Merge commit '4f142aa1058f14f153f8bfd2d82f04ddb9982388' into clippyup

14 files changed, 1808 insertions, 1622 deletions

diff --git a/clippy_lints/src/utils/author.rs b/clippy_lints/src/utils/author.rs
index e069de8cb5c..0c052d86eda 100644
--- a/clippy_lints/src/utils/author.rs
+++ b/clippy_lints/src/utils/author.rs
@@ -12,6 +12,7 @@ use rustc_hir::{
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::{Ident, Symbol};
+use std::cell::Cell;
 use std::fmt::{Display, Formatter, Write as _};
 
 declare_clippy_lint! {
@@ -37,15 +38,13 @@ declare_clippy_lint! {
     ///
     /// ```rust,ignore
     /// // ./tests/ui/new_lint.stdout
-    /// if_chain! {
-    ///     if let ExprKind::If(ref cond, ref then, None) = item.kind,
-    ///     if let ExprKind::Binary(BinOp::Eq, ref left, ref right) = cond.kind,
-    ///     if let ExprKind::Path(ref path) = left.kind,
-    ///     if let ExprKind::Lit(ref lit) = right.kind,
-    ///     if let LitKind::Int(42, _) = lit.node,
-    ///     then {
-    ///         // report your lint here
-    ///     }
+    /// if ExprKind::If(ref cond, ref then, None) = item.kind
+    ///     && let ExprKind::Binary(BinOp::Eq, ref left, ref right) = cond.kind
+    ///     && let ExprKind::Path(ref path) = left.kind
+    ///     && let ExprKind::Lit(ref lit) = right.kind
+    ///     && let LitKind::Int(42, _) = lit.node
+    /// {
+    ///     // report your lint here
     /// }
     /// ```
     pub LINT_AUTHOR,
@@ -91,15 +90,16 @@ macro_rules! field {
     };
 }
 
-fn prelude() {
-    println!("if_chain! {{");
-}
-
-fn done() {
-    println!("    then {{");
-    println!("        // report your lint here");
-    println!("    }}");
-    println!("}}");
+/// Print a condition of a let chain, `chain!(self, "let Some(x) = y")` will print
+/// `if let Some(x) = y` on the first call and `    && let Some(x) = y` thereafter
+macro_rules! chain {
+    ($self:ident, $($t:tt)*) => {
+        if $self.first.take() {
+            println!("if {}", format_args!($($t)*));
+        } else {
+            println!("    && {}", format_args!($($t)*));
+        }
+    }
 }
 
 impl<'tcx> LateLintPass<'tcx> for Author {
@@ -149,9 +149,10 @@ fn check_item(cx: &LateContext<'_>, hir_id: HirId) {
 
 fn check_node(cx: &LateContext<'_>, hir_id: HirId, f: impl Fn(&PrintVisitor<'_, '_>)) {
     if has_attr(cx, hir_id) {
-        prelude();
         f(&PrintVisitor::new(cx));
-        done();
+        println!("{{");
+        println!("    // report your lint here");
+        println!("}}");
     }
 }
 
@@ -195,7 +196,9 @@ struct PrintVisitor<'a, 'tcx> {
     cx: &'a LateContext<'tcx>,
     /// Fields are the current index that needs to be appended to pattern
     /// binding names
-    ids: std::cell::Cell<FxHashMap<&'static str, u32>>,
+    ids: Cell<FxHashMap<&'static str, u32>>,
+    /// Currently at the first condition in the if chain
+    first: Cell<bool>,
 }
 
 #[allow(clippy::unused_self)]
@@ -203,7 +206,8 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
     fn new(cx: &'a LateContext<'tcx>) -> Self {
         Self {
             cx,
-            ids: std::cell::Cell::default(),
+            ids: Cell::default(),
+            first: Cell::new(true),
         }
     }
 
@@ -226,10 +230,10 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
 
     fn option<T: Copy>(&self, option: &Binding<Option<T>>, name: &'static str, f: impl Fn(&Binding<T>)) {
         match option.value {
-            None => out!("if {option}.is_none();"),
+            None => chain!(self, "{option}.is_none()"),
             Some(value) => {
                 let value = &self.bind(name, value);
-                out!("if let Some({value}) = {option};");
+                chain!(self, "let Some({value}) = {option}");
                 f(value);
             },
         }
@@ -237,9 +241,9 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
 
     fn slice<T>(&self, slice: &Binding<&[T]>, f: impl Fn(&Binding<&T>)) {
         if slice.value.is_empty() {
-            out!("if {slice}.is_empty();");
+            chain!(self, "{slice}.is_empty()");
         } else {
-            out!("if {slice}.len() == {};", slice.value.len());
+            chain!(self, "{slice}.len() == {}", slice.value.len());
             for (i, value) in slice.value.iter().enumerate() {
                 let name = format!("{slice}[{i}]");
                 f(&Binding { name, value });
@@ -254,23 +258,23 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
     }
 
     fn ident(&self, ident: &Binding<Ident>) {
-        out!("if {ident}.as_str() == {:?};", ident.value.as_str());
+        chain!(self, "{ident}.as_str() == {:?}", ident.value.as_str());
     }
 
     fn symbol(&self, symbol: &Binding<Symbol>) {
-        out!("if {symbol}.as_str() == {:?};", symbol.value.as_str());
+        chain!(self, "{symbol}.as_str() == {:?}", symbol.value.as_str());
     }
 
     fn qpath(&self, qpath: &Binding<&QPath<'_>>) {
         if let QPath::LangItem(lang_item, ..) = *qpath.value {
-            out!("if matches!({qpath}, QPath::LangItem(LangItem::{lang_item:?}, _));");
+            chain!(self, "matches!({qpath}, QPath::LangItem(LangItem::{lang_item:?}, _))");
         } else {
-            out!("if match_qpath({qpath}, &[{}]);", path_to_string(qpath.value));
+            chain!(self, "match_qpath({qpath}, &[{}])", path_to_string(qpath.value));
         }
     }
 
     fn lit(&self, lit: &Binding<&Lit>) {
-        let kind = |kind| out!("if let LitKind::{kind} = {lit}.node;");
+        let kind = |kind| chain!(self, "let LitKind::{kind} = {lit}.node");
         macro_rules! kind {
             ($($t:tt)*) => (kind(format_args!($($t)*)));
         }
@@ -298,7 +302,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
             LitKind::ByteStr(ref vec) => {
                 bind!(self, vec);
                 kind!("ByteStr(ref {vec})");
-                out!("if let [{:?}] = **{vec};", vec.value);
+                chain!(self, "let [{:?}] = **{vec}", vec.value);
             },
             LitKind::Str(s, _) => {
                 bind!(self, s);
@@ -311,15 +315,15 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
     fn arm(&self, arm: &Binding<&hir::Arm<'_>>) {
         self.pat(field!(arm.pat));
         match arm.value.guard {
-            None => out!("if {arm}.guard.is_none();"),
+            None => chain!(self, "{arm}.guard.is_none()"),
             Some(hir::Guard::If(expr)) => {
                 bind!(self, expr);
-                out!("if let Some(Guard::If({expr})) = {arm}.guard;");
+                chain!(self, "let Some(Guard::If({expr})) = {arm}.guard");
                 self.expr(expr);
             },
             Some(hir::Guard::IfLet(let_expr)) => {
                 bind!(self, let_expr);
-                out!("if let Some(Guard::IfLet({let_expr}) = {arm}.guard;");
+                chain!(self, "let Some(Guard::IfLet({let_expr}) = {arm}.guard");
                 self.pat(field!(let_expr.pat));
                 self.expr(field!(let_expr.init));
             },
@@ -331,9 +335,10 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
     fn expr(&self, expr: &Binding<&hir::Expr<'_>>) {
         if let Some(higher::While { condition, body }) = higher::While::hir(expr.value) {
             bind!(self, condition, body);
-            out!(
-                "if let Some(higher::While {{ condition: {condition}, body: {body} }}) \
-                = higher::While::hir({expr});"
+            chain!(
+                self,
+                "let Some(higher::While {{ condition: {condition}, body: {body} }}) \
+                = higher::While::hir({expr})"
             );
             self.expr(condition);
             self.expr(body);
@@ -347,9 +352,10 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
         }) = higher::WhileLet::hir(expr.value)
         {
             bind!(self, let_pat, let_expr, if_then);
-            out!(
-                "if let Some(higher::WhileLet {{ let_pat: {let_pat}, let_expr: {let_expr}, if_then: {if_then} }}) \
-                = higher::WhileLet::hir({expr});"
+            chain!(
+                self,
+                "let Some(higher::WhileLet {{ let_pat: {let_pat}, let_expr: {let_expr}, if_then: {if_then} }}) \
+                = higher::WhileLet::hir({expr})"
             );
             self.pat(let_pat);
             self.expr(let_expr);
@@ -359,9 +365,10 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
 
         if let Some(higher::ForLoop { pat, arg, body, .. }) = higher::ForLoop::hir(expr.value) {
             bind!(self, pat, arg, body);
-            out!(
-                "if let Some(higher::ForLoop {{ pat: {pat}, arg: {arg}, body: {body}, .. }}) \
-                = higher::ForLoop::hir({expr});"
+            chain!(
+                self,
+                "let Some(higher::ForLoop {{ pat: {pat}, arg: {arg}, body: {body}, .. }}) \
+                = higher::ForLoop::hir({expr})"
             );
             self.pat(pat);
             self.expr(arg);
@@ -369,7 +376,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
             return;
         }
 
-        let kind = |kind| out!("if let ExprKind::{kind} = {expr}.kind;");
+        let kind = |kind| chain!(self, "let ExprKind::{kind} = {expr}.kind");
         macro_rules! kind {
             ($($t:tt)*) => (kind(format_args!($($t)*)));
         }
@@ -383,7 +390,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 // if it's a path
                 if let Some(TyKind::Path(ref qpath)) = let_expr.value.ty.as_ref().map(|ty| &ty.kind) {
                     bind!(self, qpath);
-                    out!("if let TyKind::Path(ref {qpath}) = {let_expr}.ty.kind;");
+                    chain!(self, "let TyKind::Path(ref {qpath}) = {let_expr}.ty.kind");
                     self.qpath(qpath);
                 }
                 self.expr(field!(let_expr.init));
@@ -419,7 +426,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
             ExprKind::Binary(op, left, right) => {
                 bind!(self, op, left, right);
                 kind!("Binary({op}, {left}, {right})");
-                out!("if BinOpKind::{:?} == {op}.node;", op.value.node);
+                chain!(self, "BinOpKind::{:?} == {op}.node", op.value.node);
                 self.expr(left);
                 self.expr(right);
             },
@@ -438,7 +445,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 kind!("Cast({expr}, {cast_ty})");
                 if let TyKind::Path(ref qpath) = cast_ty.value.kind {
                     bind!(self, qpath);
-                    out!("if let TyKind::Path(ref {qpath}) = {cast_ty}.kind;");
+                    chain!(self, "let TyKind::Path(ref {qpath}) = {cast_ty}.kind");
                     self.qpath(qpath);
                 }
                 self.expr(expr);
@@ -485,7 +492,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
 
                 bind!(self, fn_decl, body_id);
                 kind!("Closure(CaptureBy::{capture_clause:?}, {fn_decl}, {body_id}, _, {movability})");
-                out!("if let {ret_ty} = {fn_decl}.output;");
+                chain!(self, "let {ret_ty} = {fn_decl}.output");
                 self.body(body_id);
             },
             ExprKind::Yield(sub, source) => {
@@ -509,7 +516,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
             ExprKind::AssignOp(op, target, value) => {
                 bind!(self, op, target, value);
                 kind!("AssignOp({op}, {target}, {value})");
-                out!("if BinOpKind::{:?} == {op}.node;", op.value.node);
+                chain!(self, "BinOpKind::{:?} == {op}.node", op.value.node);
                 self.expr(target);
                 self.expr(value);
             },
@@ -573,10 +580,10 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
                 kind!("Repeat({value}, {length})");
                 self.expr(value);
                 match length.value {
-                    ArrayLen::Infer(..) => out!("if let ArrayLen::Infer(..) = length;"),
+                    ArrayLen::Infer(..) => chain!(self, "let ArrayLen::Infer(..) = length"),
                     ArrayLen::Body(anon_const) => {
                         bind!(self, anon_const);
-                        out!("if let ArrayLen::Body({anon_const}) = {length};");
+                        chain!(self, "let ArrayLen::Body({anon_const}) = {length}");
                         self.body(field!(anon_const.body));
                     },
                 }
@@ -600,12 +607,12 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
     fn body(&self, body_id: &Binding<hir::BodyId>) {
         let expr = self.cx.tcx.hir().body(body_id.value).value;
         bind!(self, expr);
-        out!("let {expr} = &cx.tcx.hir().body({body_id}).value;");
+        chain!(self, "{expr} = &cx.tcx.hir().body({body_id}).value");
         self.expr(expr);
     }
 
     fn pat(&self, pat: &Binding<&hir::Pat<'_>>) {
-        let kind = |kind| out!("if let PatKind::{kind} = {pat}.kind;");
+        let kind = |kind| chain!(self, "let PatKind::{kind} = {pat}.kind");
         macro_rules! kind {
             ($($t:tt)*) => (kind(format_args!($($t)*)));
         }
@@ -688,7 +695,7 @@ impl<'a, 'tcx> PrintVisitor<'a, 'tcx> {
     }
 
