[ty] Initial implementation of declaration and definition providers. (#19371)

This PR implements "go to definition" and "go to declaration"
functionality for name nodes only. Future PRs will add support for
attributes, module names in import statements, keyword argument names,
etc.

This PR:
* Registers a declaration and definition request handler for the
language server.
* Splits out the `goto_type_definition` into its own module. The `goto`
module contains functionality that is common to `goto_type_definition`,
`goto_declaration` and `goto_definition`.
* Roughs in a new module `stub_mapping` that is not yet implemented. It
will be responsible for mapping a definition in a stub file to its
corresponding definition(s) in an implementation (source) file.
* Adds a new IDE support function `definitions_for_name` that collects
all of the definitions associated with a name and resolves any imports
(recursively) to find the original definitions associated with that
name.
* Adds a new `VisibleAncestorsIter` stuct that iterates up the scope
hierarchy but skips scopes that are not visible to starting scope.

---------

Co-authored-by: UnboundVariable <unbound@gmail.com>

crates/ty_server/src/server.rs

@@ -5,9 +5,9 @@ use crate::PositionEncoding;
 use crate::session::{AllOptions, ClientOptions, DiagnosticMode, Session};
 use lsp_server::Connection;
 use lsp_types::{
-    ClientCapabilities, DiagnosticOptions, DiagnosticServerCapabilities, HoverProviderCapability,
-    InitializeParams, InlayHintOptions, InlayHintServerCapabilities, MessageType,
-    SemanticTokensLegend, SemanticTokensOptions, SemanticTokensServerCapabilities,
+    ClientCapabilities, DeclarationCapability, DiagnosticOptions, DiagnosticServerCapabilities,
+    HoverProviderCapability, InitializeParams, InlayHintOptions, InlayHintServerCapabilities,
+    MessageType, SemanticTokensLegend, SemanticTokensOptions, SemanticTokensServerCapabilities,
     ServerCapabilities, SignatureHelpOptions, TextDocumentSyncCapability, TextDocumentSyncKind,
     TextDocumentSyncOptions, TypeDefinitionProviderCapability, Url, WorkDoneProgressOptions,
 };
@@ -194,6 +194,8 @@ impl Server {
                 },
             )),
             type_definition_provider: Some(TypeDefinitionProviderCapability::Simple(true)),
+            definition_provider: Some(lsp_types::OneOf::Left(true)),
+            declaration_provider: Some(DeclarationCapability::Simple(true)),
             hover_provider: Some(HoverProviderCapability::Simple(true)),
             signature_help_provider: Some(SignatureHelpOptions {
                 trigger_characters: Some(vec!["(".to_string(), ",".to_string()]),

crates/ty_server/src/server/api.rs

@@ -44,6 +44,14 @@ pub(super) fn request(req: server::Request) -> Task {
         >(
             req, BackgroundSchedule::Worker
         ),
+        requests::GotoDeclarationRequestHandler::METHOD => background_document_request_task::<
+            requests::GotoDeclarationRequestHandler,
+        >(
+            req, BackgroundSchedule::Worker
+        ),
+        requests::GotoDefinitionRequestHandler::METHOD => background_document_request_task::<
+            requests::GotoDefinitionRequestHandler,
+        >(req, BackgroundSchedule::Worker),
         requests::HoverRequestHandler::METHOD => background_document_request_task::<
             requests::HoverRequestHandler,
         >(req, BackgroundSchedule::Worker),

crates/ty_server/src/server/api/requests.rs

@@ -1,5 +1,7 @@
 mod completion;
 mod diagnostic;
+mod goto_declaration;
+mod goto_definition;
 mod goto_type_definition;
 mod hover;
 mod inlay_hints;
@@ -11,6 +13,8 @@ mod workspace_diagnostic;
 
 pub(super) use completion::CompletionRequestHandler;
 pub(super) use diagnostic::DocumentDiagnosticRequestHandler;
+pub(super) use goto_declaration::GotoDeclarationRequestHandler;
+pub(super) use goto_definition::GotoDefinitionRequestHandler;
 pub(super) use goto_type_definition::GotoTypeDefinitionRequestHandler;
 pub(super) use hover::HoverRequestHandler;
 pub(super) use inlay_hints::InlayHintRequestHandler;

