fix clippy::into_iter_on_ref: use .iter() instead of into_iter() on references.

Author: matthiaskrgr

src/librustc_traits/chalk/db.rs

@@ -141,7 +141,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
 
         let predicates = self.tcx.predicates_of(adt_def.did).predicates;
         let where_clauses: Vec<_> = predicates
-            .into_iter()
+            .iter()
             .map(|(wc, _)| wc.subst(self.tcx, bound_vars))
             .filter_map(|wc| LowerInto::<Option<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>>>::lower_into(wc, &self.interner))
             .collect();
@@ -187,7 +187,7 @@ impl<'tcx> chalk_solve::RustIrDatabase<RustInterner<'tcx>> for RustIrDatabase<'t
 
         let predicates = self.tcx.predicates_defined_on(def_id).predicates;
         let where_clauses: Vec<_> = predicates
-            .into_iter()
+            .iter()
             .map(|(wc, _)| wc.subst(self.tcx, &bound_vars))
             .filter_map(|wc| LowerInto::<Option<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>>>::lower_into(wc, &self.interner)).collect();
 

src/librustc_ty/ty.rs

@@ -443,7 +443,7 @@ fn opaque_type_projection_predicates(
 
     let bounds = tcx.predicates_of(def_id);
     let predicates =
-        util::elaborate_predicates(tcx, bounds.predicates.into_iter().map(|&(pred, _)| pred));
+        util::elaborate_predicates(tcx, bounds.predicates.iter().map(|&(pred, _)| pred));
 
     let filtered_predicates = predicates.filter_map(|obligation| {
         let pred = obligation.predicate;