     fn stmt(&self, stmt: &Binding<&hir::Stmt<'_>>) {
-        let kind = |kind| out!("if let StmtKind::{kind} = {stmt}.kind;");
+        let kind = |kind| chain!(self, "let StmtKind::{kind} = {stmt}.kind");
         macro_rules! kind {
             ($($t:tt)*) => (kind(format_args!($($t)*)));
         }
diff --git a/clippy_lints/src/utils/internal_lints.rs b/clippy_lints/src/utils/internal_lints.rs
index 85bcbc7ad23..71f6c9909dd 100644
--- a/clippy_lints/src/utils/internal_lints.rs
+++ b/clippy_lints/src/utils/internal_lints.rs
@@ -1,1566 +1,12 @@
-use crate::utils::internal_lints::metadata_collector::is_deprecated_lint;
-use clippy_utils::consts::{constant_simple, Constant};
-use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
-use clippy_utils::macros::root_macro_call_first_node;
-use clippy_utils::source::{snippet, snippet_with_applicability};
-use clippy_utils::ty::match_type;
-use clippy_utils::{
-    def_path_res, higher, is_else_clause, is_expn_of, is_expr_path_def_path, is_lint_allowed, match_any_def_paths,
-    match_def_path, method_calls, paths, peel_blocks_with_stmt, peel_hir_expr_refs, SpanlessEq,
-};
-use if_chain::if_chain;
-use rustc_ast as ast;
-use rustc_ast::ast::{Crate, ItemKind, LitKind, ModKind, NodeId};
-use rustc_ast::visit::FnKind;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_errors::Applicability;
-use rustc_hir as hir;
-use rustc_hir::def::{DefKind, Namespace, Res};
-use rustc_hir::def_id::DefId;
-use rustc_hir::hir_id::CRATE_HIR_ID;
-use rustc_hir::intravisit::Visitor;
-use rustc_hir::{
-    BinOpKind, Block, Closure, Expr, ExprKind, HirId, Item, Local, MutTy, Mutability, Node, Path, Stmt, StmtKind,
-    TyKind, UnOp,
-};
-use rustc_hir_analysis::hir_ty_to_ty;
-use rustc_lint::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintContext};
-use rustc_middle::hir::nested_filter;
-use rustc_middle::mir::interpret::{Allocation, ConstValue, GlobalAlloc};
-use rustc_middle::ty::{
-    self, fast_reject::SimplifiedTypeGen, subst::GenericArgKind, AssocKind, DefIdTree, FloatTy, Ty,
-};
-use rustc_semver::RustcVersion;
-use rustc_session::{declare_lint_pass, declare_tool_lint, impl_lint_pass};
-use rustc_span::source_map::Spanned;
-use rustc_span::symbol::{Ident, Symbol};
-use rustc_span::{sym, BytePos, Span};
-
-use std::borrow::{Borrow, Cow};
-use std::str;
-
-#[cfg(feature = "internal")]
+pub mod clippy_lints_internal;
+pub mod collapsible_calls;
+pub mod compiler_lint_functions;
+pub mod if_chain_style;
+pub mod interning_defined_symbol;
+pub mod invalid_paths;
+pub mod lint_without_lint_pass;
 pub mod metadata_collector;
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for various things we like to keep tidy in clippy.
-    ///
-    /// ### Why is this bad?
-    /// We like to pretend we're an example of tidy code.
-    ///
-    /// ### Example
-    /// Wrong ordering of the util::paths constants.
-    pub CLIPPY_LINTS_INTERNAL,
-    internal,
-    "various things that will negatively affect your clippy experience"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Ensures every lint is associated to a `LintPass`.
-    ///
-    /// ### Why is this bad?
-    /// The compiler only knows lints via a `LintPass`. Without
-    /// putting a lint to a `LintPass::get_lints()`'s return, the compiler will not
-    /// know the name of the lint.
-    ///
-    /// ### Known problems
-    /// Only checks for lints associated using the
-    /// `declare_lint_pass!`, `impl_lint_pass!`, and `lint_array!` macros.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// declare_lint! { pub LINT_1, ... }
-    /// declare_lint! { pub LINT_2, ... }
-    /// declare_lint! { pub FORGOTTEN_LINT, ... }
-    /// // ...
-    /// declare_lint_pass!(Pass => [LINT_1, LINT_2]);
-    /// // missing FORGOTTEN_LINT
-    /// ```
-    pub LINT_WITHOUT_LINT_PASS,
-    internal,
-    "declaring a lint without associating it in a LintPass"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for calls to `cx.span_lint*` and suggests to use the `utils::*`
-    /// variant of the function.
-    ///
-    /// ### Why is this bad?
-    /// The `utils::*` variants also add a link to the Clippy documentation to the
-    /// warning/error messages.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// cx.span_lint(LINT_NAME, "message");
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// utils::span_lint(cx, LINT_NAME, "message");
-    /// ```
-    pub COMPILER_LINT_FUNCTIONS,
-    internal,
-    "usage of the lint functions of the compiler instead of the utils::* variant"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for calls to `cx.outer().expn_data()` and suggests to use
-    /// the `cx.outer_expn_data()`
-    ///
-    /// ### Why is this bad?
-    /// `cx.outer_expn_data()` is faster and more concise.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// expr.span.ctxt().outer().expn_data()
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// expr.span.ctxt().outer_expn_data()
-    /// ```
-    pub OUTER_EXPN_EXPN_DATA,
-    internal,
-    "using `cx.outer_expn().expn_data()` instead of `cx.outer_expn_data()`"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Not an actual lint. This lint is only meant for testing our customized internal compiler
-    /// error message by calling `panic`.
-    ///
-    /// ### Why is this bad?
-    /// ICE in large quantities can damage your teeth
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// 🍦🍦🍦🍦🍦
-    /// ```
-    pub PRODUCE_ICE,
-    internal,
-    "this message should not appear anywhere as we ICE before and don't emit the lint"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for cases of an auto-generated lint without an updated description,
-    /// i.e. `default lint description`.
-    ///
-    /// ### Why is this bad?
-    /// Indicates that the lint is not finished.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// declare_lint! { pub COOL_LINT, nursery, "default lint description" }
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// declare_lint! { pub COOL_LINT, nursery, "a great new lint" }
-    /// ```
-    pub DEFAULT_LINT,
-    internal,
-    "found 'default lint description' in a lint declaration"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Lints `span_lint_and_then` function calls, where the
-    /// closure argument has only one statement and that statement is a method
-    /// call to `span_suggestion`, `span_help`, `span_note` (using the same
-    /// span), `help` or `note`.
-    ///
-    /// These usages of `span_lint_and_then` should be replaced with one of the
-    /// wrapper functions `span_lint_and_sugg`, span_lint_and_help`, or
-    /// `span_lint_and_note`.
-    ///
-    /// ### Why is this bad?
-    /// Using the wrapper `span_lint_and_*` functions, is more
-    /// convenient, readable and less error prone.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
-    ///     diag.span_suggestion(
-    ///         expr.span,
-    ///         help_msg,
-    ///         sugg.to_string(),
-    ///         Applicability::MachineApplicable,
-    ///     );
-    /// });
-    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
-    ///     diag.span_help(expr.span, help_msg);
-    /// });
-    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
-    ///     diag.help(help_msg);
-    /// });
-    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
-    ///     diag.span_note(expr.span, note_msg);
-    /// });
-    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
-    ///     diag.note(note_msg);
-    /// });
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// span_lint_and_sugg(
-    ///     cx,
-    ///     TEST_LINT,
-    ///     expr.span,
-    ///     lint_msg,
-    ///     help_msg,
-    ///     sugg.to_string(),
-    ///     Applicability::MachineApplicable,
-    /// );
-    /// span_lint_and_help(cx, TEST_LINT, expr.span, lint_msg, Some(expr.span), help_msg);
-    /// span_lint_and_help(cx, TEST_LINT, expr.span, lint_msg, None, help_msg);
-    /// span_lint_and_note(cx, TEST_LINT, expr.span, lint_msg, Some(expr.span), note_msg);
-    /// span_lint_and_note(cx, TEST_LINT, expr.span, lint_msg, None, note_msg);
-    /// ```
-    pub COLLAPSIBLE_SPAN_LINT_CALLS,
-    internal,
-    "found collapsible `span_lint_and_then` calls"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for usages of def paths when a diagnostic item or a `LangItem` could be used.
-    ///
-    /// ### Why is this bad?
-    /// The path for an item is subject to change and is less efficient to look up than a
-    /// diagnostic item or a `LangItem`.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// utils::match_type(cx, ty, &paths::VEC)
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// utils::is_type_diagnostic_item(cx, ty, sym::Vec)
-    /// ```
-    pub UNNECESSARY_DEF_PATH,
-    internal,
-    "using a def path when a diagnostic item or a `LangItem` is available"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks the paths module for invalid paths.
-    ///
-    /// ### Why is this bad?
-    /// It indicates a bug in the code.
-    ///
-    /// ### Example
-    /// None.
-    pub INVALID_PATHS,
-    internal,
-    "invalid path"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for interning symbols that have already been pre-interned and defined as constants.
-    ///
-    /// ### Why is this bad?
-    /// It's faster and easier to use the symbol constant.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// let _ = sym!(f32);
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// let _ = sym::f32;
-    /// ```
-    pub INTERNING_DEFINED_SYMBOL,
-    internal,
-    "interning a symbol that is pre-interned and defined as a constant"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for unnecessary conversion from Symbol to a string.
-    ///
-    /// ### Why is this bad?
-    /// It's faster use symbols directly instead of strings.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// symbol.as_str() == "clippy";
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// symbol == sym::clippy;
-    /// ```
-    pub UNNECESSARY_SYMBOL_STR,
-    internal,
-    "unnecessary conversion between Symbol and string"
-}
-
-declare_clippy_lint! {
-    /// Finds unidiomatic usage of `if_chain!`
-    pub IF_CHAIN_STYLE,
-    internal,
-    "non-idiomatic `if_chain!` usage"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for invalid `clippy::version` attributes.
-    ///
-    /// Valid values are:
-    /// * "pre 1.29.0"
-    /// * any valid semantic version
-    pub INVALID_CLIPPY_VERSION_ATTRIBUTE,
-    internal,
-    "found an invalid `clippy::version` attribute"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for declared clippy lints without the `clippy::version` attribute.
-    ///
-    pub MISSING_CLIPPY_VERSION_ATTRIBUTE,
-    internal,
-    "found clippy lint without `clippy::version` attribute"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Check that the `extract_msrv_attr!` macro is used, when a lint has a MSRV.
-    ///
-    pub MISSING_MSRV_ATTR_IMPL,
-    internal,
-    "checking if all necessary steps were taken when adding a MSRV to a lint"
-}
-
-declare_clippy_lint! {
-    /// ### What it does
-    /// Checks for cases of an auto-generated deprecated lint without an updated reason,
-    /// i.e. `"default deprecation note"`.
-    ///
-    /// ### Why is this bad?
-    /// Indicates that the documentation is incomplete.
-    ///
-    /// ### Example
-    /// ```rust,ignore
-    /// declare_deprecated_lint! {
-    ///     /// ### What it does
-    ///     /// Nothing. This lint has been deprecated.
-    ///     ///
-    ///     /// ### Deprecation reason
-    ///     /// TODO
-    ///     #[clippy::version = "1.63.0"]
-    ///     pub COOL_LINT,
-    ///     "default deprecation note"
-    /// }
-    /// ```
-    ///
-    /// Use instead:
-    /// ```rust,ignore
-    /// declare_deprecated_lint! {
-    ///     /// ### What it does
-    ///     /// Nothing. This lint has been deprecated.
-    ///     ///
-    ///     /// ### Deprecation reason
-    ///     /// This lint has been replaced by `cooler_lint`
-    ///     #[clippy::version = "1.63.0"]
-    ///     pub COOL_LINT,
-    ///     "this lint has been replaced by `cooler_lint`"
-    /// }
-    /// ```
-    pub DEFAULT_DEPRECATION_REASON,
-    internal,
-    "found 'default deprecation note' in a deprecated lint declaration"
-}
-
-declare_lint_pass!(ClippyLintsInternal => [CLIPPY_LINTS_INTERNAL]);
-
-impl EarlyLintPass for ClippyLintsInternal {
-    fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &Crate) {
-        if let Some(utils) = krate.items.iter().find(|item| item.ident.name.as_str() == "utils") {
-            if let ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) = utils.kind {
-                if let Some(paths) = items.iter().find(|item| item.ident.name.as_str() == "paths") {
-                    if let ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) = paths.kind {
-                        let mut last_name: Option<&str> = None;
-                        for item in items {
-                            let name = item.ident.as_str();
-                            if let Some(last_name) = last_name {
-                                if *last_name > *name {
-                                    span_lint(
-                                        cx,
-                                        CLIPPY_LINTS_INTERNAL,
-                                        item.span,
-                                        "this constant should be before the previous constant due to lexical \
-                                         ordering",
-                                    );
-                                }
-                            }
-                            last_name = Some(name);
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-#[derive(Clone, Debug, Default)]
-pub struct LintWithoutLintPass {
-    declared_lints: FxHashMap<Symbol, Span>,
-    registered_lints: FxHashSet<Symbol>,
-}
-
-impl_lint_pass!(LintWithoutLintPass => [DEFAULT_LINT, LINT_WITHOUT_LINT_PASS, INVALID_CLIPPY_VERSION_ATTRIBUTE, MISSING_CLIPPY_VERSION_ATTRIBUTE, DEFAULT_DEPRECATION_REASON]);
-
-impl<'tcx> LateLintPass<'tcx> for LintWithoutLintPass {
-    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
-        if is_lint_allowed(cx, DEFAULT_LINT, item.hir_id())
-            || is_lint_allowed(cx, DEFAULT_DEPRECATION_REASON, item.hir_id())
-        {
-            return;
-        }
-
-        if let hir::ItemKind::Static(ty, Mutability::Not, body_id) = item.kind {
-            let is_lint_ref_ty = is_lint_ref_type(cx, ty);
-            if is_deprecated_lint(cx, ty) || is_lint_ref_ty {
-                check_invalid_clippy_version_attribute(cx, item);
-
-                let expr = &cx.tcx.hir().body(body_id).value;
-                let fields;
-                if is_lint_ref_ty {
-                    if let ExprKind::AddrOf(_, _, inner_exp) = expr.kind
-                        && let ExprKind::Struct(_, struct_fields, _) = inner_exp.kind {
-                            fields = struct_fields;
-                    } else {
-                        return;
-                    }
-                } else if let ExprKind::Struct(_, struct_fields, _) = expr.kind {
-                    fields = struct_fields;
-                } else {
-                    return;
-                }
-
-                let field = fields
-                    .iter()
-                    .find(|f| f.ident.as_str() == "desc")
-                    .expect("lints must have a description field");
-
-                if let ExprKind::Lit(Spanned {
-                    node: LitKind::Str(ref sym, _),
-                    ..
-                }) = field.expr.kind
-                {
-                    let sym_str = sym.as_str();
-                    if is_lint_ref_ty {
-                        if sym_str == "default lint description" {
-                            span_lint(
-                                cx,
-                                DEFAULT_LINT,
-                                item.span,
-                                &format!("the lint `{}` has the default lint description", item.ident.name),
-                            );
-                        }
-
-                        self.declared_lints.insert(item.ident.name, item.span);
-                    } else if sym_str == "default deprecation note" {
-                        span_lint(
-                            cx,
-                            DEFAULT_DEPRECATION_REASON,
-                            item.span,
-                            &format!("the lint `{}` has the default deprecation reason", item.ident.name),
-                        );
-                    }
-                }
-            }
-        } else if let Some(macro_call) = root_macro_call_first_node(cx, item) {
-            if !matches!(
-                cx.tcx.item_name(macro_call.def_id).as_str(),
-                "impl_lint_pass" | "declare_lint_pass"
-            ) {
-                return;
-            }
-            if let hir::ItemKind::Impl(hir::Impl {
-                of_trait: None,
-                items: impl_item_refs,
-                ..
-            }) = item.kind
-            {
-                let mut collector = LintCollector {
-                    output: &mut self.registered_lints,
-                    cx,
-                };
-                let body_id = cx.tcx.hir().body_owned_by(
-                    cx.tcx.hir().local_def_id(
-                        impl_item_refs
-                            .iter()
-                            .find(|iiref| iiref.ident.as_str() == "get_lints")
-                            .expect("LintPass needs to implement get_lints")
-                            .id
