Export file referrer query as experimental/parentModule

See: https://github.com/microsoft/language-server-protocol/issues/1002

crates/ide/src/ide/file_references.rs

@@ -0,0 +1,15 @@
+use crate::{DefDatabase, FileId};
+
+pub(crate) fn file_references(db: &dyn DefDatabase, file: FileId) -> Vec<FileId> {
+    let mut refs = db
+        .module_references(file)
+        .iter()
+        .copied()
+        .collect::<Vec<_>>();
+    refs.sort();
+    refs
+}
+
+pub(crate) fn file_referrers(db: &dyn DefDatabase, file: FileId) -> Vec<FileId> {
+    db.module_referrers(file).into_vec()
+}

crates/ide/src/ide/mod.rs

@@ -2,6 +2,7 @@ mod assists;
 mod completion;
 mod diagnostics;
 mod expand_selection;
+mod file_references;
 mod goto_definition;
 mod highlight_related;
 mod hover;
@@ -134,6 +135,8 @@ impl Analysis {
         Cancelled::catch(|| f(&self.db))
     }
 
+    //// LSP standard ////
+
     pub fn expand_selection(&self, frange: FileRange) -> Cancellable<Option<Vec<TextRange>>> {
         self.with_db(|db| expand_selection::expand_selection(db, frange))
     }
@@ -197,4 +200,14 @@ impl Analysis {
     pub fn highlight_related(&self, fpos: FilePos) -> Cancellable<Vec<HlRelated>> {
         self.with_db(|db| highlight_related::highlight_related(db, fpos).unwrap_or_default())
     }
+
+    //// Custom extensions ////
+
+    pub fn file_references(&self, file: FileId) -> Cancellable<Vec<FileId>> {
+        self.with_db(|db| file_references::file_references(db, file))
+    }
+
+    pub fn file_referrers(&self, file: FileId) -> Cancellable<Vec<FileId>> {
+        self.with_db(|db| file_references::file_referrers(db, file))
+    }
 }

crates/nil/src/handler.rs

@@ -330,3 +330,17 @@ pub(crate) fn document_highlight(
     let ret = convert::to_document_highlight(&line_map, &ret);
     Ok(Some(ret))
 }
+
+pub(crate) fn parent_module(
+    snap: StateSnapshot,
+    params: TextDocumentPositionParams,
+) -> Result<Option<GotoDefinitionResponse>> {
+    let (file, _) = convert::from_file(&snap.vfs(), &params.text_document)?;
+    let files = snap.analysis.file_referrers(file)?;
+    let vfs = snap.vfs();
+    let locs = files
+        .into_iter()
+        .map(|file| convert::to_location(&vfs, FileRange::new(file, TextRange::default())))
+        .collect();
+    Ok(Some(GotoDefinitionResponse::Array(locs)))
+}

crates/nil/src/lib.rs

@@ -2,6 +2,7 @@ mod capabilities;
 mod config;
 mod convert;
 mod handler;
+mod lsp_ext;
 mod semantic_tokens;
 mod server;
 mod vfs;

crates/nil/src/lsp_ext.rs

@@ -0,0 +1,10 @@
+use lsp_types::request::Request;
+
+/// https://github.com/microsoft/language-server-protocol/issues/1002
+pub enum ParentModule {}
+
+impl Request for ParentModule {
+    type Params = lsp_types::TextDocumentPositionParams;
+    type Result = Option<lsp_types::GotoDefinitionResponse>;
+    const METHOD: &'static str = "experimental/parentModule";
+}

crates/nil/src/server.rs

@@ -1,5 +1,5 @@
 use crate::config::{Config, CONFIG_KEY};
-use crate::{convert, handler, LspError, UrlExt, Vfs, MAX_FILE_LEN};
+use crate::{convert, handler, lsp_ext, LspError, UrlExt, Vfs, MAX_FILE_LEN};
 use anyhow::{anyhow, bail, Context, Result};
 use crossbeam_channel::{Receiver, Sender};
 use ide::{Analysis, AnalysisHost, Cancelled, FlakeInfo, VfsPath};
@@ -273,6 +273,7 @@ impl Server {
             .on::<req::DocumentLinkRequest>(handler::document_links)
             .on::<req::CodeActionRequest>(handler::code_action)
             .on::<req::DocumentHighlightRequest>(handler::document_highlight)
+            .on::<lsp_ext::ParentModule>(handler::parent_module)
             .finish();
     }