fix(language_server): output correct position for parser & semantic errors (#14010)

see oxc-project/coc-oxc#50

The "real" error should still be on the editor side.

Author: Sysix

crates/oxc_language_server/src/snapshots/fixtures_linter_invalid_syntax@debugger.ts.snap

@@ -8,8 +8,10 @@ file: fixtures/linter/invalid_syntax/debugger.ts
 code: ""
 code_description.href: "None"
 message: "Unexpected token"
-range: Range { start: Position { line: 2147483647, character: 2147483647 }, end: Position { line: 2147483647, character: 2147483647 } }
-related_information: None
+range: Range { start: Position { line: 0, character: 9 }, end: Position { line: 0, character: 10 } }
+related_information[0].message: ""
+related_information[0].location.uri: "file://<variable>/fixtures/linter/invalid_syntax/debugger.ts"
+related_information[0].location.range: Range { start: Position { line: 0, character: 9 }, end: Position { line: 0, character: 10 } }
 severity: Some(Error)
 source: Some("oxc")
 tags: None

crates/oxc_linter/src/lsp.rs

@@ -65,17 +65,37 @@ pub struct MessageWithPosition<'a> {
     pub fixes: PossibleFixesWithPosition<'a>,
 }
 
-impl From<OxcDiagnostic> for MessageWithPosition<'_> {
-    fn from(from: OxcDiagnostic) -> Self {
-        Self {
-            message: from.message.clone(),
-            labels: None,
-            help: from.help.clone(),
-            severity: from.severity,
-            code: from.code.clone(),
-            url: from.url.clone(),
-            fixes: PossibleFixesWithPosition::None,
-        }
+// clippy: the source field is checked and assumed to be less than 4GB, and
+// we assume that the fix offset will not exceed 2GB in either direction
+#[expect(clippy::cast_possible_truncation)]
+pub fn oxc_diagnostic_to_message_with_position<'a>(
+    diagnostic: &OxcDiagnostic,
+    source_text: &str,
+    rope: &Rope,
+) -> MessageWithPosition<'a> {
+    let labels = diagnostic.labels.as_ref().map(|labels| {
+        labels
+            .iter()
+            .map(|labeled_span| {
+                let offset = labeled_span.offset() as u32;
+                let start_position = offset_to_position(rope, offset, source_text);
+                let end_position =
+                    offset_to_position(rope, offset + labeled_span.len() as u32, source_text);
+                let message = labeled_span.label().map(|label| Cow::Owned(label.to_string()));
+
+                SpanPositionMessage::new(start_position, end_position).with_message(message)
+            })
+            .collect::<Vec<_>>()
+    });
+
+    MessageWithPosition {
+        message: diagnostic.message.clone(),
+        severity: diagnostic.severity,
+        help: diagnostic.help.clone(),
+        url: diagnostic.url.clone(),
+        code: diagnostic.code.clone(),
+        labels,
+        fixes: PossibleFixesWithPosition::None,
     }
 }
 

crates/oxc_linter/src/service/runtime.rs

@@ -682,7 +682,9 @@ impl Runtime {
 
         use oxc_data_structures::rope::Rope;
 
-        use crate::lsp::message_to_message_with_position;
+        use crate::lsp::{
+            message_to_message_with_position, oxc_diagnostic_to_message_with_position,
+        };
 
         // Wrap allocator in `MessageCloner` so can clone `Message`s into it
         let message_cloner = MessageCloner::new(allocator);
@@ -715,10 +717,15 @@ impl Runtime {
                                 }
                                 Err(diagnostics) => {
                                     if !diagnostics.is_empty() {
-                                        messages
-                                            .lock()
-                                            .unwrap()
-                                            .extend(diagnostics.into_iter().map(Into::into));
+                                        messages.lock().unwrap().extend(
+                                            diagnostics.into_iter().map(|diagnostic| {
+                                                oxc_diagnostic_to_message_with_position(
+                                                    &diagnostic,
+                                                    source_text,
+                                                    rope,
+                                                )
+                                            }),
+                                        );
                                     }
                                     None
                                 }
@@ -745,8 +752,7 @@ impl Runtime {
             });
         });
 
-        // ToDo: oxc_diagnostic::Error is not compatible with MessageWithPosition
-        // send use OxcDiagnostic or even better the MessageWithPosition struct
+        // The receiving messages should be only file system reads or source type errors
         // while let Ok(diagnostics) = receiver.recv() {
         //     if let Some(diagnostics) = diagnostics {
         //         messages.lock().unwrap().extend(