diff --git a/src/librustc_builtin_macros/format.rs b/src/librustc_builtin_macros/format.rs
index 3724a83a9498..81c97bcea050 100644
--- a/src/librustc_builtin_macros/format.rs
+++ b/src/librustc_builtin_macros/format.rs
@@ -476,7 +476,7 @@ impl<'a, 'b> Context<'a, 'b> {
                 match ty {
                     Placeholder(_) => {
                         // record every (position, type) combination only once
-                        let ref mut seen_ty = self.arg_unique_types[arg];
+                        let seen_ty = &mut self.arg_unique_types[arg];
                         let i = seen_ty.iter().position(|x| *x == ty).unwrap_or_else(|| {
                             let i = seen_ty.len();
                             seen_ty.push(ty);
@@ -526,7 +526,7 @@ impl<'a, 'b> Context<'a, 'b> {
 
         // Map the arguments
         for i in 0..args_len {
-            let ref arg_types = self.arg_types[i];
+            let arg_types = &self.arg_types[i];
             let arg_offsets = arg_types.iter().map(|offset| sofar + *offset).collect::<Vec<_>>();
             self.arg_index_map.push(arg_offsets);
             sofar += self.arg_unique_types[i].len();
@@ -597,7 +597,7 @@ impl<'a, 'b> Context<'a, 'b> {
                             let arg_idx = match arg_index_consumed.get_mut(i) {
                                 None => 0, // error already emitted elsewhere
                                 Some(offset) => {
-                                    let ref idx_map = self.arg_index_map[i];
+                                    let idx_map = &self.arg_index_map[i];
                                     // unwrap_or branch: error already emitted elsewhere
                                     let arg_idx = *idx_map.get(*offset).unwrap_or(&0);
                                     *offset += 1;
@@ -721,7 +721,7 @@ impl<'a, 'b> Context<'a, 'b> {
             let name = names_pos[i];
             let span = self.ecx.with_def_site_ctxt(e.span);
             pats.push(self.ecx.pat_ident(span, name));
-            for ref arg_ty in self.arg_unique_types[i].iter() {
+            for arg_ty in self.arg_unique_types[i].iter() {
                 locals.push(Context::format_arg(self.ecx, self.macsp, e.span, arg_ty, name));
             }
             heads.push(self.ecx.expr_addr_of(e.span, e));
diff --git a/src/librustc_builtin_macros/global_allocator.rs b/src/librustc_builtin_macros/global_allocator.rs
index 8de7455a09a6..5d16be3206aa 100644
--- a/src/librustc_builtin_macros/global_allocator.rs
+++ b/src/librustc_builtin_macros/global_allocator.rs
@@ -57,12 +57,12 @@ impl AllocFnFactory<'_, '_> {
     fn allocator_fn(&self, method: &AllocatorMethod) -> Stmt {
         let mut abi_args = Vec::new();
         let mut i = 0;
-        let ref mut mk = || {
+        let mut mk = || {
             let name = self.cx.ident_of(&format!("arg{}", i), self.span);
             i += 1;
             name
         };
-        let args = method.inputs.iter().map(|ty| self.arg_ty(ty, &mut abi_args, mk)).collect();
+        let args = method.inputs.iter().map(|ty| self.arg_ty(ty, &mut abi_args, &mut mk)).collect();
         let result = self.call_allocator(method.name, args);
         let (output_ty, output_expr) = self.ret_ty(&method.output, result);
         let decl = self.cx.fn_decl(abi_args, ast::FnRetTy::Ty(output_ty));
diff --git a/src/librustc_builtin_macros/test.rs b/src/librustc_builtin_macros/test.rs
index 7fe65f28532d..bc194a3eec4c 100644
--- a/src/librustc_builtin_macros/test.rs
+++ b/src/librustc_builtin_macros/test.rs
@@ -313,7 +313,7 @@ fn should_fail(i: &ast::Item) -> bool {
 fn should_panic(cx: &ExtCtxt<'_>, i: &ast::Item) -> ShouldPanic {
     match attr::find_by_name(&i.attrs, sym::should_panic) {
         Some(attr) => {
-            let ref sd = cx.parse_sess.span_diagnostic;
+            let sd = &cx.parse_sess.span_diagnostic;
 
