diff --git a/clippy_lints/src/assertions_on_constants.rs b/clippy_lints/src/assertions_on_constants.rs
index cb9347a923d..891e865b245 100644
--- a/clippy_lints/src/assertions_on_constants.rs
+++ b/clippy_lints/src/assertions_on_constants.rs
@@ -1,5 +1,6 @@
 use clippy_utils::consts::{constant, Constant};
 use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::higher;
 use clippy_utils::source::snippet_opt;
 use clippy_utils::{is_direct_expn_of, is_expn_of, match_panic_call};
 use if_chain::if_chain;
@@ -116,8 +117,8 @@ enum AssertKind {
 /// where `message` is any expression and `c` is a constant bool.
 fn match_assert_with_message<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<AssertKind> {
     if_chain! {
-        if let ExprKind::If(cond, then, _) = expr.kind;
-        if let ExprKind::Unary(UnOp::Not, expr) = cond.kind;
+        if let Some(higher::If { cond, then, .. }) = higher::If::hir(expr);
+        if let ExprKind::Unary(UnOp::Not, ref expr) = cond.kind;
         // bind the first argument of the `assert!` macro
         if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.typeck_results(), expr);
         // block
diff --git a/clippy_lints/src/blocks_in_if_conditions.rs b/clippy_lints/src/blocks_in_if_conditions.rs
index 9b2e4f8998e..51d95cc6f0b 100644
--- a/clippy_lints/src/blocks_in_if_conditions.rs
+++ b/clippy_lints/src/blocks_in_if_conditions.rs
@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
+use clippy_utils::higher;
 use clippy_utils::source::snippet_block_with_applicability;
 use clippy_utils::ty::implements_trait;
 use clippy_utils::{differing_macro_contexts, get_parent_expr};
@@ -92,7 +93,7 @@ impl<'tcx> LateLintPass<'tcx> for BlocksInIfConditions {
         if in_external_macro(cx.sess(), expr.span) {
             return;
         }
-        if let ExprKind::If(cond, _, _) = &expr.kind {
+        if let Some(higher::If { cond, .. }) = higher::If::hir(expr) {
             if let ExprKind::Block(block, _) = &cond.kind {
                 if block.rules == BlockCheckMode::DefaultBlock {
                     if block.stmts.is_empty() {
diff --git a/clippy_lints/src/collapsible_match.rs b/clippy_lints/src/collapsible_match.rs
index a403a9846ba..6b63c2cf157 100644
--- a/clippy_lints/src/collapsible_match.rs
+++ b/clippy_lints/src/collapsible_match.rs
@@ -1,9 +1,9 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::visitors::LocalUsedVisitor;
-use clippy_utils::{is_lang_ctor, path_to_local, peel_ref_operators, SpanlessEq};
+use clippy_utils::{higher, is_lang_ctor, path_to_local, peel_ref_operators, SpanlessEq};
 use if_chain::if_chain;
 use rustc_hir::LangItem::OptionNone;
-use rustc_hir::{Arm, Expr, ExprKind, Guard, HirId, Pat, PatKind, StmtKind};
+use rustc_hir::{Expr, ExprKind, Guard, HirId, Pat, PatKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{MultiSpan, Span};
@@ -49,22 +49,44 @@ declare_lint_pass!(CollapsibleMatch => [COLLAPSIBLE_MATCH]);
 
 impl<'tcx> LateLintPass<'tcx> for CollapsibleMatch {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'tcx>) {
+        if let Some(higher::IfLet {
+            let_pat,
+            if_then,
+            if_else,
+            ..
+        }) = higher::IfLet::hir(expr)
+        {
+            check_arm(cx, if_then, None, let_pat, if_else);
+
+            check_if_let(cx, if_then, let_pat);
+        }
+
         if let ExprKind::Match(_expr, arms, _source) = expr.kind {
-            if let Some(wild_arm) = arms.iter().rfind(|arm| arm_is_wild_like(cx, arm)) {
+            if let Some(wild_arm) = arms.iter().rfind(|arm| is_wild_like(cx, &arm.pat.kind, &arm.guard)) {
                 for arm in arms {
-                    check_arm(arm, wild_arm, cx);
+                    check_arm(cx, arm.body, arm.guard.as_ref(), arm.pat, Some(wild_arm.body));
                 }
             }
+
+            if let Some(first_arm) = arms.get(0) {
+                check_if_let(cx, &first_arm.body, &first_arm.pat);
+            }
         }
     }
 }
 
-fn check_arm<'tcx>(arm: &Arm<'tcx>, wild_outer_arm: &Arm<'tcx>, cx: &LateContext<'tcx>) {
-    let expr = strip_singleton_blocks(arm.body);
+fn check_arm<'tcx>(
+    cx: &LateContext<'tcx>,
+    outer_block: &'tcx Expr<'tcx>,
+    outer_guard: Option<&Guard<'tcx>>,
+    outer_pat: &'tcx Pat<'tcx>,
+    wild_outer_block: Option<&'tcx Expr<'tcx>>,
+) {
+    let expr = strip_singleton_blocks(outer_block);
     if_chain! {
         if let ExprKind::Match(expr_in, arms_inner, _) = expr.kind;
         // the outer arm pattern and the inner match
-        if expr_in.span.ctxt() == arm.pat.span.ctxt();
+        if expr_in.span.ctxt() == outer_pat.span.ctxt();
         // there must be no more than two arms in the inner match for this lint
         if arms_inner.len() == 2;
         // no if guards on the inner match
@@ -73,18 +95,18 @@ fn check_arm<'tcx>(arm: &Arm<'tcx>, wild_outer_arm: &Arm<'tcx>, cx: &LateContext
         // match <local> { .. }
         if let Some(binding_id) = path_to_local(peel_ref_operators(cx, expr_in));
         // one of the branches must be "wild-like"
-        if let Some(wild_inner_arm_idx) = arms_inner.iter().rposition(|arm_inner| arm_is_wild_like(cx, arm_inner));
+        if let Some(wild_inner_arm_idx) = arms_inner.iter().rposition(|arm_inner| is_wild_like(cx, &arm_inner.pat.kind, &arm_inner.guard));
         let (wild_inner_arm, non_wild_inner_arm) =
             (&arms_inner[wild_inner_arm_idx], &arms_inner[1 - wild_inner_arm_idx]);
         if !pat_contains_or(non_wild_inner_arm.pat);
         // the binding must come from the pattern of the containing match arm
         // ..<local>.. => match <local> { .. }
-        if let Some(binding_span) = find_pat_binding(arm.pat, binding_id);
+        if let Some(binding_span) = find_pat_binding(outer_pat, binding_id);
         // the "wild-like" branches must be equal
-        if SpanlessEq::new(cx).eq_expr(wild_inner_arm.body, wild_outer_arm.body);
+        if wild_outer_block.map(|el| SpanlessEq::new(cx).eq_expr(wild_inner_arm.body, el)).unwrap_or(true);
         // the binding must not be used in the if guard
         let mut used_visitor = LocalUsedVisitor::new(cx, binding_id);
-        if match arm.guard {
+        if match outer_guard {
             None => true,
             Some(Guard::If(expr) | Guard::IfLet(_, expr)) => !used_visitor.check_expr(expr),
         };
@@ -107,6 +129,31 @@ fn check_arm<'tcx>(arm: &Arm<'tcx>, wild_outer_arm: &Arm<'tcx>, cx: &LateContext
     }
 }
 
+fn check_if_let<'tcx>(cx: &LateContext<'tcx>, outer_expr: &'tcx Expr<'tcx>, outer_pat: &'tcx Pat<'tcx>) {
+    let block_inner = strip_singleton_blocks(outer_expr);
+    if_chain! {
+        if let Some(higher::IfLet { if_then: inner_if_then, let_expr: inner_let_expr, let_pat: inner_let_pat, .. }) = higher::IfLet::hir(block_inner);
+        if let Some(binding_id) = path_to_local(peel_ref_operators(cx, inner_let_expr));
+        if let Some(binding_span) = find_pat_binding(outer_pat, binding_id);
+        let mut used_visitor = LocalUsedVisitor::new(cx, binding_id);
+        if !used_visitor.check_expr(inner_if_then);
+        then {
+            span_lint_and_then(
+                cx,
+                COLLAPSIBLE_MATCH,
+                block_inner.span,
+                "unnecessary nested `if let` or `match`",
+                |diag| {
+                    let mut help_span = MultiSpan::from_spans(vec![binding_span, inner_let_pat.span]);
+                    help_span.push_span_label(binding_span, "replace this binding".into());
+                    help_span.push_span_label(inner_let_pat.span, "with this pattern".into());
+                    diag.span_help(help_span, "the outer pattern can be modified to include the inner pattern");
+                },
+            );
+        }
+    }
+}
+
 fn strip_singleton_blocks<'hir>(mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
     while let ExprKind::Block(block, _) = expr.kind {
         match (block.stmts, block.expr) {
@@ -122,13 +169,13 @@ fn strip_singleton_blocks<'hir>(mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir>
 }
 
 /// A "wild-like" pattern is wild ("_") or `None`.
-/// For this lint to apply, both the outer and inner match expressions
+/// For this lint to apply, both the outer and inner patterns
 /// must have "wild-like" branches that can be combined.
-fn arm_is_wild_like(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
-    if arm.guard.is_some() {
+fn is_wild_like(cx: &LateContext<'_>, pat_kind: &PatKind<'_>, arm_guard: &Option<Guard<'_>>) -> bool {
+    if arm_guard.is_some() {
         return false;
     }
-    match arm.pat.kind {
+    match pat_kind {
         PatKind::Binding(..) | PatKind::Wild => true,
         PatKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone),
         _ => false,
diff --git a/clippy_lints/src/copies.rs b/clippy_lints/src/copies.rs
index 2dcd5545799..5eb99cfe24f 100644
--- a/clippy_lints/src/copies.rs
+++ b/clippy_lints/src/copies.rs
@@ -316,9 +316,10 @@ fn scan_block_for_eq(cx: &LateContext<'tcx>, blocks: &[&Block<'tcx>]) -> Option<
     let mut start_eq = usize::MAX;
     let mut end_eq = usize::MAX;
     let mut expr_eq = true;
-    for win in blocks.windows(2) {
-        let l_stmts = win[0].stmts;
-        let r_stmts = win[1].stmts;
+    let mut iter = blocks.windows(2);
+    while let Some(&[win0, win1]) = iter.next() {
+        let l_stmts = win0.stmts;
+        let r_stmts = win1.stmts;
 
         // `SpanlessEq` now keeps track of the locals and is therefore context sensitive clippy#6752.
         // The comparison therefore needs to be done in a way that builds the correct context.
@@ -335,22 +336,22 @@ fn scan_block_for_eq(cx: &LateContext<'tcx>, blocks: &[&Block<'tcx>]) -> Option<
             it1.zip(it2)
                 .fold(0, |acc, (l, r)| if evaluator.eq_stmt(l, r) { acc + 1 } else { 0 })
         };
-        let block_expr_eq = both(&win[0].expr, &win[1].expr, |l, r| evaluator.eq_expr(l, r));
+        let block_expr_eq = both(&win0.expr, &win1.expr, |l, r| evaluator.eq_expr(l, r));
 
         // IF_SAME_THEN_ELSE
         if_chain! {
             if block_expr_eq;
             if l_stmts.len() == r_stmts.len();
             if l_stmts.len() == current_start_eq;
-            if !is_lint_allowed(cx, IF_SAME_THEN_ELSE, win[0].hir_id);
-            if !is_lint_allowed(cx, IF_SAME_THEN_ELSE, win[1].hir_id);
+            if !is_lint_allowed(cx, IF_SAME_THEN_ELSE, win0.hir_id);
+            if !is_lint_allowed(cx, IF_SAME_THEN_ELSE, win1.hir_id);
             then {
                 span_lint_and_note(
                     cx,
                     IF_SAME_THEN_ELSE,
-                    win[0].span,
+                    win0.span,
                     "this `if` has identical blocks",
-                    Some(win[1].span),
+                    Some(win1.span),
                     "same as this",
                 );
 
diff --git a/clippy_lints/src/dereference.rs b/clippy_lints/src/dereference.rs
index ded7001ad8c..7825e5f6ed5 100644
--- a/clippy_lints/src/dereference.rs
+++ b/clippy_lints/src/dereference.rs
@@ -232,6 +232,7 @@ fn is_linted_explicit_deref_position(parent: Option<Node<'_>>, child_id: HirId,
         | ExprKind::If(..)
         | ExprKind::Loop(..)
         | ExprKind::Match(..)
+        | ExprKind::Let(..)
         | ExprKind::Closure(..)
         | ExprKind::Block(..)
         | ExprKind::Assign(..)
diff --git a/clippy_lints/src/entry.rs b/clippy_lints/src/entry.rs
index e1d0d65edb1..627f746ec99 100644
--- a/clippy_lints/src/entry.rs
+++ b/clippy_lints/src/entry.rs
@@ -1,3 +1,4 @@
+use clippy_utils::higher;
 use clippy_utils::{
     can_move_expr_to_closure_no_visit,
     diagnostics::span_lint_and_sugg,
@@ -5,6 +6,7 @@ use clippy_utils::{
     source::{reindent_multiline, snippet_indent, snippet_with_applicability, snippet_with_context},
     SpanlessEq,
 };
+use core::fmt::Write;
 use rustc_errors::Applicability;
 use rustc_hir::{
     intravisit::{walk_expr, ErasedMap, NestedVisitorMap, Visitor},
@@ -13,7 +15,6 @@ use rustc_hir::{
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{Span, SyntaxContext, DUMMY_SP};
-use std::fmt::Write;
 
 declare_clippy_lint! {
     /// ### What it does
@@ -62,10 +63,11 @@ declare_lint_pass!(HashMapPass => [MAP_ENTRY]);
 impl<'tcx> LateLintPass<'tcx> for HashMapPass {
     #[allow(clippy::too_many_lines)]
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        let (cond_expr, then_expr, else_expr) = match expr.kind {
-            ExprKind::If(c, t, e) => (c, t, e),
+        let (cond_expr, then_expr, else_expr) = match higher::If::hir(expr) {
+            Some(higher::If { cond, then, r#else }) => (cond, then, r#else),
             _ => return,
         };
+
         let (map_ty, contains_expr) = match try_parse_contains(cx, cond_expr) {
             Some(x) => x,
             None => return,
diff --git a/clippy_lints/src/eta_reduction.rs b/clippy_lints/src/eta_reduction.rs
index 192b69e18f9..f6a64a8ca60 100644
--- a/clippy_lints/src/eta_reduction.rs
+++ b/clippy_lints/src/eta_reduction.rs
@@ -100,7 +100,7 @@ fn check_closure<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
 
         if ex.span.ctxt() != expr.span.ctxt() {
             if decl.inputs.is_empty() {
-                if let Some(VecArgs::Vec(&[])) = higher::vec_macro(cx, ex) {
+                if let Some(VecArgs::Vec(&[])) = higher::VecArgs::hir(cx, ex) {
                     // replace `|| vec![]` with `Vec::new`
                     span_lint_and_sugg(
                         cx,
diff --git a/clippy_lints/src/floating_point_arithmetic.rs b/clippy_lints/src/floating_point_arithmetic.rs
index b01c0cdd846..d12482e7b7b 100644
--- a/clippy_lints/src/floating_point_arithmetic.rs
+++ b/clippy_lints/src/floating_point_arithmetic.rs
@@ -3,6 +3,7 @@ use clippy_utils::consts::{
     Constant::{Int, F32, F64},
 };
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::{eq_expr_value, get_parent_expr, numeric_literal, sugg};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
@@ -545,11 +546,11 @@ fn are_negated<'a>(cx: &LateContext<'_>, expr1: &'a Expr<'a>, expr2: &'a Expr<'a
 
 fn check_custom_abs(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
-        if let ExprKind::If(cond, body, else_body) = expr.kind;
-        if let ExprKind::Block(block, _) = body.kind;
+        if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr);
+        if let ExprKind::Block(block, _) = then.kind;
         if block.stmts.is_empty();
         if let Some(if_body_expr) = block.expr;
-        if let Some(ExprKind::Block(else_block, _)) = else_body.map(|el| &el.kind);
+        if let Some(ExprKind::Block(else_block, _)) = r#else.map(|el| &el.kind);
         if else_block.stmts.is_empty();
         if let Some(else_body_expr) = else_block.expr;
         if let Some((if_expr_positive, body)) = are_negated(cx, if_body_expr, else_body_expr);
diff --git a/clippy_lints/src/if_let_mutex.rs b/clippy_lints/src/if_let_mutex.rs
index d3ddeda9fd1..e2d3905eacb 100644
--- a/clippy_lints/src/if_let_mutex.rs
+++ b/clippy_lints/src/if_let_mutex.rs
@@ -1,9 +1,10 @@
 use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::higher;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::SpanlessEq;
 use if_chain::if_chain;
 use rustc_hir::intravisit::{self as visit, NestedVisitorMap, Visitor};
-use rustc_hir::{Expr, ExprKind, MatchSource};
+use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::hir::map::Map;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -42,7 +43,7 @@ declare_clippy_lint! {
 declare_lint_pass!(IfLetMutex => [IF_LET_MUTEX]);
 
 impl<'tcx> LateLintPass<'tcx> for IfLetMutex {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, ex: &'tcx Expr<'tcx>) {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         let mut arm_visit = ArmVisitor {
             mutex_lock_called: false,
             found_mutex: None,
@@ -53,25 +54,23 @@ impl<'tcx> LateLintPass<'tcx> for IfLetMutex {
             found_mutex: None,
             cx,
         };
-        if let ExprKind::Match(
-            op,
-            arms,
-            MatchSource::IfLetDesugar {
-                contains_else_clause: true,
-            },
-        ) = ex.kind
+        if let Some(higher::IfLet {
+            let_expr,
+            if_then,
+            if_else: Some(if_else),
+            ..
+        }) = higher::IfLet::hir(expr)
         {
-            op_visit.visit_expr(op);
+            op_visit.visit_expr(let_expr);
             if op_visit.mutex_lock_called {
-                for arm in arms {
-                    arm_visit.visit_arm(arm);
-                }
+                arm_visit.visit_expr(if_then);
+                arm_visit.visit_expr(if_else);
 
