Fixes #883.

crates/aiken-lang/src/format.rs

@@ -476,9 +476,14 @@ impl<'comments> Formatter<'comments> {
 
         let doc_comments = self.doc_comments(arg.location.start);
 
-        let doc = arg
+        let doc = match &arg.annotation {
+            None => arg.arg_name.to_doc(),
+            Some(a) => arg
                 .arg_name
                 .to_doc()
+                .append(": ")
+                .append(self.annotation(a)),
+        }
         .append(" via ")
         .append(self.expr(&arg.via, false))
         .group();

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

@@ -744,3 +744,14 @@ fn fail_expr() {
         "#
     );
 }
+
+#[test]
+fn fuzzer_annotations() {
+    assert_format!(
+        r#"
+        test foo(n: Int via int()) {
+          todo
+        }
+        "#
+    );
+}

crates/aiken-lang/src/tests/snapshots/fuzzer_annotations.snap

@@ -0,0 +1,7 @@
+---
+source: crates/aiken-lang/src/tests/format.rs
+description: "Code:\n\ntest foo(n: Int via int()) {\n  todo\n}\n"
+---
+test foo(n: Int via int()) {
+  todo
+}