Some ICE debugging aids

rust-lang · fee1-dead · Dec 12, 2022 · Dec 12, 2022 · Dec 12, 2022 · Dec 17, 2022
commit ed61be60da3b5dd28abd4ec4956df9eb896183c9
diff --git a/compiler/rustc_middle/src/ty/subst.rs b/compiler/rustc_middle/src/ty/subst.rs
@@ -348,7 +348,7 @@ impl<'tcx> InternalSubsts<'tcx> {
         substs.reserve(defs.params.len());
         for param in &defs.params {
             let kind = mk_kind(param, substs);
-            assert_eq!(param.index as usize, substs.len());
+            assert_eq!(param.index as usize, substs.len(), "{substs:#?}, {defs:#?}");
             substs.push(kind);
         }
     }