use values() or keys() respectively when iterating only over keys or values of maps.

7 files changed, 9 insertions, 9 deletions

diff --git a/src/librustc/traits/structural_impls.rs b/src/librustc/traits/structural_impls.rs
index 48ed29f2bb3..2fcb70c489d 100644
--- a/src/librustc/traits/structural_impls.rs
+++ b/src/librustc/traits/structural_impls.rs
@@ -234,7 +234,7 @@ impl BoundNamesCollector {
             start = false;
             write!(fmt, "{}", r)?;
         }
-        for (_, t) in &self.types {
+        for t in self.types.values() {
             if !start {
                 write!(fmt, ", ")?;
             }
diff --git a/src/librustc_builtin_macros/format.rs b/src/librustc_builtin_macros/format.rs
index 6e2b3ec5fd2..3724a83a949 100644
--- a/src/librustc_builtin_macros/format.rs
+++ b/src/librustc_builtin_macros/format.rs
@@ -188,7 +188,7 @@ fn parse_args<'a>(
                 let mut err = ecx
                     .struct_span_err(e.span, "positional arguments cannot follow named arguments");
                 err.span_label(e.span, "positional arguments must be before named arguments");
-                for (_, pos) in &names {
+                for pos in names.values() {
                     err.span_label(args[*pos].span, "named argument");
                 }
                 err.emit();
diff --git a/src/librustc_hir/hir.rs b/src/librustc_hir/hir.rs
index 1a74b50b57e..f948e22e84b 100644
--- a/src/librustc_hir/hir.rs
+++ b/src/librustc_hir/hir.rs
@@ -679,15 +679,15 @@ impl Crate<'_> {
     where
         V: itemlikevisit::ItemLikeVisitor<'hir>,
     {
-        for (_, item) in &self.items {
+        for item in self.items.values() {
             visitor.visit_item(item);
         }
 
-        for (_, trait_item) in &self.trait_items {
+        for trait_item in self.trait_items.values() {
             visitor.visit_trait_item(trait_item);
         }
 
-        for (_, impl_item) in &self.impl_items {
+        for impl_item in self.impl_items.values() {
             visitor.visit_impl_item(impl_item);
         }
     }
diff --git a/src/librustc_infer/infer/lexical_region_resolve/mod.rs b/src/librustc_infer/infer/lexical_region_resolve/mod.rs
index fc9f3bb0767..b7278ecd5e4 100644
--- a/src/librustc_infer/infer/lexical_region_resolve/mod.rs
+++ b/src/librustc_infer/infer/lexical_region_resolve/mod.rs
@@ -751,7 +751,7 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
         let dummy_source = graph.add_node(());
         let dummy_sink = graph.add_node(());
 
-        for (constraint, _) in &self.data.constraints {
+        for constraint in self.data.constraints.keys() {
             match *constraint {
                 Constraint::VarSubVar(a_id, b_id) => {
                     graph.add_edge(
diff --git a/src/librustc_infer/infer/region_constraints/leak_check.rs b/src/librustc_infer/infer/region_constraints/leak_check.rs
index 74ffdc7a4f0..bbd4f3b3550 100644
--- a/src/librustc_infer/infer/region_constraints/leak_check.rs
+++ b/src/librustc_infer/infer/region_constraints/leak_check.rs
@@ -34,7 +34,7 @@ impl<'tcx> RegionConstraintCollector<'tcx> {
         assert!(self.in_snapshot());
 
         // Go through each placeholder that we created.
-        for (_, &placeholder_region) in placeholder_map {
+        for &placeholder_region in placeholder_map.values() {
             // Find the universe this placeholder inhabits.
             let placeholder = match placeholder_region {
                 ty::RePlaceholder(p) => p,
diff --git a/src/librustc_resolve/late/lifetimes.rs b/src/librustc_resolve/late/lifetimes.rs
index 463452e45ce..193b6d75935 100644
--- a/src/librustc_resolve/late/lifetimes.rs
+++ b/src/librustc_resolve/late/lifetimes.rs
@@ -347,7 +347,7 @@ fn krate(tcx: TyCtxt<'_>) -> NamedRegionMap {
             lifetime_uses: &mut Default::default(),
             missing_named_lifetime_spots: vec![],
         };
-        for (_, item) in &krate.items {
+        for item in krate.items.values() {
             visitor.visit_item(item);
         }
     }
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index bef14d3f4a3..199b476cb9a 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -1652,7 +1652,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         }
 
         for (projection_bound, _) in &bounds.projection_bounds {
-            for (_, def_ids) in &mut associated_types {
+            for def_ids in associated_types.values_mut() {
                 def_ids.remove(&projection_bound.projection_def_id());
             }
         }