                 if arm_visit.mutex_lock_called && arm_visit.same_mutex(cx, op_visit.found_mutex.unwrap()) {
                     span_lint_and_help(
                         cx,
                         IF_LET_MUTEX,
-                        ex.span,
+                        expr.span,
                         "calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a deadlock",
                         None,
                         "move the lock call outside of the `if let ...` expression",
diff --git a/clippy_lints/src/if_let_some_result.rs b/clippy_lints/src/if_let_some_result.rs
index 587307811a1..cd813c639db 100644
--- a/clippy_lints/src/if_let_some_result.rs
+++ b/clippy_lints/src/if_let_some_result.rs
@@ -1,10 +1,11 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::method_chain_args;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::ty::is_type_diagnostic_item;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind, MatchSource, PatKind, QPath};
+use rustc_hir::{Expr, ExprKind, PatKind, QPath};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
@@ -44,17 +45,17 @@ declare_lint_pass!(OkIfLet => [IF_LET_SOME_RESULT]);
 impl<'tcx> LateLintPass<'tcx> for OkIfLet {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if_chain! { //begin checking variables
-            if let ExprKind::Match(op, body, MatchSource::IfLetDesugar { .. }) = expr.kind; //test if expr is if let
-            if let ExprKind::MethodCall(_, ok_span, result_types, _) = op.kind; //check is expr.ok() has type Result<T,E>.ok(, _)
-            if let PatKind::TupleStruct(QPath::Resolved(_, x), y, _)  = body[0].pat.kind; //get operation
-            if method_chain_args(op, &["ok"]).is_some(); //test to see if using ok() methoduse std::marker::Sized;
+            if let Some(higher::IfLet { let_pat, let_expr, .. }) = higher::IfLet::hir(expr);
+            if let ExprKind::MethodCall(_, ok_span, ref result_types, _) = let_expr.kind; //check is expr.ok() has type Result<T,E>.ok(, _)
+            if let PatKind::TupleStruct(QPath::Resolved(_, ref x), ref y, _)  = let_pat.kind; //get operation
+            if method_chain_args(let_expr, &["ok"]).is_some(); //test to see if using ok() methoduse std::marker::Sized;
             if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(&result_types[0]), sym::result_type);
             if rustc_hir_pretty::to_string(rustc_hir_pretty::NO_ANN, |s| s.print_path(x, false)) == "Some";
 
             then {
                 let mut applicability = Applicability::MachineApplicable;
                 let some_expr_string = snippet_with_applicability(cx, y[0].span, "", &mut applicability);
-                let trimmed_ok = snippet_with_applicability(cx, op.span.until(ok_span), "", &mut applicability);
+                let trimmed_ok = snippet_with_applicability(cx, let_expr.span.until(ok_span), "", &mut applicability);
                 let sugg = format!(
                     "if let Ok({}) = {}",
                     some_expr_string,
@@ -63,7 +64,7 @@ impl<'tcx> LateLintPass<'tcx> for OkIfLet {
                 span_lint_and_sugg(
                     cx,
                     IF_LET_SOME_RESULT,
-                    expr.span.with_hi(op.span.hi()),
+                    expr.span.with_hi(let_expr.span.hi()),
                     "matching on `Some` with `ok()` is redundant",
                     &format!("consider matching on `Ok({})` and removing the call to `ok` instead", some_expr_string),
                     sugg,
diff --git a/clippy_lints/src/if_then_some_else_none.rs b/clippy_lints/src/if_then_some_else_none.rs
index 17b9a2f888e..a2dac57454f 100644
--- a/clippy_lints/src/if_then_some_else_none.rs
+++ b/clippy_lints/src/if_then_some_else_none.rs
@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::source::snippet_with_macro_callsite;
-use clippy_utils::{is_else_clause, is_lang_ctor, meets_msrv, msrvs};
+use clippy_utils::{higher, is_else_clause, is_lang_ctor, meets_msrv, msrvs};
 use if_chain::if_chain;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
 use rustc_hir::{Expr, ExprKind};
@@ -70,7 +70,7 @@ impl LateLintPass<'_> for IfThenSomeElseNone {
         }
 
         if_chain! {
-            if let ExprKind::If(cond, then, Some(els)) = expr.kind;
+            if let Some(higher::If { cond, then, r#else: Some(els) }) = higher::If::hir(expr);
             if let ExprKind::Block(then_block, _) = then.kind;
             if let Some(then_expr) = then_block.expr;
             if let ExprKind::Call(then_call, [then_arg]) = then_expr.kind;
diff --git a/clippy_lints/src/implicit_saturating_sub.rs b/clippy_lints/src/implicit_saturating_sub.rs
index 0a7d31dce2f..79d4d7ddcbc 100644
--- a/clippy_lints/src/implicit_saturating_sub.rs
+++ b/clippy_lints/src/implicit_saturating_sub.rs
@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::{in_macro, SpanlessEq};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
@@ -42,7 +43,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitSaturatingSub {
             return;
         }
         if_chain! {
-            if let ExprKind::If(cond, then, None) = &expr.kind;
+            if let Some(higher::If { cond, then, .. }) = higher::If::hir(expr);
 
             // Check if the conditional expression is a binary operation
             if let ExprKind::Binary(ref cond_op, cond_left, cond_right) = cond.kind;
diff --git a/clippy_lints/src/indexing_slicing.rs b/clippy_lints/src/indexing_slicing.rs
index 8c1f1073309..f52f090d387 100644
--- a/clippy_lints/src/indexing_slicing.rs
+++ b/clippy_lints/src/indexing_slicing.rs
@@ -96,7 +96,7 @@ impl<'tcx> LateLintPass<'tcx> for IndexingSlicing {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
         if let ExprKind::Index(array, index) = &expr.kind {
             let ty = cx.typeck_results().expr_ty(array).peel_refs();
-            if let Some(range) = higher::range(index) {
+            if let Some(range) = higher::Range::hir(index) {
                 // Ranged indexes, i.e., &x[n..m], &x[n..], &x[..n] and &x[..]
                 if let ty::Array(_, s) = ty.kind() {
                     let size: u128 = if let Some(size) = s.try_eval_usize(cx.tcx, cx.param_env) {
diff --git a/clippy_lints/src/infinite_iter.rs b/clippy_lints/src/infinite_iter.rs
index 2411a3175b9..58646385def 100644
--- a/clippy_lints/src/infinite_iter.rs
+++ b/clippy_lints/src/infinite_iter.rs
@@ -172,7 +172,7 @@ fn is_infinite(cx: &LateContext<'_>, expr: &Expr<'_>) -> Finiteness {
                 Finite
             }
         },
-        ExprKind::Struct(..) => higher::range(expr).map_or(false, |r| r.end.is_none()).into(),
+        ExprKind::Struct(..) => higher::Range::hir(expr).map_or(false, |r| r.end.is_none()).into(),
         _ => Finite,
     }
 }
diff --git a/clippy_lints/src/let_if_seq.rs b/clippy_lints/src/let_if_seq.rs
index 13f0d43cf8d..0594b73dd38 100644
--- a/clippy_lints/src/let_if_seq.rs
+++ b/clippy_lints/src/let_if_seq.rs
@@ -64,7 +64,7 @@ impl<'tcx> LateLintPass<'tcx> for LetIfSeq {
                 if let hir::StmtKind::Local(local) = stmt.kind;
                 if let hir::PatKind::Binding(mode, canonical_id, ident, None) = local.pat.kind;
                 if let hir::StmtKind::Expr(if_) = expr.kind;
-                if let hir::ExprKind::If(cond, then, ref else_) = if_.kind;
+                if let hir::ExprKind::If(hir::Expr { kind: hir::ExprKind::DropTemps(cond), ..}, then, else_) = if_.kind;
                 let mut used_visitor = LocalUsedVisitor::new(cx, canonical_id);
                 if !used_visitor.check_expr(cond);
                 if let hir::ExprKind::Block(then, _) = then.kind;
@@ -79,7 +79,7 @@ impl<'tcx> LateLintPass<'tcx> for LetIfSeq {
                     );
                     if has_interior_mutability { return; }
 
-                    let (default_multi_stmts, default) = if let Some(else_) = *else_ {
+                    let (default_multi_stmts, default) = if let Some(else_) = else_ {
                         if let hir::ExprKind::Block(else_, _) = else_.kind {
                             if let Some(default) = check_assign(cx, canonical_id, else_) {
                                 (else_.stmts.len() > 1, default)
diff --git a/clippy_lints/src/loops/manual_flatten.rs b/clippy_lints/src/loops/manual_flatten.rs
index 64ff7574f86..9f2bc3c7eba 100644
--- a/clippy_lints/src/loops/manual_flatten.rs
+++ b/clippy_lints/src/loops/manual_flatten.rs
@@ -1,11 +1,12 @@
 use super::utils::make_iterator_snippet;
 use super::MANUAL_FLATTEN;
 use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::higher;
 use clippy_utils::{is_lang_ctor, path_to_local_id};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionSome, ResultOk};
-use rustc_hir::{Expr, ExprKind, MatchSource, Pat, PatKind, StmtKind};
+use rustc_hir::{Expr, ExprKind, Pat, PatKind, StmtKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
 use rustc_span::source_map::Span;
@@ -36,14 +37,12 @@ pub(super) fn check<'tcx>(
 
         if_chain! {
             if let Some(inner_expr) = inner_expr;
-            if let ExprKind::Match(
-                match_expr, match_arms, MatchSource::IfLetDesugar{ contains_else_clause: false }
-            ) = inner_expr.kind;
+            if let Some(higher::IfLet { let_pat, let_expr, if_else: None, .. }) = higher::IfLet::hir(inner_expr);
             // Ensure match_expr in `if let` statement is the same as the pat from the for-loop
             if let PatKind::Binding(_, pat_hir_id, _, _) = pat.kind;
-            if path_to_local_id(match_expr, pat_hir_id);
+            if path_to_local_id(let_expr, pat_hir_id);
             // Ensure the `if let` statement is for the `Some` variant of `Option` or the `Ok` variant of `Result`
-            if let PatKind::TupleStruct(ref qpath, _, _) = match_arms[0].pat.kind;
+            if let PatKind::TupleStruct(ref qpath, _, _) = let_pat.kind;
             let some_ctor = is_lang_ctor(cx, qpath, OptionSome);
             let ok_ctor = is_lang_ctor(cx, qpath, ResultOk);
             if some_ctor || ok_ctor;
@@ -55,7 +54,7 @@ pub(super) fn check<'tcx>(
                 // Prepare the help message
                 let mut applicability = Applicability::MaybeIncorrect;
                 let arg_snippet = make_iterator_snippet(cx, arg, &mut applicability);
-                let copied = match cx.typeck_results().expr_ty(match_expr).kind() {
+                let copied = match cx.typeck_results().expr_ty(let_expr).kind() {
                     ty::Ref(_, inner, _) => match inner.kind() {
                         ty::Ref(..) => ".copied()",
                         _ => ""
diff --git a/clippy_lints/src/loops/manual_memcpy.rs b/clippy_lints/src/loops/manual_memcpy.rs
index a98e2dc1372..2525b14e1c5 100644
--- a/clippy_lints/src/loops/manual_memcpy.rs
+++ b/clippy_lints/src/loops/manual_memcpy.rs
@@ -27,7 +27,7 @@ pub(super) fn check<'tcx>(
         start: Some(start),
         end: Some(end),
         limits,
-    }) = higher::range(arg)
+    }) = higher::Range::hir(arg)
     {
         // the var must be a single name
         if let PatKind::Binding(_, canonical_id, _, _) = pat.kind {
diff --git a/clippy_lints/src/loops/mod.rs b/clippy_lints/src/loops/mod.rs
index 7ca54d53972..bd9de5e08d7 100644
--- a/clippy_lints/src/loops/mod.rs
+++ b/clippy_lints/src/loops/mod.rs
@@ -551,7 +551,7 @@ declare_lint_pass!(Loops => [
 impl<'tcx> LateLintPass<'tcx> for Loops {
     #[allow(clippy::too_many_lines)]
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if let Some((pat, arg, body, span)) = higher::for_loop(expr) {
+        if let Some(higher::ForLoop { pat, arg, body, span }) = higher::ForLoop::hir(expr) {
             // we don't want to check expanded macros
             // this check is not at the top of the function
             // since higher::for_loop expressions are marked as expansions
@@ -580,8 +580,8 @@ impl<'tcx> LateLintPass<'tcx> for Loops {
 
         while_let_on_iterator::check(cx, expr);
 
-        if let Some((cond, body)) = higher::while_loop(expr) {
-            while_immutable_condition::check(cx, cond, body);
+        if let Some(higher::While { if_cond, if_then, .. }) = higher::While::hir(&expr) {
+            while_immutable_condition::check(cx, if_cond, if_then);
         }
 
         needless_collect::check(expr, cx);
diff --git a/clippy_lints/src/loops/mut_range_bound.rs b/clippy_lints/src/loops/mut_range_bound.rs
index 1e54a1e2de1..344dc5074d3 100644
--- a/clippy_lints/src/loops/mut_range_bound.rs
+++ b/clippy_lints/src/loops/mut_range_bound.rs
@@ -14,7 +14,7 @@ pub(super) fn check(cx: &LateContext<'_>, arg: &Expr<'_>, body: &Expr<'_>) {
         start: Some(start),
         end: Some(end),
         ..
-    }) = higher::range(arg)
+    }) = higher::Range::hir(arg)
     {
         let mut_ids = vec![check_for_mutability(cx, start), check_for_mutability(cx, end)];
         if mut_ids[0].is_some() || mut_ids[1].is_some() {
diff --git a/clippy_lints/src/loops/needless_range_loop.rs b/clippy_lints/src/loops/needless_range_loop.rs
index 3810d0dcc05..3f77e7af927 100644
--- a/clippy_lints/src/loops/needless_range_loop.rs
+++ b/clippy_lints/src/loops/needless_range_loop.rs
@@ -34,7 +34,7 @@ pub(super) fn check<'tcx>(
         start: Some(start),
         ref end,
         limits,
-    }) = higher::range(arg)
+    }) = higher::Range::hir(arg)
     {
         // the var must be a single name
         if let PatKind::Binding(_, canonical_id, ident, _) = pat.kind {
diff --git a/clippy_lints/src/loops/never_loop.rs b/clippy_lints/src/loops/never_loop.rs
index 6d9f6215ed4..2c46971d5f7 100644
--- a/clippy_lints/src/loops/never_loop.rs
+++ b/clippy_lints/src/loops/never_loop.rs
@@ -1,7 +1,7 @@
 use super::utils::make_iterator_snippet;
 use super::NEVER_LOOP;
 use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::higher;
+use clippy_utils::higher::ForLoop;
 use clippy_utils::source::snippet;
 use rustc_errors::Applicability;
 use rustc_hir::{Block, Expr, ExprKind, HirId, InlineAsmOperand, LoopSource, Node, Pat, Stmt, StmtKind};
@@ -16,7 +16,7 @@ pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
                     if_chain! {
                         if let LoopSource::ForLoop = source;
                         if let Some((_, Node::Expr(parent_match))) = cx.tcx.hir().parent_iter(expr.hir_id).nth(1);
-                        if let Some((pat, iterator, _, for_span)) = higher::for_loop(parent_match);
+                        if let Some(ForLoop { arg: iterator, pat, span: for_span, .. }) = ForLoop::hir(parent_match);
                         then {
                             // Suggests using an `if let` instead. This is `Unspecified` because the
                             // loop may (probably) contain `break` statements which would be invalid
@@ -111,6 +111,7 @@ fn never_loop_expr(expr: &Expr<'_>, main_loop_id: HirId) -> NeverLoopResult {
         | ExprKind::Unary(_, e)
         | ExprKind::Cast(e, _)
         | ExprKind::Type(e, _)
+        | ExprKind::Let(_, e, _)
         | ExprKind::Field(e, _)
         | ExprKind::AddrOf(_, _, e)
         | ExprKind::Struct(_, _, Some(e))
@@ -128,7 +129,7 @@ fn never_loop_expr(expr: &Expr<'_>, main_loop_id: HirId) -> NeverLoopResult {
             // Break can come from the inner loop so remove them.
             absorb_break(&never_loop_block(b, main_loop_id))
         },
-        ExprKind::If(e, e2, ref e3) => {
+        ExprKind::If(e, e2, e3) => {
             let e1 = never_loop_expr(e, main_loop_id);
             let e2 = never_loop_expr(e2, main_loop_id);
             let e3 = e3
@@ -156,7 +157,7 @@ fn never_loop_expr(expr: &Expr<'_>, main_loop_id: HirId) -> NeverLoopResult {
                 NeverLoopResult::AlwaysBreak
             }
         },
-        ExprKind::Break(_, ref e) | ExprKind::Ret(ref e) => e.as_ref().map_or(NeverLoopResult::AlwaysBreak, |e| {
+        ExprKind::Break(_, e) | ExprKind::Ret(e) => e.as_ref().map_or(NeverLoopResult::AlwaysBreak, |e| {
             combine_seq(never_loop_expr(e, main_loop_id), NeverLoopResult::AlwaysBreak)
         }),
         ExprKind::InlineAsm(asm) => asm
diff --git a/clippy_lints/src/loops/while_let_loop.rs b/clippy_lints/src/loops/while_let_loop.rs
index 9c172079852..6be410ca8e3 100644
--- a/clippy_lints/src/loops/while_let_loop.rs
+++ b/clippy_lints/src/loops/while_let_loop.rs
@@ -1,8 +1,9 @@
 use super::WHILE_LET_LOOP;
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::source::snippet_with_applicability;
 use rustc_errors::Applicability;
-use rustc_hir::{Block, Expr, ExprKind, MatchSource, StmtKind};
+use rustc_hir::{Block, Expr, ExprKind, MatchSource, Pat, StmtKind};
 use rustc_lint::{LateContext, LintContext};
 use rustc_middle::lint::in_external_macro;
 
