[ty] Show related information in diagnostic (#17359)

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

@@ -7,11 +7,13 @@ use lsp_types::{
     NumberOrString, Range, RelatedFullDocumentDiagnosticReport,
 };
 
-use crate::document::ToRangeExt;
+use crate::PositionEncoding;
+use crate::document::{FileRangeExt, ToRangeExt};
 use crate::server::api::traits::{BackgroundDocumentRequestHandler, RequestHandler};
 use crate::server::{Result, client::Notifier};
 use crate::session::DocumentSnapshot;
-use ruff_db::diagnostic::Severity;
+use ruff_db::diagnostic::{Annotation, Severity, SubDiagnostic};
+use ruff_db::files::FileRange;
 use ruff_db::source::{line_index, source_text};
 use ty_project::{Db, ProjectDatabase};
 
@@ -116,6 +118,31 @@ fn to_lsp_diagnostic(
         })
         .flatten();
 
+    let mut related_information = Vec::new();
+
+    related_information.extend(
+        diagnostic
+            .secondary_annotations()
+            .filter_map(|annotation| annotation_to_related_information(db, annotation, encoding)),
+    );
+
+    for sub_diagnostic in diagnostic.sub_diagnostics() {
+        related_information.extend(sub_diagnostic_to_related_information(
+            db,
+            sub_diagnostic,
+            encoding,
+        ));
+
+        related_information.extend(
+            sub_diagnostic
+                .annotations()
+                .iter()
+                .filter_map(|annotation| {
+                    annotation_to_related_information(db, annotation, encoding)
+                }),
+        );
+    }
+
     Diagnostic {
         range,
         severity: Some(severity),
@@ -124,7 +151,41 @@ fn to_lsp_diagnostic(
         code_description,
         source: Some("ty".into()),
         message: diagnostic.concise_message().to_string(),
-        related_information: None,
+        related_information: Some(related_information),
         data: None,
     }
 }
+
+fn annotation_to_related_information(
+    db: &dyn Db,
+    annotation: &Annotation,
+    encoding: PositionEncoding,
+) -> Option<lsp_types::DiagnosticRelatedInformation> {
+    let span = annotation.get_span();
+
+    let annotation_message = annotation.get_message()?;
+    let range = FileRange::try_from(span).ok()?;
+    let location = range.to_location(db.upcast(), encoding)?;
+
+    Some(lsp_types::DiagnosticRelatedInformation {
+        location,
+        message: annotation_message.to_string(),
+    })
+}
+
+fn sub_diagnostic_to_related_information(
+    db: &dyn Db,
+    diagnostic: &SubDiagnostic,
+    encoding: PositionEncoding,
+) -> Option<lsp_types::DiagnosticRelatedInformation> {
+    let primary_annotation = diagnostic.primary_annotation()?;
+
+    let span = primary_annotation.get_span();
+    let range = FileRange::try_from(span).ok()?;
+    let location = range.to_location(db.upcast(), encoding)?;
+
+    Some(lsp_types::DiagnosticRelatedInformation {
+        location,
+        message: diagnostic.concise_message().to_string(),
+    })
+}

crates/ty_server/src/session/capabilities.rs

@@ -38,8 +38,7 @@ impl ResolvedClientCapabilities {
         let document_changes = client_capabilities
             .workspace
             .as_ref()
-            .and_then(|workspace| workspace.workspace_edit.as_ref())
-            .and_then(|workspace_edit| workspace_edit.document_changes)
+            .and_then(|workspace| workspace.workspace_edit.as_ref()?.document_changes)
             .unwrap_or_default();
 
         let declaration_link_support = client_capabilities