-                            .hir_id(),
-                    ),
-                );
-                collector.visit_expr(cx.tcx.hir().body(body_id).value);
-            }
-        }
-    }
-
-    fn check_crate_post(&mut self, cx: &LateContext<'tcx>) {
-        if is_lint_allowed(cx, LINT_WITHOUT_LINT_PASS, CRATE_HIR_ID) {
-            return;
-        }
-
-        for (lint_name, &lint_span) in &self.declared_lints {
-            // When using the `declare_tool_lint!` macro, the original `lint_span`'s
-            // file points to "<rustc macros>".
-            // `compiletest-rs` thinks that's an error in a different file and
-            // just ignores it. This causes the test in compile-fail/lint_pass
-            // not able to capture the error.
-            // Therefore, we need to climb the macro expansion tree and find the
-            // actual span that invoked `declare_tool_lint!`:
-            let lint_span = lint_span.ctxt().outer_expn_data().call_site;
-
-            if !self.registered_lints.contains(lint_name) {
-                span_lint(
-                    cx,
-                    LINT_WITHOUT_LINT_PASS,
-                    lint_span,
-                    &format!("the lint `{lint_name}` is not added to any `LintPass`"),
-                );
-            }
-        }
-    }
-}
-
-fn is_lint_ref_type<'tcx>(cx: &LateContext<'tcx>, ty: &hir::Ty<'_>) -> bool {
-    if let TyKind::Rptr(
-        _,
-        MutTy {
-            ty: inner,
-            mutbl: Mutability::Not,
-        },
-    ) = ty.kind
-    {
-        if let TyKind::Path(ref path) = inner.kind {
-            if let Res::Def(DefKind::Struct, def_id) = cx.qpath_res(path, inner.hir_id) {
-                return match_def_path(cx, def_id, &paths::LINT);
-            }
-        }
-    }
-
-    false
-}
-
-fn check_invalid_clippy_version_attribute(cx: &LateContext<'_>, item: &'_ Item<'_>) {
-    if let Some(value) = extract_clippy_version_value(cx, item) {
-        // The `sym!` macro doesn't work as it only expects a single token.
-        // It's better to keep it this way and have a direct `Symbol::intern` call here.
-        if value == Symbol::intern("pre 1.29.0") {
-            return;
-        }
-
-        if RustcVersion::parse(value.as_str()).is_err() {
-            span_lint_and_help(
-                cx,
-                INVALID_CLIPPY_VERSION_ATTRIBUTE,
-                item.span,
-                "this item has an invalid `clippy::version` attribute",
-                None,
-                "please use a valid semantic version, see `doc/adding_lints.md`",
-            );
-        }
-    } else {
-        span_lint_and_help(
-            cx,
-            MISSING_CLIPPY_VERSION_ATTRIBUTE,
-            item.span,
-            "this lint is missing the `clippy::version` attribute or version value",
-            None,
-            "please use a `clippy::version` attribute, see `doc/adding_lints.md`",
-        );
-    }
-}
-
-/// This function extracts the version value of a `clippy::version` attribute if the given value has
-/// one
-fn extract_clippy_version_value(cx: &LateContext<'_>, item: &'_ Item<'_>) -> Option<Symbol> {
-    let attrs = cx.tcx.hir().attrs(item.hir_id());
-    attrs.iter().find_map(|attr| {
-        if_chain! {
-            // Identify attribute
-            if let ast::AttrKind::Normal(ref attr_kind) = &attr.kind;
-            if let [tool_name, attr_name] = &attr_kind.item.path.segments[..];
-            if tool_name.ident.name == sym::clippy;
-            if attr_name.ident.name == sym::version;
-            if let Some(version) = attr.value_str();
-            then {
-                Some(version)
-            } else {
-                None
-            }
-        }
-    })
-}
-
-struct LintCollector<'a, 'tcx> {
-    output: &'a mut FxHashSet<Symbol>,
-    cx: &'a LateContext<'tcx>,
-}
-
-impl<'a, 'tcx> Visitor<'tcx> for LintCollector<'a, 'tcx> {
-    type NestedFilter = nested_filter::All;
-
-    fn visit_path(&mut self, path: &'tcx Path<'_>, _: HirId) {
-        if path.segments.len() == 1 {
-            self.output.insert(path.segments[0].ident.name);
-        }
-    }
-
-    fn nested_visit_map(&mut self) -> Self::Map {
-        self.cx.tcx.hir()
-    }
-}
-
-#[derive(Clone, Default)]
-pub struct CompilerLintFunctions {
-    map: FxHashMap<&'static str, &'static str>,
-}
-
-impl CompilerLintFunctions {
-    #[must_use]
-    pub fn new() -> Self {
-        let mut map = FxHashMap::default();
-        map.insert("span_lint", "utils::span_lint");
-        map.insert("struct_span_lint", "utils::span_lint");
-        map.insert("lint", "utils::span_lint");
-        map.insert("span_lint_note", "utils::span_lint_and_note");
-        map.insert("span_lint_help", "utils::span_lint_and_help");
-        Self { map }
-    }
-}
-
-impl_lint_pass!(CompilerLintFunctions => [COMPILER_LINT_FUNCTIONS]);
-
-impl<'tcx> LateLintPass<'tcx> for CompilerLintFunctions {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if is_lint_allowed(cx, COMPILER_LINT_FUNCTIONS, expr.hir_id) {
-            return;
-        }
-
-        if_chain! {
-            if let ExprKind::MethodCall(path, self_arg, _, _) = &expr.kind;
-            let fn_name = path.ident;
-            if let Some(sugg) = self.map.get(fn_name.as_str());
-            let ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
-            if match_type(cx, ty, &paths::EARLY_CONTEXT)
-                || match_type(cx, ty, &paths::LATE_CONTEXT);
-            then {
-                span_lint_and_help(
-                    cx,
-                    COMPILER_LINT_FUNCTIONS,
-                    path.ident.span,
-                    "usage of a compiler lint function",
-                    None,
-                    &format!("please use the Clippy variant of this function: `{sugg}`"),
-                );
-            }
-        }
-    }
-}
-
-declare_lint_pass!(OuterExpnDataPass => [OUTER_EXPN_EXPN_DATA]);
-
-impl<'tcx> LateLintPass<'tcx> for OuterExpnDataPass {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if is_lint_allowed(cx, OUTER_EXPN_EXPN_DATA, expr.hir_id) {
-            return;
-        }
-
-        let (method_names, arg_lists, spans) = method_calls(expr, 2);
-        let method_names: Vec<&str> = method_names.iter().map(Symbol::as_str).collect();
-        if_chain! {
-            if let ["expn_data", "outer_expn"] = method_names.as_slice();
-            let (self_arg, args)= arg_lists[1];
-            if args.is_empty();
-            let self_ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
-            if match_type(cx, self_ty, &paths::SYNTAX_CONTEXT);
-            then {
-                span_lint_and_sugg(
-                    cx,
-                    OUTER_EXPN_EXPN_DATA,
-                    spans[1].with_hi(expr.span.hi()),
-                    "usage of `outer_expn().expn_data()`",
-                    "try",
-                    "outer_expn_data()".to_string(),
-                    Applicability::MachineApplicable,
-                );
-            }
-        }
-    }
-}
-
-declare_lint_pass!(ProduceIce => [PRODUCE_ICE]);
-
-impl EarlyLintPass for ProduceIce {
-    fn check_fn(&mut self, _: &EarlyContext<'_>, fn_kind: FnKind<'_>, _: Span, _: NodeId) {
-        assert!(!is_trigger_fn(fn_kind), "Would you like some help with that?");
-    }
-}
-
-fn is_trigger_fn(fn_kind: FnKind<'_>) -> bool {
-    match fn_kind {
-        FnKind::Fn(_, ident, ..) => ident.name.as_str() == "it_looks_like_you_are_trying_to_kill_clippy",
-        FnKind::Closure(..) => false,
-    }
-}
-
-declare_lint_pass!(CollapsibleCalls => [COLLAPSIBLE_SPAN_LINT_CALLS]);
-
-impl<'tcx> LateLintPass<'tcx> for CollapsibleCalls {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        if is_lint_allowed(cx, COLLAPSIBLE_SPAN_LINT_CALLS, expr.hir_id) {
-            return;
-        }
-
-        if_chain! {
-            if let ExprKind::Call(func, and_then_args) = expr.kind;
-            if is_expr_path_def_path(cx, func, &["clippy_utils", "diagnostics", "span_lint_and_then"]);
-            if and_then_args.len() == 5;
-            if let ExprKind::Closure(&Closure { body, .. }) = &and_then_args[4].kind;
-            let body = cx.tcx.hir().body(body);
-            let only_expr = peel_blocks_with_stmt(body.value);
-            if let ExprKind::MethodCall(ps, recv, span_call_args, _) = &only_expr.kind;
-            if let ExprKind::Path(..) = recv.kind;
-            then {
-                let and_then_snippets = get_and_then_snippets(cx, and_then_args);
-                let mut sle = SpanlessEq::new(cx).deny_side_effects();
-                match ps.ident.as_str() {
-                    "span_suggestion" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
-                        suggest_suggestion(cx, expr, &and_then_snippets, &span_suggestion_snippets(cx, span_call_args));
-                    },
-                    "span_help" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
-                        let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
-                        suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), true);
-                    },
-                    "span_note" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
-                        let note_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
-                        suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), true);
-                    },
-                    "help" => {
-                        let help_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
-                        suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), false);
-                    }
-                    "note" => {
-                        let note_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
-                        suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), false);
-                    }
-                    _  => (),
-                }
-            }
-        }
-    }
-}
-
-struct AndThenSnippets<'a> {
-    cx: Cow<'a, str>,
-    lint: Cow<'a, str>,
-    span: Cow<'a, str>,
-    msg: Cow<'a, str>,
-}
-
-fn get_and_then_snippets<'a, 'hir>(cx: &LateContext<'_>, and_then_snippets: &'hir [Expr<'hir>]) -> AndThenSnippets<'a> {
-    let cx_snippet = snippet(cx, and_then_snippets[0].span, "cx");
-    let lint_snippet = snippet(cx, and_then_snippets[1].span, "..");
-    let span_snippet = snippet(cx, and_then_snippets[2].span, "span");
-    let msg_snippet = snippet(cx, and_then_snippets[3].span, r#""...""#);
-
-    AndThenSnippets {
-        cx: cx_snippet,
-        lint: lint_snippet,
-        span: span_snippet,
-        msg: msg_snippet,
-    }
-}
-
-struct SpanSuggestionSnippets<'a> {
-    help: Cow<'a, str>,
-    sugg: Cow<'a, str>,
-    applicability: Cow<'a, str>,
-}
-
-fn span_suggestion_snippets<'a, 'hir>(
-    cx: &LateContext<'_>,
-    span_call_args: &'hir [Expr<'hir>],
-) -> SpanSuggestionSnippets<'a> {
-    let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
-    let sugg_snippet = snippet(cx, span_call_args[2].span, "..");
-    let applicability_snippet = snippet(cx, span_call_args[3].span, "Applicability::MachineApplicable");
-
-    SpanSuggestionSnippets {
-        help: help_snippet,
-        sugg: sugg_snippet,
-        applicability: applicability_snippet,
-    }
-}
-
-fn suggest_suggestion(
-    cx: &LateContext<'_>,
-    expr: &Expr<'_>,
-    and_then_snippets: &AndThenSnippets<'_>,
-    span_suggestion_snippets: &SpanSuggestionSnippets<'_>,
-) {
-    span_lint_and_sugg(
-        cx,
-        COLLAPSIBLE_SPAN_LINT_CALLS,
-        expr.span,
-        "this call is collapsible",
-        "collapse into",
-        format!(
-            "span_lint_and_sugg({}, {}, {}, {}, {}, {}, {})",
-            and_then_snippets.cx,
-            and_then_snippets.lint,
-            and_then_snippets.span,
-            and_then_snippets.msg,
-            span_suggestion_snippets.help,
-            span_suggestion_snippets.sugg,
-            span_suggestion_snippets.applicability
-        ),
-        Applicability::MachineApplicable,
-    );
-}
-
-fn suggest_help(
-    cx: &LateContext<'_>,
-    expr: &Expr<'_>,
-    and_then_snippets: &AndThenSnippets<'_>,
-    help: &str,
-    with_span: bool,
-) {
-    let option_span = if with_span {
-        format!("Some({})", and_then_snippets.span)
-    } else {
-        "None".to_string()
-    };
-
-    span_lint_and_sugg(
-        cx,
-        COLLAPSIBLE_SPAN_LINT_CALLS,
-        expr.span,
-        "this call is collapsible",
-        "collapse into",
-        format!(
-            "span_lint_and_help({}, {}, {}, {}, {}, {help})",
-            and_then_snippets.cx, and_then_snippets.lint, and_then_snippets.span, and_then_snippets.msg, &option_span,
-        ),
-        Applicability::MachineApplicable,
-    );
-}
-
-fn suggest_note(
-    cx: &LateContext<'_>,
-    expr: &Expr<'_>,
-    and_then_snippets: &AndThenSnippets<'_>,
-    note: &str,
-    with_span: bool,
-) {
-    let note_span = if with_span {
-        format!("Some({})", and_then_snippets.span)
-    } else {
-        "None".to_string()
-    };
-
-    span_lint_and_sugg(
-        cx,
-        COLLAPSIBLE_SPAN_LINT_CALLS,
-        expr.span,
-        "this call is collapsible",
-        "collapse into",
-        format!(
-            "span_lint_and_note({}, {}, {}, {}, {note_span}, {note})",
-            and_then_snippets.cx, and_then_snippets.lint, and_then_snippets.span, and_then_snippets.msg,
-        ),
-        Applicability::MachineApplicable,
-    );
-}
-
-declare_lint_pass!(UnnecessaryDefPath => [UNNECESSARY_DEF_PATH]);
-
-#[allow(clippy::too_many_lines)]
-impl<'tcx> LateLintPass<'tcx> for UnnecessaryDefPath {
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        enum Item {
-            LangItem(Symbol),
-            DiagnosticItem(Symbol),
-        }
-        static PATHS: &[&[&str]] = &[
-            &["clippy_utils", "match_def_path"],
-            &["clippy_utils", "match_trait_method"],
-            &["clippy_utils", "ty", "match_type"],
-            &["clippy_utils", "is_expr_path_def_path"],
-        ];
-
-        if is_lint_allowed(cx, UNNECESSARY_DEF_PATH, expr.hir_id) {
-            return;
-        }
-
-        if_chain! {
-            if let ExprKind::Call(func, [cx_arg, def_arg, args@..]) = expr.kind;
-            if let ExprKind::Path(path) = &func.kind;
-            if let Some(id) = cx.qpath_res(path, func.hir_id).opt_def_id();
-            if let Some(which_path) = match_any_def_paths(cx, id, PATHS);
-            let item_arg = if which_path == 4 { &args[1] } else { &args[0] };
-            // Extract the path to the matched type
-            if let Some(segments) = path_to_matched_type(cx, item_arg);
-            let segments: Vec<&str> = segments.iter().map(|sym| &**sym).collect();
-            if let Some(def_id) = def_path_res(cx, &segments[..], None).opt_def_id();
-            then {
-                // def_path_res will match field names before anything else, but for this we want to match
-                // inherent functions first.
-                let def_id = if cx.tcx.def_kind(def_id) == DefKind::Field {
-                    let method_name = *segments.last().unwrap();
-                    cx.tcx.def_key(def_id).parent
-                        .and_then(|parent_idx|
-                            cx.tcx.inherent_impls(DefId { index: parent_idx, krate: def_id.krate }).iter()
-                                .find_map(|impl_id| cx.tcx.associated_items(*impl_id)
-                                    .find_by_name_and_kind(
-                                        cx.tcx,
-                                        Ident::from_str(method_name),
-                                        AssocKind::Fn,
-                                        *impl_id,
-                                    )
-                                )
-                        )
-                        .map_or(def_id, |item| item.def_id)
-                } else {
-                    def_id
-                };
-
-                // Check if the target item is a diagnostic item or LangItem.
-                let (msg, item) = if let Some(item_name)
-                    = cx.tcx.diagnostic_items(def_id.krate).id_to_name.get(&def_id)
-                {
-                    (
-                        "use of a def path to a diagnostic item",
-                        Item::DiagnosticItem(*item_name),
-                    )
-                } else if let Some(lang_item) = cx.tcx.lang_items().items().iter().position(|id| *id == Some(def_id)) {
-                    let lang_items = def_path_res(cx, &["rustc_hir", "lang_items", "LangItem"], Some(Namespace::TypeNS)).def_id();
-                    let item_name = cx.tcx.adt_def(lang_items).variants().iter().nth(lang_item).unwrap().name;
-                    (
-                        "use of a def path to a `LangItem`",
-                        Item::LangItem(item_name),
-                    )
-                } else {
-                    return;
-                };
-
-                let has_ctor = match cx.tcx.def_kind(def_id) {
-                    DefKind::Struct => {
-                        let variant = cx.tcx.adt_def(def_id).non_enum_variant();
-                        variant.ctor_def_id.is_some() && variant.fields.iter().all(|f| f.vis.is_public())
-                    }
-                    DefKind::Variant => {
-                        let variant = cx.tcx.adt_def(cx.tcx.parent(def_id)).variant_with_id(def_id);
-                        variant.ctor_def_id.is_some() && variant.fields.iter().all(|f| f.vis.is_public())
-                    }
-                    _ => false,
-                };
-
-                let mut app = Applicability::MachineApplicable;