@@ -11,41 +12,25 @@ pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, loop_block: &'
     let inner_stmt_expr = extract_expr_from_first_stmt(loop_block);
     // or extract the first expression (if any) from the block
     if let Some(inner) = inner_stmt_expr.or_else(|| extract_first_expr(loop_block)) {
-        if let ExprKind::Match(matchexpr, arms, ref source) = inner.kind {
-            // ensure "if let" compatible match structure
-            match *source {
-                MatchSource::Normal | MatchSource::IfLetDesugar { .. } => {
-                    if arms.len() == 2
-                        && arms[0].guard.is_none()
-                        && arms[1].guard.is_none()
-                        && is_simple_break_expr(arms[1].body)
-                    {
-                        if in_external_macro(cx.sess(), expr.span) {
-                            return;
-                        }
+        if let Some(higher::IfLet {
+            let_pat,
+            let_expr,
+            if_else: Some(if_else),
+            ..
+        }) = higher::IfLet::hir(inner)
+        {
+            if is_simple_break_expr(if_else) {
+                could_be_while_let(cx, expr, let_pat, let_expr);
+            }
+        }
 
-                        // NOTE: we used to build a body here instead of using
-                        // ellipsis, this was removed because:
-                        // 1) it was ugly with big bodies;
-                        // 2) it was not indented properly;
-                        // 3) it wasn’t very smart (see #675).
-                        let mut applicability = Applicability::HasPlaceholders;
-                        span_lint_and_sugg(
-                            cx,
-                            WHILE_LET_LOOP,
-                            expr.span,
-                            "this loop could be written as a `while let` loop",
-                            "try",
-                            format!(
-                                "while let {} = {} {{ .. }}",
-                                snippet_with_applicability(cx, arms[0].pat.span, "..", &mut applicability),
-                                snippet_with_applicability(cx, matchexpr.span, "..", &mut applicability),
-                            ),
-                            applicability,
-                        );
-                    }
-                },
-                _ => (),
+        if let ExprKind::Match(ref matchexpr, ref arms, MatchSource::Normal) = inner.kind {
+            if arms.len() == 2
+                && arms[0].guard.is_none()
+                && arms[1].guard.is_none()
+                && is_simple_break_expr(&arms[1].body)
+            {
+                could_be_while_let(cx, expr, &arms[0].pat, matchexpr);
             }
         }
     }
@@ -54,14 +39,12 @@ pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, loop_block: &'
 /// If a block begins with a statement (possibly a `let` binding) and has an
 /// expression, return it.
 fn extract_expr_from_first_stmt<'tcx>(block: &Block<'tcx>) -> Option<&'tcx Expr<'tcx>> {
-    if block.stmts.is_empty() {
-        return None;
-    }
-    if let StmtKind::Local(local) = block.stmts[0].kind {
-        local.init //.map(|expr| expr)
-    } else {
-        None
+    if let Some(first_stmt) = block.stmts.get(0) {
+        if let StmtKind::Local(local) = first_stmt.kind {
+            return local.init;
+        }
     }
+    None
 }
 
 /// If a block begins with an expression (with or without semicolon), return it.
@@ -86,3 +69,34 @@ fn is_simple_break_expr(expr: &Expr<'_>) -> bool {
         _ => false,
     }
 }
+
+fn could_be_while_let<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    let_pat: &'tcx Pat<'_>,
+    let_expr: &'tcx Expr<'_>,
+) {
+    if in_external_macro(cx.sess(), expr.span) {
+        return;
+    }
+
+    // NOTE: we used to build a body here instead of using
+    // ellipsis, this was removed because:
+    // 1) it was ugly with big bodies;
+    // 2) it was not indented properly;
+    // 3) it wasn’t very smart (see #675).
+    let mut applicability = Applicability::HasPlaceholders;
+    span_lint_and_sugg(
+        cx,
+        WHILE_LET_LOOP,
+        expr.span,
+        "this loop could be written as a `while let` loop",
+        "try",
+        format!(
+            "while let {} = {} {{ .. }}",
+            snippet_with_applicability(cx, let_pat.span, "..", &mut applicability),
+            snippet_with_applicability(cx, let_expr.span, "..", &mut applicability),
+        ),
+        applicability,
+    );
+}
diff --git a/clippy_lints/src/loops/while_let_on_iterator.rs b/clippy_lints/src/loops/while_let_on_iterator.rs
index ef822e0cbe5..0757d329125 100644
--- a/clippy_lints/src/loops/while_let_on_iterator.rs
+++ b/clippy_lints/src/loops/while_let_on_iterator.rs
@@ -1,5 +1,6 @@
 use super::WHILE_LET_ON_ITERATOR;
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::{
     get_enclosing_loop_or_closure, is_refutable, is_trait_method, match_def_path, paths, visitors::is_res_used,
@@ -7,27 +8,31 @@ use clippy_utils::{
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, ErasedMap, NestedVisitorMap, Visitor};
-use rustc_hir::{def::Res, Expr, ExprKind, HirId, Local, MatchSource, Mutability, Node, PatKind, QPath, UnOp};
+use rustc_hir::{def::Res, Expr, ExprKind, HirId, Local, Mutability, PatKind, QPath, UnOp};
 use rustc_lint::LateContext;
 use rustc_span::{symbol::sym, Span, Symbol};
 
 pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
     let (scrutinee_expr, iter_expr, some_pat, loop_expr) = if_chain! {
-        if let ExprKind::Match(scrutinee_expr, [arm, _], MatchSource::WhileLetDesugar) = expr.kind;
+        if let Some(higher::WhileLet {
+            if_then,
+            let_pat,
+            let_expr,
+            ..
+        }) = higher::WhileLet::hir(expr);
         // check for `Some(..)` pattern
-        if let PatKind::TupleStruct(QPath::Resolved(None, pat_path), some_pat, _) = arm.pat.kind;
+        if let PatKind::TupleStruct(QPath::Resolved(None, pat_path), some_pat, _) = let_pat.kind;
         if let Res::Def(_, pat_did) = pat_path.res;
         if match_def_path(cx, pat_did, &paths::OPTION_SOME);
         // check for call to `Iterator::next`
-        if let ExprKind::MethodCall(method_name, _, [iter_expr], _) = scrutinee_expr.kind;
+        if let ExprKind::MethodCall(method_name, _, [iter_expr], _) = let_expr.kind;
         if method_name.ident.name == sym::next;
-        if is_trait_method(cx, scrutinee_expr, sym::Iterator);
-        if let Some(iter_expr) = try_parse_iter_expr(cx, iter_expr);
+        if is_trait_method(cx, let_expr, sym::Iterator);
+        if let Some(iter_expr_struct) = try_parse_iter_expr(cx, iter_expr);
         // get the loop containing the match expression
-        if let Some((_, Node::Expr(loop_expr))) = cx.tcx.hir().parent_iter(expr.hir_id).nth(1);
-        if !uses_iter(cx, &iter_expr, arm.body);
+        if !uses_iter(cx, &iter_expr_struct, if_then);
         then {
-            (scrutinee_expr, iter_expr, some_pat, loop_expr)
+            (let_expr, iter_expr_struct, some_pat, expr)
         } else {
             return;
         }
@@ -81,6 +86,7 @@ struct IterExpr {
     /// The path being used.
     path: Res,
 }
+
 /// Parses any expression to find out which field of which variable is used. Will return `None` if
 /// the expression might have side effects.
 fn try_parse_iter_expr(cx: &LateContext<'_>, mut e: &Expr<'_>) -> Option<IterExpr> {
@@ -285,6 +291,7 @@ fn needs_mutable_borrow(cx: &LateContext<'tcx>, iter_expr: &IterExpr, loop_expr:
     }
     impl Visitor<'tcx> for NestedLoopVisitor<'a, 'b, 'tcx> {
         type Map = ErasedMap<'tcx>;
+
         fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
             NestedVisitorMap::None
         }
diff --git a/clippy_lints/src/manual_map.rs b/clippy_lints/src/manual_map.rs
index 7dec1595e0d..53d97f77543 100644
--- a/clippy_lints/src/manual_map.rs
+++ b/clippy_lints/src/manual_map.rs
@@ -1,5 +1,6 @@
 use crate::{map_unit_fn::OPTION_MAP_UNIT_FN, matches::MATCH_AS_REF};
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::source::{snippet_with_applicability, snippet_with_context};
 use clippy_utils::ty::{is_type_diagnostic_item, peel_mid_ty_refs_is_mutable};
 use clippy_utils::{
@@ -9,7 +10,7 @@ use clippy_utils::{
 use rustc_ast::util::parser::PREC_POSTFIX;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
-use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, HirId, MatchSource, Mutability, Pat, PatKind};
+use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, HirId, Mutability, Pat, PatKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -43,163 +44,176 @@ declare_lint_pass!(ManualMap => [MANUAL_MAP]);
 impl LateLintPass<'_> for ManualMap {
     #[allow(clippy::too_many_lines)]
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if let ExprKind::Match(
-            scrutinee,
-            [arm1 @ Arm { guard: None, .. }, arm2 @ Arm { guard: None, .. }],
-            match_kind,
-        ) = expr.kind
+        if let Some(higher::IfLet {
+            let_pat,
+            let_expr,
+            if_then,
+            if_else: Some(if_else),
+        }) = higher::IfLet::hir(expr)
         {
-            if in_external_macro(cx.sess(), expr.span) || in_constant(cx, expr.hir_id) {
-                return;
-            }
+            manage_lint(cx, expr, (&let_pat.kind, if_then), (&PatKind::Wild, if_else), let_expr);
+        }
 
-            let (scrutinee_ty, ty_ref_count, ty_mutability) =
-                peel_mid_ty_refs_is_mutable(cx.typeck_results().expr_ty(scrutinee));
-            if !(is_type_diagnostic_item(cx, scrutinee_ty, sym::option_type)
-                && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::option_type))
-            {
-                return;
-            }
-
-            let expr_ctxt = expr.span.ctxt();
-            let (some_expr, some_pat, pat_ref_count, is_wild_none) = match (
-                try_parse_pattern(cx, arm1.pat, expr_ctxt),
-                try_parse_pattern(cx, arm2.pat, expr_ctxt),
-            ) {
-                (Some(OptionPat::Wild), Some(OptionPat::Some { pattern, ref_count }))
-                    if is_none_expr(cx, arm1.body) =>
-                {
-                    (arm2.body, pattern, ref_count, true)
-                },
-                (Some(OptionPat::None), Some(OptionPat::Some { pattern, ref_count }))
-                    if is_none_expr(cx, arm1.body) =>
-                {
-                    (arm2.body, pattern, ref_count, false)
-                },
-                (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::Wild))
-                    if is_none_expr(cx, arm2.body) =>
-                {
-                    (arm1.body, pattern, ref_count, true)
-                },
-                (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::None))
-                    if is_none_expr(cx, arm2.body) =>
-                {
-                    (arm1.body, pattern, ref_count, false)
-                },
-                _ => return,
-            };
-
-            // Top level or patterns aren't allowed in closures.
-            if matches!(some_pat.kind, PatKind::Or(_)) {
-                return;
-            }
-
-            let some_expr = match get_some_expr(cx, some_expr, expr_ctxt) {
-                Some(expr) => expr,
-                None => return,
-            };
-
-            // These two lints will go back and forth with each other.
-            if cx.typeck_results().expr_ty(some_expr) == cx.tcx.types.unit
-                && !is_lint_allowed(cx, OPTION_MAP_UNIT_FN, expr.hir_id)
-            {
-                return;
-            }
-
-            // `map` won't perform any adjustments.
-            if !cx.typeck_results().expr_adjustments(some_expr).is_empty() {
-                return;
-            }
-
-            if !can_move_expr_to_closure(cx, some_expr) {
-                return;
-            }
-
-            // Determine which binding mode to use.
-            let explicit_ref = some_pat.contains_explicit_ref_binding();
-            let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then(|| ty_mutability));
-
-            let as_ref_str = match binding_ref {
-                Some(Mutability::Mut) => ".as_mut()",
-                Some(Mutability::Not) => ".as_ref()",
-                None => "",
-            };
-
-            let mut app = Applicability::MachineApplicable;
-
-            // Remove address-of expressions from the scrutinee. Either `as_ref` will be called, or
-            // it's being passed by value.
-            let scrutinee = peel_hir_expr_refs(scrutinee).0;
-            let (scrutinee_str, _) = snippet_with_context(cx, scrutinee.span, expr_ctxt, "..", &mut app);
-            let scrutinee_str =
-                if scrutinee.span.ctxt() == expr.span.ctxt() && scrutinee.precedence().order() < PREC_POSTFIX {
-                    format!("({})", scrutinee_str)
-                } else {
-                    scrutinee_str.into()
-                };
-
-            let body_str = if let PatKind::Binding(annotation, id, some_binding, None) = some_pat.kind {
-                match can_pass_as_func(cx, id, some_expr) {
-                    Some(func) if func.span.ctxt() == some_expr.span.ctxt() => {
-                        snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
-                    },
-                    _ => {
-                        if path_to_local_id(some_expr, id)
-                            && !is_lint_allowed(cx, MATCH_AS_REF, expr.hir_id)
-                            && binding_ref.is_some()
-                        {
-                            return;
-                        }
-
-                        // `ref` and `ref mut` annotations were handled earlier.
-                        let annotation = if matches!(annotation, BindingAnnotation::Mutable) {
-                            "mut "
-                        } else {
-                            ""
-                        };
-                        format!(
-                            "|{}{}| {}",
-                            annotation,
-                            some_binding,
-                            snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
-                        )
-                    },
-                }
-            } else if !is_wild_none && explicit_ref.is_none() {
-                // TODO: handle explicit reference annotations.
-                format!(
-                    "|{}| {}",
-                    snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0,
-                    snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
-                )
-            } else {
-                // Refutable bindings and mixed reference annotations can't be handled by `map`.
-                return;
-            };
-
-            span_lint_and_sugg(
+        if let ExprKind::Match(scrutinee, [then @ Arm { guard: None, .. }, r#else @ Arm { guard: None, .. }], _) =
+            expr.kind
+        {
+            manage_lint(
                 cx,
-                MANUAL_MAP,
-                expr.span,
-                "manual implementation of `Option::map`",
-                "try this",
-                if matches!(match_kind, MatchSource::IfLetDesugar { .. }) && is_else_clause(cx.tcx, expr) {
-                    format!("{{ {}{}.map({}) }}", scrutinee_str, as_ref_str, body_str)
-                } else {
-                    format!("{}{}.map({})", scrutinee_str, as_ref_str, body_str)
-                },
-                app,
+                expr,
+                (&then.pat.kind, then.body),
+                (&r#else.pat.kind, r#else.body),
+                scrutinee,
             );
         }
     }
 }
 
+fn manage_lint<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx Expr<'_>,
+    then: (&'tcx PatKind<'_>, &'tcx Expr<'_>),
+    r#else: (&'tcx PatKind<'_>, &'tcx Expr<'_>),
+    scrut: &'tcx Expr<'_>,
+) {
+    if in_external_macro(cx.sess(), expr.span) || in_constant(cx, expr.hir_id) {
+        return;
+    }
+
+    let (scrutinee_ty, ty_ref_count, ty_mutability) = peel_mid_ty_refs_is_mutable(cx.typeck_results().expr_ty(scrut));
+    if !(is_type_diagnostic_item(cx, scrutinee_ty, sym::option_type)
+        && is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::option_type))
+    {
+        return;
+    }
+
+    let (then_pat, then_expr) = then;
+    let (else_pat, else_expr) = r#else;
+
+    let expr_ctxt = expr.span.ctxt();
+    let (some_expr, some_pat, pat_ref_count, is_wild_none) = match (
+        try_parse_pattern(cx, then_pat, expr_ctxt),
+        try_parse_pattern(cx, else_pat, expr_ctxt),
+    ) {
+        (Some(OptionPat::Wild), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_expr) => {
+            (else_expr, pattern, ref_count, true)
+        },
+        (Some(OptionPat::None), Some(OptionPat::Some { pattern, ref_count })) if is_none_expr(cx, then_expr) => {
+            (else_expr, pattern, ref_count, false)
+        },
+        (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::Wild)) if is_none_expr(cx, else_expr) => {
+            (then_expr, pattern, ref_count, true)
+        },
+        (Some(OptionPat::Some { pattern, ref_count }), Some(OptionPat::None)) if is_none_expr(cx, else_expr) => {
+            (then_expr, pattern, ref_count, false)
+        },
+        _ => return,
+    };
+
+    // Top level or patterns aren't allowed in closures.
+    if matches!(some_pat.kind, PatKind::Or(_)) {
+        return;
+    }
+
+    let some_expr = match get_some_expr(cx, some_expr, expr_ctxt) {
+        Some(expr) => expr,
+        None => return,
+    };
+
+    if cx.typeck_results().expr_ty(some_expr) == cx.tcx.types.unit && !is_lint_allowed(cx, OPTION_MAP_UNIT_FN, expr.hir_id) {
+        return;
+    }
+
+    // `map` won't perform any adjustments.
+    if !cx.typeck_results().expr_adjustments(some_expr).is_empty() {
+        return;
+    }
+
+    if !can_move_expr_to_closure(cx, some_expr) {
+        return;
+    }
+
+    // Determine which binding mode to use.
+    let explicit_ref = some_pat.contains_explicit_ref_binding();
+    let binding_ref = explicit_ref.or_else(|| (ty_ref_count != pat_ref_count).then(|| ty_mutability));
+
+    let as_ref_str = match binding_ref {
+        Some(Mutability::Mut) => ".as_mut()",
+        Some(Mutability::Not) => ".as_ref()",
+        None => "",
+    };
+
+    let mut app = Applicability::MachineApplicable;
+
+    // Remove address-of expressions from the scrutinee. Either `as_ref` will be called, or
+    // it's being passed by value.
+    let scrutinee = peel_hir_expr_refs(scrut).0;
+    let (scrutinee_str, _) = snippet_with_context(cx, scrutinee.span, expr_ctxt, "..", &mut app);
+    let scrutinee_str = if scrutinee.span.ctxt() == expr.span.ctxt() && scrutinee.precedence().order() < PREC_POSTFIX {
+        format!("({})", scrutinee_str)
+    } else {
+        scrutinee_str.into()
+    };
+
+    let body_str = if let PatKind::Binding(annotation, id, some_binding, None) = some_pat.kind {
+        match can_pass_as_func(cx, id, some_expr) {
+            Some(func) if func.span.ctxt() == some_expr.span.ctxt() => {
+                snippet_with_applicability(cx, func.span, "..", &mut app).into_owned()
+            },
+            _ => {
+                if path_to_local_id(some_expr, id)
+                    && !is_lint_allowed(cx, MATCH_AS_REF, expr.hir_id)
+                    && binding_ref.is_some()
+                {
+                    return;
+                }
+
+                // `ref` and `ref mut` annotations were handled earlier.
+                let annotation = if matches!(annotation, BindingAnnotation::Mutable) {
+                    "mut "
+                } else {
+                    ""
+                };
+                format!(
+                    "|{}{}| {}",
+                    annotation,
+                    some_binding,
+                    snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
+                )
+            },
+        }
+    } else if !is_wild_none && explicit_ref.is_none() {
+        // TODO: handle explicit reference annotations.
+        format!(
+            "|{}| {}",
+            snippet_with_context(cx, some_pat.span, expr_ctxt, "..", &mut app).0,
+            snippet_with_context(cx, some_expr.span, expr_ctxt, "..", &mut app).0
+        )
+    } else {
+        // Refutable bindings and mixed reference annotations can't be handled by `map`.
+        return;
+    };
+
+    span_lint_and_sugg(
+        cx,
+        MANUAL_MAP,
+        expr.span,
+        "manual implementation of `Option::map`",
+        "try this",
+        if is_else_clause(cx.tcx, expr) {
+            format!("{{ {}{}.map({}) }}", scrutinee_str, as_ref_str, body_str)
+        } else {
+            format!("{}{}.map({})", scrutinee_str, as_ref_str, body_str)
+        },
+        app,
+    );
+}
+
 // Checks whether the expression could be passed as a function, or whether a closure is needed.
 // Returns the function to be passed to `map` if it exists.
 fn can_pass_as_func(cx: &LateContext<'tcx>, binding: HirId, expr: &'tcx Expr<'_>) -> Option<&'tcx Expr<'tcx>> {
     match expr.kind {
         ExprKind::Call(func, [arg])
-            if path_to_local_id(arg, binding) && cx.typeck_results().expr_adjustments(arg).is_empty() =>
+            if path_to_local_id (arg, binding) && cx.typeck_results().expr_adjustments(arg).is_empty() =>
         {
             Some(func)
         },
@@ -221,21 +235,28 @@ enum OptionPat<'a> {
 
