Fix comment formatting wrongly assuming false invariant.

crates/aiken-lang/src/format.rs

@@ -1799,9 +1799,11 @@ fn printed_comments<'a, 'comments>(
 
     let mut doc = Vec::new();
     while let Some(c) = comments.next() {
+        match c {
+            None => continue,
+            Some(c) => {
                 // There will never be consecutive empty lines (None values),
                 // and whenever we peek a None, we advance past it.
-        let c = c.expect("no consecutive empty lines");
                 doc.push("//".to_doc().append(Document::String(c.to_string())));
                 match comments.peek() {
                     // Next line is a comment
@@ -1826,6 +1828,8 @@ fn printed_comments<'a, 'comments>(
                     }
                 }
             }
+        }
+    }
     let doc = concat(doc);
     if trailing_newline {
         Some(doc.force_break())

crates/aiken-lang/src/tests/check.rs

@@ -322,25 +322,6 @@ fn utf8_hex_literal_warning() {
     ))
 }
 
-#[test]
-fn weird_comments() {
-    let source_code = r#"
-        // A
-
-        /// B
-
-        // C
-        fn foo () {
-          todo
-        }
-    "#;
-
-    assert!(matches!(
-        check(parse(source_code)),
-        Err((_, Error::UnexpectedDocComment { .. }))
-    ))
-}
-
 #[test]
 fn discarded_let_bindings() {
     let source_code = r#"

crates/aiken-lang/src/tests/format.rs

@@ -638,6 +638,15 @@ fn weird_comments() {
         /// B
 
         /// C
+        fn foo() {
+          todo
+        }
+
+        // E
+
+        /// F
+
+        // G
         fn bar() {
           todo
         }
@@ -648,6 +657,14 @@ fn weird_comments() {
 
         /// B
         /// C
+        fn foo() {
+          todo
+        }
+
+        // E
+
+        // G
+        /// F
         fn bar() {
           todo
         }

crates/aiken-lang/src/tipo/error.rs

@@ -892,13 +892,6 @@ The best thing to do from here is to remove it."#))]
         #[label("{} arguments", if *count < 2 { "not enough" } else { "too many" })]
         location: Span,
     },
-
-    #[error("I ran into a lonely doc comment not attached to any function definition.")]
-    #[diagnostic(code("unexpected::doc_comment"))]
-    UnexpectedDocComment {
-        #[label("unexpected doc comment")]
-        location: Span,
-    },
 }
 
 impl Error {