Rework how we send diagnostics to client.

The previous way of sending from the thread pool suffered from stale
diagnostics due to being canceled before we could clear the old ones.

The key change is moving to sending diagnostics from the main loop
thread, but doing all the hard work in the thread pool. This should
provide the best of both worlds, with little to no of the downsides.

This should hopefully fix a lot of issues, but we'll need testing in
each individual issue to be sure.

1 files changed, 21 insertions, 45 deletions

diff --git a/crates/ra_cargo_watch/src/conv.rs b/crates/ra_cargo_watch/src/conv.rs
index 8fba400ae..506370535 100644
--- a/crates/ra_cargo_watch/src/conv.rs
+++ b/crates/ra_cargo_watch/src/conv.rs
@@ -1,12 +1,11 @@
 //! This module provides the functionality needed to convert diagnostics from
 //! `cargo check` json format to the LSP diagnostic format.
 use cargo_metadata::diagnostic::{
-    Applicability, Diagnostic as RustDiagnostic, DiagnosticLevel, DiagnosticSpan,
-    DiagnosticSpanMacroExpansion,
+    Diagnostic as RustDiagnostic, DiagnosticLevel, DiagnosticSpan, DiagnosticSpanMacroExpansion,
 };
 use lsp_types::{
-    Diagnostic, DiagnosticRelatedInformation, DiagnosticSeverity, DiagnosticTag, Location,
-    NumberOrString, Position, Range, Url,
+    CodeAction, Diagnostic, DiagnosticRelatedInformation, DiagnosticSeverity, DiagnosticTag,
+    Location, NumberOrString, Position, Range, TextEdit, Url, WorkspaceEdit,
 };
 use std::{
     fmt::Write,
@@ -117,38 +116,9 @@ fn is_deprecated(rd: &RustDiagnostic) -> bool {
     }
 }
 
-#[derive(Clone, Debug)]
-pub struct SuggestedFix {
-    pub title: String,
-    pub location: Location,
-    pub replacement: String,
-    pub applicability: Applicability,
-    pub diagnostics: Vec<Diagnostic>,
-}
-
-impl std::cmp::PartialEq<SuggestedFix> for SuggestedFix {
-    fn eq(&self, other: &SuggestedFix) -> bool {
-        if self.title == other.title
-            && self.location == other.location
-            && self.replacement == other.replacement
-        {
-            // Applicability doesn't impl PartialEq...
-            match (&self.applicability, &other.applicability) {
-                (Applicability::MachineApplicable, Applicability::MachineApplicable) => true,
-                (Applicability::HasPlaceholders, Applicability::HasPlaceholders) => true,
-                (Applicability::MaybeIncorrect, Applicability::MaybeIncorrect) => true,
-                (Applicability::Unspecified, Applicability::Unspecified) => true,
-                _ => false,
-            }
-        } else {
-            false
-        }
-    }
-}
-
 enum MappedRustChildDiagnostic {
     Related(DiagnosticRelatedInformation),
-    SuggestedFix(SuggestedFix),
+    SuggestedFix(CodeAction),
     MessageLine(String),
 }
 
@@ -176,12 +146,20 @@ fn map_rust_child_diagnostic(
             rd.message.clone()
         };
 
-        MappedRustChildDiagnostic::SuggestedFix(SuggestedFix {
+        let edit = {
+            let edits = vec![TextEdit::new(location.range, suggested_replacement.clone())];
+            let mut edit_map = std::collections::HashMap::new();
+            edit_map.insert(location.uri, edits);
+            WorkspaceEdit::new(edit_map)
+        };
+
+        MappedRustChildDiagnostic::SuggestedFix(CodeAction {
             title,
-            location,
-            replacement: suggested_replacement.clone(),
-            applicability: span.suggestion_applicability.clone().unwrap_or(Applicability::Unknown),
-            diagnostics: vec![],
+            kind: Some("quickfix".to_string()),
+            diagnostics: None,
+            edit: Some(edit),
+            command: None,
+            is_preferred: None,
         })
     } else {
         MappedRustChildDiagnostic::Related(DiagnosticRelatedInformation {
@@ -195,7 +173,7 @@ fn map_rust_child_diagnostic(
 pub(crate) struct MappedRustDiagnostic {
     pub location: Location,
     pub diagnostic: Diagnostic,
-    pub suggested_fixes: Vec<SuggestedFix>,
+    pub fixes: Vec<CodeAction>,
 }
 
 /// Converts a Rust root diagnostic to LSP form
@@ -250,15 +228,13 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
         }
     }
 
-    let mut suggested_fixes = vec![];
+    let mut fixes = vec![];
     let mut message = rd.message.clone();
     for child in &rd.children {
         let child = map_rust_child_diagnostic(&child, workspace_root);
         match child {
             MappedRustChildDiagnostic::Related(related) => related_information.push(related),
-            MappedRustChildDiagnostic::SuggestedFix(suggested_fix) => {
-                suggested_fixes.push(suggested_fix)
-            }
+            MappedRustChildDiagnostic::SuggestedFix(code_action) => fixes.push(code_action.into()),
             MappedRustChildDiagnostic::MessageLine(message_line) => {
                 write!(&mut message, "\n{}", message_line).unwrap();
 
@@ -295,7 +271,7 @@ pub(crate) fn map_rust_diagnostic_to_lsp(
         tags: if !tags.is_empty() { Some(tags) } else { None },
     };
 
-    Some(MappedRustDiagnostic { location, diagnostic, suggested_fixes })
+    Some(MappedRustDiagnostic { location, diagnostic, fixes })
 }
 
 /// Returns a `Url` object from a given path, will lowercase drive letters if present.