 // Try to parse into a recognized `Option` pattern.
 // i.e. `_`, `None`, `Some(..)`, or a reference to any of those.
-fn try_parse_pattern(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ctxt: SyntaxContext) -> Option<OptionPat<'tcx>> {
-    fn f(cx: &LateContext<'tcx>, pat: &'tcx Pat<'_>, ref_count: usize, ctxt: SyntaxContext) -> Option<OptionPat<'tcx>> {
-        match pat.kind {
+fn try_parse_pattern(
+    cx: &LateContext<'tcx>,
+    pat_kind: &'tcx PatKind<'_>,
+    ctxt: SyntaxContext,
+) -> Option<OptionPat<'tcx>> {
+    fn f(
+        cx: &LateContext<'tcx>,
+        pat_kind: &'tcx PatKind<'_>,
+        ref_count: usize,
+        ctxt: SyntaxContext,
+    ) -> Option<OptionPat<'tcx>> {
+        match pat_kind {
             PatKind::Wild => Some(OptionPat::Wild),
-            PatKind::Ref(pat, _) => f(cx, pat, ref_count + 1, ctxt),
+            PatKind::Ref(ref_pat, _) => f(cx, &ref_pat.kind, ref_count + 1, ctxt),
             PatKind::Path(ref qpath) if is_lang_ctor(cx, qpath, OptionNone) => Some(OptionPat::None),
-            PatKind::TupleStruct(ref qpath, [pattern], _)
-                if is_lang_ctor(cx, qpath, OptionSome) && pat.span.ctxt() == ctxt =>
-            {
+            PatKind::TupleStruct(ref qpath, [pattern], _) if is_lang_ctor(cx, qpath, OptionSome) => {
                 Some(OptionPat::Some { pattern, ref_count })
             },
             _ => None,
         }
     }
-    f(cx, pat, 0, ctxt)
+    f(cx, pat_kind, 0, ctxt)
 }
 
 // Checks for an expression wrapped by the `Some` constructor. Returns the contained expression.
diff --git a/clippy_lints/src/manual_strip.rs b/clippy_lints/src/manual_strip.rs
index db12c377488..4e040508b6b 100644
--- a/clippy_lints/src/manual_strip.rs
+++ b/clippy_lints/src/manual_strip.rs
@@ -73,7 +73,7 @@ impl<'tcx> LateLintPass<'tcx> for ManualStrip {
         }
 
         if_chain! {
-            if let ExprKind::If(cond, then, _) = &expr.kind;
+            if let Some(higher::If { cond, then, .. }) = higher::If::hir(expr);
             if let ExprKind::MethodCall(_, _, [target_arg, pattern], _) = cond.kind;
             if let Some(method_def_id) = cx.typeck_results().type_dependent_def_id(cond.hir_id);
             if let ExprKind::Path(target_path) = &target_arg.kind;
@@ -212,7 +212,7 @@ fn find_stripping<'tcx>(
                 if is_ref_str(self.cx, ex);
                 let unref = peel_ref(ex);
                 if let ExprKind::Index(indexed, index) = &unref.kind;
-                if let Some(higher::Range { start, end, .. }) = higher::range(index);
+                if let Some(higher::Range { start, end, .. }) = higher::Range::hir(index);
                 if let ExprKind::Path(path) = &indexed.kind;
                 if self.cx.qpath_res(path, ex.hir_id) == self.target;
                 then {
diff --git a/clippy_lints/src/matches.rs b/clippy_lints/src/matches.rs
index 5360c02f905..a183d0c66e8 100644
--- a/clippy_lints/src/matches.rs
+++ b/clippy_lints/src/matches.rs
@@ -2,6 +2,7 @@ use clippy_utils::consts::{constant, miri_to_const, Constant};
 use clippy_utils::diagnostics::{
     multispan_sugg, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then,
 };
+use clippy_utils::higher;
 use clippy_utils::source::{expr_block, indent_of, snippet, snippet_block, snippet_opt, snippet_with_applicability};
 use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::{implements_trait, is_type_diagnostic_item, match_type, peel_mid_ty_refs};
@@ -12,8 +13,10 @@ use clippy_utils::{
     strip_pat_refs,
 };
 use clippy_utils::{paths, search_same, SpanlessEq, SpanlessHash};
+use core::array;
+use core::iter::{once, ExactSizeIterator};
 use if_chain::if_chain;
-use rustc_ast::ast::LitKind;
+use rustc_ast::ast::{Attribute, LitKind};
 use rustc_errors::Applicability;
 use rustc_hir::def::{CtorKind, DefKind, Res};
 use rustc_hir::LangItem::{OptionNone, OptionSome};
@@ -628,8 +631,11 @@ impl<'tcx> LateLintPass<'tcx> for Matches {
                 check_match_single_binding(cx, ex, arms, expr);
             }
         }
-        if let ExprKind::Match(ex, arms, _) = expr.kind {
-            check_match_ref_pats(cx, ex, arms, expr);
+        if let ExprKind::Match(ref ex, ref arms, _) = expr.kind {
+            check_match_ref_pats(cx, ex, arms.iter().map(|el| el.pat), expr);
+        }
+        if let Some(higher::IfLet { let_pat, let_expr, .. }) = higher::IfLet::hir(expr) {
+            check_match_ref_pats(cx, let_expr, once(let_pat), expr);
         }
     }
 
@@ -1179,39 +1185,40 @@ fn is_panic_block(block: &Block<'_>) -> bool {
     }
 }
 
-fn check_match_ref_pats(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
-    if has_only_ref_pats(arms) {
-        let mut suggs = Vec::with_capacity(arms.len() + 1);
-        let (title, msg) = if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, inner) = ex.kind {
-            let span = ex.span.source_callsite();
-            suggs.push((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
-            (
-                "you don't need to add `&` to both the expression and the patterns",
-                "try",
-            )
-        } else {
-            let span = ex.span.source_callsite();
-            suggs.push((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
-            (
-                "you don't need to add `&` to all patterns",
-                "instead of prefixing all patterns with `&`, you can dereference the expression",
-            )
-        };
-
-        suggs.extend(arms.iter().filter_map(|a| {
-            if let PatKind::Ref(refp, _) = a.pat.kind {
-                Some((a.pat.span, snippet(cx, refp.span, "..").to_string()))
-            } else {
-                None
-            }
-        }));
-
-        span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| {
-            if !expr.span.from_expansion() {
-                multispan_sugg(diag, msg, suggs);
-            }
-        });
+fn check_match_ref_pats<'a, 'b, I>(cx: &LateContext<'_>, ex: &Expr<'_>, pats: I, expr: &Expr<'_>)
+where
+    'b: 'a,
+    I: Clone + Iterator<Item = &'a Pat<'b>>,
+{
+    if !has_only_ref_pats(pats.clone()) {
+        return;
     }
+
+    let (first_sugg, msg, title);
+    let span = ex.span.source_callsite();
+    if let ExprKind::AddrOf(BorrowKind::Ref, Mutability::Not, ref inner) = ex.kind {
+        first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, inner, "..").to_string()));
+        msg = "try";
+        title = "you don't need to add `&` to both the expression and the patterns";
+    } else {
+        first_sugg = once((span, Sugg::hir_with_macro_callsite(cx, ex, "..").deref().to_string()));
+        msg = "instead of prefixing all patterns with `&`, you can dereference the expression";
+        title = "you don't need to add `&` to all patterns";
+    }
+
+    let remaining_suggs = pats.filter_map(|pat| {
+        if let PatKind::Ref(ref refp, _) = pat.kind {
+            Some((pat.span, snippet(cx, refp.span, "..").to_string()))
+        } else {
+            None
+        }
+    });
+
+    span_lint_and_then(cx, MATCH_REF_PATS, expr.span, title, |diag| {
+        if !expr.span.from_expansion() {
+            multispan_sugg(diag, msg, first_sugg.chain(remaining_suggs));
+        }
+    });
 }
 
 fn check_match_as_ref(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>) {
@@ -1286,46 +1293,99 @@ fn check_wild_in_or_pats(cx: &LateContext<'_>, arms: &[Arm<'_>]) {
 
 /// Lint a `match` or `if let .. { .. } else { .. }` expr that could be replaced by `matches!`
 fn check_match_like_matches<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> bool {
-    if let ExprKind::Match(ex, arms, ref match_source) = &expr.kind {
-        match match_source {
-            MatchSource::Normal => find_matches_sugg(cx, ex, arms, expr, false),
-            MatchSource::IfLetDesugar { .. } => find_matches_sugg(cx, ex, arms, expr, true),
-            _ => false,
-        }
-    } else {
-        false
+    if let Some(higher::IfLet {
+        let_pat,
+        let_expr,
+        if_then,
+        if_else: Some(if_else),
+    }) = higher::IfLet::hir(expr)
+    {
+        return find_matches_sugg(
+            cx,
+            let_expr,
+            array::IntoIter::new([(&[][..], Some(let_pat), if_then, None), (&[][..], None, if_else, None)]),
+            expr,
+            true,
+        );
     }
+
+    if let ExprKind::Match(scrut, arms, MatchSource::Normal) = expr.kind {
+        return find_matches_sugg(
+            cx,
+            scrut,
+            arms.iter().map(|arm| {
+                (
+                    cx.tcx.hir().attrs(arm.hir_id),
+                    Some(arm.pat),
+                    arm.body,
+                    arm.guard.as_ref(),
+                )
+            }),
+            expr,
+            false,
+        );
+    }
+
+    false
 }
 
-/// Lint a `match` or desugared `if let` for replacement by `matches!`
-fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr: &Expr<'_>, desugared: bool) -> bool {
+/// Lint a `match` or `if let` for replacement by `matches!`
+fn find_matches_sugg<'a, 'b, I>(
+    cx: &LateContext<'_>,
+    ex: &Expr<'_>,
+    mut iter: I,
+    expr: &Expr<'_>,
+    is_if_let: bool,
+) -> bool
+where
+    'b: 'a,
+    I: Clone
+        + DoubleEndedIterator
+        + ExactSizeIterator
+        + Iterator<
+            Item = (
+                &'a [Attribute],
+                Option<&'a Pat<'b>>,
+                &'a Expr<'b>,
+                Option<&'a Guard<'b>>,
+            ),
+        >,
+{
     if_chain! {
-        if arms.len() >= 2;
+        if iter.len() >= 2;
         if cx.typeck_results().expr_ty(expr).is_bool();
-        if let Some((b1_arm, b0_arms)) = arms.split_last();
-        if let Some(b0) = find_bool_lit(&b0_arms[0].body.kind, desugared);
-        if let Some(b1) = find_bool_lit(&b1_arm.body.kind, desugared);
-        if is_wild(b1_arm.pat);
+        if let Some((_, last_pat_opt, last_expr, _)) = iter.next_back();
+        let iter_without_last = iter.clone();
+        if let Some((first_attrs, _, first_expr, first_guard)) = iter.next();
+        if let Some(b0) = find_bool_lit(&first_expr.kind, is_if_let);
+        if let Some(b1) = find_bool_lit(&last_expr.kind, is_if_let);
         if b0 != b1;
-        let if_guard = &b0_arms[0].guard;
-        if if_guard.is_none() || b0_arms.len() == 1;
-        if cx.tcx.hir().attrs(b0_arms[0].hir_id).is_empty();
-        if b0_arms[1..].iter()
+        if first_guard.is_none() || iter.len() == 0;
+        if first_attrs.is_empty();
+        if iter
             .all(|arm| {
-                find_bool_lit(&arm.body.kind, desugared).map_or(false, |b| b == b0) &&
-                arm.guard.is_none() && cx.tcx.hir().attrs(arm.hir_id).is_empty()
+                find_bool_lit(&arm.2.kind, is_if_let).map_or(false, |b| b == b0) && arm.3.is_none() && arm.0.is_empty()
             });
         then {
+            if let Some(ref last_pat) = last_pat_opt {
+                if !is_wild(last_pat) {
+                    return false;
+                }
+            }
+
             // The suggestion may be incorrect, because some arms can have `cfg` attributes
             // evaluated into `false` and so such arms will be stripped before.
             let mut applicability = Applicability::MaybeIncorrect;
             let pat = {
                 use itertools::Itertools as _;
-                b0_arms.iter()
-                    .map(|arm| snippet_with_applicability(cx, arm.pat.span, "..", &mut applicability))
+                iter_without_last
+                    .filter_map(|arm| {
+                        let pat_span = arm.1?.span;
+                        Some(snippet_with_applicability(cx, pat_span, "..", &mut applicability))
+                    })
                     .join(" | ")
             };
-            let pat_and_guard = if let Some(Guard::If(g)) = if_guard {
+            let pat_and_guard = if let Some(Guard::If(g)) = first_guard {
                 format!("{} if {}", pat, snippet_with_applicability(cx, g.span, "..", &mut applicability))
             } else {
                 pat
@@ -1342,7 +1402,7 @@ fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr
                 cx,
                 MATCH_LIKE_MATCHES_MACRO,
                 expr.span,
-                &format!("{} expression looks like `matches!` macro", if desugared { "if let .. else" } else { "match" }),
+                &format!("{} expression looks like `matches!` macro", if is_if_let { "if let .. else" } else { "match" }),
                 "try this",
                 format!(
                     "{}matches!({}, {})",
@@ -1360,7 +1420,7 @@ fn find_matches_sugg(cx: &LateContext<'_>, ex: &Expr<'_>, arms: &[Arm<'_>], expr
 }
 
 /// Extract a `bool` or `{ bool }`
-fn find_bool_lit(ex: &ExprKind<'_>, desugared: bool) -> Option<bool> {
+fn find_bool_lit(ex: &ExprKind<'_>, is_if_let: bool) -> Option<bool> {
     match ex {
         ExprKind::Lit(Spanned {
             node: LitKind::Bool(b), ..
@@ -1372,7 +1432,7 @@ fn find_bool_lit(ex: &ExprKind<'_>, desugared: bool) -> Option<bool> {
                 ..
             },
             _,
-        ) if desugared => {
+        ) if is_if_let => {
             if let ExprKind::Lit(Spanned {
                 node: LitKind::Bool(b), ..
             }) = exp.kind
@@ -1644,19 +1704,26 @@ fn is_ref_some_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> Option<BindingAnnotat
     None
 }
 
