Merge commit '0e87918536' into clippyup

CHANGELOG.md

@@ -2103,6 +2103,7 @@ Released 2018-09-13
 [`if_let_some_result`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_let_some_result
 [`if_not_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_not_else
 [`if_same_then_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_same_then_else
+[`if_then_some_else_none`]: https://rust-lang.github.io/rust-clippy/master/index.html#if_then_some_else_none
 [`ifs_same_cond`]: https://rust-lang.github.io/rust-clippy/master/index.html#ifs_same_cond
 [`implicit_clone`]: https://rust-lang.github.io/rust-clippy/master/index.html#implicit_clone
 [`implicit_hasher`]: https://rust-lang.github.io/rust-clippy/master/index.html#implicit_hasher

CONTRIBUTING.md

@@ -18,11 +18,13 @@ All contributors are expected to follow the [Rust Code of Conduct].
     - [Finding something to fix/improve](#finding-something-to-fiximprove)
   - [Writing code](#writing-code)
   - [Getting code-completion for rustc internals to work](#getting-code-completion-for-rustc-internals-to-work)
+    - [IntelliJ Rust](#intellij-rust)
+    - [Rust Analyzer](#rust-analyzer)
   - [How Clippy works](#how-clippy-works)
-  - [Syncing changes between Clippy and `rust-lang/rust`](#syncing-changes-between-clippy-and-rust-langrust)
+  - [Syncing changes between Clippy and [`rust-lang/rust`]](#syncing-changes-between-clippy-and-rust-langrust)
     - [Patching git-subtree to work with big repos](#patching-git-subtree-to-work-with-big-repos)
-    - [Performing the sync from `rust-lang/rust` to Clippy](#performing-the-sync-from-rust-langrust-to-clippy)
+    - [Performing the sync from [`rust-lang/rust`] to Clippy](#performing-the-sync-from-rust-langrust-to-clippy)
-    - [Performing the sync from Clippy to `rust-lang/rust`](#performing-the-sync-from-clippy-to-rust-langrust)
+    - [Performing the sync from Clippy to [`rust-lang/rust`]](#performing-the-sync-from-clippy-to-rust-langrust)
     - [Defining remotes](#defining-remotes)
   - [Issue and PR triage](#issue-and-pr-triage)
   - [Bors and Homu](#bors-and-homu)
@@ -105,21 +107,41 @@ quick read.
 
 ## Getting code-completion for rustc internals to work
 
-Unfortunately, [`rust-analyzer`][ra_homepage] does not (yet?) understand how Clippy uses compiler-internals
+### IntelliJ Rust
+Unfortunately, [`IntelliJ Rust`][IntelliJ_rust_homepage] does not (yet?) understand how Clippy uses compiler-internals
 using `extern crate` and it also needs to be able to read the source files of the rustc-compiler which are not
 available via a `rustup` component at the time of writing.
 To work around this, you need to have a copy of the [rustc-repo][rustc_repo] available which can be obtained via
 `git clone https://github.com/rust-lang/rust/`.
 Then you can run a `cargo dev` command to automatically make Clippy use the rustc-repo via path-dependencies
-which rust-analyzer will be able to understand.
+which `IntelliJ Rust` will be able to understand.
-Run `cargo dev ra_setup --repo-path <repo-path>` where `<repo-path>` is an absolute path to the rustc repo
+Run `cargo dev ide_setup --repo-path <repo-path>` where `<repo-path>` is a path to the rustc repo
 you just cloned.
 The command will add path-dependencies pointing towards rustc-crates inside the rustc repo to
 Clippys `Cargo.toml`s and should allow rust-analyzer to understand most of the types that Clippy uses.
 Just make sure to remove the dependencies again before finally making a pull request!
 
