Improve formatting of function autocompletion labels in Rust

Co-Authored-By: Nathan Sobo <nathan@zed.dev>
Co-Authored-By: Max Brunsfeld <max@zed.dev>

crates/editor/src/multi_buffer.rs

@@ -883,6 +883,7 @@ impl MultiBuffer {
                                 completion.old_range.end,
                             ),
                         new_text: completion.new_text,
+                        label: completion.label,
                         lsp_completion: completion.lsp_completion,
                     })
                     .collect()
@@ -939,6 +940,7 @@ impl MultiBuffer {
                     old_range: completion.old_range.start.text_anchor
                         ..completion.old_range.end.text_anchor,
                     new_text: completion.new_text,
+                    label: completion.label,
                     lsp_completion: completion.lsp_completion,
                 },
                 true,

crates/language/src/buffer.rs

@@ -119,6 +119,7 @@ pub struct Diagnostic {
 pub struct Completion<T> {
     pub old_range: Range<T>,
     pub new_text: String,
+    pub label: Option<String>,
     pub lsp_completion: lsp::CompletionItem,
 }
 
@@ -203,6 +204,7 @@ pub trait File {
         &self,
         buffer_id: u64,
         position: Anchor,
+        language: Option<Arc<Language>>,
         cx: &mut MutableAppContext,
     ) -> Task<Result<Vec<Completion<Anchor>>>>;
 
@@ -286,6 +288,7 @@ impl File for FakeFile {
         &self,
         _: u64,
         _: Anchor,
+        _: Option<Arc<Language>>,
         _: &mut MutableAppContext,
     ) -> Task<Result<Vec<Completion<Anchor>>>> {
         Task::ready(Ok(Default::default()))
@@ -1800,10 +1803,11 @@ impl Buffer {
         } else {
             return Task::ready(Ok(Default::default()));
         };
+        let language = self.language.clone();
 
         if let Some(file) = file.as_local() {
-            let server = if let Some(lang) = self.language_server.as_ref() {
-                lang.server.clone()
+            let server = if let Some(language_server) = self.language_server.as_ref() {
+                language_server.server.clone()
             } else {
                 return Task::ready(Ok(Default::default()));
             };
@@ -1850,6 +1854,7 @@ impl Buffer {
                             Some(Completion {
                                 old_range: this.anchor_before(old_range.start)..this.anchor_after(old_range.end),
                                 new_text,
+                                label: language.as_ref().and_then(|l| l.label_for_completion(&lsp_completion)),
                                 lsp_completion,
                             })
                         } else {
@@ -1859,7 +1864,12 @@ impl Buffer {
                 })
             })
         } else {
-            file.completions(self.remote_id(), self.anchor_before(position), cx.as_mut())
+            file.completions(
+                self.remote_id(),
+                self.anchor_before(position),
+                language,
+                cx.as_mut(),
+            )
         }
     }
 
@@ -2668,7 +2678,7 @@ impl Default for Diagnostic {
 
 impl<T> Completion<T> {
     pub fn label(&self) -> &str {
-        &self.lsp_completion.label
+        self.label.as_deref().unwrap_or(&self.lsp_completion.label)
     }
 
     pub fn filter_range(&self) -> Range<usize> {

crates/language/src/language.rs

@@ -43,8 +43,11 @@ pub trait ToLspPosition {
     fn to_lsp_position(self) -> lsp::Position;
 }
 
-pub trait DiagnosticProcessor: 'static + Send + Sync {
+pub trait LspPostProcessor: 'static + Send + Sync {
     fn process_diagnostics(&self, diagnostics: &mut lsp::PublishDiagnosticsParams);
+    fn label_for_completion(&self, _completion: &lsp::CompletionItem) -> Option<String> {
+        None
+    }
 }
 
 #[derive(Default, Deserialize)]
@@ -77,7 +80,7 @@ pub struct BracketPair {
 pub struct Language {
     pub(crate) config: LanguageConfig,
     pub(crate) grammar: Option<Arc<Grammar>>,
-    pub(crate) diagnostic_processor: Option<Box<dyn DiagnosticProcessor>>,
+    pub(crate) lsp_post_processor: Option<Box<dyn LspPostProcessor>>,
 }
 
 pub struct Grammar {
@@ -144,7 +147,7 @@ impl Language {
                     highlight_map: Default::default(),
                 })
             }),
-            diagnostic_processor: None,
+            lsp_post_processor: None,
         }
     }
 
@@ -188,8 +191,8 @@ impl Language {
         Ok(self)
     }
 
-    pub fn with_diagnostics_processor(mut self, processor: impl DiagnosticProcessor) -> Self {
-        self.diagnostic_processor = Some(Box::new(processor));
+    pub fn with_lsp_post_processor(mut self, processor: impl LspPostProcessor) -> Self {
+        self.lsp_post_processor = Some(Box::new(processor));
         self
     }
 
@@ -241,11 +244,17 @@ impl Language {
     }
 
     pub fn process_diagnostics(&self, diagnostics: &mut lsp::PublishDiagnosticsParams) {
-        if let Some(processor) = self.diagnostic_processor.as_ref() {
+        if let Some(processor) = self.lsp_post_processor.as_ref() {
             processor.process_diagnostics(diagnostics);
         }
     }
 