             match attr.meta_item_list() {
                 // Handle #[should_panic(expected = "foo")]
@@ -378,7 +378,7 @@ fn test_type(cx: &ExtCtxt<'_>) -> TestType {
 
 fn has_test_signature(cx: &ExtCtxt<'_>, i: &ast::Item) -> bool {
     let has_should_panic_attr = attr::contains_name(&i.attrs, sym::should_panic);
-    let ref sd = cx.parse_sess.span_diagnostic;
+    let sd = &cx.parse_sess.span_diagnostic;
     if let ast::ItemKind::Fn(_, ref sig, ref generics, _) = i.kind {
         if let ast::Unsafe::Yes(span) = sig.header.unsafety {
             sd.struct_span_err(i.span, "unsafe functions cannot be used for tests")
diff --git a/src/librustc_builtin_macros/test_harness.rs b/src/librustc_builtin_macros/test_harness.rs
index 51a217028055..e7e1ad8eda78 100644
--- a/src/librustc_builtin_macros/test_harness.rs
+++ b/src/librustc_builtin_macros/test_harness.rs
@@ -326,7 +326,7 @@ fn mk_main(cx: &mut TestCtxt<'_>) -> P<ast::Item> {
 /// &[&test1, &test2]
 fn mk_tests_slice(cx: &TestCtxt<'_>, sp: Span) -> P<ast::Expr> {
     debug!("building test vector from {} tests", cx.test_cases.len());
-    let ref ecx = cx.ext_cx;
+    let ecx = &cx.ext_cx;
 
     ecx.expr_vec_slice(
         sp,
diff --git a/src/librustc_infer/traits/select.rs b/src/librustc_infer/traits/select.rs
index 4c312c9fce25..fd94e3b69940 100644
--- a/src/librustc_infer/traits/select.rs
+++ b/src/librustc_infer/traits/select.rs
@@ -1341,7 +1341,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         stack: &TraitObligationStack<'o, 'tcx>,
     ) -> Result<SelectionCandidateSet<'tcx>, SelectionError<'tcx>> {
         let TraitObligationStack { obligation, .. } = *stack;
-        let ref obligation = Obligation {
+        let obligation = &Obligation {
             param_env: obligation.param_env,
             cause: obligation.cause.clone(),
             recursion_depth: obligation.recursion_depth,
diff --git a/src/librustc_mir/transform/promote_consts.rs b/src/librustc_mir/transform/promote_consts.rs
index 286740f99dde..9fe21964b988 100644
--- a/src/librustc_mir/transform/promote_consts.rs
+++ b/src/librustc_mir/transform/promote_consts.rs
@@ -920,7 +920,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
             let (blocks, local_decls) = self.source.basic_blocks_and_local_decls_mut();
             match candidate {
                 Candidate::Ref(loc) => {
-                    let ref mut statement = blocks[loc.block].statements[loc.statement_index];
+                    let statement = &mut blocks[loc.block].statements[loc.statement_index];
                     match statement.kind {
                         StatementKind::Assign(box (
                             _,
@@ -971,7 +971,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                     }
                 }
                 Candidate::Repeat(loc) => {
-                    let ref mut statement = blocks[loc.block].statements[loc.statement_index];
+                    let statement = &mut blocks[loc.block].statements[loc.statement_index];
                     match statement.kind {
                         StatementKind::Assign(box (_, Rvalue::Repeat(ref mut operand, _))) => {
                             let ty = operand.ty(local_decls, self.tcx);
diff --git a/src/librustc_mir_build/hair/pattern/_match.rs b/src/librustc_mir_build/hair/pattern/_match.rs
index 4c7e6e1754aa..5b054c045224 100644
--- a/src/librustc_mir_build/hair/pattern/_match.rs
+++ b/src/librustc_mir_build/hair/pattern/_match.rs
@@ -2331,7 +2331,7 @@ fn specialize_one_pattern<'p, 'tcx>(
         PatKind::Binding { .. } | PatKind::Wild => Some(ctor_wild_subpatterns.iter().collect()),
 
         PatKind::Variant { adt_def, variant_index, ref subpatterns, .. } => {
-            let ref variant = adt_def.variants[variant_index];
+            let variant = &adt_def.variants[variant_index];
             let is_non_exhaustive = cx.is_foreign_non_exhaustive_variant(pat.ty, variant);
             Some(Variant(variant.def_id))
                 .filter(|variant_constructor| variant_constructor == constructor)