-                let cx_snip = snippet_with_applicability(cx, cx_arg.span, "..", &mut app);
-                let def_snip = snippet_with_applicability(cx, def_arg.span, "..", &mut app);
-                let (sugg, with_note) = match (which_path, item) {
-                    // match_def_path
-                    (0, Item::DiagnosticItem(item)) =>
-                        (format!("{cx_snip}.tcx.is_diagnostic_item(sym::{item}, {def_snip})"), has_ctor),
-                    (0, Item::LangItem(item)) => (
-                        format!("{cx_snip}.tcx.lang_items().require(LangItem::{item}).ok() == Some({def_snip})"),
-                        has_ctor
-                    ),
-                    // match_trait_method
-                    (1, Item::DiagnosticItem(item)) =>
-                        (format!("is_trait_method({cx_snip}, {def_snip}, sym::{item})"), false),
-                    // match_type
-                    (2, Item::DiagnosticItem(item)) =>
-                        (format!("is_type_diagnostic_item({cx_snip}, {def_snip}, sym::{item})"), false),
-                    (2, Item::LangItem(item)) =>
-                        (format!("is_type_lang_item({cx_snip}, {def_snip}, LangItem::{item})"), false),
-                    // is_expr_path_def_path
-                    (3, Item::DiagnosticItem(item)) if has_ctor => (
-                        format!(
-                            "is_res_diag_ctor({cx_snip}, path_res({cx_snip}, {def_snip}), sym::{item})",
-                        ),
-                        false,
-                    ),
-                    (3, Item::LangItem(item)) if has_ctor => (
-                        format!(
-                            "is_res_lang_ctor({cx_snip}, path_res({cx_snip}, {def_snip}), LangItem::{item})",
-                        ),
-                        false,
-                    ),
-                    (3, Item::DiagnosticItem(item)) =>
-                        (format!("is_path_diagnostic_item({cx_snip}, {def_snip}, sym::{item})"), false),
-                    (3, Item::LangItem(item)) => (
-                        format!(
-                            "path_res({cx_snip}, {def_snip}).opt_def_id()\
-                                .map_or(false, |id| {cx_snip}.tcx.lang_items().require(LangItem::{item}).ok() == Some(id))",
-                        ),
-                        false,
-                    ),
-                    _ => return,
-                };
-
-                span_lint_and_then(
-                    cx,
-                    UNNECESSARY_DEF_PATH,
-                    expr.span,
-                    msg,
-                    |diag| {
-                        diag.span_suggestion(expr.span, "try", sugg, app);
-                        if with_note {
-                            diag.help(
-                                "if this `DefId` came from a constructor expression or pattern then the \
-                                    parent `DefId` should be used instead"
-                            );
-                        }
-                    },
-                );
-            }
-        }
-    }
-}
-
-fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Vec<String>> {
-    match peel_hir_expr_refs(expr).0.kind {
-        ExprKind::Path(ref qpath) => match cx.qpath_res(qpath, expr.hir_id) {
-            Res::Local(hir_id) => {
-                let parent_id = cx.tcx.hir().get_parent_node(hir_id);
-                if let Some(Node::Local(Local { init: Some(init), .. })) = cx.tcx.hir().find(parent_id) {
-                    path_to_matched_type(cx, init)
-                } else {
-                    None
-                }
-            },
-            Res::Def(DefKind::Static(_), def_id) => read_mir_alloc_def_path(
-                cx,
-                cx.tcx.eval_static_initializer(def_id).ok()?.inner(),
-                cx.tcx.type_of(def_id),
-            ),
-            Res::Def(DefKind::Const, def_id) => match cx.tcx.const_eval_poly(def_id).ok()? {
-                ConstValue::ByRef { alloc, offset } if offset.bytes() == 0 => {
-                    read_mir_alloc_def_path(cx, alloc.inner(), cx.tcx.type_of(def_id))
-                },
-                _ => None,
-            },
-            _ => None,
-        },
-        ExprKind::Array(exprs) => exprs
-            .iter()
-            .map(|expr| {
-                if let ExprKind::Lit(lit) = &expr.kind {
-                    if let LitKind::Str(sym, _) = lit.node {
-                        return Some((*sym.as_str()).to_owned());
-                    }
-                }
-
-                None
-            })
-            .collect(),
-        _ => None,
-    }
-}
-
-fn read_mir_alloc_def_path<'tcx>(cx: &LateContext<'tcx>, alloc: &'tcx Allocation, ty: Ty<'_>) -> Option<Vec<String>> {
-    let (alloc, ty) = if let ty::Ref(_, ty, Mutability::Not) = *ty.kind() {
-        let &alloc = alloc.provenance().values().next()?;
-        if let GlobalAlloc::Memory(alloc) = cx.tcx.global_alloc(alloc) {
-            (alloc.inner(), ty)
-        } else {
-            return None;
-        }
-    } else {
-        (alloc, ty)
-    };
-
-    if let ty::Array(ty, _) | ty::Slice(ty) = *ty.kind()
-        && let ty::Ref(_, ty, Mutability::Not) = *ty.kind()
-        && ty.is_str()
-    {
-        alloc
-            .provenance()
-            .values()
-            .map(|&alloc| {
-                if let GlobalAlloc::Memory(alloc) = cx.tcx.global_alloc(alloc) {
-                    let alloc = alloc.inner();
-                    str::from_utf8(alloc.inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len()))
-                        .ok().map(ToOwned::to_owned)
-                } else {
-                    None
-                }
-            })
-            .collect()
-    } else {
-        None
-    }
-}
-
-// This is not a complete resolver for paths. It works on all the paths currently used in the paths
-// module.  That's all it does and all it needs to do.
-pub fn check_path(cx: &LateContext<'_>, path: &[&str]) -> bool {
-    if def_path_res(cx, path, None) != Res::Err {
-        return true;
-    }
-
-    // Some implementations can't be found by `path_to_res`, particularly inherent
-    // implementations of native types. Check lang items.
-    let path_syms: Vec<_> = path.iter().map(|p| Symbol::intern(p)).collect();
-    let lang_items = cx.tcx.lang_items();
-    // This list isn't complete, but good enough for our current list of paths.
-    let incoherent_impls = [
-        SimplifiedTypeGen::FloatSimplifiedType(FloatTy::F32),
-        SimplifiedTypeGen::FloatSimplifiedType(FloatTy::F64),
-        SimplifiedTypeGen::SliceSimplifiedType,
-        SimplifiedTypeGen::StrSimplifiedType,
-    ]
-    .iter()
-    .flat_map(|&ty| cx.tcx.incoherent_impls(ty));
-    for item_def_id in lang_items.items().iter().flatten().chain(incoherent_impls) {
-        let lang_item_path = cx.get_def_path(*item_def_id);
-        if path_syms.starts_with(&lang_item_path) {
-            if let [item] = &path_syms[lang_item_path.len()..] {
-                if matches!(
-                    cx.tcx.def_kind(*item_def_id),
-                    DefKind::Mod | DefKind::Enum | DefKind::Trait
-                ) {
-                    for child in cx.tcx.module_children(*item_def_id) {
-                        if child.ident.name == *item {
-                            return true;
-                        }
-                    }
-                } else {
-                    for child in cx.tcx.associated_item_def_ids(*item_def_id) {
-                        if cx.tcx.item_name(*child) == *item {
-                            return true;
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    false
-}
-
-declare_lint_pass!(InvalidPaths => [INVALID_PATHS]);
-
-impl<'tcx> LateLintPass<'tcx> for InvalidPaths {
-    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
-        let local_def_id = &cx.tcx.parent_module(item.hir_id());
-        let mod_name = &cx.tcx.item_name(local_def_id.to_def_id());
-        if_chain! {
-            if mod_name.as_str() == "paths";
-            if let hir::ItemKind::Const(ty, body_id) = item.kind;
-            let ty = hir_ty_to_ty(cx.tcx, ty);
-            if let ty::Array(el_ty, _) = &ty.kind();
-            if let ty::Ref(_, el_ty, _) = &el_ty.kind();
-            if el_ty.is_str();
-            let body = cx.tcx.hir().body(body_id);
-            let typeck_results = cx.tcx.typeck_body(body_id);
-            if let Some(Constant::Vec(path)) = constant_simple(cx, typeck_results, body.value);
-            let path: Vec<&str> = path.iter().map(|x| {
-                    if let Constant::Str(s) = x {
-                        s.as_str()
-                    } else {
-                        // We checked the type of the constant above
-                        unreachable!()
-                    }
-                }).collect();
-            if !check_path(cx, &path[..]);
-            then {
-                span_lint(cx, INVALID_PATHS, item.span, "invalid path");
-            }
-        }
-    }
-}
-
-#[derive(Default)]
-pub struct InterningDefinedSymbol {
-    // Maps the symbol value to the constant DefId.
-    symbol_map: FxHashMap<u32, DefId>,
-}
-
-impl_lint_pass!(InterningDefinedSymbol => [INTERNING_DEFINED_SYMBOL, UNNECESSARY_SYMBOL_STR]);
-
-impl<'tcx> LateLintPass<'tcx> for InterningDefinedSymbol {
-    fn check_crate(&mut self, cx: &LateContext<'_>) {
-        if !self.symbol_map.is_empty() {
-            return;
-        }
-
-        for &module in &[&paths::KW_MODULE, &paths::SYM_MODULE] {
-            if let Some(def_id) = def_path_res(cx, module, None).opt_def_id() {
-                for item in cx.tcx.module_children(def_id).iter() {
-                    if_chain! {
-                        if let Res::Def(DefKind::Const, item_def_id) = item.res;
-                        let ty = cx.tcx.type_of(item_def_id);
-                        if match_type(cx, ty, &paths::SYMBOL);
-                        if let Ok(ConstValue::Scalar(value)) = cx.tcx.const_eval_poly(item_def_id);
-                        if let Ok(value) = value.to_u32();
-                        then {
-                            self.symbol_map.insert(value, item_def_id);
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if_chain! {
-            if let ExprKind::Call(func, [arg]) = &expr.kind;
-            if let ty::FnDef(def_id, _) = cx.typeck_results().expr_ty(func).kind();
-            if match_def_path(cx, *def_id, &paths::SYMBOL_INTERN);
-            if let Some(Constant::Str(arg)) = constant_simple(cx, cx.typeck_results(), arg);
-            let value = Symbol::intern(&arg).as_u32();
-            if let Some(&def_id) = self.symbol_map.get(&value);
-            then {
-                span_lint_and_sugg(
-                    cx,
-                    INTERNING_DEFINED_SYMBOL,
-                    is_expn_of(expr.span, "sym").unwrap_or(expr.span),
-                    "interning a defined symbol",
-                    "try",
-                    cx.tcx.def_path_str(def_id),
-                    Applicability::MachineApplicable,
-                );
-            }
-        }
-        if let ExprKind::Binary(op, left, right) = expr.kind {
-            if matches!(op.node, BinOpKind::Eq | BinOpKind::Ne) {
-                let data = [
-                    (left, self.symbol_str_expr(left, cx)),
-                    (right, self.symbol_str_expr(right, cx)),
-                ];
-                match data {
-                    // both operands are a symbol string
-                    [(_, Some(left)), (_, Some(right))] => {
-                        span_lint_and_sugg(
-                            cx,
-                            UNNECESSARY_SYMBOL_STR,
-                            expr.span,
-                            "unnecessary `Symbol` to string conversion",
-                            "try",
-                            format!(
-                                "{} {} {}",
-                                left.as_symbol_snippet(cx),
-                                op.node.as_str(),
-                                right.as_symbol_snippet(cx),
-                            ),
-                            Applicability::MachineApplicable,
-                        );
-                    },
-                    // one of the operands is a symbol string
-                    [(expr, Some(symbol)), _] | [_, (expr, Some(symbol))] => {
-                        // creating an owned string for comparison
-                        if matches!(symbol, SymbolStrExpr::Expr { is_to_owned: true, .. }) {
-                            span_lint_and_sugg(
-                                cx,
-                                UNNECESSARY_SYMBOL_STR,
-                                expr.span,
-                                "unnecessary string allocation",
-                                "try",
-                                format!("{}.as_str()", symbol.as_symbol_snippet(cx)),
-                                Applicability::MachineApplicable,
-                            );
-                        }
-                    },
-                    // nothing found
-                    [(_, None), (_, None)] => {},
-                }
-            }
-        }
-    }
-}
-
-impl InterningDefinedSymbol {
-    fn symbol_str_expr<'tcx>(&self, expr: &'tcx Expr<'tcx>, cx: &LateContext<'tcx>) -> Option<SymbolStrExpr<'tcx>> {
-        static IDENT_STR_PATHS: &[&[&str]] = &[&paths::IDENT_AS_STR, &paths::TO_STRING_METHOD];
-        static SYMBOL_STR_PATHS: &[&[&str]] = &[
-            &paths::SYMBOL_AS_STR,
-            &paths::SYMBOL_TO_IDENT_STRING,
-            &paths::TO_STRING_METHOD,
-        ];
-        let call = if_chain! {
-            if let ExprKind::AddrOf(_, _, e) = expr.kind;
-            if let ExprKind::Unary(UnOp::Deref, e) = e.kind;
-            then { e } else { expr }
-        };
-        if_chain! {
-            // is a method call
-            if let ExprKind::MethodCall(_, item, [], _) = call.kind;
-            if let Some(did) = cx.typeck_results().type_dependent_def_id(call.hir_id);
-            let ty = cx.typeck_results().expr_ty(item);
-            // ...on either an Ident or a Symbol
-            if let Some(is_ident) = if match_type(cx, ty, &paths::SYMBOL) {
-                Some(false)
-            } else if match_type(cx, ty, &paths::IDENT) {
-                Some(true)
-            } else {
-                None
-            };
-            // ...which converts it to a string
-            let paths = if is_ident { IDENT_STR_PATHS } else { SYMBOL_STR_PATHS };
-            if let Some(path) = paths.iter().find(|path| match_def_path(cx, did, path));
-            then {
-                let is_to_owned = path.last().unwrap().ends_with("string");
-                return Some(SymbolStrExpr::Expr {
-                    item,
-                    is_ident,
-                    is_to_owned,
-                });
-            }
-        }
-        // is a string constant
-        if let Some(Constant::Str(s)) = constant_simple(cx, cx.typeck_results(), expr) {
-            let value = Symbol::intern(&s).as_u32();
-            // ...which matches a symbol constant
-            if let Some(&def_id) = self.symbol_map.get(&value) {
-                return Some(SymbolStrExpr::Const(def_id));
-            }
-        }
-        None
-    }
-}
-
-enum SymbolStrExpr<'tcx> {
-    /// a string constant with a corresponding symbol constant
-    Const(DefId),
-    /// a "symbol to string" expression like `symbol.as_str()`
-    Expr {
-        /// part that evaluates to `Symbol` or `Ident`
-        item: &'tcx Expr<'tcx>,
-        is_ident: bool,
-        /// whether an owned `String` is created like `to_ident_string()`
-        is_to_owned: bool,
-    },
-}
-
-impl<'tcx> SymbolStrExpr<'tcx> {
-    /// Returns a snippet that evaluates to a `Symbol` and is const if possible
-    fn as_symbol_snippet(&self, cx: &LateContext<'_>) -> Cow<'tcx, str> {
-        match *self {
-            Self::Const(def_id) => cx.tcx.def_path_str(def_id).into(),
-            Self::Expr { item, is_ident, .. } => {
-                let mut snip = snippet(cx, item.span.source_callsite(), "..");
-                if is_ident {
-                    // get `Ident.name`
-                    snip.to_mut().push_str(".name");
-                }
-                snip
-            },
-        }
-    }
-}
-
-declare_lint_pass!(IfChainStyle => [IF_CHAIN_STYLE]);
-
-impl<'tcx> LateLintPass<'tcx> for IfChainStyle {
-    fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx hir::Block<'_>) {
-        let (local, after, if_chain_span) = if_chain! {
-            if let [Stmt { kind: StmtKind::Local(local), .. }, after @ ..] = block.stmts;
-            if let Some(if_chain_span) = is_expn_of(block.span, "if_chain");
-            then { (local, after, if_chain_span) } else { return }
-        };
-        if is_first_if_chain_expr(cx, block.hir_id, if_chain_span) {
-            span_lint(
-                cx,
-                IF_CHAIN_STYLE,
-                if_chain_local_span(cx, local, if_chain_span),
-                "`let` expression should be above the `if_chain!`",
-            );
-        } else if local.span.ctxt() == block.span.ctxt() && is_if_chain_then(after, block.expr, if_chain_span) {
-            span_lint(
-                cx,
-                IF_CHAIN_STYLE,
-                if_chain_local_span(cx, local, if_chain_span),
-                "`let` expression should be inside `then { .. }`",
-            );
-        }
-    }
-
-    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
-        let (cond, then, els) = if let Some(higher::IfOrIfLet { cond, r#else, then }) = higher::IfOrIfLet::hir(expr) {
-            (cond, then, r#else.is_some())
-        } else {
-            return;
-        };
