From d38dbcb19f6ef1c5ffcf7869767674ef3d6d045f Mon Sep 17 00:00:00 2001
From: Hannah McLaughlin <h@mcla.ug>
Date: Sun, 15 Nov 2020 21:14:00 +0000
Subject: [PATCH] Improve error message when we try to get_type on something
 that does not have a type

---
 compiler/rustc_metadata/src/rmeta/decoder.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index a1df1a63fc5..19340dd51de 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -947,7 +947,12 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_type(&self, id: DefIndex, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
-        self.root.tables.ty.get(self, id).unwrap().decode((self, tcx))
+        self.root
+            .tables
+            .ty
+            .get(self, id)
+            .unwrap_or_else(|| panic!("Not a type: {:?}", id))
+            .decode((self, tcx))
     }
 
     fn get_stability(&self, id: DefIndex) -> Option<attr::Stability> {