fix(parser): prevent panic in object item parser (#285)

Fixes #284

crates/hcl-edit/src/parser/expr.rs

@@ -431,12 +431,12 @@ fn object_items<'i, 's>(
 
                     // Associate the trailing comment with the item value, updating the span if it
                     // already has a decor suffix.
-                    let suffix_start = match decor.suffix() {
-                        Some(suffix) => suffix.span().unwrap().start,
-                        None => comment_span.start,
+                    let suffix_span = match decor.suffix().and_then(RawString::span) {
+                        Some(span) => span.start..comment_span.end,
+                        None => comment_span,
                     };
 
-                    decor.set_suffix(RawString::from_span(suffix_start..comment_span.end));
+                    decor.set_suffix(RawString::from_span(suffix_span));
 
                     line_ending
                         .value(ObjectValueTerminator::Newline)

crates/hcl-edit/tests/regressions.rs

@@ -57,3 +57,18 @@ fn issue_270() {
     body.set_prefer_omit_trailing_newline(true);
     assert_eq!(body.to_string(), no_trailing_newline);
 }
+
+#[test]
+fn issue_284() {
+    let input = r#"
+      locals {
+        test = {
+          a = b// this comment breaks the parser
+          c = d // but this one doesn't
+        }
+      }
+    "#;
+
+    let res: Result<Body, _> = input.parse();
+    assert!(res.is_ok());
+}