From 3fd3835fdfa32f574e07765cf8fcda84a969ba89 Mon Sep 17 00:00:00 2001
From: Lukas Kalbertodt <lukas.kalbertodt@gmail.com>
Date: Fri, 14 May 2021 21:23:39 +0200
Subject: [PATCH] Error on unexpected extra tokens in attribute

---
 macro/src/ir.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/macro/src/ir.rs b/macro/src/ir.rs
index fe375f5..a79f0da 100644
--- a/macro/src/ir.rs
+++ b/macro/src/ir.rs
@@ -175,6 +175,7 @@ impl Parse for InternalAttr {
             "default" => {
                 let _: Token![=] = input.parse()?;
                 let expr = Expr::from_lit(input.parse()?)?;
+                assert_empty(input)?;
                 Ok(Self::Default(expr))
             }
 
@@ -182,3 +183,11 @@ impl Parse for InternalAttr {
         }
     }
 }
+
+fn assert_empty(input: ParseStream) -> Result<(), Error> {
+    if input.is_empty() {
+        Ok(())
+    } else {
+        Err(Error::new(input.span(), "unexpected tokens, expected no more tokens in this context"))
+    }
+}