-fn has_only_ref_pats(arms: &[Arm<'_>]) -> bool {
-    let mapped = arms
-        .iter()
-        .map(|a| {
-            match a.pat.kind {
-                PatKind::Ref(..) => Some(true), // &-patterns
-                PatKind::Wild => Some(false),   // an "anything" wildcard is also fine
-                _ => None,                      // any other pattern is not fine
+fn has_only_ref_pats<'a, 'b, I>(pats: I) -> bool
+where
+    'b: 'a,
+    I: Iterator<Item = &'a Pat<'b>>,
+{
+    let mut at_least_one_is_true = false;
+    for opt in pats.map(|pat| match pat.kind {
+        PatKind::Ref(..) => Some(true), // &-patterns
+        PatKind::Wild => Some(false),   // an "anything" wildcard is also fine
+        _ => None,                      // any other pattern is not fine
+    }) {
+        if let Some(inner) = opt {
+            if inner {
+                at_least_one_is_true = true;
             }
-        })
-        .collect::<Option<Vec<bool>>>();
-    // look for Some(v) where there's at least one true element
-    mapped.map_or(false, |v| v.iter().any(|el| *el))
+        } else {
+            return false;
+        }
+    }
+    at_least_one_is_true
 }
 
 pub fn overlapping<T>(ranges: &[SpannedRange<T>]) -> Option<(&SpannedRange<T>, &SpannedRange<T>)>
@@ -1745,6 +1812,7 @@ where
 mod redundant_pattern_match {
     use super::REDUNDANT_PATTERN_MATCHING;
     use clippy_utils::diagnostics::span_lint_and_then;
+    use clippy_utils::higher;
     use clippy_utils::source::{snippet, snippet_with_applicability};
     use clippy_utils::ty::{implements_trait, is_type_diagnostic_item, is_type_lang_item, match_type};
     use clippy_utils::{is_lang_ctor, is_qpath_def_path, is_trait_method, paths};
@@ -1755,22 +1823,27 @@ mod redundant_pattern_match {
     use rustc_hir::LangItem::{OptionNone, OptionSome, PollPending, PollReady, ResultErr, ResultOk};
     use rustc_hir::{
         intravisit::{walk_expr, ErasedMap, NestedVisitorMap, Visitor},
-        Arm, Block, Expr, ExprKind, LangItem, MatchSource, Node, PatKind, QPath,
+        Arm, Block, Expr, ExprKind, LangItem, MatchSource, Node, Pat, PatKind, QPath,
     };
     use rustc_lint::LateContext;
     use rustc_middle::ty::{self, subst::GenericArgKind, Ty};
     use rustc_span::sym;
 
     pub fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if let ExprKind::Match(op, arms, ref match_source) = &expr.kind {
-            match match_source {
-                MatchSource::Normal => find_sugg_for_match(cx, expr, op, arms),
-                MatchSource::IfLetDesugar { contains_else_clause } => {
-                    find_sugg_for_if_let(cx, expr, op, &arms[0], "if", *contains_else_clause);
-                },
-                MatchSource::WhileLetDesugar => find_sugg_for_if_let(cx, expr, op, &arms[0], "while", false),
-                _ => {},
-            }
+        if let Some(higher::IfLet {
+            if_else,
+            let_pat,
+            let_expr,
+            ..
+        }) = higher::IfLet::ast(cx, expr)
+        {
+            find_sugg_for_if_let(cx, expr, let_pat, let_expr, "if", if_else.is_some())
+        }
+        if let ExprKind::Match(op, arms, MatchSource::Normal) = &expr.kind {
+            find_sugg_for_match(cx, expr, op, arms)
+        }
+        if let Some(higher::WhileLet { let_pat, let_expr, .. }) = higher::WhileLet::hir(expr) {
+            find_sugg_for_if_let(cx, expr, let_pat, let_expr, "while", false)
         }
     }
 
@@ -1924,18 +1997,18 @@ mod redundant_pattern_match {
     fn find_sugg_for_if_let<'tcx>(
         cx: &LateContext<'tcx>,
         expr: &'tcx Expr<'_>,
-        op: &'tcx Expr<'tcx>,
-        arm: &Arm<'_>,
+        let_pat: &Pat<'_>,
+        let_expr: &'tcx Expr<'_>,
         keyword: &'static str,
         has_else: bool,
     ) {
         // also look inside refs
-        let mut kind = &arm.pat.kind;
+        let mut kind = &let_pat.kind;
         // if we have &None for example, peel it so we can detect "if let None = x"
         if let PatKind::Ref(inner, _mutability) = kind {
             kind = &inner.kind;
         }
-        let op_ty = cx.typeck_results().expr_ty(op);
+        let op_ty = cx.typeck_results().expr_ty(let_expr);
         // Determine which function should be used, and the type contained by the corresponding
         // variant.
         let (good_method, inner_ty) = match kind {
@@ -1989,38 +2062,38 @@ mod redundant_pattern_match {
         // scrutinee would be, so they have to be considered as well.
         // e.g. in `if let Some(x) = foo.lock().unwrap().baz.as_ref() { .. }` the lock will be held
         // for the duration if body.
-        let needs_drop = type_needs_ordered_drop(cx, check_ty) || temporaries_need_ordered_drop(cx, op);
+        let needs_drop = type_needs_ordered_drop(cx, check_ty) || temporaries_need_ordered_drop(cx, let_expr);
 
         // check that `while_let_on_iterator` lint does not trigger
         if_chain! {
             if keyword == "while";
-            if let ExprKind::MethodCall(method_path, _, _, _) = op.kind;
+            if let ExprKind::MethodCall(method_path, _, _, _) = let_expr.kind;
             if method_path.ident.name == sym::next;
-            if is_trait_method(cx, op, sym::Iterator);
+            if is_trait_method(cx, let_expr, sym::Iterator);
             then {
                 return;
             }
         }
 
-        let result_expr = match &op.kind {
+        let result_expr = match &let_expr.kind {
             ExprKind::AddrOf(_, _, borrowed) => borrowed,
-            _ => op,
+            _ => let_expr,
         };
         span_lint_and_then(
             cx,
             REDUNDANT_PATTERN_MATCHING,
-            arm.pat.span,
+            let_pat.span,
             &format!("redundant pattern matching, consider using `{}`", good_method),
             |diag| {
-                // while let ... = ... { ... }
+                // if/while let ... = ... { ... }
                 // ^^^^^^^^^^^^^^^^^^^^^^^^^^^
                 let expr_span = expr.span;
 
-                // while let ... = ... { ... }
+                // if/while let ... = ... { ... }
                 //                 ^^^
                 let op_span = result_expr.span.source_callsite();
 
-                // while let ... = ... { ... }
+                // if/while let ... = ... { ... }
                 // ^^^^^^^^^^^^^^^^^^^
                 let span = expr_span.until(op_span.shrink_to_hi());
 
diff --git a/clippy_lints/src/methods/iter_next_slice.rs b/clippy_lints/src/methods/iter_next_slice.rs
index a49851de38e..6954da67e32 100644
--- a/clippy_lints/src/methods/iter_next_slice.rs
+++ b/clippy_lints/src/methods/iter_next_slice.rs
@@ -18,7 +18,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, cal
     // since it is already covered by `&loops::ITER_NEXT_LOOP`
     let mut parent_expr_opt = get_parent_expr(cx, expr);
     while let Some(parent_expr) = parent_expr_opt {
-        if higher::for_loop(parent_expr).is_some() {
+        if higher::ForLoop::hir(parent_expr).is_some() {
             return;
         }
         parent_expr_opt = get_parent_expr(cx, parent_expr);
@@ -29,7 +29,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>, cal
         if_chain! {
             if let hir::ExprKind::Index(caller_var, index_expr) = &caller_expr.kind;
             if let Some(higher::Range { start: Some(start_expr), end: None, limits: ast::RangeLimits::HalfOpen })
-                = higher::range(index_expr);
+                = higher::Range::hir(index_expr);
             if let hir::ExprKind::Lit(ref start_lit) = &start_expr.kind;
             if let ast::LitKind::Int(start_idx, _) = start_lit.node;
             then {
diff --git a/clippy_lints/src/mut_mut.rs b/clippy_lints/src/mut_mut.rs
index d5032c5ba7f..610152a217f 100644
--- a/clippy_lints/src/mut_mut.rs
+++ b/clippy_lints/src/mut_mut.rs
@@ -53,7 +53,7 @@ impl<'a, 'tcx> intravisit::Visitor<'tcx> for MutVisitor<'a, 'tcx> {
             return;
         }
 
-        if let Some((_, arg, body, _)) = higher::for_loop(expr) {
+        if let Some(higher::ForLoop { arg, body, .. }) = higher::ForLoop::hir(expr) {
             // A `for` loop lowers to:
             // ```rust
             // match ::std::iter::Iterator::next(&mut iter) {
diff --git a/clippy_lints/src/needless_bool.rs b/clippy_lints/src/needless_bool.rs
index 36f2829a5b9..c9dd94400ef 100644
--- a/clippy_lints/src/needless_bool.rs
+++ b/clippy_lints/src/needless_bool.rs
@@ -3,6 +3,7 @@
 //! This lint is **warn** by default
 
 use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
+use clippy_utils::higher;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::sugg::Sugg;
 use clippy_utils::{is_else_clause, is_expn_of};
@@ -77,10 +78,15 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessBool {
         if e.span.from_expansion() {
             return;
         }
-        if let ExprKind::If(pred, then_block, Some(else_expr)) = e.kind {
+        if let Some(higher::If {
+            cond,
+            then,
+            r#else: Some(r#else),
+        }) = higher::If::hir(e)
+        {
             let reduce = |ret, not| {
                 let mut applicability = Applicability::MachineApplicable;
-                let snip = Sugg::hir_with_applicability(cx, pred, "<predicate>", &mut applicability);
+                let snip = Sugg::hir_with_applicability(cx, cond, "<predicate>", &mut applicability);
                 let mut snip = if not { !snip } else { snip };
 
                 if ret {
@@ -101,8 +107,8 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessBool {
                     applicability,
                 );
             };
-            if let ExprKind::Block(then_block, _) = then_block.kind {
-                match (fetch_bool_block(then_block), fetch_bool_expr(else_expr)) {
+            if let ExprKind::Block(then, _) = then.kind {
+                match (fetch_bool_block(then), fetch_bool_expr(r#else)) {
                     (RetBool(true), RetBool(true)) | (Bool(true), Bool(true)) => {
                         span_lint(
                             cx,
diff --git a/clippy_lints/src/non_expressive_names.rs b/clippy_lints/src/non_expressive_names.rs
index f6254aa715a..ac21eb5275f 100644
--- a/clippy_lints/src/non_expressive_names.rs
+++ b/clippy_lints/src/non_expressive_names.rs
@@ -1,7 +1,6 @@
 use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
 use rustc_ast::ast::{
-    Arm, AssocItem, AssocItemKind, Attribute, Block, FnDecl, FnKind, Item, ItemKind, Local, Pat,
-    PatKind,
+    Arm, AssocItem, AssocItemKind, Attribute, Block, FnDecl, FnKind, Item, ItemKind, Local, Pat, PatKind,
 };
 use rustc_ast::visit::{walk_block, walk_expr, walk_pat, Visitor};
 use rustc_lint::{EarlyContext, EarlyLintPass};
diff --git a/clippy_lints/src/option_if_let_else.rs b/clippy_lints/src/option_if_let_else.rs
index 7aef3a5f34c..d0b0bad5eb1 100644
--- a/clippy_lints/src/option_if_let_else.rs
+++ b/clippy_lints/src/option_if_let_else.rs
@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::sugg::Sugg;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::usage::contains_return_break_continue_macro;
@@ -6,7 +7,7 @@ use clippy_utils::{eager_or_lazy, in_macro, is_else_clause, is_lang_ctor};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::OptionSome;
-use rustc_hir::{Arm, BindingAnnotation, Block, Expr, ExprKind, MatchSource, Mutability, PatKind, UnOp};
+use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, Mutability, PatKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
@@ -84,20 +85,20 @@ struct OptionIfLetElseOccurence {
 
 /// Extracts the body of a given arm. If the arm contains only an expression,
 /// then it returns the expression. Otherwise, it returns the entire block
-fn extract_body_from_arm<'a>(arm: &'a Arm<'a>) -> Option<&'a Expr<'a>> {
+fn extract_body_from_expr<'a>(expr: &'a Expr<'a>) -> Option<&'a Expr<'a>> {
     if let ExprKind::Block(
         Block {
-            stmts: statements,
-            expr: Some(expr),
+            stmts: block_stmts,
+            expr: Some(block_expr),
             ..
         },
         _,
-    ) = &arm.body.kind
+    ) = expr.kind
     {
-        if let [] = statements {
-            Some(expr)
+        if let [] = block_stmts {
+            Some(block_expr)
         } else {
-            Some(arm.body)
+            Some(expr)
         }
     } else {
         None
@@ -121,37 +122,33 @@ fn format_option_in_sugg(cx: &LateContext<'_>, cond_expr: &Expr<'_>, as_ref: boo
 /// If this expression is the option if let/else construct we're detecting, then
 /// this function returns an `OptionIfLetElseOccurence` struct with details if
 /// this construct is found, or None if this construct is not found.
-fn detect_option_if_let_else<'tcx>(
-    cx: &'_ LateContext<'tcx>,
-    expr: &'_ Expr<'tcx>,
-) -> Option<OptionIfLetElseOccurence> {
+fn detect_option_if_let_else<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'tcx>) -> Option<OptionIfLetElseOccurence> {
     if_chain! {
         if !in_macro(expr.span); // Don't lint macros, because it behaves weirdly
-        if let ExprKind::Match(cond_expr, arms, MatchSource::IfLetDesugar{contains_else_clause: true}) = &expr.kind;
+        if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else: Some(if_else) }) = higher::IfLet::hir(expr);
         if !is_else_clause(cx.tcx, expr);
-        if arms.len() == 2;
-        if !is_result_ok(cx, cond_expr); // Don't lint on Result::ok because a different lint does it already
-        if let PatKind::TupleStruct(struct_qpath, [inner_pat], _) = &arms[0].pat.kind;
+        if !is_result_ok(cx, let_expr); // Don't lint on Result::ok because a different lint does it already
+        if let PatKind::TupleStruct(struct_qpath, [inner_pat], _) = &let_pat.kind;
         if is_lang_ctor(cx, struct_qpath, OptionSome);
         if let PatKind::Binding(bind_annotation, _, id, _) = &inner_pat.kind;
-        if !contains_return_break_continue_macro(arms[0].body);
-        if !contains_return_break_continue_macro(arms[1].body);
+        if !contains_return_break_continue_macro(if_then);
+        if !contains_return_break_continue_macro(if_else);
 
         then {
             let capture_mut = if bind_annotation == &BindingAnnotation::Mutable { "mut " } else { "" };
-            let some_body = extract_body_from_arm(&arms[0])?;
-            let none_body = extract_body_from_arm(&arms[1])?;
+            let some_body = extract_body_from_expr(if_then)?;
+            let none_body = extract_body_from_expr(if_else)?;
             let method_sugg = if eager_or_lazy::is_eagerness_candidate(cx, none_body) { "map_or" } else { "map_or_else" };
             let capture_name = id.name.to_ident_string();
-            let (as_ref, as_mut) = match &cond_expr.kind {
+            let (as_ref, as_mut) = match &let_expr.kind {
                 ExprKind::AddrOf(_, Mutability::Not, _) => (true, false),
                 ExprKind::AddrOf(_, Mutability::Mut, _) => (false, true),
                 _ => (bind_annotation == &BindingAnnotation::Ref, bind_annotation == &BindingAnnotation::RefMut),
             };
-            let cond_expr = match &cond_expr.kind {
+            let cond_expr = match let_expr.kind {
                 // Pointer dereferencing happens automatically, so we can omit it in the suggestion
                 ExprKind::Unary(UnOp::Deref, expr) | ExprKind::AddrOf(_, _, expr) => expr,
-                _ => cond_expr,
+                _ => let_expr,
             };
             Some(OptionIfLetElseOccurence {
                 option: format_option_in_sugg(cx, cond_expr, as_ref, as_mut),
diff --git a/clippy_lints/src/pattern_type_mismatch.rs b/clippy_lints/src/pattern_type_mismatch.rs
index 4534f6e2516..35cff4141a9 100644
--- a/clippy_lints/src/pattern_type_mismatch.rs
+++ b/clippy_lints/src/pattern_type_mismatch.rs
@@ -104,22 +104,25 @@ impl<'tcx> LateLintPass<'tcx> for PatternTypeMismatch {
     }
 
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if let ExprKind::Match(expr, arms, source) = expr.kind {
-            match source {
-                MatchSource::Normal | MatchSource::IfLetDesugar { .. } | MatchSource::WhileLetDesugar => {
-                    if let Some(expr_ty) = cx.typeck_results().node_type_opt(expr.hir_id) {
-                        'pattern_checks: for arm in arms {
-                            let pat = &arm.pat;
-                            if in_external_macro(cx.sess(), pat.span) {
-                                continue 'pattern_checks;
-                            }
-                            if apply_lint(cx, pat, expr_ty, DerefPossible::Possible) {
-                                break 'pattern_checks;
-                            }
-                        }
+        if let ExprKind::Match(scrutinee, arms, MatchSource::Normal) = expr.kind {
+            if let Some(expr_ty) = cx.typeck_results().node_type_opt(scrutinee.hir_id) {
+                'pattern_checks: for arm in arms {
+                    let pat = &arm.pat;
+                    if in_external_macro(cx.sess(), pat.span) {
+                        continue 'pattern_checks;
                     }
-                },
-                _ => (),
+                    if apply_lint(cx, pat, expr_ty, DerefPossible::Possible) {
+                        break 'pattern_checks;
+                    }
+                }
+            }
+        }
+        if let ExprKind::Let(let_pat, let_expr, _) = expr.kind {
+            if let Some(ref expr_ty) = cx.typeck_results().node_type_opt(let_expr.hir_id) {
+                if in_external_macro(cx.sess(), let_pat.span) {
+                    return;
+                }
+                apply_lint(cx, let_pat, expr_ty, DerefPossible::Possible);
             }
         }
     }
diff --git a/clippy_lints/src/question_mark.rs b/clippy_lints/src/question_mark.rs
index 0e682c692c7..91085c13ac4 100644
--- a/clippy_lints/src/question_mark.rs
+++ b/clippy_lints/src/question_mark.rs
@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::higher;
 use clippy_utils::is_lang_ctor;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::sugg::Sugg;
@@ -7,7 +8,7 @@ use clippy_utils::{eq_expr_value, path_to_local_id};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
-use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, MatchSource, PatKind, StmtKind};
+use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, PatKind, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
@@ -50,10 +51,10 @@ impl QuestionMark {
     /// If it matches, it will suggest to use the question mark operator instead
     fn check_is_none_and_early_return_none(cx: &LateContext<'_>, expr: &Expr<'_>) {
         if_chain! {
-            if let ExprKind::If(if_expr, body, else_) = &expr.kind;
-            if let ExprKind::MethodCall(segment, _, args, _) = &if_expr.kind;
+            if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr);
+            if let ExprKind::MethodCall(segment, _, args, _) = &cond.kind;
             if segment.ident.name == sym!(is_none);
-            if Self::expression_returns_none(cx, body);
+            if Self::expression_returns_none(cx, then);
             if let Some(subject) = args.get(0);
             if Self::is_option(cx, subject);
 