-        let then_block = match then.kind {
-            ExprKind::Block(block, _) => block,
-            _ => return,
-        };
-        let if_chain_span = is_expn_of(expr.span, "if_chain");
-        if !els {
-            check_nested_if_chains(cx, expr, then_block, if_chain_span);
-        }
-        let if_chain_span = match if_chain_span {
-            None => return,
-            Some(span) => span,
-        };
-        // check for `if a && b;`
-        if_chain! {
-            if let ExprKind::Binary(op, _, _) = cond.kind;
-            if op.node == BinOpKind::And;
-            if cx.sess().source_map().is_multiline(cond.span);
-            then {
-                span_lint(cx, IF_CHAIN_STYLE, cond.span, "`if a && b;` should be `if a; if b;`");
-            }
-        }
-        if is_first_if_chain_expr(cx, expr.hir_id, if_chain_span)
-            && is_if_chain_then(then_block.stmts, then_block.expr, if_chain_span)
-        {
-            span_lint(cx, IF_CHAIN_STYLE, expr.span, "`if_chain!` only has one `if`");
-        }
-    }
-}
-
-fn check_nested_if_chains(
-    cx: &LateContext<'_>,
-    if_expr: &Expr<'_>,
-    then_block: &Block<'_>,
-    if_chain_span: Option<Span>,
-) {
-    #[rustfmt::skip]
-    let (head, tail) = match *then_block {
-        Block { stmts, expr: Some(tail), .. } => (stmts, tail),
-        Block {
-            stmts: &[
-                ref head @ ..,
-                Stmt { kind: StmtKind::Expr(tail) | StmtKind::Semi(tail), .. }
-            ],
-            ..
-        } => (head, tail),
-        _ => return,
-    };
-    if_chain! {
-        if let Some(higher::IfOrIfLet { r#else: None, .. }) = higher::IfOrIfLet::hir(tail);
-        let sm = cx.sess().source_map();
-        if head
-            .iter()
-            .all(|stmt| matches!(stmt.kind, StmtKind::Local(..)) && !sm.is_multiline(stmt.span));
-        if if_chain_span.is_some() || !is_else_clause(cx.tcx, if_expr);
-        then {} else { return }
-    }
-    let (span, msg) = match (if_chain_span, is_expn_of(tail.span, "if_chain")) {
-        (None, Some(_)) => (if_expr.span, "this `if` can be part of the inner `if_chain!`"),
-        (Some(_), None) => (tail.span, "this `if` can be part of the outer `if_chain!`"),
-        (Some(a), Some(b)) if a != b => (b, "this `if_chain!` can be merged with the outer `if_chain!`"),
-        _ => return,
-    };
-    span_lint_and_then(cx, IF_CHAIN_STYLE, span, msg, |diag| {
-        let (span, msg) = match head {
-            [] => return,
-            [stmt] => (stmt.span, "this `let` statement can also be in the `if_chain!`"),
-            [a, .., b] => (
-                a.span.to(b.span),
-                "these `let` statements can also be in the `if_chain!`",
-            ),
-        };
-        diag.span_help(span, msg);
-    });
-}
-
-fn is_first_if_chain_expr(cx: &LateContext<'_>, hir_id: HirId, if_chain_span: Span) -> bool {
-    cx.tcx
-        .hir()
-        .parent_iter(hir_id)
-        .find(|(_, node)| {
-            #[rustfmt::skip]
-            !matches!(node, Node::Expr(Expr { kind: ExprKind::Block(..), .. }) | Node::Stmt(_))
-        })
-        .map_or(false, |(id, _)| {
-            is_expn_of(cx.tcx.hir().span(id), "if_chain") != Some(if_chain_span)
-        })
-}
-
-/// Checks a trailing slice of statements and expression of a `Block` to see if they are part
-/// of the `then {..}` portion of an `if_chain!`
-fn is_if_chain_then(stmts: &[Stmt<'_>], expr: Option<&Expr<'_>>, if_chain_span: Span) -> bool {
-    let span = if let [stmt, ..] = stmts {
-        stmt.span
-    } else if let Some(expr) = expr {
-        expr.span
-    } else {
-        // empty `then {}`
-        return true;
-    };
-    is_expn_of(span, "if_chain").map_or(true, |span| span != if_chain_span)
-}
-
-/// Creates a `Span` for `let x = ..;` in an `if_chain!` call.
-fn if_chain_local_span(cx: &LateContext<'_>, local: &Local<'_>, if_chain_span: Span) -> Span {
-    let mut span = local.pat.span;
-    if let Some(init) = local.init {
-        span = span.to(init.span);
-    }
-    span.adjust(if_chain_span.ctxt().outer_expn());
-    let sm = cx.sess().source_map();
-    let span = sm.span_extend_to_prev_str(span, "let", false, true).unwrap_or(span);
-    let span = sm.span_extend_to_next_char(span, ';', false);
-    Span::new(
-        span.lo() - BytePos(3),
-        span.hi() + BytePos(1),
-        span.ctxt(),
-        span.parent(),
-    )
-}
-
-declare_lint_pass!(MsrvAttrImpl => [MISSING_MSRV_ATTR_IMPL]);
-
-impl LateLintPass<'_> for MsrvAttrImpl {
-    fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) {
-        if_chain! {
-            if let hir::ItemKind::Impl(hir::Impl {
-                of_trait: Some(lint_pass_trait_ref),
-                self_ty,
-                items,
-                ..
-            }) = &item.kind;
-            if let Some(lint_pass_trait_def_id) = lint_pass_trait_ref.trait_def_id();
-            let is_late_pass = match_def_path(cx, lint_pass_trait_def_id, &paths::LATE_LINT_PASS);
-            if is_late_pass || match_def_path(cx, lint_pass_trait_def_id, &paths::EARLY_LINT_PASS);
-            let self_ty = hir_ty_to_ty(cx.tcx, self_ty);
-            if let ty::Adt(self_ty_def, _) = self_ty.kind();
-            if self_ty_def.is_struct();
-            if self_ty_def.all_fields().any(|f| {
-                cx.tcx
-                    .type_of(f.did)
-                    .walk()
-                    .filter(|t| matches!(t.unpack(), GenericArgKind::Type(_)))
-                    .any(|t| match_type(cx, t.expect_ty(), &paths::RUSTC_VERSION))
-            });
-            if !items.iter().any(|item| item.ident.name == sym!(enter_lint_attrs));
-            then {
-                let context = if is_late_pass { "LateContext" } else { "EarlyContext" };
-                let lint_pass = if is_late_pass { "LateLintPass" } else { "EarlyLintPass" };
-                let span = cx.sess().source_map().span_through_char(item.span, '{');
-                span_lint_and_sugg(
-                    cx,
-                    MISSING_MSRV_ATTR_IMPL,
-                    span,
-                    &format!("`extract_msrv_attr!` macro missing from `{lint_pass}` implementation"),
-                    &format!("add `extract_msrv_attr!({context})` to the `{lint_pass}` implementation"),
-                    format!("{}\n    extract_msrv_attr!({context});", snippet(cx, span, "..")),
-                    Applicability::MachineApplicable,
-                );
-            }
-        }
-    }
-}
+pub mod msrv_attr_impl;
+pub mod outer_expn_data_pass;
+pub mod produce_ice;
+pub mod unnecessary_def_path;
diff --git a/clippy_lints/src/utils/internal_lints/clippy_lints_internal.rs b/clippy_lints/src/utils/internal_lints/clippy_lints_internal.rs
new file mode 100644
index 00000000000..da9514dd15e
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/clippy_lints_internal.rs
@@ -0,0 +1,49 @@
+use clippy_utils::diagnostics::span_lint;
+use rustc_ast::ast::{Crate, ItemKind, ModKind};
+use rustc_lint::{EarlyContext, EarlyLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for various things we like to keep tidy in clippy.
+    ///
+    /// ### Why is this bad?
+    /// We like to pretend we're an example of tidy code.
+    ///
+    /// ### Example
+    /// Wrong ordering of the util::paths constants.
+    pub CLIPPY_LINTS_INTERNAL,
+    internal,
+    "various things that will negatively affect your clippy experience"
+}
+
+declare_lint_pass!(ClippyLintsInternal => [CLIPPY_LINTS_INTERNAL]);
+
+impl EarlyLintPass for ClippyLintsInternal {
+    fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &Crate) {
+        if let Some(utils) = krate.items.iter().find(|item| item.ident.name.as_str() == "utils") {
+            if let ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) = utils.kind {
+                if let Some(paths) = items.iter().find(|item| item.ident.name.as_str() == "paths") {
+                    if let ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) = paths.kind {
+                        let mut last_name: Option<&str> = None;
+                        for item in items {
+                            let name = item.ident.as_str();
+                            if let Some(last_name) = last_name {
+                                if *last_name > *name {
+                                    span_lint(
+                                        cx,
+                                        CLIPPY_LINTS_INTERNAL,
+                                        item.span,
+                                        "this constant should be before the previous constant due to lexical \
+                                         ordering",
+                                    );
+                                }
+                            }
+                            last_name = Some(name);
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
diff --git a/clippy_lints/src/utils/internal_lints/collapsible_calls.rs b/clippy_lints/src/utils/internal_lints/collapsible_calls.rs
new file mode 100644
index 00000000000..d7666b77f6e
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/collapsible_calls.rs
@@ -0,0 +1,245 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::{is_expr_path_def_path, is_lint_allowed, peel_blocks_with_stmt, SpanlessEq};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_hir::{Closure, Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+use std::borrow::{Borrow, Cow};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Lints `span_lint_and_then` function calls, where the
+    /// closure argument has only one statement and that statement is a method
+    /// call to `span_suggestion`, `span_help`, `span_note` (using the same
+    /// span), `help` or `note`.
+    ///
+    /// These usages of `span_lint_and_then` should be replaced with one of the
+    /// wrapper functions `span_lint_and_sugg`, span_lint_and_help`, or
+    /// `span_lint_and_note`.
+    ///
+    /// ### Why is this bad?
+    /// Using the wrapper `span_lint_and_*` functions, is more
+    /// convenient, readable and less error prone.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
+    ///     diag.span_suggestion(
+    ///         expr.span,
+    ///         help_msg,
+    ///         sugg.to_string(),
+    ///         Applicability::MachineApplicable,
+    ///     );
+    /// });
+    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
+    ///     diag.span_help(expr.span, help_msg);
+    /// });
+    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
+    ///     diag.help(help_msg);
+    /// });
+    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
+    ///     diag.span_note(expr.span, note_msg);
+    /// });
+    /// span_lint_and_then(cx, TEST_LINT, expr.span, lint_msg, |diag| {
+    ///     diag.note(note_msg);
+    /// });
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// span_lint_and_sugg(
+    ///     cx,
+    ///     TEST_LINT,
+    ///     expr.span,
+    ///     lint_msg,
+    ///     help_msg,
+    ///     sugg.to_string(),
+    ///     Applicability::MachineApplicable,
+    /// );
+    /// span_lint_and_help(cx, TEST_LINT, expr.span, lint_msg, Some(expr.span), help_msg);
+    /// span_lint_and_help(cx, TEST_LINT, expr.span, lint_msg, None, help_msg);
+    /// span_lint_and_note(cx, TEST_LINT, expr.span, lint_msg, Some(expr.span), note_msg);
+    /// span_lint_and_note(cx, TEST_LINT, expr.span, lint_msg, None, note_msg);
+    /// ```
+    pub COLLAPSIBLE_SPAN_LINT_CALLS,
+    internal,
+    "found collapsible `span_lint_and_then` calls"
+}
+
+declare_lint_pass!(CollapsibleCalls => [COLLAPSIBLE_SPAN_LINT_CALLS]);
+
+impl<'tcx> LateLintPass<'tcx> for CollapsibleCalls {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
+        if is_lint_allowed(cx, COLLAPSIBLE_SPAN_LINT_CALLS, expr.hir_id) {
+            return;
+        }
+
+        if_chain! {
+            if let ExprKind::Call(func, and_then_args) = expr.kind;
+            if is_expr_path_def_path(cx, func, &["clippy_utils", "diagnostics", "span_lint_and_then"]);
+            if and_then_args.len() == 5;
+            if let ExprKind::Closure(&Closure { body, .. }) = &and_then_args[4].kind;
+            let body = cx.tcx.hir().body(body);
+            let only_expr = peel_blocks_with_stmt(body.value);
+            if let ExprKind::MethodCall(ps, recv, span_call_args, _) = &only_expr.kind;
+            if let ExprKind::Path(..) = recv.kind;
+            then {
+                let and_then_snippets = get_and_then_snippets(cx, and_then_args);
+                let mut sle = SpanlessEq::new(cx).deny_side_effects();
+                match ps.ident.as_str() {
+                    "span_suggestion" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
+                        suggest_suggestion(
+                            cx,
+                            expr,
+                            &and_then_snippets,
+                            &span_suggestion_snippets(cx, span_call_args),
+                        );
+                    },
+                    "span_help" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
+                        let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
+                        suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), true);
+                    },
+                    "span_note" if sle.eq_expr(&and_then_args[2], &span_call_args[0]) => {
+                        let note_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
+                        suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), true);
+                    },
+                    "help" => {
+                        let help_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
+                        suggest_help(cx, expr, &and_then_snippets, help_snippet.borrow(), false);
+                    },
+                    "note" => {
+                        let note_snippet = snippet(cx, span_call_args[0].span, r#""...""#);
+                        suggest_note(cx, expr, &and_then_snippets, note_snippet.borrow(), false);
+                    },
+                    _ => (),
+                }
+            }
+        }
+    }
+}
+
+struct AndThenSnippets<'a> {
+    cx: Cow<'a, str>,
+    lint: Cow<'a, str>,
+    span: Cow<'a, str>,
+    msg: Cow<'a, str>,
+}
+
+fn get_and_then_snippets<'a, 'hir>(cx: &LateContext<'_>, and_then_snippets: &'hir [Expr<'hir>]) -> AndThenSnippets<'a> {
+    let cx_snippet = snippet(cx, and_then_snippets[0].span, "cx");
+    let lint_snippet = snippet(cx, and_then_snippets[1].span, "..");
+    let span_snippet = snippet(cx, and_then_snippets[2].span, "span");
+    let msg_snippet = snippet(cx, and_then_snippets[3].span, r#""...""#);
+
+    AndThenSnippets {
+        cx: cx_snippet,
+        lint: lint_snippet,
+        span: span_snippet,
+        msg: msg_snippet,
+    }
+}
+
+struct SpanSuggestionSnippets<'a> {
+    help: Cow<'a, str>,
+    sugg: Cow<'a, str>,
+    applicability: Cow<'a, str>,
+}
+
+fn span_suggestion_snippets<'a, 'hir>(
+    cx: &LateContext<'_>,
+    span_call_args: &'hir [Expr<'hir>],
+) -> SpanSuggestionSnippets<'a> {
+    let help_snippet = snippet(cx, span_call_args[1].span, r#""...""#);
+    let sugg_snippet = snippet(cx, span_call_args[2].span, "..");
+    let applicability_snippet = snippet(cx, span_call_args[3].span, "Applicability::MachineApplicable");
+
+    SpanSuggestionSnippets {
+        help: help_snippet,
+        sugg: sugg_snippet,
+        applicability: applicability_snippet,
+    }
+}
+
+fn suggest_suggestion(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    and_then_snippets: &AndThenSnippets<'_>,
+    span_suggestion_snippets: &SpanSuggestionSnippets<'_>,
+) {
+    span_lint_and_sugg(
+        cx,
+        COLLAPSIBLE_SPAN_LINT_CALLS,
+        expr.span,
+        "this call is collapsible",
+        "collapse into",
+        format!(
+            "span_lint_and_sugg({}, {}, {}, {}, {}, {}, {})",
+            and_then_snippets.cx,
+            and_then_snippets.lint,
+            and_then_snippets.span,
+            and_then_snippets.msg,
+            span_suggestion_snippets.help,
+            span_suggestion_snippets.sugg,
+            span_suggestion_snippets.applicability
+        ),
+        Applicability::MachineApplicable,
+    );
+}
+
+fn suggest_help(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    and_then_snippets: &AndThenSnippets<'_>,
+    help: &str,
+    with_span: bool,
+) {
+    let option_span = if with_span {
+        format!("Some({})", and_then_snippets.span)
+    } else {
+        "None".to_string()
+    };
+
+    span_lint_and_sugg(
+        cx,
+        COLLAPSIBLE_SPAN_LINT_CALLS,
+        expr.span,
+        "this call is collapsible",
+        "collapse into",
+        format!(
+            "span_lint_and_help({}, {}, {}, {}, {}, {help})",
+            and_then_snippets.cx, and_then_snippets.lint, and_then_snippets.span, and_then_snippets.msg, &option_span,
+        ),
+        Applicability::MachineApplicable,
+    );
+}
+
+fn suggest_note(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    and_then_snippets: &AndThenSnippets<'_>,
+    note: &str,
+    with_span: bool,
+) {
+    let note_span = if with_span {
+        format!("Some({})", and_then_snippets.span)
+    } else {
+        "None".to_string()
+    };
+
+    span_lint_and_sugg(
+        cx,
+        COLLAPSIBLE_SPAN_LINT_CALLS,
+        expr.span,
+        "this call is collapsible",
+        "collapse into",
+        format!(
+            "span_lint_and_note({}, {}, {}, {}, {note_span}, {note})",
+            and_then_snippets.cx, and_then_snippets.lint, and_then_snippets.span, and_then_snippets.msg,
+        ),
+        Applicability::MachineApplicable,
+    );
+}
