refactor(service): add diagnostic code for syntax error

crates/service/src/files.rs

@@ -1,9 +1,9 @@
 use crate::InternUri;
 use line_index::{LineIndex, TextSize};
-use lsp_types::{Diagnostic, DiagnosticSeverity, Position, Range, Uri};
+use lsp_types::{Diagnostic, DiagnosticSeverity, NumberOrString, Position, Range, Uri};
 use rowan::GreenNode;
 use std::rc::Rc;
-use wat_parser::Parser;
+use wat_parser::{Message, Parser};
 
 #[salsa::query_group(Files)]
 pub(crate) trait FilesCtx: salsa::Database {
@@ -47,6 +47,14 @@ fn parse(db: &dyn FilesCtx, uri: InternUri) -> (GreenNode, Vec<Diagnostic>) {
                 ),
                 severity: Some(DiagnosticSeverity::ERROR),
                 source: Some("wat".into()),
+                code: if let Message::Name(name) = error.message {
+                    Some(NumberOrString::String(format!(
+                        "syntax/{}",
+                        name.replace(' ', "-")
+                    )))
+                } else {
+                    None
+                },
                 message: format!("syntax error: {}", error.message),
                 ..Default::default()
             }

crates/service/tests/diagnostics/mod.rs

@@ -15,6 +15,8 @@ mod multi_modules;
 #[cfg(test)]
 mod shadow;
 #[cfg(test)]
+mod syntax;
+#[cfg(test)]
 mod typeck;
 #[cfg(test)]
 mod undef;

crates/service/tests/diagnostics/snapshots/features__diagnostics__syntax__blocks.snap

@@ -0,0 +1,25 @@
+---
+source: crates/service/tests/diagnostics/syntax.rs
+expression: response
+---
+{
+  "kind": "full",
+  "items": [
+    {
+      "range": {
+        "start": {
+          "line": 2,
+          "character": 2
+        },
+        "end": {
+          "line": 2,
+          "character": 8
+        }
+      },
+      "severity": 1,
+      "code": "syntax/module-field",
+      "source": "wat",
+      "message": "syntax error: expected module field"
+    }
+  ]
+}

crates/service/tests/diagnostics/syntax.rs

@@ -0,0 +1,18 @@
+use super::*;
+use insta::assert_json_snapshot;
+use lsp_types::Uri;
+use wat_service::LanguageService;
+
+#[test]
+fn blocks() {
+    let uri = "untitled:test".parse::<Uri>().unwrap();
+    let source = "
+(module
+  (fnuc))
+";
+    let mut service = LanguageService::default();
+    service.commit(uri.clone(), source.into());
+    allow_unused(&mut service, uri.clone());
+    let response = service.pull_diagnostics(create_params(uri));
+    assert_json_snapshot!(response);
+}