temporarily revert "ice on ambguity in mir typeck"

Reverts #116530

1 files changed, 4 insertions, 12 deletions

diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
index e87e585ef0b..cd09aaff2d9 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs
@@ -157,18 +157,10 @@ where
         }
 
         let mut region_constraints = QueryRegionConstraints::default();
-        let (output, error_info, mut obligations) =
-            Q::fully_perform_into(self, infcx, &mut region_constraints)
-                .map_err(|_| {
-                    infcx.tcx.sess.span_delayed_bug(span, format!("error performing {self:?}"))
-                })
-                .and_then(|(output, error_info, obligations, certainty)| match certainty {
-                    Certainty::Proven => Ok((output, error_info, obligations)),
-                    Certainty::Ambiguous => Err(infcx
-                        .tcx
-                        .sess
-                        .span_delayed_bug(span, format!("ambiguity performing {self:?}"))),
-                })?;
+        let (output, error_info, mut obligations, _) =
+            Q::fully_perform_into(self, infcx, &mut region_constraints).map_err(|_| {
+                infcx.tcx.sess.span_delayed_bug(span, format!("error performing {self:?}"))
+            })?;
 
         // Typically, instantiating NLL query results does not
         // create obligations. However, in some cases there