diff --git a/clippy_lints/src/utils/internal_lints/compiler_lint_functions.rs b/clippy_lints/src/utils/internal_lints/compiler_lint_functions.rs
new file mode 100644
index 00000000000..cacd05262a2
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/compiler_lint_functions.rs
@@ -0,0 +1,77 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::ty::match_type;
+use clippy_utils::{is_lint_allowed, paths};
+use if_chain::if_chain;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for calls to `cx.span_lint*` and suggests to use the `utils::*`
+    /// variant of the function.
+    ///
+    /// ### Why is this bad?
+    /// The `utils::*` variants also add a link to the Clippy documentation to the
+    /// warning/error messages.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// cx.span_lint(LINT_NAME, "message");
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// utils::span_lint(cx, LINT_NAME, "message");
+    /// ```
+    pub COMPILER_LINT_FUNCTIONS,
+    internal,
+    "usage of the lint functions of the compiler instead of the utils::* variant"
+}
+
+impl_lint_pass!(CompilerLintFunctions => [COMPILER_LINT_FUNCTIONS]);
+
+#[derive(Clone, Default)]
+pub struct CompilerLintFunctions {
+    map: FxHashMap<&'static str, &'static str>,
+}
+
+impl CompilerLintFunctions {
+    #[must_use]
+    pub fn new() -> Self {
+        let mut map = FxHashMap::default();
+        map.insert("span_lint", "utils::span_lint");
+        map.insert("struct_span_lint", "utils::span_lint");
+        map.insert("lint", "utils::span_lint");
+        map.insert("span_lint_note", "utils::span_lint_and_note");
+        map.insert("span_lint_help", "utils::span_lint_and_help");
+        Self { map }
+    }
+}
+
+impl<'tcx> LateLintPass<'tcx> for CompilerLintFunctions {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+        if is_lint_allowed(cx, COMPILER_LINT_FUNCTIONS, expr.hir_id) {
+            return;
+        }
+
+        if_chain! {
+            if let ExprKind::MethodCall(path, self_arg, _, _) = &expr.kind;
+            let fn_name = path.ident;
+            if let Some(sugg) = self.map.get(fn_name.as_str());
+            let ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
+            if match_type(cx, ty, &paths::EARLY_CONTEXT) || match_type(cx, ty, &paths::LATE_CONTEXT);
+            then {
+                span_lint_and_help(
+                    cx,
+                    COMPILER_LINT_FUNCTIONS,
+                    path.ident.span,
+                    "usage of a compiler lint function",
+                    None,
+                    &format!("please use the Clippy variant of this function: `{sugg}`"),
+                );
+            }
+        }
+    }
+}
diff --git a/clippy_lints/src/utils/internal_lints/if_chain_style.rs b/clippy_lints/src/utils/internal_lints/if_chain_style.rs
new file mode 100644
index 00000000000..883a5c08e5c
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/if_chain_style.rs
@@ -0,0 +1,164 @@
+use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
+use clippy_utils::{higher, is_else_clause, is_expn_of};
+use if_chain::if_chain;
+use rustc_hir as hir;
+use rustc_hir::{BinOpKind, Block, Expr, ExprKind, HirId, Local, Node, Stmt, StmtKind};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::{BytePos, Span};
+
+declare_clippy_lint! {
+    /// Finds unidiomatic usage of `if_chain!`
+    pub IF_CHAIN_STYLE,
+    internal,
+    "non-idiomatic `if_chain!` usage"
+}
+
+declare_lint_pass!(IfChainStyle => [IF_CHAIN_STYLE]);
+
+impl<'tcx> LateLintPass<'tcx> for IfChainStyle {
+    fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx hir::Block<'_>) {
+        let (local, after, if_chain_span) = if_chain! {
+            if let [Stmt { kind: StmtKind::Local(local), .. }, after @ ..] = block.stmts;
+            if let Some(if_chain_span) = is_expn_of(block.span, "if_chain");
+            then { (local, after, if_chain_span) } else { return }
+        };
+        if is_first_if_chain_expr(cx, block.hir_id, if_chain_span) {
+            span_lint(
+                cx,
+                IF_CHAIN_STYLE,
+                if_chain_local_span(cx, local, if_chain_span),
+                "`let` expression should be above the `if_chain!`",
+            );
+        } else if local.span.ctxt() == block.span.ctxt() && is_if_chain_then(after, block.expr, if_chain_span) {
+            span_lint(
+                cx,
+                IF_CHAIN_STYLE,
+                if_chain_local_span(cx, local, if_chain_span),
+                "`let` expression should be inside `then { .. }`",
+            );
+        }
+    }
+
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
+        let (cond, then, els) = if let Some(higher::IfOrIfLet { cond, r#else, then }) = higher::IfOrIfLet::hir(expr) {
+            (cond, then, r#else.is_some())
+        } else {
+            return;
+        };
+        let ExprKind::Block(then_block, _) = then.kind else { return };
+        let if_chain_span = is_expn_of(expr.span, "if_chain");
+        if !els {
+            check_nested_if_chains(cx, expr, then_block, if_chain_span);
+        }
+        let Some(if_chain_span) = if_chain_span else { return };
+        // check for `if a && b;`
+        if_chain! {
+            if let ExprKind::Binary(op, _, _) = cond.kind;
+            if op.node == BinOpKind::And;
+            if cx.sess().source_map().is_multiline(cond.span);
+            then {
+                span_lint(cx, IF_CHAIN_STYLE, cond.span, "`if a && b;` should be `if a; if b;`");
+            }
+        }
+        if is_first_if_chain_expr(cx, expr.hir_id, if_chain_span)
+            && is_if_chain_then(then_block.stmts, then_block.expr, if_chain_span)
+        {
+            span_lint(cx, IF_CHAIN_STYLE, expr.span, "`if_chain!` only has one `if`");
+        }
+    }
+}
+
+fn check_nested_if_chains(
+    cx: &LateContext<'_>,
+    if_expr: &Expr<'_>,
+    then_block: &Block<'_>,
+    if_chain_span: Option<Span>,
+) {
+    #[rustfmt::skip]
+    let (head, tail) = match *then_block {
+        Block { stmts, expr: Some(tail), .. } => (stmts, tail),
+        Block {
+            stmts: &[
+                ref head @ ..,
+                Stmt { kind: StmtKind::Expr(tail) | StmtKind::Semi(tail), .. }
+            ],
+            ..
+        } => (head, tail),
+        _ => return,
+    };
+    if_chain! {
+        if let Some(higher::IfOrIfLet { r#else: None, .. }) = higher::IfOrIfLet::hir(tail);
+        let sm = cx.sess().source_map();
+        if head
+            .iter()
+            .all(|stmt| matches!(stmt.kind, StmtKind::Local(..)) && !sm.is_multiline(stmt.span));
+        if if_chain_span.is_some() || !is_else_clause(cx.tcx, if_expr);
+        then {
+        } else {
+            return;
+        }
+    }
+    let (span, msg) = match (if_chain_span, is_expn_of(tail.span, "if_chain")) {
+        (None, Some(_)) => (if_expr.span, "this `if` can be part of the inner `if_chain!`"),
+        (Some(_), None) => (tail.span, "this `if` can be part of the outer `if_chain!`"),
+        (Some(a), Some(b)) if a != b => (b, "this `if_chain!` can be merged with the outer `if_chain!`"),
+        _ => return,
+    };
+    span_lint_and_then(cx, IF_CHAIN_STYLE, span, msg, |diag| {
+        let (span, msg) = match head {
+            [] => return,
+            [stmt] => (stmt.span, "this `let` statement can also be in the `if_chain!`"),
+            [a, .., b] => (
+                a.span.to(b.span),
+                "these `let` statements can also be in the `if_chain!`",
+            ),
+        };
+        diag.span_help(span, msg);
+    });
+}
+
+fn is_first_if_chain_expr(cx: &LateContext<'_>, hir_id: HirId, if_chain_span: Span) -> bool {
+    cx.tcx
+        .hir()
+        .parent_iter(hir_id)
+        .find(|(_, node)| {
+            #[rustfmt::skip]
+            !matches!(node, Node::Expr(Expr { kind: ExprKind::Block(..), .. }) | Node::Stmt(_))
+        })
+        .map_or(false, |(id, _)| {
+            is_expn_of(cx.tcx.hir().span(id), "if_chain") != Some(if_chain_span)
+        })
+}
+
+/// Checks a trailing slice of statements and expression of a `Block` to see if they are part
+/// of the `then {..}` portion of an `if_chain!`
+fn is_if_chain_then(stmts: &[Stmt<'_>], expr: Option<&Expr<'_>>, if_chain_span: Span) -> bool {
+    let span = if let [stmt, ..] = stmts {
+        stmt.span
+    } else if let Some(expr) = expr {
+        expr.span
+    } else {
+        // empty `then {}`
+        return true;
+    };
+    is_expn_of(span, "if_chain").map_or(true, |span| span != if_chain_span)
+}
+
+/// Creates a `Span` for `let x = ..;` in an `if_chain!` call.
+fn if_chain_local_span(cx: &LateContext<'_>, local: &Local<'_>, if_chain_span: Span) -> Span {
+    let mut span = local.pat.span;
+    if let Some(init) = local.init {
+        span = span.to(init.span);
+    }
+    span.adjust(if_chain_span.ctxt().outer_expn());
+    let sm = cx.sess().source_map();
+    let span = sm.span_extend_to_prev_str(span, "let", false, true).unwrap_or(span);
+    let span = sm.span_extend_to_next_char(span, ';', false);
+    Span::new(
+        span.lo() - BytePos(3),
+        span.hi() + BytePos(1),
+        span.ctxt(),
+        span.parent(),
+    )
+}
diff --git a/clippy_lints/src/utils/internal_lints/interning_defined_symbol.rs b/clippy_lints/src/utils/internal_lints/interning_defined_symbol.rs
new file mode 100644
index 00000000000..096b601572b
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/interning_defined_symbol.rs
@@ -0,0 +1,239 @@
+use clippy_utils::consts::{constant_simple, Constant};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::ty::match_type;
+use clippy_utils::{def_path_res, is_expn_of, match_def_path, paths};
+use if_chain::if_chain;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_errors::Applicability;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def_id::DefId;
+use rustc_hir::{BinOpKind, Expr, ExprKind, UnOp};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::mir::interpret::ConstValue;
+use rustc_middle::ty::{self};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::Symbol;
+
+use std::borrow::Cow;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for interning symbols that have already been pre-interned and defined as constants.
+    ///
+    /// ### Why is this bad?
+    /// It's faster and easier to use the symbol constant.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// let _ = sym!(f32);
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// let _ = sym::f32;
+    /// ```
+    pub INTERNING_DEFINED_SYMBOL,
+    internal,
+    "interning a symbol that is pre-interned and defined as a constant"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for unnecessary conversion from Symbol to a string.
+    ///
+    /// ### Why is this bad?
+    /// It's faster use symbols directly instead of strings.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// symbol.as_str() == "clippy";
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// symbol == sym::clippy;
+    /// ```
+    pub UNNECESSARY_SYMBOL_STR,
+    internal,
+    "unnecessary conversion between Symbol and string"
+}
+
+#[derive(Default)]
+pub struct InterningDefinedSymbol {
+    // Maps the symbol value to the constant DefId.
+    symbol_map: FxHashMap<u32, DefId>,
+}
+
+impl_lint_pass!(InterningDefinedSymbol => [INTERNING_DEFINED_SYMBOL, UNNECESSARY_SYMBOL_STR]);
+
+impl<'tcx> LateLintPass<'tcx> for InterningDefinedSymbol {
+    fn check_crate(&mut self, cx: &LateContext<'_>) {
+        if !self.symbol_map.is_empty() {
+            return;
+        }
+
+        for &module in &[&paths::KW_MODULE, &paths::SYM_MODULE] {
+            if let Some(def_id) = def_path_res(cx, module, None).opt_def_id() {
+                for item in cx.tcx.module_children(def_id).iter() {
+                    if_chain! {
+                        if let Res::Def(DefKind::Const, item_def_id) = item.res;
+                        let ty = cx.tcx.type_of(item_def_id);
+                        if match_type(cx, ty, &paths::SYMBOL);
+                        if let Ok(ConstValue::Scalar(value)) = cx.tcx.const_eval_poly(item_def_id);
+                        if let Ok(value) = value.to_u32();
+                        then {
+                            self.symbol_map.insert(value, item_def_id);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
+        if_chain! {
+            if let ExprKind::Call(func, [arg]) = &expr.kind;
+            if let ty::FnDef(def_id, _) = cx.typeck_results().expr_ty(func).kind();
+            if match_def_path(cx, *def_id, &paths::SYMBOL_INTERN);
+            if let Some(Constant::Str(arg)) = constant_simple(cx, cx.typeck_results(), arg);
+            let value = Symbol::intern(&arg).as_u32();
+            if let Some(&def_id) = self.symbol_map.get(&value);
+            then {
+                span_lint_and_sugg(
+                    cx,
+                    INTERNING_DEFINED_SYMBOL,
+                    is_expn_of(expr.span, "sym").unwrap_or(expr.span),
+                    "interning a defined symbol",
+                    "try",
+                    cx.tcx.def_path_str(def_id),
+                    Applicability::MachineApplicable,
+                );
+            }
+        }
+        if let ExprKind::Binary(op, left, right) = expr.kind {
+            if matches!(op.node, BinOpKind::Eq | BinOpKind::Ne) {
+                let data = [
+                    (left, self.symbol_str_expr(left, cx)),
+                    (right, self.symbol_str_expr(right, cx)),
+                ];
+                match data {
+                    // both operands are a symbol string
+                    [(_, Some(left)), (_, Some(right))] => {
+                        span_lint_and_sugg(
+                            cx,
+                            UNNECESSARY_SYMBOL_STR,
+                            expr.span,
+                            "unnecessary `Symbol` to string conversion",
+                            "try",
+                            format!(
+                                "{} {} {}",
+                                left.as_symbol_snippet(cx),
+                                op.node.as_str(),
+                                right.as_symbol_snippet(cx),
+                            ),
+                            Applicability::MachineApplicable,
+                        );
+                    },
+                    // one of the operands is a symbol string
+                    [(expr, Some(symbol)), _] | [_, (expr, Some(symbol))] => {
+                        // creating an owned string for comparison
+                        if matches!(symbol, SymbolStrExpr::Expr { is_to_owned: true, .. }) {
+                            span_lint_and_sugg(
+                                cx,
+                                UNNECESSARY_SYMBOL_STR,
+                                expr.span,
+                                "unnecessary string allocation",
+                                "try",
+                                format!("{}.as_str()", symbol.as_symbol_snippet(cx)),
+                                Applicability::MachineApplicable,
+                            );
+                        }
+                    },
+                    // nothing found
+                    [(_, None), (_, None)] => {},
+                }
+            }
+        }
+    }
+}
+
+impl InterningDefinedSymbol {
+    fn symbol_str_expr<'tcx>(&self, expr: &'tcx Expr<'tcx>, cx: &LateContext<'tcx>) -> Option<SymbolStrExpr<'tcx>> {
+        static IDENT_STR_PATHS: &[&[&str]] = &[&paths::IDENT_AS_STR, &paths::TO_STRING_METHOD];
+        static SYMBOL_STR_PATHS: &[&[&str]] = &[
+            &paths::SYMBOL_AS_STR,
+            &paths::SYMBOL_TO_IDENT_STRING,
+            &paths::TO_STRING_METHOD,
+        ];
+        let call = if_chain! {
+            if let ExprKind::AddrOf(_, _, e) = expr.kind;
+            if let ExprKind::Unary(UnOp::Deref, e) = e.kind;
+            then { e } else { expr }
+        };
+        if_chain! {
+            // is a method call
+            if let ExprKind::MethodCall(_, item, [], _) = call.kind;
+            if let Some(did) = cx.typeck_results().type_dependent_def_id(call.hir_id);
+            let ty = cx.typeck_results().expr_ty(item);
+            // ...on either an Ident or a Symbol
+            if let Some(is_ident) = if match_type(cx, ty, &paths::SYMBOL) {
+                Some(false)
+            } else if match_type(cx, ty, &paths::IDENT) {
+                Some(true)
+            } else {
+                None
+            };
+            // ...which converts it to a string
+            let paths = if is_ident { IDENT_STR_PATHS } else { SYMBOL_STR_PATHS };
+            if let Some(path) = paths.iter().find(|path| match_def_path(cx, did, path));
+            then {
+                let is_to_owned = path.last().unwrap().ends_with("string");
+                return Some(SymbolStrExpr::Expr {
+                    item,
+                    is_ident,
+                    is_to_owned,
+                });
+            }
+        }
+        // is a string constant
+        if let Some(Constant::Str(s)) = constant_simple(cx, cx.typeck_results(), expr) {
+            let value = Symbol::intern(&s).as_u32();
+            // ...which matches a symbol constant
+            if let Some(&def_id) = self.symbol_map.get(&value) {
+                return Some(SymbolStrExpr::Const(def_id));
+            }
+        }
+        None
+    }
+}
+
+enum SymbolStrExpr<'tcx> {
+    /// a string constant with a corresponding symbol constant
+    Const(DefId),
+    /// a "symbol to string" expression like `symbol.as_str()`
+    Expr {
+        /// part that evaluates to `Symbol` or `Ident`
+        item: &'tcx Expr<'tcx>,
+        is_ident: bool,
+        /// whether an owned `String` is created like `to_ident_string()`