-[ra_homepage]: https://rust-analyzer.github.io/
 [rustc_repo]: https://github.com/rust-lang/rust/
+[IntelliJ_rust_homepage]: https://intellij-rust.github.io/
+
+### Rust Analyzer
+As of [#6869][6869], [`rust-analyzer`][ra_homepage] can understand that Clippy uses compiler-internals
+using `extern crate` when `package.metadata.rust-analyzer.rustc_private` is set to `true` in Clippys `Cargo.toml.`
+You will required a `nightly` toolchain with the `rustc-dev` component installed.
+Make sure that in the `rust-analyzer` configuration, you set
+```
+{ "rust-analyzer.rustcSource": "discover" }
+```
+and
+```
+{ "rust-analyzer.updates.channel": "nightly" }
+```
+You should be able to see information on things like `Expr` or `EarlyContext` now if you hover them, also
+a lot more type hints.
+This will work with `rust-analyzer 2021-03-15` shipped in nightly `1.52.0-nightly (107896c32 2021-03-15)` or later.
+
+[ra_homepage]: https://rust-analyzer.github.io/
+[6869]: https://github.com/rust-lang/rust-clippy/pull/6869
 
 ## How Clippy works
 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "clippy"
-version = "0.1.52"
+version = "0.1.53"
 authors = ["The Rust Clippy Developers"]
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"
 repository = "https://github.com/rust-lang/rust-clippy"
@@ -37,6 +37,8 @@ clippy-mini-macro-test = { version = "0.2", path = "mini-macro" }
 serde = { version = "1.0", features = ["derive"] }
 derive-new = "0.5"
 regex = "1.4"
+quote = "1"
+syn = { version = "1", features = ["full"] }
 
 # A noop dependency that changes in the Rust repository, it's a bit of a hack.
 # See the `src/tools/rustc-workspace-hack/README.md` file in `rust-lang/rust`

clippy_dev/src/fmt.rs

@@ -90,7 +90,7 @@ pub fn run(check: bool, verbose: bool) {
             },
             CliError::RaSetupActive => {
                 eprintln!(
-                    "error: a local rustc repo is enabled as path dependency via `cargo dev ra_setup`.
+                    "error: a local rustc repo is enabled as path dependency via `cargo dev ide_setup`.
 Not formatting because that would format the local repo as well!
 Please revert the changes to Cargo.tomls first."
                 );

clippy_dev/src/ide_setup.rs

@@ -55,7 +55,7 @@ fn inject_deps_into_manifest(
     // do not inject deps if we have aleady done so
     if cargo_toml.contains("[target.'cfg(NOT_A_PLATFORM)'.dependencies]") {
         eprintln!(
-            "cargo dev ra_setup: warning: deps already found inside {}, doing nothing.",
+            "cargo dev ide_setup: warning: deps already found inside {}, doing nothing.",
             manifest_path
         );
         return Ok(());

clippy_dev/src/lib.rs

@@ -12,8 +12,8 @@ use walkdir::WalkDir;
 
 pub mod bless;
 pub mod fmt;
+pub mod ide_setup;
 pub mod new_lint;
-pub mod ra_setup;
 pub mod serve;
 pub mod stderr_length_check;
 pub mod update_lints;

clippy_dev/src/main.rs

@@ -1,7 +1,7 @@
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
 
 use clap::{App, Arg, ArgMatches, SubCommand};
-use clippy_dev::{bless, fmt, new_lint, ra_setup, serve, stderr_length_check, update_lints};
+use clippy_dev::{bless, fmt, ide_setup, new_lint, serve, stderr_length_check, update_lints};
 fn main() {
     let matches = get_clap_config();
 
@@ -34,7 +34,7 @@ fn main() {
         ("limit_stderr_length", _) => {
             stderr_length_check::check();
         },
-        ("ra_setup", Some(matches)) => ra_setup::run(matches.value_of("rustc-repo-path")),
+        ("ide_setup", Some(matches)) => ide_setup::run(matches.value_of("rustc-repo-path")),
         ("serve", Some(matches)) => {
             let port = matches.value_of("port").unwrap().parse().unwrap();
             let lint = matches.value_of("lint");
@@ -138,8 +138,8 @@ fn get_clap_config<'a>() -> ArgMatches<'a> {
                 .about("Ensures that stderr files do not grow longer than a certain amount of lines."),
         )
         .subcommand(
-            SubCommand::with_name("ra_setup")
+            SubCommand::with_name("ide_setup")
-                .about("Alter dependencies so rust-analyzer can find rustc internals")
+                .about("Alter dependencies so Intellij Rust can find rustc internals")
                 .arg(
                     Arg::with_name("rustc-repo-path")
                         .long("repo-path")