@@ -61,9 +62,9 @@ impl QuestionMark {
                 let mut applicability = Applicability::MachineApplicable;
                 let receiver_str = &Sugg::hir_with_applicability(cx, subject, "..", &mut applicability);
                 let mut replacement: Option<String> = None;
-                if let Some(else_) = else_ {
+                if let Some(else_inner) = r#else {
                     if_chain! {
-                        if let ExprKind::Block(block, None) = &else_.kind;
+                        if let ExprKind::Block(block, None) = &else_inner.kind;
                         if block.stmts.is_empty();
                         if let Some(block_expr) = &block.expr;
                         if eq_expr_value(cx, subject, block_expr);
@@ -96,25 +97,23 @@ impl QuestionMark {
 
     fn check_if_let_some_and_early_return_none(cx: &LateContext<'_>, expr: &Expr<'_>) {
         if_chain! {
-            if let ExprKind::Match(subject, arms, source) = &expr.kind;
-            if *source == MatchSource::IfLetDesugar { contains_else_clause: true };
-            if Self::is_option(cx, subject);
+            if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else: Some(if_else) }) = higher::IfLet::hir(expr);
+            if Self::is_option(cx, let_expr);
 
-            if let PatKind::TupleStruct(path1, fields, None) = &arms[0].pat.kind;
+            if let PatKind::TupleStruct(ref path1, fields, None) = let_pat.kind;
             if is_lang_ctor(cx, path1, OptionSome);
             if let PatKind::Binding(annot, bind_id, _, _) = fields[0].kind;
             let by_ref = matches!(annot, BindingAnnotation::Ref | BindingAnnotation::RefMut);
 
-            if let ExprKind::Block(block, None) = &arms[0].body.kind;
+            if let ExprKind::Block(ref block, None) = if_then.kind;
             if block.stmts.is_empty();
             if let Some(trailing_expr) = &block.expr;
             if path_to_local_id(trailing_expr, bind_id);
 
-            if let PatKind::Wild = arms[1].pat.kind;
-            if Self::expression_returns_none(cx, arms[1].body);
+            if Self::expression_returns_none(cx, if_else);
             then {
                 let mut applicability = Applicability::MachineApplicable;
-                let receiver_str = snippet_with_applicability(cx, subject.span, "..", &mut applicability);
+                let receiver_str = snippet_with_applicability(cx, let_expr.span, "..", &mut applicability);
                 let replacement = format!(
                     "{}{}?",
                     receiver_str,
diff --git a/clippy_lints/src/ranges.rs b/clippy_lints/src/ranges.rs
index 0179bd48ee3..0114a2f97a2 100644
--- a/clippy_lints/src/ranges.rs
+++ b/clippy_lints/src/ranges.rs
@@ -329,7 +329,7 @@ fn check_range_zip_with_len(cx: &LateContext<'_>, path: &PathSegment<'_>, args:
         if let ExprKind::MethodCall(iter_path, _, iter_args, _) = iter.kind;
         if iter_path.ident.name == sym::iter;
         // range expression in `.zip()` call: `0..x.len()`
-        if let Some(higher::Range { start: Some(start), end: Some(end), .. }) = higher::range(zip_arg);
+        if let Some(higher::Range { start: Some(start), end: Some(end), .. }) = higher::Range::hir(zip_arg);
         if is_integer_const(cx, start, 0);
         // `.len()` call
         if let ExprKind::MethodCall(len_path, _, len_args, _) = end.kind;
@@ -337,7 +337,7 @@ fn check_range_zip_with_len(cx: &LateContext<'_>, path: &PathSegment<'_>, args:
         // `.iter()` and `.len()` called on same `Path`
         if let ExprKind::Path(QPath::Resolved(_, iter_path)) = iter_args[0].kind;
         if let ExprKind::Path(QPath::Resolved(_, len_path)) = len_args[0].kind;
-        if SpanlessEq::new(cx).eq_path_segments(iter_path.segments, len_path.segments);
+        if SpanlessEq::new(cx).eq_path_segments(&iter_path.segments, &len_path.segments);
         then {
             span_lint(cx,
                 RANGE_ZIP_WITH_LEN,
@@ -356,7 +356,7 @@ fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
             start,
             end: Some(end),
             limits: RangeLimits::HalfOpen
-        }) = higher::range(expr);
+        }) = higher::Range::hir(expr);
         if let Some(y) = y_plus_one(cx, end);
         then {
             let span = if expr.span.from_expansion() {
@@ -401,7 +401,7 @@ fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
 // inclusive range minus one: `x..=(y-1)`
 fn check_inclusive_range_minus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
-        if let Some(higher::Range { start, end: Some(end), limits: RangeLimits::Closed }) = higher::range(expr);
+        if let Some(higher::Range { start, end: Some(end), limits: RangeLimits::Closed }) = higher::Range::hir(expr);
         if let Some(y) = y_minus_one(cx, end);
         then {
             span_lint_and_then(
@@ -438,8 +438,8 @@ fn check_reversed_empty_range(cx: &LateContext<'_>, expr: &Expr<'_>) {
     fn is_for_loop_arg(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
         let mut cur_expr = expr;
         while let Some(parent_expr) = get_parent_expr(cx, cur_expr) {
-            match higher::for_loop(parent_expr) {
-                Some((_, args, _, _)) if args.hir_id == expr.hir_id => return true,
+            match higher::ForLoop::hir(parent_expr) {
+                Some(higher::ForLoop { arg, .. }) if arg.hir_id == expr.hir_id => return true,
                 _ => cur_expr = parent_expr,
             }
         }
@@ -455,7 +455,7 @@ fn check_reversed_empty_range(cx: &LateContext<'_>, expr: &Expr<'_>) {
     }
 
     if_chain! {
-        if let Some(higher::Range { start: Some(start), end: Some(end), limits }) = higher::range(expr);
+        if let Some(higher::Range { start: Some(start), end: Some(end), limits }) = higher::Range::hir(expr);
         let ty = cx.typeck_results().expr_ty(start);
         if let ty::Int(_) | ty::Uint(_) = ty.kind();
         if let Some((start_idx, _)) = constant(cx, cx.typeck_results(), start);
diff --git a/clippy_lints/src/redundant_clone.rs b/clippy_lints/src/redundant_clone.rs
index eeeac35a6d5..530b3396abe 100644
--- a/clippy_lints/src/redundant_clone.rs
+++ b/clippy_lints/src/redundant_clone.rs
@@ -725,7 +725,7 @@ fn rvalue_locals(rvalue: &mir::Rvalue<'_>, mut visit: impl FnMut(mir::Local)) {
         BinaryOp(_, box (lhs, rhs)) | CheckedBinaryOp(_, box (lhs, rhs)) => {
             visit_op(lhs);
             visit_op(rhs);
-        }
+        },
         _ => (),
     }
 }
diff --git a/clippy_lints/src/returns.rs b/clippy_lints/src/returns.rs
index db4b1002ce1..e153288aa58 100644
--- a/clippy_lints/src/returns.rs
+++ b/clippy_lints/src/returns.rs
@@ -212,14 +212,6 @@ fn check_final_expr<'tcx>(
                     check_final_expr(cx, arm.body, Some(arm.body.span), RetReplacement::Block);
                 }
             },
-            MatchSource::IfLetDesugar {
-                contains_else_clause: true,
-            } => {
-                if let ExprKind::Block(ifblock, _) = arms[0].body.kind {
-                    check_block_return(cx, ifblock);
-                }
-                check_final_expr(cx, arms[1].body, None, RetReplacement::Empty);
-            },
             _ => (),
         },
         ExprKind::DropTemps(expr) => check_final_expr(cx, expr, None, RetReplacement::Empty),
diff --git a/clippy_lints/src/suspicious_operation_groupings.rs b/clippy_lints/src/suspicious_operation_groupings.rs
index a8e962d1af3..44d5ff0b63a 100644
--- a/clippy_lints/src/suspicious_operation_groupings.rs
+++ b/clippy_lints/src/suspicious_operation_groupings.rs
@@ -588,7 +588,7 @@ fn ident_difference_expr_with_base_location(
         | (ForLoop(_, _, _, _), ForLoop(_, _, _, _))
         | (While(_, _, _), While(_, _, _))
         | (If(_, _, _), If(_, _, _))
-        | (Let(_, _), Let(_, _))
+        | (Let(_, _, _), Let(_, _, _))
         | (Type(_, _), Type(_, _))
         | (Cast(_, _), Cast(_, _))
         | (Lit(_), Lit(_))
diff --git a/clippy_lints/src/unnested_or_patterns.rs b/clippy_lints/src/unnested_or_patterns.rs
index c8a231341b7..d6cf7190abb 100644
--- a/clippy_lints/src/unnested_or_patterns.rs
+++ b/clippy_lints/src/unnested_or_patterns.rs
@@ -67,7 +67,7 @@ impl EarlyLintPass for UnnestedOrPatterns {
 
     fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &ast::Expr) {
         if meets_msrv(self.msrv.as_ref(), &msrvs::OR_PATTERNS) {
-            if let ast::ExprKind::Let(pat, _) = &e.kind {
+            if let ast::ExprKind::Let(pat, _, _) = &e.kind {
                 lint_unnested_or_patterns(cx, pat);
             }
         }
diff --git a/clippy_lints/src/unwrap.rs b/clippy_lints/src/unwrap.rs
index c5b8acb9982..bffd9f3612b 100644
--- a/clippy_lints/src/unwrap.rs
+++ b/clippy_lints/src/unwrap.rs
@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::higher;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::{differing_macro_contexts, usage::is_potentially_mutated};
 use if_chain::if_chain;
@@ -160,11 +161,11 @@ impl<'a, 'tcx> Visitor<'tcx> for UnwrappableVariablesVisitor<'a, 'tcx> {
         if in_external_macro(self.cx.tcx.sess, expr.span) {
             return;
         }
-        if let ExprKind::If(cond, then, els) = &expr.kind {
+        if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr) {
             walk_expr(self, cond);
             self.visit_branch(cond, then, false);
-            if let Some(els) = els {
-                self.visit_branch(cond, els, true);
+            if let Some(else_inner) = r#else {
+                self.visit_branch(cond, else_inner, true);
             }
         } else {
             // find `unwrap[_err]()` calls:
diff --git a/clippy_lints/src/utils/author.rs b/clippy_lints/src/utils/author.rs
index 61fd375a989..f93d7782e25 100644
--- a/clippy_lints/src/utils/author.rs
+++ b/clippy_lints/src/utils/author.rs
@@ -208,6 +208,15 @@ impl<'tcx> Visitor<'tcx> for PrintVisitor {
         print!("    if let ExprKind::");
         let current = format!("{}.kind", self.current);
         match expr.kind {
+            ExprKind::Let(pat, expr, _) => {
+                let let_pat = self.next("pat");
+                let let_expr = self.next("expr");
+                println!("    Let(ref {}, ref {}, _) = {};", let_pat, let_expr, current);
+                self.current = let_expr;
+                self.visit_expr(expr);
+                self.current = let_pat;
+                self.visit_pat(pat);
+            },
             ExprKind::Box(inner) => {
                 let inner_pat = self.next("inner");
                 println!("Box(ref {}) = {};", inner_pat, current);
diff --git a/clippy_lints/src/utils/inspector.rs b/clippy_lints/src/utils/inspector.rs
index f7ddee12dcf..6bf216cec16 100644
--- a/clippy_lints/src/utils/inspector.rs
+++ b/clippy_lints/src/utils/inspector.rs
@@ -66,28 +66,6 @@ impl<'tcx> LateLintPass<'tcx> for DeepCodeInspector {
             hir::ImplItemKind::TyAlias(_) => println!("associated type"),
         }
     }
-    // fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx
-    // hir::TraitItem) {
-    // if !has_attr(&item.attrs) {
-    // return;
-    // }
-    // }
-    //
-    // fn check_variant(&mut self, cx: &LateContext<'tcx>, var: &'tcx
-    // hir::Variant, _:
-    // &hir::Generics) {
-    // if !has_attr(&var.node.attrs) {
-    // return;
-    // }
-    // }
-    //
-    // fn check_field_def(&mut self, cx: &LateContext<'tcx>, field: &'tcx
-    // hir::FieldDef) {
-    // if !has_attr(&field.attrs) {
-    // return;
-    // }
-    // }
-    //
 
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
         if !has_attr(cx.sess(), cx.tcx.hir().attrs(expr.hir_id)) {
@@ -127,13 +105,6 @@ impl<'tcx> LateLintPass<'tcx> for DeepCodeInspector {
             hir::StmtKind::Expr(e) | hir::StmtKind::Semi(e) => print_expr(cx, e, 0),
         }
     }
-    // fn check_foreign_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx
-    // hir::ForeignItem) {
-    // if !has_attr(&item.attrs) {
-    // return;
-    // }
-    // }
-    //
 }
 
 fn has_attr(sess: &Session, attrs: &[Attribute]) -> bool {
@@ -171,6 +142,10 @@ fn print_expr(cx: &LateContext<'_>, expr: &hir::Expr<'_>, indent: usize) {
                 print_expr(cx, arg, indent + 1);
             }
         },
+        hir::ExprKind::Let(ref pat, ref expr, _) => {
+            print_pat(cx, pat, indent + 1);
+            print_expr(cx, expr, indent + 1);
+        },
         hir::ExprKind::MethodCall(path, _, args, _) => {
             println!("{}MethodCall", ind);
             println!("{}method name: {}", ind, path.ident.name);
diff --git a/clippy_lints/src/vec.rs b/clippy_lints/src/vec.rs
index 32fa46f042c..95a45fa937f 100644
--- a/clippy_lints/src/vec.rs
+++ b/clippy_lints/src/vec.rs
@@ -49,8 +49,8 @@ impl<'tcx> LateLintPass<'tcx> for UselessVec {
         if_chain! {
             if let ty::Ref(_, ty, _) = cx.typeck_results().expr_ty_adjusted(expr).kind();
             if let ty::Slice(..) = ty.kind();
-            if let ExprKind::AddrOf(BorrowKind::Ref, mutability, addressee) = expr.kind;
-            if let Some(vec_args) = higher::vec_macro(cx, addressee);
+            if let ExprKind::AddrOf(BorrowKind::Ref, mutability, ref addressee) = expr.kind;
+            if let Some(vec_args) = higher::VecArgs::hir(cx, addressee);
             then {
                 self.check_vec_macro(cx, &vec_args, mutability, expr.span);
             }
@@ -58,8 +58,8 @@ impl<'tcx> LateLintPass<'tcx> for UselessVec {
 
         // search for `for _ in vec![…]`
         if_chain! {
-            if let Some((_, arg, _, _)) = higher::for_loop(expr);
-            if let Some(vec_args) = higher::vec_macro(cx, arg);
+            if let Some(higher::ForLoop { arg, .. }) = higher::ForLoop::hir(expr);
+            if let Some(vec_args) = higher::VecArgs::hir(cx, arg);
             if is_copy(cx, vec_type(cx.typeck_results().expr_ty_adjusted(arg)));
             then {
                 // report the error around the `vec!` not inside `<std macros>:`
diff --git a/clippy_utils/src/ast_utils.rs b/clippy_utils/src/ast_utils.rs
index 30c2260d15c..7ea07a15aea 100644
--- a/clippy_utils/src/ast_utils.rs
+++ b/clippy_utils/src/ast_utils.rs
@@ -158,7 +158,7 @@ pub fn eq_expr(l: &Expr, r: &Expr) -> bool {
         (Unary(lo, l), Unary(ro, r)) => mem::discriminant(lo) == mem::discriminant(ro) && eq_expr(l, r),
         (Lit(l), Lit(r)) => l.kind == r.kind,
         (Cast(l, lt), Cast(r, rt)) | (Type(l, lt), Type(r, rt)) => eq_expr(l, r) && eq_ty(lt, rt),
-        (Let(lp, le), Let(rp, re)) => eq_pat(lp, rp) && eq_expr(le, re),
+        (Let(lp, le, _), Let(rp, re, _)) => eq_pat(lp, rp) && eq_expr(le, re),
         (If(lc, lt, le), If(rc, rt, re)) => eq_expr(lc, rc) && eq_block(lt, rt) && eq_expr_opt(le, re),
         (While(lc, lt, ll), While(rc, rt, rl)) => eq_label(ll, rl) && eq_expr(lc, rc) && eq_block(lt, rt),
         (ForLoop(lp, li, lt, ll), ForLoop(rp, ri, rt, rl)) => {
diff --git a/clippy_utils/src/eager_or_lazy.rs b/clippy_utils/src/eager_or_lazy.rs
index 88b115a63d7..29e2559fc6d 100644
--- a/clippy_utils/src/eager_or_lazy.rs
+++ b/clippy_utils/src/eager_or_lazy.rs
@@ -60,6 +60,7 @@ fn identify_some_pure_patterns(expr: &Expr<'_>) -> bool {
         | ExprKind::MethodCall(..)
         | ExprKind::Binary(..)
         | ExprKind::Unary(..)
+        | ExprKind::Let(..)
         | ExprKind::Cast(..)
         | ExprKind::Type(..)
         | ExprKind::DropTemps(..)
diff --git a/clippy_utils/src/higher.rs b/clippy_utils/src/higher.rs
index 884180f0586..29b698e56e3 100644
--- a/clippy_utils/src/higher.rs
+++ b/clippy_utils/src/higher.rs
@@ -1,5 +1,4 @@
-//! This module contains functions for retrieve the original AST from lowered
-//! `hir`.
+//! This module contains functions that retrieves specifiec elements.
 