+        is_to_owned: bool,
+    },
+}
+
+impl<'tcx> SymbolStrExpr<'tcx> {
+    /// Returns a snippet that evaluates to a `Symbol` and is const if possible
+    fn as_symbol_snippet(&self, cx: &LateContext<'_>) -> Cow<'tcx, str> {
+        match *self {
+            Self::Const(def_id) => cx.tcx.def_path_str(def_id).into(),
+            Self::Expr { item, is_ident, .. } => {
+                let mut snip = snippet(cx, item.span.source_callsite(), "..");
+                if is_ident {
+                    // get `Ident.name`
+                    snip.to_mut().push_str(".name");
+                }
+                snip
+            },
+        }
+    }
+}
diff --git a/clippy_lints/src/utils/internal_lints/invalid_paths.rs b/clippy_lints/src/utils/internal_lints/invalid_paths.rs
new file mode 100644
index 00000000000..25532dd4e26
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/invalid_paths.rs
@@ -0,0 +1,108 @@
+use clippy_utils::consts::{constant_simple, Constant};
+use clippy_utils::def_path_res;
+use clippy_utils::diagnostics::span_lint;
+use if_chain::if_chain;
+use rustc_hir as hir;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::Item;
+use rustc_hir_analysis::hir_ty_to_ty;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::ty::{self, fast_reject::SimplifiedTypeGen, FloatTy};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::Symbol;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks the paths module for invalid paths.
+    ///
+    /// ### Why is this bad?
+    /// It indicates a bug in the code.
+    ///
+    /// ### Example
+    /// None.
+    pub INVALID_PATHS,
+    internal,
+    "invalid path"
+}
+
+declare_lint_pass!(InvalidPaths => [INVALID_PATHS]);
+
+impl<'tcx> LateLintPass<'tcx> for InvalidPaths {
+    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
+        let local_def_id = &cx.tcx.parent_module(item.hir_id());
+        let mod_name = &cx.tcx.item_name(local_def_id.to_def_id());
+        if_chain! {
+            if mod_name.as_str() == "paths";
+            if let hir::ItemKind::Const(ty, body_id) = item.kind;
+            let ty = hir_ty_to_ty(cx.tcx, ty);
+            if let ty::Array(el_ty, _) = &ty.kind();
+            if let ty::Ref(_, el_ty, _) = &el_ty.kind();
+            if el_ty.is_str();
+            let body = cx.tcx.hir().body(body_id);
+            let typeck_results = cx.tcx.typeck_body(body_id);
+            if let Some(Constant::Vec(path)) = constant_simple(cx, typeck_results, body.value);
+            let path: Vec<&str> = path
+                .iter()
+                .map(|x| {
+                    if let Constant::Str(s) = x {
+                        s.as_str()
+                    } else {
+                        // We checked the type of the constant above
+                        unreachable!()
+                    }
+                })
+                .collect();
+            if !check_path(cx, &path[..]);
+            then {
+                span_lint(cx, INVALID_PATHS, item.span, "invalid path");
+            }
+        }
+    }
+}
+
+// This is not a complete resolver for paths. It works on all the paths currently used in the paths
+// module.  That's all it does and all it needs to do.
+pub fn check_path(cx: &LateContext<'_>, path: &[&str]) -> bool {
+    if def_path_res(cx, path, None) != Res::Err {
+        return true;
+    }
+
+    // Some implementations can't be found by `path_to_res`, particularly inherent
+    // implementations of native types. Check lang items.
+    let path_syms: Vec<_> = path.iter().map(|p| Symbol::intern(p)).collect();
+    let lang_items = cx.tcx.lang_items();
+    // This list isn't complete, but good enough for our current list of paths.
+    let incoherent_impls = [
+        SimplifiedTypeGen::FloatSimplifiedType(FloatTy::F32),
+        SimplifiedTypeGen::FloatSimplifiedType(FloatTy::F64),
+        SimplifiedTypeGen::SliceSimplifiedType,
+        SimplifiedTypeGen::StrSimplifiedType,
+    ]
+    .iter()
+    .flat_map(|&ty| cx.tcx.incoherent_impls(ty));
+    for item_def_id in lang_items.items().iter().flatten().chain(incoherent_impls) {
+        let lang_item_path = cx.get_def_path(*item_def_id);
+        if path_syms.starts_with(&lang_item_path) {
+            if let [item] = &path_syms[lang_item_path.len()..] {
+                if matches!(
+                    cx.tcx.def_kind(*item_def_id),
+                    DefKind::Mod | DefKind::Enum | DefKind::Trait
+                ) {
+                    for child in cx.tcx.module_children(*item_def_id) {
+                        if child.ident.name == *item {
+                            return true;
+                        }
+                    }
+                } else {
+                    for child in cx.tcx.associated_item_def_ids(*item_def_id) {
+                        if cx.tcx.item_name(*child) == *item {
+                            return true;
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    false
+}
diff --git a/clippy_lints/src/utils/internal_lints/lint_without_lint_pass.rs b/clippy_lints/src/utils/internal_lints/lint_without_lint_pass.rs
new file mode 100644
index 00000000000..0dac64376b0
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/lint_without_lint_pass.rs
@@ -0,0 +1,342 @@
+use crate::utils::internal_lints::metadata_collector::is_deprecated_lint;
+use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
+use clippy_utils::macros::root_macro_call_first_node;
+use clippy_utils::{is_lint_allowed, match_def_path, paths};
+use if_chain::if_chain;
+use rustc_ast as ast;
+use rustc_ast::ast::LitKind;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_hir as hir;
+use rustc_hir::def::{DefKind, Res};
+use rustc_hir::hir_id::CRATE_HIR_ID;
+use rustc_hir::intravisit::Visitor;
+use rustc_hir::{ExprKind, HirId, Item, MutTy, Mutability, Path, TyKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::hir::nested_filter;
+use rustc_semver::RustcVersion;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::source_map::Spanned;
+use rustc_span::symbol::Symbol;
+use rustc_span::{sym, Span};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Ensures every lint is associated to a `LintPass`.
+    ///
+    /// ### Why is this bad?
+    /// The compiler only knows lints via a `LintPass`. Without
+    /// putting a lint to a `LintPass::get_lints()`'s return, the compiler will not
+    /// know the name of the lint.
+    ///
+    /// ### Known problems
+    /// Only checks for lints associated using the
+    /// `declare_lint_pass!`, `impl_lint_pass!`, and `lint_array!` macros.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// declare_lint! { pub LINT_1, ... }
+    /// declare_lint! { pub LINT_2, ... }
+    /// declare_lint! { pub FORGOTTEN_LINT, ... }
+    /// // ...
+    /// declare_lint_pass!(Pass => [LINT_1, LINT_2]);
+    /// // missing FORGOTTEN_LINT
+    /// ```
+    pub LINT_WITHOUT_LINT_PASS,
+    internal,
+    "declaring a lint without associating it in a LintPass"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for cases of an auto-generated lint without an updated description,
+    /// i.e. `default lint description`.
+    ///
+    /// ### Why is this bad?
+    /// Indicates that the lint is not finished.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// declare_lint! { pub COOL_LINT, nursery, "default lint description" }
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// declare_lint! { pub COOL_LINT, nursery, "a great new lint" }
+    /// ```
+    pub DEFAULT_LINT,
+    internal,
+    "found 'default lint description' in a lint declaration"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for invalid `clippy::version` attributes.
+    ///
+    /// Valid values are:
+    /// * "pre 1.29.0"
+    /// * any valid semantic version
+    pub INVALID_CLIPPY_VERSION_ATTRIBUTE,
+    internal,
+    "found an invalid `clippy::version` attribute"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for declared clippy lints without the `clippy::version` attribute.
+    ///
+    pub MISSING_CLIPPY_VERSION_ATTRIBUTE,
+    internal,
+    "found clippy lint without `clippy::version` attribute"
+}
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for cases of an auto-generated deprecated lint without an updated reason,
+    /// i.e. `"default deprecation note"`.
+    ///
+    /// ### Why is this bad?
+    /// Indicates that the documentation is incomplete.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// declare_deprecated_lint! {
+    ///     /// ### What it does
+    ///     /// Nothing. This lint has been deprecated.
+    ///     ///
+    ///     /// ### Deprecation reason
+    ///     /// TODO
+    ///     #[clippy::version = "1.63.0"]
+    ///     pub COOL_LINT,
+    ///     "default deprecation note"
+    /// }
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// declare_deprecated_lint! {
+    ///     /// ### What it does
+    ///     /// Nothing. This lint has been deprecated.
+    ///     ///
+    ///     /// ### Deprecation reason
+    ///     /// This lint has been replaced by `cooler_lint`
+    ///     #[clippy::version = "1.63.0"]
+    ///     pub COOL_LINT,
+    ///     "this lint has been replaced by `cooler_lint`"
+    /// }
+    /// ```
+    pub DEFAULT_DEPRECATION_REASON,
+    internal,
+    "found 'default deprecation note' in a deprecated lint declaration"
+}
+
+#[derive(Clone, Debug, Default)]
+pub struct LintWithoutLintPass {
+    declared_lints: FxHashMap<Symbol, Span>,
+    registered_lints: FxHashSet<Symbol>,
+}
+
+impl_lint_pass!(LintWithoutLintPass => [DEFAULT_LINT, LINT_WITHOUT_LINT_PASS, INVALID_CLIPPY_VERSION_ATTRIBUTE, MISSING_CLIPPY_VERSION_ATTRIBUTE, DEFAULT_DEPRECATION_REASON]);
+
+impl<'tcx> LateLintPass<'tcx> for LintWithoutLintPass {
+    fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
+        if is_lint_allowed(cx, DEFAULT_LINT, item.hir_id())
+            || is_lint_allowed(cx, DEFAULT_DEPRECATION_REASON, item.hir_id())
+        {
+            return;
+        }
+
+        if let hir::ItemKind::Static(ty, Mutability::Not, body_id) = item.kind {
+            let is_lint_ref_ty = is_lint_ref_type(cx, ty);
+            if is_deprecated_lint(cx, ty) || is_lint_ref_ty {
+                check_invalid_clippy_version_attribute(cx, item);
+
+                let expr = &cx.tcx.hir().body(body_id).value;
+                let fields;
+                if is_lint_ref_ty {
+                    if let ExprKind::AddrOf(_, _, inner_exp) = expr.kind
+                        && let ExprKind::Struct(_, struct_fields, _) = inner_exp.kind {
+                            fields = struct_fields;
+                    } else {
+                        return;
+                    }
+                } else if let ExprKind::Struct(_, struct_fields, _) = expr.kind {
+                    fields = struct_fields;
+                } else {
+                    return;
+                }
+
+                let field = fields
+                    .iter()
+                    .find(|f| f.ident.as_str() == "desc")
+                    .expect("lints must have a description field");
+
+                if let ExprKind::Lit(Spanned {
+                    node: LitKind::Str(ref sym, _),
+                    ..
+                }) = field.expr.kind
+                {
+                    let sym_str = sym.as_str();
+                    if is_lint_ref_ty {
+                        if sym_str == "default lint description" {
+                            span_lint(
+                                cx,
+                                DEFAULT_LINT,
+                                item.span,
+                                &format!("the lint `{}` has the default lint description", item.ident.name),
+                            );
+                        }
+
+                        self.declared_lints.insert(item.ident.name, item.span);
+                    } else if sym_str == "default deprecation note" {
+                        span_lint(
+                            cx,
+                            DEFAULT_DEPRECATION_REASON,
+                            item.span,
+                            &format!("the lint `{}` has the default deprecation reason", item.ident.name),
+                        );
+                    }
+                }
+            }
+        } else if let Some(macro_call) = root_macro_call_first_node(cx, item) {
+            if !matches!(
+                cx.tcx.item_name(macro_call.def_id).as_str(),
+                "impl_lint_pass" | "declare_lint_pass"
+            ) {
+                return;
+            }
+            if let hir::ItemKind::Impl(hir::Impl {
+                of_trait: None,
+                items: impl_item_refs,
+                ..
+            }) = item.kind
+            {
+                let mut collector = LintCollector {
+                    output: &mut self.registered_lints,
+                    cx,
+                };
+                let body_id = cx.tcx.hir().body_owned_by(
+                    cx.tcx.hir().local_def_id(
+                        impl_item_refs
+                            .iter()
+                            .find(|iiref| iiref.ident.as_str() == "get_lints")
+                            .expect("LintPass needs to implement get_lints")
+                            .id
+                            .hir_id(),
+                    ),
+                );
+                collector.visit_expr(cx.tcx.hir().body(body_id).value);
+            }
+        }
+    }
+
+    fn check_crate_post(&mut self, cx: &LateContext<'tcx>) {
+        if is_lint_allowed(cx, LINT_WITHOUT_LINT_PASS, CRATE_HIR_ID) {
+            return;
+        }
+
+        for (lint_name, &lint_span) in &self.declared_lints {
+            // When using the `declare_tool_lint!` macro, the original `lint_span`'s
+            // file points to "<rustc macros>".
+            // `compiletest-rs` thinks that's an error in a different file and
+            // just ignores it. This causes the test in compile-fail/lint_pass
+            // not able to capture the error.
+            // Therefore, we need to climb the macro expansion tree and find the
+            // actual span that invoked `declare_tool_lint!`:
+            let lint_span = lint_span.ctxt().outer_expn_data().call_site;
+
+            if !self.registered_lints.contains(lint_name) {
+                span_lint(
+                    cx,
+                    LINT_WITHOUT_LINT_PASS,
+                    lint_span,
+                    &format!("the lint `{lint_name}` is not added to any `LintPass`"),
+                );
+            }
+        }
+    }
+}
+
+pub(super) fn is_lint_ref_type<'tcx>(cx: &LateContext<'tcx>, ty: &hir::Ty<'_>) -> bool {
+    if let TyKind::Rptr(
+        _,
+        MutTy {
+            ty: inner,
+            mutbl: Mutability::Not,
+        },
+    ) = ty.kind
+    {
+        if let TyKind::Path(ref path) = inner.kind {
+            if let Res::Def(DefKind::Struct, def_id) = cx.qpath_res(path, inner.hir_id) {
+                return match_def_path(cx, def_id, &paths::LINT);
+            }
+        }
+    }
+
+    false
+}
+
+fn check_invalid_clippy_version_attribute(cx: &LateContext<'_>, item: &'_ Item<'_>) {
+    if let Some(value) = extract_clippy_version_value(cx, item) {
+        // The `sym!` macro doesn't work as it only expects a single token.
+        // It's better to keep it this way and have a direct `Symbol::intern` call here.
+        if value == Symbol::intern("pre 1.29.0") {
+            return;
+        }
+
+        if RustcVersion::parse(value.as_str()).is_err() {
+            span_lint_and_help(
+                cx,
+                INVALID_CLIPPY_VERSION_ATTRIBUTE,
+                item.span,
+                "this item has an invalid `clippy::version` attribute",
+                None,
+                "please use a valid semantic version, see `doc/adding_lints.md`",
+            );
+        }
+    } else {
+        span_lint_and_help(
+            cx,
+            MISSING_CLIPPY_VERSION_ATTRIBUTE,
+            item.span,
+            "this lint is missing the `clippy::version` attribute or version value",
+            None,
+            "please use a `clippy::version` attribute, see `doc/adding_lints.md`",
+        );
+    }
+}
+
+/// This function extracts the version value of a `clippy::version` attribute if the given value has
+/// one
+pub(super) fn extract_clippy_version_value(cx: &LateContext<'_>, item: &'_ Item<'_>) -> Option<Symbol> {
+    let attrs = cx.tcx.hir().attrs(item.hir_id());
+    attrs.iter().find_map(|attr| {
+        if_chain! {
+            // Identify attribute
+            if let ast::AttrKind::Normal(ref attr_kind) = &attr.kind;
+            if let [tool_name, attr_name] = &attr_kind.item.path.segments[..];
+            if tool_name.ident.name == sym::clippy;
+            if attr_name.ident.name == sym::version;
+            if let Some(version) = attr.value_str();
+            then { Some(version) } else { None }
+        }
+    })
+}
+
+struct LintCollector<'a, 'tcx> {
+    output: &'a mut FxHashSet<Symbol>,
+    cx: &'a LateContext<'tcx>,
+}
+
+impl<'a, 'tcx> Visitor<'tcx> for LintCollector<'a, 'tcx> {
+    type NestedFilter = nested_filter::All;
+
+    fn visit_path(&mut self, path: &'tcx Path<'_>, _: HirId) {
+        if path.segments.len() == 1 {
+            self.output.insert(path.segments[0].ident.name);
+        }
+    }
+
+    fn nested_visit_map(&mut self) -> Self::Map {
+        self.cx.tcx.hir()
+    }
+}
diff --git a/clippy_lints/src/utils/internal_lints/metadata_collector.rs b/clippy_lints/src/utils/internal_lints/metadata_collector.rs
index c84191bb010..d06a616e4b3 100644
--- a/clippy_lints/src/utils/internal_lints/metadata_collector.rs
+++ b/clippy_lints/src/utils/internal_lints/metadata_collector.rs
@@ -8,7 +8,7 @@
 //! a simple mistake)
 