clippy_lints/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "clippy_lints"
 # begin automatic update
-version = "0.1.52"
+version = "0.1.53"
 # end automatic update
 authors = ["The Rust Clippy Developers"]
 description = "A bunch of helpful lints to avoid common pitfalls in Rust"
@@ -20,7 +20,6 @@ pulldown-cmark = { version = "0.8", default-features = false }
 quine-mc_cluskey = "0.2.2"
 regex-syntax = "0.6"
 serde = { version = "1.0", features = ["derive"] }
-smallvec = { version = "1", features = ["union"] }
 toml = "0.5.3"
 unicode-normalization = "0.1"
 semver = "0.11"
@@ -28,8 +27,6 @@ rustc-semver = "1.1.0"
 # NOTE: cargo requires serde feat in its url dep
 # see <https://github.com/rust-lang/rust/pull/63587#issuecomment-522343864>
 url = { version = "2.1.0", features = ["serde"] }
-quote = "1"
-syn = { version = "1", features = ["full"] }
 
 [features]
 deny-warnings = []

clippy_lints/src/approx_const.rs

@@ -1,4 +1,4 @@
-use crate::utils::span_lint;
+use clippy_utils::diagnostics::span_lint;
 use rustc_ast::ast::{FloatTy, LitFloatType, LitKind};
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/arithmetic.rs

@@ -1,5 +1,5 @@
 use crate::consts::constant_simple;
-use crate::utils::span_lint;
+use clippy_utils::diagnostics::span_lint;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};

clippy_lints/src/as_conversions.rs

@@ -1,10 +1,9 @@
+use clippy_utils::diagnostics::span_lint_and_help;
 use rustc_ast::ast::{Expr, ExprKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use crate::utils::span_lint_and_help;
-
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of `as` conversions.
     ///

clippy_lints/src/asm_syntax.rs

@@ -1,6 +1,6 @@
 use std::fmt;
 
-use crate::utils::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_and_help;
 use rustc_ast::ast::{Expr, ExprKind, InlineAsmOptions};
 use rustc_lint::{EarlyContext, EarlyLintPass, Lint};
 use rustc_session::{declare_lint_pass, declare_tool_lint};

clippy_lints/src/assertions_on_constants.rs

@@ -1,5 +1,7 @@
 use crate::consts::{constant, Constant};
-use crate::utils::{is_direct_expn_of, is_expn_of, match_panic_call, snippet_opt, span_lint_and_help};
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::source::snippet_opt;
+use clippy_utils::{is_direct_expn_of, is_expn_of, match_panic_call};
 use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/assign_ops.rs

@@ -1,7 +1,8 @@
-use crate::utils::{
+use clippy_utils::diagnostics::span_lint_and_then;
-    eq_expr_value, get_trait_def_id, implements_trait, snippet_opt, span_lint_and_then, trait_ref_of_method,
+use clippy_utils::source::snippet_opt;
-};
+use clippy_utils::ty::implements_trait;
-use crate::utils::{higher, sugg};
+use clippy_utils::{eq_expr_value, get_trait_def_id, trait_ref_of_method};
+use clippy_utils::{higher, paths, sugg};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
@@ -92,7 +93,7 @@ impl<'tcx> LateLintPass<'tcx> for AssignOps {
                              $($trait_name:ident),+) => {
                                 match $op {
                                     $(hir::BinOpKind::$trait_name => {
-                                        let [krate, module] = crate::utils::paths::OPS_MODULE;
+                                        let [krate, module] = paths::OPS_MODULE;
                                         let path: [&str; 3] = [krate, module, concat!(stringify!($trait_name), "Assign")];
                                         let trait_id = if let Some(trait_id) = get_trait_def_id($cx, &path) {
                                             trait_id

clippy_lints/src/async_yields_async.rs

@@ -1,4 +1,6 @@
-use crate::utils::{implements_trait, snippet, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet;
+use clippy_utils::ty::implements_trait;
 use rustc_errors::Applicability;
 use rustc_hir::{AsyncGeneratorKind, Body, BodyId, ExprKind, GeneratorKind, QPath};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/atomic_ordering.rs