crates/ty_server/src/server/api/requests/goto_declaration.rs

@@ -0,0 +1,75 @@
+use std::borrow::Cow;
+
+use lsp_types::request::{GotoDeclaration, GotoDeclarationParams};
+use lsp_types::{GotoDefinitionResponse, Url};
+use ruff_db::source::{line_index, source_text};
+use ty_ide::goto_declaration;
+use ty_project::ProjectDatabase;
+
+use crate::document::{PositionExt, ToLink};
+use crate::server::api::traits::{
+    BackgroundDocumentRequestHandler, RequestHandler, RetriableRequestHandler,
+};
+use crate::session::DocumentSnapshot;
+use crate::session::client::Client;
+
+pub(crate) struct GotoDeclarationRequestHandler;
+
+impl RequestHandler for GotoDeclarationRequestHandler {
+    type RequestType = GotoDeclaration;
+}
+
+impl BackgroundDocumentRequestHandler for GotoDeclarationRequestHandler {
+    fn document_url(params: &GotoDeclarationParams) -> Cow<Url> {
+        Cow::Borrowed(&params.text_document_position_params.text_document.uri)
+    }
+
+    fn run_with_snapshot(
+        db: &ProjectDatabase,
+        snapshot: DocumentSnapshot,
+        _client: &Client,
+        params: GotoDeclarationParams,
+    ) -> crate::server::Result<Option<GotoDefinitionResponse>> {
+        if snapshot.client_settings().is_language_services_disabled() {
+            return Ok(None);
+        }
+
+        let Some(file) = snapshot.file(db) else {
+            return Ok(None);
+        };
+
+        let source = source_text(db, file);
+        let line_index = line_index(db, file);
+        let offset = params.text_document_position_params.position.to_text_size(
+            &source,
+            &line_index,
+            snapshot.encoding(),
+        );
+
+        let Some(ranged) = goto_declaration(db, file, offset) else {
+            return Ok(None);
+        };
+
+        if snapshot
+            .resolved_client_capabilities()
+            .type_definition_link_support
+        {
+            let src = Some(ranged.range);
+            let links: Vec<_> = ranged
+                .into_iter()
+                .filter_map(|target| target.to_link(db, src, snapshot.encoding()))
+                .collect();
+
+            Ok(Some(GotoDefinitionResponse::Link(links)))
+        } else {
+            let locations: Vec<_> = ranged
+                .into_iter()
+                .filter_map(|target| target.to_location(db, snapshot.encoding()))
+                .collect();
+
+            Ok(Some(GotoDefinitionResponse::Array(locations)))
+        }
+    }
+}
+
+impl RetriableRequestHandler for GotoDeclarationRequestHandler {}

crates/ty_server/src/server/api/requests/goto_definition.rs

@@ -0,0 +1,75 @@
+use std::borrow::Cow;
+
+use lsp_types::request::GotoDefinition;
+use lsp_types::{GotoDefinitionParams, GotoDefinitionResponse, Url};
+use ruff_db::source::{line_index, source_text};
+use ty_ide::goto_definition;
+use ty_project::ProjectDatabase;
+
+use crate::document::{PositionExt, ToLink};
+use crate::server::api::traits::{
+    BackgroundDocumentRequestHandler, RequestHandler, RetriableRequestHandler,
+};
+use crate::session::DocumentSnapshot;
+use crate::session::client::Client;
+
+pub(crate) struct GotoDefinitionRequestHandler;
+
+impl RequestHandler for GotoDefinitionRequestHandler {
+    type RequestType = GotoDefinition;
+}
+
+impl BackgroundDocumentRequestHandler for GotoDefinitionRequestHandler {
+    fn document_url(params: &GotoDefinitionParams) -> Cow<Url> {
+        Cow::Borrowed(&params.text_document_position_params.text_document.uri)
+    }
+
+    fn run_with_snapshot(
+        db: &ProjectDatabase,
+        snapshot: DocumentSnapshot,
+        _client: &Client,
+        params: GotoDefinitionParams,
+    ) -> crate::server::Result<Option<GotoDefinitionResponse>> {
+        if snapshot.client_settings().is_language_services_disabled() {
+            return Ok(None);
+        }
+
+        let Some(file) = snapshot.file(db) else {
+            return Ok(None);
+        };
+
+        let source = source_text(db, file);
+        let line_index = line_index(db, file);
+        let offset = params.text_document_position_params.position.to_text_size(
+            &source,
+            &line_index,
+            snapshot.encoding(),
+        );
+
+        let Some(ranged) = goto_definition(db, file, offset) else {
+            return Ok(None);
+        };
+
+        if snapshot
+            .resolved_client_capabilities()
+            .type_definition_link_support
+        {
+            let src = Some(ranged.range);
+            let links: Vec<_> = ranged
+                .into_iter()
+                .filter_map(|target| target.to_link(db, src, snapshot.encoding()))
+                .collect();
+
+            Ok(Some(GotoDefinitionResponse::Link(links)))
+        } else {
+            let locations: Vec<_> = ranged
+                .into_iter()
+                .filter_map(|target| target.to_location(db, snapshot.encoding()))
+                .collect();
+
+            Ok(Some(GotoDefinitionResponse::Array(locations)))
+        }
+    }
+}
+
+impl RetriableRequestHandler for GotoDefinitionRequestHandler {}