 use crate::renamed_lints::RENAMED_LINTS;
-use crate::utils::internal_lints::{extract_clippy_version_value, is_lint_ref_type};
+use crate::utils::internal_lints::lint_without_lint_pass::{extract_clippy_version_value, is_lint_ref_type};
 
 use clippy_utils::diagnostics::span_lint;
 use clippy_utils::ty::{match_type, walk_ptrs_ty_depth};
@@ -532,7 +532,11 @@ fn parse_config_field_doc(doc_comment: &str) -> Option<(Vec<String>, String)> {
 
             // Extract lints
             doc_comment.make_ascii_lowercase();
-            let lints: Vec<String> = doc_comment.split_off(DOC_START.len()).split(", ").map(str::to_string).collect();
+            let lints: Vec<String> = doc_comment
+                .split_off(DOC_START.len())
+                .split(", ")
+                .map(str::to_string)
+                .collect();
 
             // Format documentation correctly
             // split off leading `.` from lint name list and indent for correct formatting
diff --git a/clippy_lints/src/utils/internal_lints/msrv_attr_impl.rs b/clippy_lints/src/utils/internal_lints/msrv_attr_impl.rs
new file mode 100644
index 00000000000..1e994e3f2b1
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/msrv_attr_impl.rs
@@ -0,0 +1,63 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::ty::match_type;
+use clippy_utils::{match_def_path, paths};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_hir_analysis::hir_ty_to_ty;
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::ty::{self, subst::GenericArgKind};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Check that the `extract_msrv_attr!` macro is used, when a lint has a MSRV.
+    ///
+    pub MISSING_MSRV_ATTR_IMPL,
+    internal,
+    "checking if all necessary steps were taken when adding a MSRV to a lint"
+}
+
+declare_lint_pass!(MsrvAttrImpl => [MISSING_MSRV_ATTR_IMPL]);
+
+impl LateLintPass<'_> for MsrvAttrImpl {
+    fn check_item(&mut self, cx: &LateContext<'_>, item: &hir::Item<'_>) {
+        if_chain! {
+            if let hir::ItemKind::Impl(hir::Impl {
+                of_trait: Some(lint_pass_trait_ref),
+                self_ty,
+                items,
+                ..
+            }) = &item.kind;
+            if let Some(lint_pass_trait_def_id) = lint_pass_trait_ref.trait_def_id();
+            let is_late_pass = match_def_path(cx, lint_pass_trait_def_id, &paths::LATE_LINT_PASS);
+            if is_late_pass || match_def_path(cx, lint_pass_trait_def_id, &paths::EARLY_LINT_PASS);
+            let self_ty = hir_ty_to_ty(cx.tcx, self_ty);
+            if let ty::Adt(self_ty_def, _) = self_ty.kind();
+            if self_ty_def.is_struct();
+            if self_ty_def.all_fields().any(|f| {
+                cx.tcx
+                    .type_of(f.did)
+                    .walk()
+                    .filter(|t| matches!(t.unpack(), GenericArgKind::Type(_)))
+                    .any(|t| match_type(cx, t.expect_ty(), &paths::RUSTC_VERSION))
+            });
+            if !items.iter().any(|item| item.ident.name == sym!(enter_lint_attrs));
+            then {
+                let context = if is_late_pass { "LateContext" } else { "EarlyContext" };
+                let lint_pass = if is_late_pass { "LateLintPass" } else { "EarlyLintPass" };
+                let span = cx.sess().source_map().span_through_char(item.span, '{');
+                span_lint_and_sugg(
+                    cx,
+                    MISSING_MSRV_ATTR_IMPL,
+                    span,
+                    &format!("`extract_msrv_attr!` macro missing from `{lint_pass}` implementation"),
+                    &format!("add `extract_msrv_attr!({context})` to the `{lint_pass}` implementation"),
+                    format!("{}\n    extract_msrv_attr!({context});", snippet(cx, span, "..")),
+                    Applicability::MachineApplicable,
+                );
+            }
+        }
+    }
+}
diff --git a/clippy_lints/src/utils/internal_lints/outer_expn_data_pass.rs b/clippy_lints/src/utils/internal_lints/outer_expn_data_pass.rs
new file mode 100644
index 00000000000..2b13fad8066
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/outer_expn_data_pass.rs
@@ -0,0 +1,62 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::ty::match_type;
+use clippy_utils::{is_lint_allowed, method_calls, paths};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::symbol::Symbol;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for calls to `cx.outer().expn_data()` and suggests to use
+    /// the `cx.outer_expn_data()`
+    ///
+    /// ### Why is this bad?
+    /// `cx.outer_expn_data()` is faster and more concise.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// expr.span.ctxt().outer().expn_data()
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// expr.span.ctxt().outer_expn_data()
+    /// ```
+    pub OUTER_EXPN_EXPN_DATA,
+    internal,
+    "using `cx.outer_expn().expn_data()` instead of `cx.outer_expn_data()`"
+}
+
+declare_lint_pass!(OuterExpnDataPass => [OUTER_EXPN_EXPN_DATA]);
+
+impl<'tcx> LateLintPass<'tcx> for OuterExpnDataPass {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
+        if is_lint_allowed(cx, OUTER_EXPN_EXPN_DATA, expr.hir_id) {
+            return;
+        }
+
+        let (method_names, arg_lists, spans) = method_calls(expr, 2);
+        let method_names: Vec<&str> = method_names.iter().map(Symbol::as_str).collect();
+        if_chain! {
+            if let ["expn_data", "outer_expn"] = method_names.as_slice();
+            let (self_arg, args) = arg_lists[1];
+            if args.is_empty();
+            let self_ty = cx.typeck_results().expr_ty(self_arg).peel_refs();
+            if match_type(cx, self_ty, &paths::SYNTAX_CONTEXT);
+            then {
+                span_lint_and_sugg(
+                    cx,
+                    OUTER_EXPN_EXPN_DATA,
+                    spans[1].with_hi(expr.span.hi()),
+                    "usage of `outer_expn().expn_data()`",
+                    "try",
+                    "outer_expn_data()".to_string(),
+                    Applicability::MachineApplicable,
+                );
+            }
+        }
+    }
+}
diff --git a/clippy_lints/src/utils/internal_lints/produce_ice.rs b/clippy_lints/src/utils/internal_lints/produce_ice.rs
new file mode 100644
index 00000000000..5899b94e16b
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/produce_ice.rs
@@ -0,0 +1,37 @@
+use rustc_ast::ast::NodeId;
+use rustc_ast::visit::FnKind;
+use rustc_lint::{EarlyContext, EarlyLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::Span;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Not an actual lint. This lint is only meant for testing our customized internal compiler
+    /// error message by calling `panic`.
+    ///
+    /// ### Why is this bad?
+    /// ICE in large quantities can damage your teeth
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// 🍦🍦🍦🍦🍦
+    /// ```
+    pub PRODUCE_ICE,
+    internal,
+    "this message should not appear anywhere as we ICE before and don't emit the lint"
+}
+
+declare_lint_pass!(ProduceIce => [PRODUCE_ICE]);
+
+impl EarlyLintPass for ProduceIce {
+    fn check_fn(&mut self, _: &EarlyContext<'_>, fn_kind: FnKind<'_>, _: Span, _: NodeId) {
+        assert!(!is_trigger_fn(fn_kind), "Would you like some help with that?");
+    }
+}
+
+fn is_trigger_fn(fn_kind: FnKind<'_>) -> bool {
+    match fn_kind {
+        FnKind::Fn(_, ident, ..) => ident.name.as_str() == "it_looks_like_you_are_trying_to_kill_clippy",
+        FnKind::Closure(..) => false,
+    }
+}
diff --git a/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs b/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
new file mode 100644
index 00000000000..4cf76f53625
--- /dev/null
+++ b/clippy_lints/src/utils/internal_lints/unnecessary_def_path.rs
@@ -0,0 +1,343 @@
+use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_then};
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::{def_path_res, is_lint_allowed, match_any_def_paths, peel_hir_expr_refs};
+use if_chain::if_chain;
+use rustc_ast::ast::LitKind;
+use rustc_data_structures::fx::FxHashSet;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_hir::def::{DefKind, Namespace, Res};
+use rustc_hir::def_id::DefId;
+use rustc_hir::{Expr, ExprKind, Local, Mutability, Node};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_middle::mir::interpret::{Allocation, ConstValue, GlobalAlloc};
+use rustc_middle::ty::{self, AssocKind, DefIdTree, Ty};
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::{Ident, Symbol};
+use rustc_span::Span;
+
+use std::str;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for usages of def paths when a diagnostic item or a `LangItem` could be used.
+    ///
+    /// ### Why is this bad?
+    /// The path for an item is subject to change and is less efficient to look up than a
+    /// diagnostic item or a `LangItem`.
+    ///
+    /// ### Example
+    /// ```rust,ignore
+    /// utils::match_type(cx, ty, &paths::VEC)
+    /// ```
+    ///
+    /// Use instead:
+    /// ```rust,ignore
+    /// utils::is_type_diagnostic_item(cx, ty, sym::Vec)
+    /// ```
+    pub UNNECESSARY_DEF_PATH,
+    internal,
+    "using a def path when a diagnostic item or a `LangItem` is available"
+}
+
+impl_lint_pass!(UnnecessaryDefPath => [UNNECESSARY_DEF_PATH]);
+
+#[derive(Default)]
+pub struct UnnecessaryDefPath {
+    array_def_ids: FxHashSet<(DefId, Span)>,
+    linted_def_ids: FxHashSet<DefId>,
+}
+
+impl<'tcx> LateLintPass<'tcx> for UnnecessaryDefPath {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx hir::Expr<'_>) {
+        if is_lint_allowed(cx, UNNECESSARY_DEF_PATH, expr.hir_id) {
+            return;
+        }
+
+        match expr.kind {
+            ExprKind::Call(func, args) => self.check_call(cx, func, args, expr.span),
+            ExprKind::Array(elements) => self.check_array(cx, elements, expr.span),
+            _ => {},
+        }
+    }
+
+    fn check_crate_post(&mut self, cx: &LateContext<'tcx>) {
+        for &(def_id, span) in &self.array_def_ids {
+            if self.linted_def_ids.contains(&def_id) {
+                continue;
+            }
+
+            let (msg, sugg) = if let Some(sym) = cx.tcx.get_diagnostic_name(def_id) {
+                ("diagnostic item", format!("sym::{sym}"))
+            } else if let Some(sym) = get_lang_item_name(cx, def_id) {
+                ("language item", format!("LangItem::{sym}"))
+            } else {
+                continue;
+            };
+
+            span_lint_and_help(
+                cx,
+                UNNECESSARY_DEF_PATH,
+                span,
+                &format!("hardcoded path to a {msg}"),
+                None,
+                &format!("convert all references to use `{sugg}`"),
+            );
+        }
+    }
+}
+
+impl UnnecessaryDefPath {
+    #[allow(clippy::too_many_lines)]
+    fn check_call(&mut self, cx: &LateContext<'_>, func: &Expr<'_>, args: &[Expr<'_>], span: Span) {
+        enum Item {
+            LangItem(Symbol),
+            DiagnosticItem(Symbol),
+        }
+        static PATHS: &[&[&str]] = &[
+            &["clippy_utils", "match_def_path"],
+            &["clippy_utils", "match_trait_method"],
+            &["clippy_utils", "ty", "match_type"],
+            &["clippy_utils", "is_expr_path_def_path"],
+        ];
+
+        if_chain! {
+            if let [cx_arg, def_arg, args @ ..] = args;
+            if let ExprKind::Path(path) = &func.kind;
+            if let Some(id) = cx.qpath_res(path, func.hir_id).opt_def_id();
+            if let Some(which_path) = match_any_def_paths(cx, id, PATHS);
+            let item_arg = if which_path == 4 { &args[1] } else { &args[0] };
+            // Extract the path to the matched type
+            if let Some(segments) = path_to_matched_type(cx, item_arg);
+            let segments: Vec<&str> = segments.iter().map(|sym| &**sym).collect();
+            if let Some(def_id) = inherent_def_path_res(cx, &segments[..]);
+            then {
+                // Check if the target item is a diagnostic item or LangItem.
+                #[rustfmt::skip]
+                let (msg, item) = if let Some(item_name)
+                    = cx.tcx.diagnostic_items(def_id.krate).id_to_name.get(&def_id)
+                {
+                    (
+                        "use of a def path to a diagnostic item",
+                        Item::DiagnosticItem(*item_name),
+                    )
+                } else if let Some(item_name) = get_lang_item_name(cx, def_id) {
+                    (
+                        "use of a def path to a `LangItem`",
+                        Item::LangItem(item_name),
+                    )
+                } else {
+                    return;
+                };
+
+                let has_ctor = match cx.tcx.def_kind(def_id) {
+                    DefKind::Struct => {
+                        let variant = cx.tcx.adt_def(def_id).non_enum_variant();
+                        variant.ctor_def_id.is_some() && variant.fields.iter().all(|f| f.vis.is_public())
+                    },
+                    DefKind::Variant => {
+                        let variant = cx.tcx.adt_def(cx.tcx.parent(def_id)).variant_with_id(def_id);
+                        variant.ctor_def_id.is_some() && variant.fields.iter().all(|f| f.vis.is_public())
+                    },
+                    _ => false,
+                };
+
+                let mut app = Applicability::MachineApplicable;
+                let cx_snip = snippet_with_applicability(cx, cx_arg.span, "..", &mut app);
+                let def_snip = snippet_with_applicability(cx, def_arg.span, "..", &mut app);
+                let (sugg, with_note) = match (which_path, item) {
+                    // match_def_path
+                    (0, Item::DiagnosticItem(item)) => (
+                        format!("{cx_snip}.tcx.is_diagnostic_item(sym::{item}, {def_snip})"),
+                        has_ctor,
+                    ),
+                    (0, Item::LangItem(item)) => (
+                        format!("{cx_snip}.tcx.lang_items().require(LangItem::{item}).ok() == Some({def_snip})"),
+                        has_ctor,
+                    ),
+                    // match_trait_method
+                    (1, Item::DiagnosticItem(item)) => {
+                        (format!("is_trait_method({cx_snip}, {def_snip}, sym::{item})"), false)
+                    },
+                    // match_type
+                    (2, Item::DiagnosticItem(item)) => (
+                        format!("is_type_diagnostic_item({cx_snip}, {def_snip}, sym::{item})"),
+                        false,
+                    ),
+                    (2, Item::LangItem(item)) => (
+                        format!("is_type_lang_item({cx_snip}, {def_snip}, LangItem::{item})"),
+                        false,
+                    ),
+                    // is_expr_path_def_path
+                    (3, Item::DiagnosticItem(item)) if has_ctor => (
+                        format!("is_res_diag_ctor({cx_snip}, path_res({cx_snip}, {def_snip}), sym::{item})",),
+                        false,
+                    ),
+                    (3, Item::LangItem(item)) if has_ctor => (
+                        format!("is_res_lang_ctor({cx_snip}, path_res({cx_snip}, {def_snip}), LangItem::{item})",),
+                        false,
+                    ),
+                    (3, Item::DiagnosticItem(item)) => (
+                        format!("is_path_diagnostic_item({cx_snip}, {def_snip}, sym::{item})"),
+                        false,
+                    ),
+                    (3, Item::LangItem(item)) => (
+                        format!(
+                            "path_res({cx_snip}, {def_snip}).opt_def_id()\
+                                .map_or(false, |id| {cx_snip}.tcx.lang_items().require(LangItem::{item}).ok() == Some(id))",
+                        ),
+                        false,
+                    ),
+                    _ => return,
+                };
+
+                span_lint_and_then(cx, UNNECESSARY_DEF_PATH, span, msg, |diag| {
+                    diag.span_suggestion(span, "try", sugg, app);
+                    if with_note {
+                        diag.help(
+                            "if this `DefId` came from a constructor expression or pattern then the \
+                                    parent `DefId` should be used instead",
+                        );
+                    }
+                });
+
+                self.linted_def_ids.insert(def_id);
+            }
+        }
+    }
+
+    fn check_array(&mut self, cx: &LateContext<'_>, elements: &[Expr<'_>], span: Span) {
+        let Some(path) = path_from_array(elements) else { return };
+
+        if let Some(def_id) = inherent_def_path_res(cx, &path.iter().map(AsRef::as_ref).collect::<Vec<_>>()) {
+            self.array_def_ids.insert((def_id, span));
+        }
+    }
+}
+
+fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Vec<String>> {
+    match peel_hir_expr_refs(expr).0.kind {
+        ExprKind::Path(ref qpath) => match cx.qpath_res(qpath, expr.hir_id) {
+            Res::Local(hir_id) => {
+                let parent_id = cx.tcx.hir().get_parent_node(hir_id);
+                if let Some(Node::Local(Local { init: Some(init), .. })) = cx.tcx.hir().find(parent_id) {
+                    path_to_matched_type(cx, init)
+                } else {
+                    None
+                }
+            },
+            Res::Def(DefKind::Static(_), def_id) => read_mir_alloc_def_path(
+                cx,
+                cx.tcx.eval_static_initializer(def_id).ok()?.inner(),
+                cx.tcx.type_of(def_id),
+            ),
+            Res::Def(DefKind::Const, def_id) => match cx.tcx.const_eval_poly(def_id).ok()? {
+                ConstValue::ByRef { alloc, offset } if offset.bytes() == 0 => {
+                    read_mir_alloc_def_path(cx, alloc.inner(), cx.tcx.type_of(def_id))
+                },
+                _ => None,
+            },
+            _ => None,
+        },
+        ExprKind::Array(exprs) => path_from_array(exprs),
+        _ => None,
+    }
+}
+
+fn read_mir_alloc_def_path<'tcx>(cx: &LateContext<'tcx>, alloc: &'tcx Allocation, ty: Ty<'_>) -> Option<Vec<String>> {
+    let (alloc, ty) = if let ty::Ref(_, ty, Mutability::Not) = *ty.kind() {
+        let &alloc = alloc.provenance().values().next()?;
+        if let GlobalAlloc::Memory(alloc) = cx.tcx.global_alloc(alloc) {
+            (alloc.inner(), ty)
+        } else {
+            return None;
+        }
+    } else {
+        (alloc, ty)
+    };
+
+    if let ty::Array(ty, _) | ty::Slice(ty) = *ty.kind()
+        && let ty::Ref(_, ty, Mutability::Not) = *ty.kind()
+        && ty.is_str()
+    {
+        alloc
+            .provenance()
+            .values()
+            .map(|&alloc| {
+                if let GlobalAlloc::Memory(alloc) = cx.tcx.global_alloc(alloc) {
+                    let alloc = alloc.inner();
+                    str::from_utf8(alloc.inspect_with_uninit_and_ptr_outside_interpreter(0..alloc.len()))
+                        .ok().map(ToOwned::to_owned)
+                } else {
+                    None
+                }
+            })
+            .collect()
+    } else {
+        None
+    }
+}
+
+fn path_from_array(exprs: &[Expr<'_>]) -> Option<Vec<String>> {
+    exprs
+        .iter()
+        .map(|expr| {
+            if let ExprKind::Lit(lit) = &expr.kind {
+                if let LitKind::Str(sym, _) = lit.node {
+                    return Some((*sym.as_str()).to_owned());
+                }
+            }
+
+            None
+        })
+        .collect()
+}
+
+// def_path_res will match field names before anything else, but for this we want to match
+// inherent functions first.
+fn inherent_def_path_res(cx: &LateContext<'_>, segments: &[&str]) -> Option<DefId> {
+    def_path_res(cx, segments, None).opt_def_id().map(|def_id| {
+        if cx.tcx.def_kind(def_id) == DefKind::Field {
+            let method_name = *segments.last().unwrap();
+            cx.tcx
+                .def_key(def_id)
+                .parent
+                .and_then(|parent_idx| {
+                    cx.tcx
+                        .inherent_impls(DefId {
+                            index: parent_idx,
+                            krate: def_id.krate,
+                        })
+                        .iter()
+                        .find_map(|impl_id| {
+                            cx.tcx.associated_items(*impl_id).find_by_name_and_kind(
+                                cx.tcx,
+                                Ident::from_str(method_name),
+                                AssocKind::Fn,
+                                *impl_id,
+                            )
+                        })
+                })
+                .map_or(def_id, |item| item.def_id)
+        } else {
+            def_id
+        }
+    })
+}
+
+fn get_lang_item_name(cx: &LateContext<'_>, def_id: DefId) -> Option<Symbol> {
+    if let Some(lang_item) = cx.tcx.lang_items().items().iter().position(|id| *id == Some(def_id)) {
+        let lang_items = def_path_res(cx, &["rustc_hir", "lang_items", "LangItem"], Some(Namespace::TypeNS)).def_id();
+        let item_name = cx
+            .tcx
+            .adt_def(lang_items)
+            .variants()
+            .iter()
+            .nth(lang_item)
+            .unwrap()
+            .name;
+        Some(item_name)
+    } else {
+        None
+    }
+}