Point at specific field in struct literal when trait fulfillment fails

[rust.git] / compiler / rustc_trait_selection / src / traits / select / mod.rs

diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index f90da95d51668b56cfbb582cbae2231ef6db371f..7bfc098e4cdf7746e608068a95c0be606f1ac1c5 100644 (file)
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -2562,11 +2562,12 @@ fn impl_or_trait_obligations(
         assert_eq!(predicates.parent, None);
         let predicates = predicates.instantiate_own(tcx, substs);
         let mut obligations = Vec::with_capacity(predicates.len());
-        for (predicate, span) in predicates {
+        for (index, (predicate, span)) in predicates.into_iter().enumerate() {
             let cause = cause.clone().derived_cause(parent_trait_pred, |derived| {
                 ImplDerivedObligation(Box::new(ImplDerivedObligationCause {
                     derived,
                     impl_def_id: def_id,
+                    impl_def_predicate_index: Some(index),
                     span,
                 }))
             });