Fix dangling anonymous functions

src/ast.rs

@@ -230,7 +230,10 @@ impl Parse for Statement {
                     }]),
                 ))
             } else {
-                todo!()
+                Ok(Self::Expression(Node {
+                    kind: Expression::FunctionDefinition(function.kind.params, function.kind.block),
+                    meta: function.meta,
+                }))
             }
         } else if peeked == Some(Token::Keyword(Keyword::Return)) {
             stream.next();