@@ -1,4 +1,5 @@
-use crate::utils::{match_def_path, span_lint_and_help};
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::match_def_path;
 use if_chain::if_chain;
 use rustc_hir::def_id::DefId;
 use rustc_hir::{Expr, ExprKind};

clippy_lints/src/attrs.rs

@@ -1,9 +1,8 @@
 //! checks for attributes
 
-use crate::utils::{
+use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_sugg, span_lint_and_then};
-    first_line_of_span, is_present_in_source, match_panic_def_id, snippet_opt, span_lint, span_lint_and_help,
+use clippy_utils::match_panic_def_id;
-    span_lint_and_sugg, span_lint_and_then, without_block_comments,
+use clippy_utils::source::{first_line_of_span, is_present_in_source, snippet_opt, without_block_comments};
-};
 use if_chain::if_chain;
 use rustc_ast::{AttrKind, AttrStyle, Attribute, Lit, LitKind, MetaItemKind, NestedMetaItem};
 use rustc_errors::Applicability;
@@ -431,7 +430,7 @@ fn is_relevant_block(cx: &LateContext<'_>, typeck_results: &ty::TypeckResults<'_
         |stmt| match &stmt.kind {
             StmtKind::Local(_) => true,
             StmtKind::Expr(expr) | StmtKind::Semi(expr) => is_relevant_expr(cx, typeck_results, expr),
-            _ => false,
+            StmtKind::Item(_) => false,
         },
     )
 }
@@ -565,7 +564,7 @@ fn check_deprecated_cfg_attr(cx: &EarlyContext<'_>, attr: &Attribute) {
         // check for `rustfmt_skip` and `rustfmt::skip`
         if let Some(skip_item) = &items[1].meta_item();
         if skip_item.has_name(sym!(rustfmt_skip)) ||
-            skip_item.path.segments.last().expect("empty path in attribute").ident.name == sym!(skip);
+            skip_item.path.segments.last().expect("empty path in attribute").ident.name == sym::skip;
         // Only lint outer attributes, because custom inner attributes are unstable
         // Tracking issue: https://github.com/rust-lang/rust/issues/54726
         if let AttrStyle::Outer = attr.style;
@@ -614,7 +613,7 @@ fn check_mismatched_target_os(cx: &EarlyContext<'_>, attr: &Attribute) {
                             }
                         }
                     },
-                    _ => {},
+                    MetaItemKind::NameValue(..) => {},
                 }
             }
         }

clippy_lints/src/await_holding_invalid.rs

@@ -1,4 +1,5 @@
-use crate::utils::{match_def_path, paths, span_lint_and_note};
+use clippy_utils::diagnostics::span_lint_and_note;
+use clippy_utils::{match_def_path, paths};
 use rustc_hir::def_id::DefId;
 use rustc_hir::{AsyncGeneratorKind, Body, BodyId, GeneratorKind};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/bit_mask.rs

@@ -1,6 +1,6 @@
 use crate::consts::{constant, Constant};
-use crate::utils::sugg::Sugg;
+use clippy_utils::diagnostics::{span_lint, span_lint_and_then};
-use crate::utils::{span_lint, span_lint_and_then};
+use clippy_utils::sugg::Sugg;
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;

clippy_lints/src/blacklisted_name.rs

@@ -1,4 +1,4 @@
-use crate::utils::span_lint;
+use clippy_utils::diagnostics::span_lint;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::{Pat, PatKind};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/blocks_in_if_conditions.rs

@@ -1,7 +1,7 @@
-use crate::utils::{
+use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
-    differing_macro_contexts, get_parent_expr, get_trait_def_id, implements_trait, paths,
+use clippy_utils::source::snippet_block_with_applicability;
-    snippet_block_with_applicability, span_lint, span_lint_and_sugg,
+use clippy_utils::ty::implements_trait;
-};
+use clippy_utils::{differing_macro_contexts, get_parent_expr};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
@@ -10,6 +10,7 @@ use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::hir::map::Map;
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for `if` conditions that use blocks containing an
@@ -61,7 +62,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ExVisitor<'a, 'tcx> {
                 if let Some(parent) = get_parent_expr(self.cx, expr);
                 if let ExprKind::MethodCall(_, _, args, _) = parent.kind;
                 let caller = self.cx.typeck_results().expr_ty(&args[0]);
-                if let Some(iter_id) = get_trait_def_id(self.cx, &paths::ITERATOR);
+                if let Some(iter_id) = self.cx.tcx.get_diagnostic_item(sym::Iterator);
                 if implements_trait(self.cx, caller, iter_id, &[]);
                 then {
                     return;