 #![deny(clippy::missing_docs_in_private_items)]
 
@@ -7,10 +6,149 @@ use crate::{is_expn_of, match_def_path, paths};
 use if_chain::if_chain;
 use rustc_ast::ast::{self, LitKind};
 use rustc_hir as hir;
-use rustc_hir::{BorrowKind, Expr, ExprKind, StmtKind, UnOp};
+use rustc_hir::{Block, BorrowKind, Expr, ExprKind, LoopSource, Node, Pat, StmtKind, UnOp};
 use rustc_lint::LateContext;
 use rustc_span::{sym, ExpnKind, Span, Symbol};
 
+/// The essential nodes of a desugared for loop as well as the entire span:
+/// `for pat in arg { body }` becomes `(pat, arg, body)`. Return `(pat, arg, body, span)`.
+pub struct ForLoop<'tcx> {
+    pub pat: &'tcx hir::Pat<'tcx>,
+    pub arg: &'tcx hir::Expr<'tcx>,
+    pub body: &'tcx hir::Expr<'tcx>,
+    pub span: Span,
+}
+
+impl<'tcx> ForLoop<'tcx> {
+    #[inline]
+    pub fn hir(expr: &Expr<'tcx>) -> Option<Self> {
+        if_chain! {
+            if let hir::ExprKind::Match(ref iterexpr, ref arms, hir::MatchSource::ForLoopDesugar) = expr.kind;
+            if let Some(first_arm) = arms.get(0);
+            if let hir::ExprKind::Call(_, ref iterargs) = iterexpr.kind;
+            if let Some(first_arg) = iterargs.get(0);
+            if iterargs.len() == 1 && arms.len() == 1 && first_arm.guard.is_none();
+            if let hir::ExprKind::Loop(ref block, ..) = first_arm.body.kind;
+            if block.expr.is_none();
+            if let [ _, _, ref let_stmt, ref body ] = *block.stmts;
+            if let hir::StmtKind::Local(ref local) = let_stmt.kind;
+            if let hir::StmtKind::Expr(ref body_expr) = body.kind;
+            then {
+                return Some(Self {
+                    pat: &*local.pat,
+                    arg: first_arg,
+                    body: body_expr,
+                    span: first_arm.span
+                });
+            }
+        }
+        None
+    }
+}
+
+pub struct If<'hir> {
+    pub cond: &'hir Expr<'hir>,
+    pub r#else: Option<&'hir Expr<'hir>>,
+    pub then: &'hir Expr<'hir>,
+}
+
+impl<'hir> If<'hir> {
+    #[inline]
+    pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
+        if let ExprKind::If(
+            Expr {
+                kind: ExprKind::DropTemps(cond),
+                ..
+            },
+            then,
+            r#else,
+        ) = expr.kind
+        {
+            Some(Self { cond, r#else, then })
+        } else {
+            None
+        }
+    }
+}
+
+pub struct IfLet<'hir> {
+    pub let_pat: &'hir Pat<'hir>,
+    pub let_expr: &'hir Expr<'hir>,
+    pub if_then: &'hir Expr<'hir>,
+    pub if_else: Option<&'hir Expr<'hir>>,
+}
+
+impl<'hir> IfLet<'hir> {
+    #[inline]
+    pub fn ast(cx: &LateContext<'tcx>, expr: &Expr<'hir>) -> Option<Self> {
+        let rslt = Self::hir(expr)?;
+        Self::is_not_within_while_context(cx, expr)?;
+        Some(rslt)
+    }
+
+    #[inline]
+    pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
+        if let ExprKind::If(
+            Expr {
+                kind: ExprKind::Let(let_pat, let_expr, _),
+                ..
+            },
+            if_then,
+            if_else,
+        ) = expr.kind
+        {
+            return Some(Self {
+                let_pat,
+                let_expr,
+                if_then,
+                if_else,
+            });
+        }
+        None
+    }
+
+    #[inline]
+    fn is_not_within_while_context(cx: &LateContext<'tcx>, expr: &Expr<'hir>) -> Option<()> {
+        let hir = cx.tcx.hir();
+        let parent = hir.get_parent_node(expr.hir_id);
+        let parent_parent = hir.get_parent_node(parent);
+        let parent_parent_node = hir.get(parent_parent);
+        if let Node::Expr(Expr {
+            kind: ExprKind::Loop(_, _, LoopSource::While, _),
+            ..
+        }) = parent_parent_node
+        {
+            return None;
+        }
+        Some(())
+    }
+}
+
+pub struct IfOrIfLet<'hir> {
+    pub cond: &'hir Expr<'hir>,
+    pub r#else: Option<&'hir Expr<'hir>>,
+    pub then: &'hir Expr<'hir>,
+}
+
+impl<'hir> IfOrIfLet<'hir> {
+    #[inline]
+    pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
+        if let ExprKind::If(cond, then, r#else) = expr.kind {
+            if let ExprKind::DropTemps(new_cond) = cond.kind {
+                return Some(Self {
+                    cond: new_cond,
+                    r#else,
+                    then,
+                });
+            }
+            if let ExprKind::Let(..) = cond.kind {
+                return Some(Self { cond, r#else, then });
+            }
+        }
+        None
+    }
+}
+
 /// Represent a range akin to `ast::ExprKind::Range`.
 #[derive(Debug, Copy, Clone)]
 pub struct Range<'a> {
@@ -22,127 +160,60 @@ pub struct Range<'a> {
     pub limits: ast::RangeLimits,
 }
 
-/// Higher a `hir` range to something similar to `ast::ExprKind::Range`.
-pub fn range<'a>(expr: &'a hir::Expr<'_>) -> Option<Range<'a>> {
-    /// Finds the field named `name` in the field. Always return `Some` for
-    /// convenience.
-    fn get_field<'c>(name: &str, fields: &'c [hir::ExprField<'_>]) -> Option<&'c hir::Expr<'c>> {
-        let expr = &fields.iter().find(|field| field.ident.name.as_str() == name)?.expr;
+impl<'a> Range<'a> {
+    /// Higher a `hir` range to something similar to `ast::ExprKind::Range`.
+    pub fn hir(expr: &'a hir::Expr<'_>) -> Option<Range<'a>> {
+        /// Finds the field named `name` in the field. Always return `Some` for
+        /// convenience.
+        fn get_field<'c>(name: &str, fields: &'c [hir::ExprField<'_>]) -> Option<&'c hir::Expr<'c>> {
+            let expr = &fields.iter().find(|field| field.ident.name.as_str() == name)?.expr;
+            Some(expr)
+        }
 
-        Some(expr)
-    }
-
-    match expr.kind {
-        hir::ExprKind::Call(path, args)
-            if matches!(
-                path.kind,
-                hir::ExprKind::Path(hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, _))
-            ) =>
-        {
-            Some(Range {
-                start: Some(&args[0]),
-                end: Some(&args[1]),
-                limits: ast::RangeLimits::Closed,
-            })
-        },
-        hir::ExprKind::Struct(path, fields, None) => match path {
-            hir::QPath::LangItem(hir::LangItem::RangeFull, _) => Some(Range {
-                start: None,
-                end: None,
-                limits: ast::RangeLimits::HalfOpen,
-            }),
-            hir::QPath::LangItem(hir::LangItem::RangeFrom, _) => Some(Range {
-                start: Some(get_field("start", fields)?),
-                end: None,
-                limits: ast::RangeLimits::HalfOpen,
-            }),
-            hir::QPath::LangItem(hir::LangItem::Range, _) => Some(Range {
-                start: Some(get_field("start", fields)?),
-                end: Some(get_field("end", fields)?),
-                limits: ast::RangeLimits::HalfOpen,
-            }),
-            hir::QPath::LangItem(hir::LangItem::RangeToInclusive, _) => Some(Range {
-                start: None,
-                end: Some(get_field("end", fields)?),
-                limits: ast::RangeLimits::Closed,
-            }),
-            hir::QPath::LangItem(hir::LangItem::RangeTo, _) => Some(Range {
-                start: None,
-                end: Some(get_field("end", fields)?),
-                limits: ast::RangeLimits::HalfOpen,
-            }),
+        match expr.kind {
+            hir::ExprKind::Call(ref path, ref args)
+                if matches!(
+                    path.kind,
+                    hir::ExprKind::Path(hir::QPath::LangItem(hir::LangItem::RangeInclusiveNew, _))
+                ) =>
+            {
+                Some(Range {
+                    start: Some(&args[0]),
+                    end: Some(&args[1]),
+                    limits: ast::RangeLimits::Closed,
+                })
+            },
+            hir::ExprKind::Struct(ref path, ref fields, None) => match path {
+                hir::QPath::LangItem(hir::LangItem::RangeFull, _) => Some(Range {
+                    start: None,
+                    end: None,
+                    limits: ast::RangeLimits::HalfOpen,
+                }),
+                hir::QPath::LangItem(hir::LangItem::RangeFrom, _) => Some(Range {
+                    start: Some(get_field("start", fields)?),
+                    end: None,
+                    limits: ast::RangeLimits::HalfOpen,
+                }),
+                hir::QPath::LangItem(hir::LangItem::Range, _) => Some(Range {
+                    start: Some(get_field("start", fields)?),
+                    end: Some(get_field("end", fields)?),
+                    limits: ast::RangeLimits::HalfOpen,
+                }),
+                hir::QPath::LangItem(hir::LangItem::RangeToInclusive, _) => Some(Range {
+                    start: None,
+                    end: Some(get_field("end", fields)?),
+                    limits: ast::RangeLimits::Closed,
+                }),
+                hir::QPath::LangItem(hir::LangItem::RangeTo, _) => Some(Range {
+                    start: None,
+                    end: Some(get_field("end", fields)?),
+                    limits: ast::RangeLimits::HalfOpen,
+                }),
+                _ => None,
+            },
             _ => None,
-        },
-        _ => None,
-    }
-}
-
-/// Checks if a `let` statement is from a `for` loop desugaring.
-pub fn is_from_for_desugar(local: &hir::Local<'_>) -> bool {
-    // This will detect plain for-loops without an actual variable binding:
-    //
-    // ```
-    // for x in some_vec {
-    //     // do stuff
-    // }
-    // ```
-    if_chain! {
-        if let Some(expr) = local.init;
-        if let hir::ExprKind::Match(_, _, hir::MatchSource::ForLoopDesugar) = expr.kind;
-        then {
-            return true;
         }
     }
-
-    // This detects a variable binding in for loop to avoid `let_unit_value`
-    // lint (see issue #1964).
-    //
-    // ```
-    // for _ in vec![()] {
-    //     // anything
-    // }
-    // ```
-    if let hir::LocalSource::ForLoopDesugar = local.source {
-        return true;
-    }
-
-    false
-}
-
-/// Recover the essential nodes of a desugared for loop as well as the entire span:
-/// `for pat in arg { body }` becomes `(pat, arg, body)`. Return `(pat, arg, body, span)`.
-pub fn for_loop<'tcx>(
-    expr: &'tcx hir::Expr<'tcx>,
-) -> Option<(&hir::Pat<'_>, &'tcx hir::Expr<'tcx>, &'tcx hir::Expr<'tcx>, Span)> {
-    if_chain! {
-        if let hir::ExprKind::Match(iterexpr, arms, hir::MatchSource::ForLoopDesugar) = expr.kind;
-        if let hir::ExprKind::Call(_, iterargs) = iterexpr.kind;
-        if iterargs.len() == 1 && arms.len() == 1 && arms[0].guard.is_none();
-        if let hir::ExprKind::Loop(block, ..) = arms[0].body.kind;
-        if block.expr.is_none();
-        if let [ _, _, ref let_stmt, ref body ] = *block.stmts;
-        if let hir::StmtKind::Local(local) = let_stmt.kind;
-        if let hir::StmtKind::Expr(expr) = body.kind;
-        then {
-            return Some((&*local.pat, &iterargs[0], expr, arms[0].span));
-        }
-    }
-    None
-}
-
-/// Recover the essential nodes of a desugared while loop:
-/// `while cond { body }` becomes `(cond, body)`.
-pub fn while_loop<'tcx>(expr: &'tcx hir::Expr<'tcx>) -> Option<(&'tcx hir::Expr<'tcx>, &'tcx hir::Expr<'tcx>)> {
-    if_chain! {
-        if let hir::ExprKind::Loop(hir::Block { expr: Some(expr), .. }, _, hir::LoopSource::While, _) = &expr.kind;
-        if let hir::ExprKind::Match(cond, arms, hir::MatchSource::WhileDesugar) = &expr.kind;
-        if let hir::ExprKind::DropTemps(cond) = &cond.kind;
-        if let [hir::Arm { body, .. }, ..] = &arms[..];
-        then {
-            return Some((cond, body));
-        }
-    }
-    None
 }
 
 /// Represent the pre-expansion arguments of a `vec!` invocation.
@@ -153,41 +224,157 @@ pub enum VecArgs<'a> {
     Vec(&'a [hir::Expr<'a>]),
 }
 
-/// Returns the arguments of the `vec!` macro if this expression was expanded
-/// from `vec!`.
-pub fn vec_macro<'e>(cx: &LateContext<'_>, expr: &'e hir::Expr<'_>) -> Option<VecArgs<'e>> {
-    if_chain! {
-        if let hir::ExprKind::Call(fun, args) = expr.kind;
-        if let hir::ExprKind::Path(ref qpath) = fun.kind;
-        if is_expn_of(fun.span, "vec").is_some();
-        if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
-        then {
-            return if match_def_path(cx, fun_def_id, &paths::VEC_FROM_ELEM) && args.len() == 2 {
-                // `vec![elem; size]` case
-                Some(VecArgs::Repeat(&args[0], &args[1]))
-            }
-            else if match_def_path(cx, fun_def_id, &paths::SLICE_INTO_VEC) && args.len() == 1 {
-                // `vec![a, b, c]` case
-                if_chain! {
-                    if let hir::ExprKind::Box(boxed) = args[0].kind;
-                    if let hir::ExprKind::Array(args) = boxed.kind;
-                    then {
-                        return Some(VecArgs::Vec(&*args));
-                    }
+impl<'a> VecArgs<'a> {
+    /// Returns the arguments of the `vec!` macro if this expression was expanded
+    /// from `vec!`.
+    pub fn hir(cx: &LateContext<'_>, expr: &'a hir::Expr<'_>) -> Option<VecArgs<'a>> {
+        if_chain! {
+            if let hir::ExprKind::Call(ref fun, ref args) = expr.kind;
+            if let hir::ExprKind::Path(ref qpath) = fun.kind;
+            if is_expn_of(fun.span, "vec").is_some();
+            if let Some(fun_def_id) = cx.qpath_res(qpath, fun.hir_id).opt_def_id();
+            then {
+                return if match_def_path(cx, fun_def_id, &paths::VEC_FROM_ELEM) && args.len() == 2 {
+                    // `vec![elem; size]` case
+                    Some(VecArgs::Repeat(&args[0], &args[1]))
                 }
+                else if match_def_path(cx, fun_def_id, &paths::SLICE_INTO_VEC) && args.len() == 1 {
+                    // `vec![a, b, c]` case
+                    if_chain! {
+                        if let hir::ExprKind::Box(ref boxed) = args[0].kind;
+                        if let hir::ExprKind::Array(ref args) = boxed.kind;
+                        then {
+                            return Some(VecArgs::Vec(&*args));
+                        }
+                    }
 
-                None
+                    None
+                }
+                else if match_def_path(cx, fun_def_id, &paths::VEC_NEW) && args.is_empty() {
+                    Some(VecArgs::Vec(&[]))
+                }
+                else {
+                    None
+                };
             }
-            else if match_def_path(cx, fun_def_id, &paths::VEC_NEW) && args.is_empty() {
-                Some(VecArgs::Vec(&[]))
-            }
-            else {
-                None
-            };
         }
-    }
 
-    None
+        None
+    }
+}
+
+pub struct While<'hir> {
+    pub if_cond: &'hir Expr<'hir>,
+    pub if_then: &'hir Expr<'hir>,
+    pub if_else: Option<&'hir Expr<'hir>>,
+}
+
+impl<'hir> While<'hir> {
+    #[inline]
+    pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
+        if let ExprKind::Loop(
+            Block {
+                expr:
+                    Some(Expr {
+                        kind:
+                            ExprKind::If(
+                                Expr {
+                                    kind: ExprKind::DropTemps(if_cond),
+                                    ..
+                                },
+                                if_then,
+                                if_else_ref,
+                            ),
+                        ..
+                    }),
+                ..
+            },
+            _,
+            LoopSource::While,
+            _,
+        ) = expr.kind
+        {
+            let if_else = *if_else_ref;
+            return Some(Self {
+                if_cond,
+                if_then,
+                if_else,
+            });
+        }
+        None
+    }
+}
+
+pub struct WhileLet<'hir> {
+    pub if_expr: &'hir Expr<'hir>,
+    pub let_pat: &'hir Pat<'hir>,
+    pub let_expr: &'hir Expr<'hir>,
+    pub if_then: &'hir Expr<'hir>,
+    pub if_else: Option<&'hir Expr<'hir>>,
+}
+
+impl<'hir> WhileLet<'hir> {
+    #[inline]
+    pub const fn hir(expr: &Expr<'hir>) -> Option<Self> {
+        if let ExprKind::Loop(
+            Block {
+                expr: Some(if_expr), ..
+            },
+            _,
+            LoopSource::While,
+            _,
+        ) = expr.kind
+        {
+            if let Expr {
+                kind:
+                    ExprKind::If(
+                        Expr {
+                            kind: ExprKind::Let(let_pat, let_expr, _),
+                            ..
+                        },
+                        if_then,
+                        if_else_ref,
+                    ),
+                ..
+            } = if_expr
+            {
+                let if_else = *if_else_ref;
+                return Some(Self {
+                    if_expr,
+                    let_pat,
+                    let_expr,
+                    if_then,
+                    if_else,
+                });
+            }
+        }
+        None
+    }
+}
+
+/// Converts a hir binary operator to the corresponding `ast` type.
+#[must_use]
+pub fn binop(op: hir::BinOpKind) -> ast::BinOpKind {
+    match op {
+        hir::BinOpKind::Eq => ast::BinOpKind::Eq,
+        hir::BinOpKind::Ge => ast::BinOpKind::Ge,
+        hir::BinOpKind::Gt => ast::BinOpKind::Gt,
+        hir::BinOpKind::Le => ast::BinOpKind::Le,
+        hir::BinOpKind::Lt => ast::BinOpKind::Lt,
+        hir::BinOpKind::Ne => ast::BinOpKind::Ne,
+        hir::BinOpKind::Or => ast::BinOpKind::Or,
+        hir::BinOpKind::Add => ast::BinOpKind::Add,
+        hir::BinOpKind::And => ast::BinOpKind::And,
+        hir::BinOpKind::BitAnd => ast::BinOpKind::BitAnd,
+        hir::BinOpKind::BitOr => ast::BinOpKind::BitOr,
+        hir::BinOpKind::BitXor => ast::BinOpKind::BitXor,
+        hir::BinOpKind::Div => ast::BinOpKind::Div,
+        hir::BinOpKind::Mul => ast::BinOpKind::Mul,
+        hir::BinOpKind::Rem => ast::BinOpKind::Rem,
+        hir::BinOpKind::Shl => ast::BinOpKind::Shl,
+        hir::BinOpKind::Shr => ast::BinOpKind::Shr,
+        hir::BinOpKind::Sub => ast::BinOpKind::Sub,
+    }
 }
 
