use .iter() instead of .into_iter() on references.

Author: matthiaskrgr

src/librustc/ty/context.rs

@@ -2291,13 +2291,13 @@ impl<'tcx> TyCtxt<'tcx> {
 
     #[inline]
     pub fn intern_tup(self, ts: &[Ty<'tcx>]) -> Ty<'tcx> {
-        let kinds: Vec<_> = ts.into_iter().map(|&t| GenericArg::from(t)).collect();
+        let kinds: Vec<_> = ts.iter().map(|&t| GenericArg::from(t)).collect();
         self.mk_ty(Tuple(self.intern_substs(&kinds)))
     }
 
     pub fn mk_tup<I: InternAs<[Ty<'tcx>], Ty<'tcx>>>(self, iter: I) -> I::Output {
         iter.intern_with(|ts| {
-            let kinds: Vec<_> = ts.into_iter().map(|&t| GenericArg::from(t)).collect();
+            let kinds: Vec<_> = ts.iter().map(|&t| GenericArg::from(t)).collect();
             self.mk_ty(Tuple(self.intern_substs(&kinds)))
         })
     }

src/librustc_builtin_macros/proc_macro_harness.rs

@@ -149,7 +149,7 @@ impl<'a> CollectProcMacros<'a> {
                         .span_err(attr.span(), "attribute must be of form: `attributes(foo, bar)`");
                     &[]
                 })
-                .into_iter()
+                .iter()
                 .filter_map(|attr| {
                     let attr = match attr.meta_item() {
                         Some(meta_item) => meta_item,

src/librustc_infer/infer/canonical/query_response.rs

@@ -630,7 +630,7 @@ pub fn make_query_region_constraints<'tcx>(
     assert!(givens.is_empty());
 
     let outlives: Vec<_> = constraints
-        .into_iter()
+        .iter()
         .map(|(k, _)| match *k {
             // Swap regions because we are going from sub (<=) to outlives
             // (>=).

src/librustc_infer/traits/on_unimplemented.rs

@@ -237,10 +237,8 @@ impl<'tcx> OnUnimplementedDirective {
             }
         }
 
-        let options: FxHashMap<Symbol, String> = options
-            .into_iter()
-            .filter_map(|(k, v)| v.as_ref().map(|v| (*k, v.to_owned())))
-            .collect();
+        let options: FxHashMap<Symbol, String> =
+            options.iter().filter_map(|(k, v)| v.as_ref().map(|v| (*k, v.to_owned()))).collect();
         OnUnimplementedNote {
             label: label.map(|l| l.format(tcx, trait_ref, &options)),
             message: message.map(|m| m.format(tcx, trait_ref, &options)),

src/librustc_infer/traits/select.rs

@@ -2411,7 +2411,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
         types
             .skip_binder()
-            .into_iter()
+            .iter()
             .flat_map(|ty| {
                 // binder moved -\
                 let ty: ty::Binder<Ty<'tcx>> = ty::Binder::bind(ty); // <----/

src/librustc_lint/builtin.rs

@@ -739,7 +739,7 @@ impl EarlyLintPass for DeprecatedAttr {
 }
 
 fn warn_if_doc(cx: &EarlyContext<'_>, node_span: Span, node_kind: &str, attrs: &[ast::Attribute]) {
-    let mut attrs = attrs.into_iter().peekable();
+    let mut attrs = attrs.iter().peekable();
 
     // Accumulate a single span for sugared doc comments.
     let mut sugared_span: Option<Span> = None;

src/librustc_mir/borrow_check/diagnostics/move_errors.rs

@@ -519,7 +519,7 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
     }
 
     fn add_move_error_details(&self, err: &mut DiagnosticBuilder<'a>, binds_to: &[Local]) {
-        for (j, local) in binds_to.into_iter().enumerate() {
+        for (j, local) in binds_to.iter().enumerate() {
             let bind_to = &self.body.local_decls[*local];
             let binding_span = bind_to.source_info.span;
 

src/librustc_mir/dataflow/generic/engine.rs

@@ -419,7 +419,7 @@ impl RustcMirAttrs {
         let mut ret = RustcMirAttrs::default();
 
         let rustc_mir_attrs = attrs
-            .into_iter()
+            .iter()
             .filter(|attr| attr.check_name(sym::rustc_mir))
             .flat_map(|attr| attr.meta_item_list().into_iter().flat_map(|v| v.into_iter()));
 

src/librustc_mir/dataflow/impls/borrows.rs

@@ -195,7 +195,7 @@ impl<'a, 'tcx> Borrows<'a, 'tcx> {
             .local_map
             .get(&place.local)
             .into_iter()
-            .flat_map(|bs| bs.into_iter())
+            .flat_map(|bs| bs.iter())
             .copied();
 
         // If the borrowed place is a local with no projections, all other borrows of this

src/librustc_mir/interpret/operand.rs

@@ -509,7 +509,7 @@ impl<'mir, 'tcx, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         &self,
         ops: &[mir::Operand<'tcx>],
     ) -> InterpResult<'tcx, Vec<OpTy<'tcx, M::PointerTag>>> {
-        ops.into_iter().map(|op| self.eval_operand(op, None)).collect()
+        ops.iter().map(|op| self.eval_operand(op, None)).collect()
     }
 
     // Used when the miri-engine runs into a constant and for extracting information from constants