clippy_lints/src/booleans.rs

@@ -1,7 +1,7 @@
-use crate::utils::{
+use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
-    eq_expr_value, get_trait_def_id, implements_trait, in_macro, is_type_diagnostic_item, paths, snippet_opt,
+use clippy_utils::source::snippet_opt;
-    span_lint_and_sugg, span_lint_and_then,
+use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
-};
+use clippy_utils::{eq_expr_value, get_trait_def_id, in_macro, paths};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;

clippy_lints/src/bytecount.rs

@@ -1,6 +1,7 @@
-use crate::utils::{
+use clippy_utils::diagnostics::span_lint_and_sugg;
-    contains_name, get_pat_name, match_type, paths, single_segment_path, snippet_with_applicability, span_lint_and_sugg,
+use clippy_utils::source::snippet_with_applicability;
-};
+use clippy_utils::ty::match_type;
+use clippy_utils::{contains_name, get_pat_name, paths, single_segment_path};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, UnOp};

clippy_lints/src/cargo_common_metadata.rs

@@ -2,7 +2,8 @@
 
 use std::path::PathBuf;
 
-use crate::utils::{run_lints, span_lint};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::run_lints;
 use rustc_hir::{hir_id::CRATE_HIR_ID, Crate};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};

clippy_lints/src/case_sensitive_file_extension_comparisons.rs

@@ -1,4 +1,4 @@
-use crate::utils::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_and_help;
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_hir::{Expr, ExprKind, PathSegment};

clippy_lints/src/casts/cast_lossless.rs

@@ -1,10 +1,12 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::in_constant;
+use clippy_utils::source::snippet_opt;
+use clippy_utils::ty::is_isize_or_usize;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, FloatTy, Ty};
 
-use crate::utils::{in_constant, is_isize_or_usize, snippet_opt, span_lint_and_sugg};
-
 use super::{utils, CAST_LOSSLESS};
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_op: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {

clippy_lints/src/casts/cast_possible_truncation.rs

@@ -1,9 +1,9 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::ty::is_isize_or_usize;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, FloatTy, Ty};
 
-use crate::utils::{is_isize_or_usize, span_lint};
-
 use super::{utils, CAST_POSSIBLE_TRUNCATION};
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {

clippy_lints/src/casts/cast_possible_wrap.rs

@@ -1,9 +1,9 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::ty::is_isize_or_usize;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::Ty;
 
-use crate::utils::{is_isize_or_usize, span_lint};
-
 use super::{utils, CAST_POSSIBLE_WRAP};
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {

clippy_lints/src/casts/cast_precision_loss.rs

@@ -1,9 +1,9 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::ty::is_isize_or_usize;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, FloatTy, Ty};
 
-use crate::utils::{is_isize_or_usize, span_lint};
-
 use super::{utils, CAST_PRECISION_LOSS};
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {

clippy_lints/src/casts/cast_ptr_alignment.rs

@@ -1,13 +1,12 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::is_hir_ty_cfg_dependant;
+use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind, GenericArg};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::symbol::sym;
 use rustc_target::abi::LayoutOf;
 
-use if_chain::if_chain;
-
-use crate::utils::{is_hir_ty_cfg_dependant, span_lint};
-
 use super::CAST_PTR_ALIGNMENT;
 
 pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {

clippy_lints/src/casts/cast_ref_to_mut.rs

@@ -1,11 +1,9 @@
+use clippy_utils::diagnostics::span_lint;
+use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind, MutTy, Mutability, TyKind, UnOp};
 use rustc_lint::LateContext;
 use rustc_middle::ty;
 
