feat(service): report top-level error tokens

crates/service/src/checker/mod.rs

@@ -7,6 +7,7 @@ mod immediates;
 mod implicit_module;
 mod multi_modules;
 mod shadow;
+mod syntax;
 mod typeck;
 mod undef;
 mod unknown_instr;
@@ -19,7 +20,8 @@ pub fn check(service: &LanguageService, uri: InternUri) -> Vec<Diagnostic> {
     let symbol_table = service.symbol_table(uri);
     let config = &service.get_config(uri);
 
-    let mut diagnostics = service.parser_result(uri).1;
+    let mut diagnostics = Vec::with_capacity(4);
+    syntax::check(service, &mut diagnostics, uri, &line_index, &root);
     root.descendants().for_each(|node| match node.kind() {
         SyntaxKind::ROOT => {
             multi_modules::check(&mut diagnostics, &line_index, &node);

crates/service/src/checker/syntax.rs

@@ -0,0 +1,33 @@
+use crate::{files::FilesCtx, helpers, InternUri, LanguageService};
+use line_index::LineIndex;
+use lsp_types::{Diagnostic, DiagnosticSeverity, NumberOrString};
+use std::rc::Rc;
+use wat_syntax::{SyntaxElement, SyntaxKind, SyntaxNode};
+
+const DIAGNOSTIC_CODE: &str = "syntax";
+
+pub fn check(
+    service: &LanguageService,
+    diags: &mut Vec<Diagnostic>,
+    uri: InternUri,
+    line_index: &LineIndex,
+    root: &SyntaxNode,
+) {
+    let mut errors = Rc::unwrap_or_clone(service.parser_result(uri).1);
+    diags.append(&mut errors);
+    diags.extend(
+        root.children_with_tokens()
+            .filter_map(|element| match element {
+                SyntaxElement::Token(token) if token.kind() == SyntaxKind::ERROR => Some(token),
+                _ => None,
+            })
+            .map(|token| Diagnostic {
+                range: helpers::rowan_range_to_lsp_range(line_index, token.text_range()),
+                severity: Some(DiagnosticSeverity::ERROR),
+                source: Some("wat".into()),
+                code: Some(NumberOrString::String(DIAGNOSTIC_CODE.into())),
+                message: "syntax error: unexpected token".into(),
+                ..Default::default()
+            }),
+    );
+}

crates/service/src/files.rs

@@ -19,7 +19,7 @@ pub(crate) trait FilesCtx: salsa::Database {
 
     #[salsa::memoized]
     #[salsa::invoke(parse)]
-    fn parser_result(&self, uri: InternUri) -> (GreenNode, Vec<Diagnostic>);
+    fn parser_result(&self, uri: InternUri) -> (GreenNode, Rc<Vec<Diagnostic>>);
 
     #[salsa::memoized]
     fn root(&self, uri: InternUri) -> GreenNode;
@@ -29,7 +29,7 @@ fn get_line_index(db: &dyn FilesCtx, uri: InternUri) -> Rc<LineIndex> {
     Rc::new(LineIndex::new(&db.source(uri)))
 }
 
-fn parse(db: &dyn FilesCtx, uri: InternUri) -> (GreenNode, Vec<Diagnostic>) {
+fn parse(db: &dyn FilesCtx, uri: InternUri) -> (GreenNode, Rc<Vec<Diagnostic>>) {
     let source = db.source(uri);
     let line_index = db.line_index(uri);
     let mut parser = Parser::new(&source);
@@ -60,7 +60,7 @@ fn parse(db: &dyn FilesCtx, uri: InternUri) -> (GreenNode, Vec<Diagnostic>) {
             }
         })
         .collect();
-    (green, syntax_errors)
+    (green, Rc::new(syntax_errors))
 }
 
 fn root(db: &dyn FilesCtx, uri: InternUri) -> GreenNode {

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

@@ -0,0 +1,25 @@
+---
+source: crates/service/tests/diagnostics/syntax.rs
+expression: response
+---
+{
+  "kind": "full",
+  "items": [
+    {
+      "range": {
+        "start": {
+          "line": 0,
+          "character": 8
+        },
+        "end": {
+          "line": 0,
+          "character": 9
+        }
+      },
+      "severity": 1,
+      "code": "syntax",
+      "source": "wat",
+      "message": "syntax error: unexpected token"
+    }
+  ]
+}

crates/service/tests/diagnostics/syntax.rs

@@ -16,3 +16,14 @@ fn blocks() {
     let response = service.pull_diagnostics(create_params(uri));
     assert_json_snapshot!(response);
 }
+
+#[test]
+fn top_level_error_token() {
+    let uri = "untitled:test".parse::<Uri>().unwrap();
+    let source = "(module))";
+    let mut service = LanguageService::default();
+    service.commit(uri.clone(), source.into());
+    calm(&mut service, uri.clone());
+    let response = service.pull_diagnostics(create_params(uri));
+    assert_json_snapshot!(response);
+}

crates/service/tests/diagnostics/unused.rs

@@ -94,7 +94,7 @@ fn type_unused() {
     let source = r#"
 (module
   (type (func))
-  (type $t (func))))
+  (type $t (func)))
 "#;
     let mut service = LanguageService::default();
     service.commit(uri.clone(), source.into());