+    pub fn label_for_completion(&self, completion: &lsp::CompletionItem) -> Option<String> {
+        self.lsp_post_processor
+            .as_ref()
+            .and_then(|p| p.label_for_completion(completion))
+    }
+
     pub fn brackets(&self) -> &[BracketPair] {
         &self.config.brackets
     }

crates/language/src/proto.rs

@@ -1,4 +1,4 @@
-use crate::{diagnostic_set::DiagnosticEntry, Completion, Diagnostic, Operation};
+use crate::{diagnostic_set::DiagnosticEntry, Completion, Diagnostic, Language, Operation};
 use anyhow::{anyhow, Result};
 use clock::ReplicaId;
 use collections::HashSet;
@@ -387,7 +387,10 @@ pub fn serialize_completion(completion: &Completion<Anchor>) -> proto::Completio
     }
 }
 
-pub fn deserialize_completion(completion: proto::Completion) -> Result<Completion<Anchor>> {
+pub fn deserialize_completion(
+    completion: proto::Completion,
+    language: Option<&Arc<Language>>,
+) -> Result<Completion<Anchor>> {
     let old_start = completion
         .old_start
         .and_then(deserialize_anchor)
@@ -396,9 +399,11 @@ pub fn deserialize_completion(completion: proto::Completion) -> Result<Completio
         .old_end
         .and_then(deserialize_anchor)
         .ok_or_else(|| anyhow!("invalid old end"))?;
+    let lsp_completion = serde_json::from_slice(&completion.lsp_completion)?;
     Ok(Completion {
         old_range: old_start..old_end,
         new_text: completion.new_text,
-        lsp_completion: serde_json::from_slice(&completion.lsp_completion)?,
+        label: language.and_then(|l| l.label_for_completion(&lsp_completion)),
+        lsp_completion,
     })
 }

crates/project/src/project.rs

@@ -1752,11 +1752,13 @@ impl Project {
             .get(&sender_id)
             .and_then(|shared_buffers| shared_buffers.get(&envelope.payload.buffer_id).cloned())
             .ok_or_else(|| anyhow!("unknown buffer id {}", envelope.payload.buffer_id))?;
+        let language = buffer.read(cx).language();
         let completion = language::proto::deserialize_completion(
             envelope
                 .payload
                 .completion
                 .ok_or_else(|| anyhow!("invalid position"))?,
+            language,
         )?;
         cx.spawn(|_, mut cx| async move {
             match buffer

crates/project/src/worktree.rs

@@ -14,7 +14,9 @@ use gpui::{
     executor, AppContext, AsyncAppContext, Entity, ModelContext, ModelHandle, MutableAppContext,
     Task,
 };
-use language::{Anchor, Buffer, Completion, DiagnosticEntry, Operation, PointUtf16, Rope};
+use language::{
+    Anchor, Buffer, Completion, DiagnosticEntry, Language, Operation, PointUtf16, Rope,
+};
 use lazy_static::lazy_static;
 use parking_lot::Mutex;
 use postage::{
@@ -1425,6 +1427,7 @@ impl language::File for File {
         &self,
         buffer_id: u64,
         position: Anchor,
+        language: Option<Arc<Language>>,
         cx: &mut MutableAppContext,
     ) -> Task<Result<Vec<Completion<Anchor>>>> {
         let worktree = self.worktree.read(cx);
@@ -1448,7 +1451,9 @@ impl language::File for File {
             response
                 .completions
                 .into_iter()
-                .map(language::proto::deserialize_completion)
+                .map(|completion| {
+                    language::proto::deserialize_completion(completion, language.as_ref())
+                })
                 .collect()
         })
     }

crates/zed/src/language.rs

@@ -9,9 +9,9 @@ use std::{str, sync::Arc};
 #[folder = "languages"]
 struct LanguageDir;
 
-struct RustDiagnosticProcessor;
+struct RustPostProcessor;
 
-impl DiagnosticProcessor for RustDiagnosticProcessor {
+impl LspPostProcessor for RustPostProcessor {
     fn process_diagnostics(&self, params: &mut lsp::PublishDiagnosticsParams) {
         lazy_static! {
             static ref REGEX: Regex = Regex::new("(?m)`([^`]+)\n`$").unwrap();
@@ -31,6 +31,15 @@ impl DiagnosticProcessor for RustDiagnosticProcessor {
             }
         }
     }
+
+    fn label_for_completion(&self, completion: &lsp::CompletionItem) -> Option<String> {
+        let detail = completion.detail.as_ref()?;
+        if detail.starts_with("fn(") {
+            Some(completion.label.replace("(…)", &detail[2..]))
+        } else {
+            None
+        }
+    }
 }
 
 pub fn build_language_registry() -> LanguageRegistry {
@@ -52,7 +61,7 @@ fn rust() -> Language {
         .unwrap()
         .with_outline_query(load_query("rust/outline.scm").as_ref())
         .unwrap()
-        .with_diagnostics_processor(RustDiagnosticProcessor)
+        .with_lsp_post_processor(RustPostProcessor)
 }
 
 fn markdown() -> Language {
@@ -72,9 +81,9 @@ fn load_query(path: &str) -> Cow<'static, str> {
 
 #[cfg(test)]
 mod tests {
-    use language::DiagnosticProcessor;
+    use language::LspPostProcessor;
 
-    use super::RustDiagnosticProcessor;
+    use super::RustPostProcessor;
 
     #[test]
     fn test_process_rust_diagnostics() {
@@ -100,7 +109,7 @@ mod tests {
                 },
             ],
         };
-        RustDiagnosticProcessor.process_diagnostics(&mut params);
+        RustPostProcessor.process_diagnostics(&mut params);
 
         assert_eq!(params.diagnostics[0].message, "use of moved value `a`");