-use if_chain::if_chain;
-
-use crate::utils::span_lint;
-
 use super::CAST_REF_TO_MUT;
 
 pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {

clippy_lints/src/casts/cast_sign_loss.rs

@@ -1,12 +1,11 @@
+use crate::consts::{constant, Constant};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::{method_chain_args, sext};
+use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty};
 
-use if_chain::if_chain;
-
-use crate::consts::{constant, Constant};
-use crate::utils::{method_chain_args, sext, span_lint};
-
 use super::CAST_SIGN_LOSS;
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_op: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {

clippy_lints/src/casts/char_lit_as_u8.rs

@@ -1,13 +1,12 @@
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet_with_applicability;
+use if_chain::if_chain;
 use rustc_ast::LitKind;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, UintTy};
 
-use if_chain::if_chain;
-
-use crate::utils::{snippet_with_applicability, span_lint_and_then};
-
 use super::CHAR_LIT_AS_U8;
 
 pub(super) fn check(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {

clippy_lints/src/casts/fn_to_numeric_cast.rs

@@ -1,10 +1,10 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty, UintTy};
 
-use crate::utils::{snippet_with_applicability, span_lint_and_sugg};
-
 use super::{utils, FN_TO_NUMERIC_CAST};
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {

clippy_lints/src/casts/fn_to_numeric_cast_with_truncation.rs

@@ -1,10 +1,10 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
 use rustc_errors::Applicability;
 use rustc_hir::Expr;
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty};
 
-use crate::utils::{snippet_with_applicability, span_lint_and_sugg};
-
 use super::{utils, FN_TO_NUMERIC_CAST_WITH_TRUNCATION};
 
 pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, cast_expr: &Expr<'_>, cast_from: Ty<'_>, cast_to: Ty<'_>) {

clippy_lints/src/casts/mod.rs

@@ -12,14 +12,13 @@ mod ptr_as_ptr;
 mod unnecessary_cast;
 mod utils;
 
+use clippy_utils::is_hir_ty_cfg_dependant;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 
-use crate::utils::is_hir_ty_cfg_dependant;
-
 declare_clippy_lint! {
     /// **What it does:** Checks for casts from any numerical to a float type where
     /// the receiving type cannot store all values from the original type without

clippy_lints/src/casts/ptr_as_ptr.rs

@@ -1,16 +1,15 @@
 use std::borrow::Cow;
 
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::meets_msrv;
+use clippy_utils::sugg::Sugg;
+use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, Mutability, TyKind};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, TypeAndMut};
 use rustc_semver::RustcVersion;
 
-use if_chain::if_chain;
-
-use crate::utils::sugg::Sugg;
-use crate::utils::{meets_msrv, span_lint_and_sugg};
-
 use super::PTR_AS_PTR;
 
 const PTR_AS_PTR_MSRV: RustcVersion = RustcVersion::new(1, 38, 0);

clippy_lints/src/casts/unnecessary_cast.rs

@@ -1,3 +1,7 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::numeric_literal::NumericLiteral;
+use clippy_utils::source::snippet_opt;
+use if_chain::if_chain;
 use rustc_ast::{LitFloatType, LitIntType, LitKind};
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, Lit, UnOp};
@@ -5,10 +9,6 @@ use rustc_lint::{LateContext, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, FloatTy, InferTy, Ty};
 
-use if_chain::if_chain;
-
-use crate::utils::{numeric_literal::NumericLiteral, snippet_opt, span_lint, span_lint_and_sugg};
-
 use super::UNNECESSARY_CAST;
 