 /// Extract args from an assert-like macro.
@@ -218,8 +405,8 @@ pub fn extract_assert_macro_args<'tcx>(e: &'tcx Expr<'tcx>) -> Option<Vec<&'tcx
             if let StmtKind::Semi(matchexpr) = block.stmts.get(0)?.kind {
                 // macros with unique arg: `{debug_}assert!` (e.g., `debug_assert!(some_condition)`)
                 if_chain! {
-                    if let ExprKind::If(clause, _, _)  = matchexpr.kind;
-                    if let ExprKind::Unary(UnOp::Not, condition) = clause.kind;
+                    if let Some(If { cond, .. }) = If::hir(matchexpr);
+                    if let ExprKind::Unary(UnOp::Not, condition) = cond.kind;
                     then {
                         return Some(vec![condition]);
                     }
@@ -345,3 +532,35 @@ impl FormatArgsExpn<'tcx> {
         }
     }
 }
+
+/// Checks if a `let` statement is from a `for` loop desugaring.
+pub fn is_from_for_desugar(local: &hir::Local<'_>) -> bool {
+    // This will detect plain for-loops without an actual variable binding:
+    //
+    // ```
+    // for x in some_vec {
+    //     // do stuff
+    // }
+    // ```
+    if_chain! {
+        if let Some(ref expr) = local.init;
+        if let hir::ExprKind::Match(_, _, hir::MatchSource::ForLoopDesugar) = expr.kind;
+        then {
+            return true;
+        }
+    }
+
+    // This detects a variable binding in for loop to avoid `let_unit_value`
+    // lint (see issue #1964).
+    //
+    // ```
+    // for _ in vec![()] {
+    //     // anything
+    // }
+    // ```
+    if let hir::LocalSource::ForLoopDesugar = local.source {
+        return true;
+    }
+
+    false
+}
diff --git a/clippy_utils/src/hir_utils.rs b/clippy_utils/src/hir_utils.rs
index fd70553e064..a44f2df2fd6 100644
--- a/clippy_utils/src/hir_utils.rs
+++ b/clippy_utils/src/hir_utils.rs
@@ -232,6 +232,9 @@ impl HirEqInterExpr<'_, '_, '_> {
             (&ExprKind::If(lc, lt, ref le), &ExprKind::If(rc, rt, ref re)) => {
                 self.eq_expr(lc, rc) && self.eq_expr(&**lt, &**rt) && both(le, re, |l, r| self.eq_expr(l, r))
             },
+            (&ExprKind::Let(ref lp, ref le, _), &ExprKind::Let(ref rp, ref re, _)) => {
+                self.eq_pat(lp, rp) && self.eq_expr(le, re)
+            },
             (&ExprKind::Lit(ref l), &ExprKind::Lit(ref r)) => l.node == r.node,
             (&ExprKind::Loop(lb, ref ll, ref lls, _), &ExprKind::Loop(rb, ref rl, ref rls, _)) => {
                 lls == rls && self.eq_block(lb, rb) && both(ll, rl, |l, r| l.ident.name == r.ident.name)
@@ -665,6 +668,10 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                     }
                 }
             },
+            ExprKind::Let(ref pat, ref expr, _) => {
+                self.hash_expr(expr);
+                self.hash_pat(pat);
+            },
             ExprKind::LlvmInlineAsm(..) | ExprKind::Err => {},
             ExprKind::Lit(ref l) => {
                 l.node.hash(&mut self.s);
diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index 1d59d6bfea1..82bfce8fe78 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -961,17 +961,6 @@ pub fn is_else_clause(tcx: TyCtxt<'_>, expr: &Expr<'_>) -> bool {
     let map = tcx.hir();
     let mut iter = map.parent_iter(expr.hir_id);
     match iter.next() {
-        Some((arm_id, Node::Arm(..))) => matches!(
-            iter.next(),
-            Some((
-                _,
-                Node::Expr(Expr {
-                    kind: ExprKind::Match(_, [_, else_arm], MatchSource::IfLetDesugar { .. }),
-                    ..
-                })
-            ))
-            if else_arm.hir_id == arm_id
-        ),
         Some((
             _,
             Node::Expr(Expr {
@@ -1370,15 +1359,15 @@ pub fn if_sequence<'tcx>(mut expr: &'tcx Expr<'tcx>) -> (Vec<&'tcx Expr<'tcx>>,
     let mut conds = Vec::new();
     let mut blocks: Vec<&Block<'_>> = Vec::new();
 
-    while let ExprKind::If(cond, then_expr, ref else_expr) = expr.kind {
-        conds.push(cond);
-        if let ExprKind::Block(block, _) = then_expr.kind {
+    while let Some(higher::IfOrIfLet { cond, then, r#else }) = higher::IfOrIfLet::hir(expr) {
+        conds.push(&*cond);
+        if let ExprKind::Block(ref block, _) = then.kind {
             blocks.push(block);
         } else {
             panic!("ExprKind::If node is not an ExprKind::Block");
         }
 
-        if let Some(else_expr) = *else_expr {
+        if let Some(ref else_expr) = r#else {
             expr = else_expr;
         } else {
             break;
diff --git a/clippy_utils/src/sugg.rs b/clippy_utils/src/sugg.rs
index 3bd75b10e90..3b494e1fc85 100644
--- a/clippy_utils/src/sugg.rs
+++ b/clippy_utils/src/sugg.rs
@@ -116,7 +116,7 @@ impl<'a> Sugg<'a> {
     /// Generate a suggestion for an expression with the given snippet. This is used by the `hir_*`
     /// function variants of `Sugg`, since these use different snippet functions.
     fn hir_from_snippet(expr: &hir::Expr<'_>, snippet: Cow<'a, str>) -> Self {
-        if let Some(range) = higher::range(expr) {
+        if let Some(range) = higher::Range::hir(expr) {
             let op = match range.limits {
                 ast::RangeLimits::HalfOpen => AssocOp::DotDot,
                 ast::RangeLimits::Closed => AssocOp::DotDotEq,
@@ -128,6 +128,7 @@ impl<'a> Sugg<'a> {
             hir::ExprKind::AddrOf(..)
             | hir::ExprKind::Box(..)
             | hir::ExprKind::If(..)
+            | hir::ExprKind::Let(..)
             | hir::ExprKind::Closure(..)
             | hir::ExprKind::Unary(..)
             | hir::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
diff --git a/tests/ui/author/if.stdout b/tests/ui/author/if.stdout
index 502b38545b8..1653de9a6f2 100644
--- a/tests/ui/author/if.stdout
+++ b/tests/ui/author/if.stdout
@@ -12,7 +12,8 @@ if_chain! {
     if let ExprKind::Lit(ref lit1) = right.kind;
     if let LitKind::Int(2, _) = lit1.node;
     if block.expr.is_none();
-    if let ExprKind::Lit(ref lit2) = cond.kind;
+    if let ExprKind::DropTemps(ref expr) = cond.kind;
+    if let ExprKind::Lit(ref lit2) = expr.kind;
     if let LitKind::Bool(true) = lit2.node;
     if let ExprKind::Block(ref block1) = then.kind;
     if block1.stmts.len() == 1;
diff --git a/tests/ui/collapsible_match.stderr b/tests/ui/collapsible_match.stderr
index 77978884900..f96917f5833 100644
--- a/tests/ui/collapsible_match.stderr
+++ b/tests/ui/collapsible_match.stderr
@@ -35,7 +35,7 @@ LL |         Ok(val) => match val {
 LL |             Some(n) => foo(n),
    |             ^^^^^^^ with this pattern
 
-error: unnecessary nested match
+error: unnecessary nested `if let` or `match`
   --> $DIR/collapsible_match.rs:25:9
    |
 LL | /         if let Some(n) = val {
@@ -51,7 +51,7 @@ LL |     if let Ok(val) = res_opt {
 LL |         if let Some(n) = val {
    |                ^^^^^^^ with this pattern
 
-error: unnecessary nested match
+error: unnecessary nested `if let` or `match`
   --> $DIR/collapsible_match.rs:32:9
    |
 LL | /         if let Some(n) = val {
@@ -87,7 +87,7 @@ LL |         match val {
 LL |             Some(n) => foo(n),
    |             ^^^^^^^ with this pattern
 
-error: unnecessary nested match
+error: unnecessary nested `if let` or `match`
   --> $DIR/collapsible_match.rs:52:13
    |
 LL | /             if let Some(n) = val {
@@ -121,7 +121,7 @@ LL |         match val {
 LL |             Some(n) => foo(n),
    |             ^^^^^^^ with this pattern
 
-error: unnecessary nested match
+error: unnecessary nested `if let` or `match`
   --> $DIR/collapsible_match.rs:72:13
    |
 LL | /             if let Some(n) = val {
diff --git a/tests/ui/crashes/ice-7410.rs b/tests/ui/crashes/ice-7410.rs
index aaa422d88c3..85fa4210321 100644
--- a/tests/ui/crashes/ice-7410.rs
+++ b/tests/ui/crashes/ice-7410.rs
@@ -4,6 +4,7 @@
 
 #![feature(lang_items, start, libc)]
 #![no_std]
+#![allow(clippy::if_same_then_else)]
 #![allow(clippy::redundant_pattern_matching)]
 
 use core::panic::PanicInfo;
diff --git a/tests/ui/crashes/issues_loop_mut_cond.rs b/tests/ui/crashes/issues_loop_mut_cond.rs
index bb238c81ebc..553c840f9b0 100644
--- a/tests/ui/crashes/issues_loop_mut_cond.rs
+++ b/tests/ui/crashes/issues_loop_mut_cond.rs
@@ -1,3 +1,4 @@
+#![allow(clippy::blocks_in_if_conditions)]
 #![allow(dead_code)]
 
 /// Issue: https://github.com/rust-lang/rust-clippy/issues/2596
diff --git a/tests/ui/infinite_loop.rs b/tests/ui/infinite_loop.rs
index 3d8fb8507e5..e518b2677b7 100644
--- a/tests/ui/infinite_loop.rs
+++ b/tests/ui/infinite_loop.rs
@@ -1,3 +1,5 @@
+#![allow(clippy::blocks_in_if_conditions)]
+
 fn fn_val(i: i32) -> i32 {
     unimplemented!()
 }
diff --git a/tests/ui/infinite_loop.stderr b/tests/ui/infinite_loop.stderr
index 1fcb29eff18..2736753c14b 100644
--- a/tests/ui/infinite_loop.stderr
+++ b/tests/ui/infinite_loop.stderr
@@ -1,5 +1,5 @@
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:21:11
+  --> $DIR/infinite_loop.rs:23:11
    |
 LL |     while y < 10 {
    |           ^^^^^^
@@ -8,7 +8,7 @@ LL |     while y < 10 {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:26:11
+  --> $DIR/infinite_loop.rs:28:11
    |
 LL |     while y < 10 && x < 3 {
    |           ^^^^^^^^^^^^^^^
@@ -16,7 +16,7 @@ LL |     while y < 10 && x < 3 {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:33:11
+  --> $DIR/infinite_loop.rs:35:11
    |
 LL |     while !cond {
    |           ^^^^^
@@ -24,7 +24,7 @@ LL |     while !cond {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:77:11
+  --> $DIR/infinite_loop.rs:79:11
    |
 LL |     while i < 3 {
    |           ^^^^^
@@ -32,7 +32,7 @@ LL |     while i < 3 {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:82:11
+  --> $DIR/infinite_loop.rs:84:11
    |
 LL |     while i < 3 && j > 0 {
    |           ^^^^^^^^^^^^^^
@@ -40,7 +40,7 @@ LL |     while i < 3 && j > 0 {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:86:11
+  --> $DIR/infinite_loop.rs:88:11
    |
 LL |     while i < 3 {
    |           ^^^^^
@@ -48,7 +48,7 @@ LL |     while i < 3 {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:101:11
+  --> $DIR/infinite_loop.rs:103:11
    |
 LL |     while i < 3 {
    |           ^^^^^
@@ -56,7 +56,7 @@ LL |     while i < 3 {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:106:11
+  --> $DIR/infinite_loop.rs:108:11
    |
 LL |     while i < 3 {
    |           ^^^^^
@@ -64,7 +64,7 @@ LL |     while i < 3 {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:172:15
+  --> $DIR/infinite_loop.rs:174:15
    |
 LL |         while self.count < n {
    |               ^^^^^^^^^^^^^^
@@ -72,7 +72,7 @@ LL |         while self.count < n {
    = note: this may lead to an infinite or to a never running loop
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:180:11
+  --> $DIR/infinite_loop.rs:182:11
    |
 LL |     while y < 10 {
    |           ^^^^^^
@@ -82,7 +82,7 @@ LL |     while y < 10 {
    = help: rewrite it as `if cond { loop { } }`
 
 error: variables in the condition are not mutated in the loop body
-  --> $DIR/infinite_loop.rs:187:11
+  --> $DIR/infinite_loop.rs:189:11
    |
 LL |     while y < 10 {
    |           ^^^^^^
diff --git a/tests/ui/match_overlapping_arm.rs b/tests/ui/match_overlapping_arm.rs
index 44c51e8112a..c84e31ea482 100644
--- a/tests/ui/match_overlapping_arm.rs
+++ b/tests/ui/match_overlapping_arm.rs
@@ -2,6 +2,7 @@
 #![feature(half_open_range_patterns)]
 #![warn(clippy::match_overlapping_arm)]
 #![allow(clippy::redundant_pattern_matching)]
+#![allow(clippy::if_same_then_else)]
 
 /// Tests for match_overlapping_arm
 
diff --git a/tests/ui/match_overlapping_arm.stderr b/tests/ui/match_overlapping_arm.stderr
index f25a66d634e..359fa49f51b 100644
--- a/tests/ui/match_overlapping_arm.stderr
+++ b/tests/ui/match_overlapping_arm.stderr
@@ -1,60 +1,60 @@
 error: some ranges overlap
-  --> $DIR/match_overlapping_arm.rs:12:9
+  --> $DIR/match_overlapping_arm.rs:13:9
    |
 LL |         0..=10 => println!("0 ... 10"),
    |         ^^^^^^
    |
    = note: `-D clippy::match-overlapping-arm` implied by `-D warnings`
 note: overlaps with this
-  --> $DIR/match_overlapping_arm.rs:13:9
+  --> $DIR/match_overlapping_arm.rs:14:9
    |
 LL |         0..=11 => println!("0 ... 11"),
    |         ^^^^^^
 
 error: some ranges overlap
-  --> $DIR/match_overlapping_arm.rs:18:9
+  --> $DIR/match_overlapping_arm.rs:19:9
    |
 LL |         0..=5 => println!("0 ... 5"),
    |         ^^^^^
    |
 note: overlaps with this
-  --> $DIR/match_overlapping_arm.rs:20:9
+  --> $DIR/match_overlapping_arm.rs:21:9
    |
 LL |         FOO..=11 => println!("0 ... 11"),
    |         ^^^^^^^^
 
 error: some ranges overlap
-  --> $DIR/match_overlapping_arm.rs:55:9
+  --> $DIR/match_overlapping_arm.rs:56:9
    |
 LL |         0..11 => println!("0 .. 11"),
    |         ^^^^^
    |
 note: overlaps with this
-  --> $DIR/match_overlapping_arm.rs:56:9
+  --> $DIR/match_overlapping_arm.rs:57:9
    |
 LL |         0..=11 => println!("0 ... 11"),
    |         ^^^^^^
 
 error: some ranges overlap
-  --> $DIR/match_overlapping_arm.rs:80:9
+  --> $DIR/match_overlapping_arm.rs:81:9
    |
 LL |         0..=10 => println!("0 ... 10"),
    |         ^^^^^^
    |
 note: overlaps with this
-  --> $DIR/match_overlapping_arm.rs:79:9
+  --> $DIR/match_overlapping_arm.rs:80:9
    |
 LL |         5..14 => println!("5 .. 14"),
    |         ^^^^^
 
 error: some ranges overlap
-  --> $DIR/match_overlapping_arm.rs:85:9
+  --> $DIR/match_overlapping_arm.rs:86:9
    |
 LL |         0..7 => println!("0 .. 7"),
    |         ^^^^
    |
 note: overlaps with this
-  --> $DIR/match_overlapping_arm.rs:86:9
+  --> $DIR/match_overlapping_arm.rs:87:9
    |
 LL |         0..=10 => println!("0 ... 10"),
    |         ^^^^^^