec::new(),
-            symbol_stack: Vec::new(),
-            in_function: false,
-            options,
-        }
+    options: SymbolsOptionsWithoutQuery,
 }
 
+impl SymbolVisitor {
     fn visit_body(&mut self, body: &[Stmt]) {
         for stmt in body {
             self.visit_stmt(stmt);
@@ -205,7 +222,7 @@ impl<'a> SymbolVisitor<'a> {
     }
 }
 
-impl SourceOrderVisitor<'_> for SymbolVisitor<'_> {
+impl SourceOrderVisitor<'_> for SymbolVisitor {
     fn visit_stmt(&mut self, stmt: &Stmt) {
         match stmt {
             Stmt::FunctionDef(func_def) => {

crates/ty_ide/src/workspace_symbols.rs

@@ -28,7 +28,7 @@ pub fn workspace_symbols(db: &dyn Db, query: &str) -> Vec<WorkspaceSymbolInfo> {
 
         for symbol in file_symbols {
             results.push(WorkspaceSymbolInfo {
-                symbol,
+                symbol: symbol.clone(),
                 file: *file,
             });
         }