 pub(super) fn check(
@@ -44,9 +44,18 @@ pub(super) fn check(
                 lint_unnecessary_cast(cx, expr, &literal_str, cast_from, cast_to);
             },
             LitKind::Int(_, LitIntType::Unsuffixed) | LitKind::Float(_, LitFloatType::Unsuffixed) => {},
+            LitKind::Int(_, LitIntType::Signed(_) | LitIntType::Unsigned(_))
+            | LitKind::Float(_, LitFloatType::Suffixed(_))
+                if cast_from.kind() == cast_to.kind() =>
+            {
+                if let Some(src) = snippet_opt(cx, lit.span) {
+                    let num_lit = NumericLiteral::from_lit_kind(&src, &lit.node).unwrap();
+                    lint_unnecessary_cast(cx, expr, num_lit.integer, cast_from, cast_to);
+                }
+            },
             _ => {
                 if cast_from.kind() == cast_to.kind() && !in_external_macro(cx.sess(), expr.span) {
-                    span_lint(
+                    span_lint_and_sugg(
                         cx,
                         UNNECESSARY_CAST,
                         expr.span,
@@ -54,6 +63,9 @@ pub(super) fn check(
                             "casting to the same type is unnecessary (`{}` -> `{}`)",
                             cast_from, cast_to
                         ),
+                        "try",
+                        literal_str,
+                        Applicability::MachineApplicable,
                     );
                     return true;
                 }

clippy_lints/src/checked_conversions.rs

@@ -1,5 +1,8 @@
 //! lint on manually implemented checked conversions that could be transformed into `try_from`
 
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::{meets_msrv, SpanlessEq};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
@@ -9,8 +12,6 @@ use rustc_middle::lint::in_external_macro;
 use rustc_semver::RustcVersion;
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 
-use crate::utils::{meets_msrv, snippet_with_applicability, span_lint_and_sugg, SpanlessEq};
-
 const CHECKED_CONVERSIONS_MSRV: RustcVersion = RustcVersion::new(1, 34, 0);
 
 declare_clippy_lint! {

clippy_lints/src/cognitive_complexity.rs

@@ -1,5 +1,9 @@
 //! calculate cognitive complexity and warn about overly complex functions
 
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::source::snippet_opt;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::LimitStack;
 use rustc_ast::ast::Attribute;
 use rustc_hir::intravisit::{walk_expr, FnKind, NestedVisitorMap, Visitor};
 use rustc_hir::{Body, Expr, ExprKind, FnDecl, HirId};
@@ -9,8 +13,6 @@ use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
 use rustc_span::{sym, BytePos};
 
-use crate::utils::{is_type_diagnostic_item, snippet_opt, span_lint_and_help, LimitStack};
-
 declare_clippy_lint! {
     /// **What it does:** Checks for methods with high cognitive complexity.
     ///

clippy_lints/src/collapsible_if.rs

@@ -12,15 +12,15 @@
 //!
 //! This lint is **warn** by default
 
+use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
+use clippy_utils::source::{snippet_block, snippet_block_with_applicability};
+use clippy_utils::sugg::Sugg;
 use if_chain::if_chain;
 use rustc_ast::ast;
+use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use crate::utils::sugg::Sugg;
-use crate::utils::{snippet_block, snippet_block_with_applicability, span_lint_and_sugg, span_lint_and_then};
-use rustc_errors::Applicability;
-
 declare_clippy_lint! {
     /// **What it does:** Checks for nested `if` statements which can be collapsed
     /// by `&&`-combining their conditions.

clippy_lints/src/collapsible_match.rs

@@ -1,5 +1,6 @@
-use crate::utils::visitors::LocalUsedVisitor;
+use clippy_utils::diagnostics::span_lint_and_then;
-use crate::utils::{path_to_local, span_lint_and_then, SpanlessEq};
+use clippy_utils::visitors::LocalUsedVisitor;
+use clippy_utils::{path_to_local, SpanlessEq};
 use if_chain::if_chain;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, Res};
 use rustc_hir::{Arm, Expr, ExprKind, Guard, HirId, Pat, PatKind, QPath, StmtKind, UnOp};

clippy_lints/src/comparison_chain.rs

@@ -1,6 +1,6 @@
-use crate::utils::{
+use clippy_utils::diagnostics::span_lint_and_help;
-    get_trait_def_id, if_sequence, implements_trait, parent_node_is_if_expr, paths, span_lint_and_help, SpanlessEq,
+use clippy_utils::ty::implements_trait;
-};
+use clippy_utils::{get_trait_def_id, if_sequence, parent_node_is_if_expr, paths, SpanlessEq};
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};

