From b2b5fa825dff427f87c577e605eaa5d382364909 Mon Sep 17 00:00:00 2001
From: Oli Scherer <git-spam-no-reply9815368754983@oli-obk.de>
Date: Mon, 25 Mar 2024 10:34:03 +0000
Subject: [PATCH] Eagerly check for accidentally registered region constraints
 instead of waiting until borrowck is done

---
 compiler/rustc_borrowck/src/type_check/canonical.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/compiler/rustc_borrowck/src/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs
index f28b786e4f7..a950f10787b 100644
--- a/compiler/rustc_borrowck/src/type_check/canonical.rs
+++ b/compiler/rustc_borrowck/src/type_check/canonical.rs
@@ -39,6 +39,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
 
         let TypeOpOutput { output, constraints, error_info } =
             op.fully_perform(self.infcx, locations.span(self.body))?;
+        if cfg!(debug_assertions) {
+            let data = self.infcx.take_and_reset_region_constraints();
+            if !data.is_empty() {
+                panic!("leftover region constraints: {data:#?}");
+            }
+        }
 
         debug!(?output, ?constraints);