lang: make output errors debuggable

crates/lang/src/lst_parser/output.rs

@@ -9,9 +9,12 @@ pub struct Output {
     pub green_node: GreenNode,
     pub errors: Vec<SyntaxError>,
 }
+
 impl std::fmt::Debug for Output {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        debug_print_green_node(NodeOrToken::Node(&self.green_node), f, 0)
+        let mut errs: Vec<&SyntaxError> = self.errors.iter().collect();
+        errs.reverse();
+        debug_print_green_node(NodeOrToken::Node(&self.green_node), f, 0, &mut errs)
     }
 }
 
@@ -19,6 +22,7 @@ fn debug_print_green_node(
     node: NodeOrToken<&GreenNodeData, &GreenTokenData>,
     f: &mut std::fmt::Formatter<'_>,
     lvl: i32,
+    errs: &mut Vec<&SyntaxError>,
 ) -> std::fmt::Result {
     for _ in 0..lvl {
         f.write_str("    ")?;
@@ -26,9 +30,18 @@ fn debug_print_green_node(
 
     match node {
         NodeOrToken::Node(n) => {
+            let kind = Lang::kind_from_raw(node.kind());
+            if kind != SyntaxKind::PARSE_ERR {
                 writeln!(f, "{:?} {{", Lang::kind_from_raw(node.kind()))?;
+            } else {
+                let err = errs
+                    .pop()
+                    .expect("all error syntax nodes should correspond to an error");
+
+                writeln!(f, "{:?}: {err:?} {{", kind)?;
+            }
             for c in n.children() {
-                debug_print_green_node(c, f, lvl + 1)?;
+                debug_print_green_node(c, f, lvl + 1, errs)?;
             }
             for _ in 0..lvl {
                 f.write_str("    ")?;