diff --git a/clippy_lints/src/await_holding_invalid.rs b/clippy_lints/src/await_holding_invalid.rs
index 58892024ce2..f136aa4572a 100644
--- a/clippy_lints/src/await_holding_invalid.rs
+++ b/clippy_lints/src/await_holding_invalid.rs
@@ -99,7 +99,11 @@ impl LateLintPass<'_> for AwaitHolding {
             };
             let def_id = cx.tcx.hir().body_owner_def_id(body_id);
             let typeck_results = cx.tcx.typeck(def_id);
-            check_interior_types(cx, &typeck_results.generator_interior_types, body.value.span);
+            check_interior_types(
+                cx,
+                &typeck_results.generator_interior_types.as_ref().skip_binder(),
+                body.value.span,
+            );
         }
     }
 }
diff --git a/clippy_lints/src/shadow.rs b/clippy_lints/src/shadow.rs
index 225fe58906f..f8396592678 100644
--- a/clippy_lints/src/shadow.rs
+++ b/clippy_lints/src/shadow.rs
@@ -342,6 +342,10 @@ fn check_expr<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, bindings: &mut
                 if let Some(ref guard) = arm.guard {
                     match guard {
                         Guard::If(if_expr) => check_expr(cx, if_expr, bindings),
+                        Guard::IfLet(guard_pat, guard_expr) => {
+                            check_pat(cx, guard_pat, Some(*guard_expr), guard_pat.span, bindings);
+                            check_expr(cx, guard_expr, bindings);
+                        },
                     }
                 }
                 check_expr(cx, &arm.body, bindings);
diff --git a/clippy_lints/src/utils/author.rs b/clippy_lints/src/utils/author.rs
index 7250de3a41c..4249dbb4e65 100644
--- a/clippy_lints/src/utils/author.rs
+++ b/clippy_lints/src/utils/author.rs
@@ -372,6 +372,18 @@ impl<'tcx> Visitor<'tcx> for PrintVisitor {
                                 self.current = if_expr_pat;
                                 self.visit_expr(if_expr);
                             },
+                            hir::Guard::IfLet(ref if_let_pat, ref if_let_expr) => {
+                                let if_let_pat_pat = self.next("pat");
+                                let if_let_expr_pat = self.next("expr");
+                                println!(
+                                    "    if let Guard::IfLet(ref {}, ref {}) = {};",
+                                    if_let_pat_pat, if_let_expr_pat, guard_pat
+                                );
+                                self.current = if_let_expr_pat;
+                                self.visit_expr(if_let_expr);
+                                self.current = if_let_pat_pat;
+                                self.visit_pat(if_let_pat);
+                            },
                         }
                     }
                     self.current = format!("{}[{}].pat", arms_pat, i);
@@ -730,6 +742,7 @@ fn desugaring_name(des: hir::MatchSource) -> String {
             "MatchSource::IfLetDesugar {{ contains_else_clause: {} }}",
             contains_else_clause
         ),
+        hir::MatchSource::IfLetGuardDesugar => "MatchSource::IfLetGuardDesugar".to_string(),
         hir::MatchSource::IfDesugar { contains_else_clause } => format!(
             "MatchSource::IfDesugar {{ contains_else_clause: {} }}",
             contains_else_clause
diff --git a/clippy_lints/src/utils/hir_utils.rs b/clippy_lints/src/utils/hir_utils.rs
index d942d4e12b1..a8fbb2ffaf0 100644
--- a/clippy_lints/src/utils/hir_utils.rs
+++ b/clippy_lints/src/utils/hir_utils.rs
@@ -169,6 +169,8 @@ impl<'a, 'tcx> SpanlessEq<'a, 'tcx> {
     fn eq_guard(&mut self, left: &Guard<'_>, right: &Guard<'_>) -> bool {
         match (left, right) {
             (Guard::If(l), Guard::If(r)) => self.eq_expr(l, r),
+            (Guard::IfLet(lp, le), Guard::IfLet(rp, re)) => self.eq_pat(lp, rp) && self.eq_expr(le, re),
+            _ => false,
         }
     }
 
@@ -669,7 +671,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
 
     pub fn hash_guard(&mut self, g: &Guard<'_>) {
         match g {
-            Guard::If(ref expr) => {
+            Guard::If(ref expr) | Guard::IfLet(_, ref expr) => {
                 self.hash_expr(expr);
             },
         }
diff --git a/clippy_lints/src/utils/inspector.rs b/clippy_lints/src/utils/inspector.rs
index 323d8745538..5d946e4bd49 100644
--- a/clippy_lints/src/utils/inspector.rs
+++ b/clippy_lints/src/utils/inspector.rs
@@ -560,5 +560,10 @@ fn print_guard(cx: &LateContext<'_>, guard: &hir::Guard<'_>, indent: usize) {
             println!("{}If", ind);
             print_expr(cx, expr, indent + 1);
         },
+        hir::Guard::IfLet(pat, expr) => {
+            println!("{}IfLet", ind);
+            print_pat(cx, pat, indent + 1);
+            print_expr(cx, expr, indent + 1);
+        },
     }
 }
diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs
index e83371f8b99..424856090f2 100644
--- a/clippy_lints/src/utils/mod.rs
+++ b/clippy_lints/src/utils/mod.rs
@@ -1480,8 +1480,8 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
             false
         },
         ty::Dynamic(binder, _) => {
-            for predicate in binder.skip_binder().iter() {
-                if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate {
+            for predicate in binder.iter() {
+                if let ty::ExistentialPredicate::Trait(ref trait_ref) = predicate.skip_binder() {
                     if must_use_attr(&cx.tcx.get_attrs(trait_ref.def_id)).is_some() {
                         return true;
                     }
diff --git a/rust-toolchain b/rust-toolchain
index ac51154f8a9..d2e84132f4e 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2020-12-14"
+channel = "nightly-2020-12-20"
 components = ["llvm-tools-preview", "rustc-dev", "rust-src", "rustfmt"]
diff --git a/tests/ui/crashes/used_underscore_binding_macro.rs b/tests/ui/crashes/used_underscore_binding_macro.rs
index 6d2124c12fe..c57a45dc7aa 100644
--- a/tests/ui/crashes/used_underscore_binding_macro.rs
+++ b/tests/ui/crashes/used_underscore_binding_macro.rs
@@ -1,7 +1,6 @@
-#![allow(clippy::useless_attribute)] //issue #2910
+// edition:2018
 
-#[macro_use]
-extern crate serde_derive;
+use serde::Deserialize;
 
 /// Tests that we do not lint for unused underscores in a `MacroAttribute`
 /// expansion