clippy_lints/src/copies.rs

@@ -1,5 +1,6 @@
-use crate::utils::{eq_expr_value, in_macro, search_same, SpanlessEq, SpanlessHash};
+use clippy_utils::diagnostics::span_lint_and_note;
-use crate::utils::{get_parent_expr, if_sequence, span_lint_and_note};
+use clippy_utils::{eq_expr_value, in_macro, search_same, SpanlessEq, SpanlessHash};
+use clippy_utils::{get_parent_expr, if_sequence};
 use rustc_hir::{Block, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};

clippy_lints/src/copy_iterator.rs

@@ -1,7 +1,11 @@
-use crate::utils::{is_copy, match_path, paths, span_lint_and_note};
+use clippy_utils::diagnostics::span_lint_and_note;
+use clippy_utils::ty::is_copy;
 use rustc_hir::{Impl, Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
+
+use if_chain::if_chain;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for types that implement `Copy` as well as
@@ -33,14 +37,16 @@ declare_lint_pass!(CopyIterator => [COPY_ITERATOR]);
 
 impl<'tcx> LateLintPass<'tcx> for CopyIterator {
     fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'_>) {
-        if let ItemKind::Impl(Impl {
+        if_chain! {
-            of_trait: Some(ref trait_ref),
+            if let ItemKind::Impl(Impl {
-            ..
+                of_trait: Some(ref trait_ref),
-        }) = item.kind
+                ..
-        {
+            }) = item.kind;
             let ty = cx.tcx.type_of(item.def_id);
-
+            if is_copy(cx, ty);
-            if is_copy(cx, ty) && match_path(&trait_ref.path, &paths::ITERATOR) {
+            if let Some(trait_id) = trait_ref.trait_def_id();
+            if cx.tcx.is_diagnostic_item(sym::Iterator, trait_id);
+            then {
                 span_lint_and_note(
                     cx,
                     COPY_ITERATOR,

clippy_lints/src/create_dir.rs

@@ -1,4 +1,6 @@
-use crate::utils::{match_def_path, paths, snippet, span_lint_and_sugg};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use clippy_utils::{match_def_path, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind};

clippy_lints/src/dbg_macro.rs

@@ -1,4 +1,5 @@
-use crate::utils::{snippet_opt, span_lint_and_help, span_lint_and_sugg};
+use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg};
+use clippy_utils::source::snippet_opt;
 use rustc_ast::ast;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_errors::Applicability;

clippy_lints/src/default.rs

@@ -1,7 +1,6 @@
-use crate::utils::{
+use clippy_utils::diagnostics::{span_lint_and_note, span_lint_and_sugg};
-    any_parent_is_automatically_derived, contains_name, match_def_path, paths, snippet_with_macro_callsite,
+use clippy_utils::source::snippet_with_macro_callsite;
-};
+use clippy_utils::{any_parent_is_automatically_derived, contains_name, match_def_path, paths};
-use crate::utils::{span_lint_and_note, span_lint_and_sugg};
 use if_chain::if_chain;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::Applicability;
@@ -105,6 +104,7 @@ impl LateLintPass<'_> for Default {
         }
     }
 
+    #[allow(clippy::too_many_lines)]
     fn check_block<'tcx>(&mut self, cx: &LateContext<'tcx>, block: &Block<'tcx>) {
         // start from the `let mut _ = _::default();` and look at all the following
         // statements, see if they re-assign the fields of the binding
@@ -198,6 +198,24 @@ impl LateLintPass<'_> for Default {
                     .collect::<Vec<String>>()
                     .join(", ");
 
+                // give correct suggestion if generics are involved (see #6944)
+                let binding_type = if_chain! {
+                    if let ty::Adt(adt_def, substs) = binding_type.kind();
+                    if !substs.is_empty();
+                    let adt_def_ty_name = cx.tcx.item_name(adt_def.did);
+                    let generic_args = substs.iter().collect::<Vec<_>>();
+                    let tys_str = generic_args
+                        .iter()
+                        .map(ToString::to_string)
+                        .collect::<Vec<_>>()
+                        .join(", ");
+                    then {
+                        format!("{}::<{}>", adt_def_ty_name, &tys_str)
+                    } else {
+                        binding_type.to_string()
+                    }
+                };
+
                 let sugg = if ext_with_default {
                     if field_list.is_empty() {
                         format!("{}::default()", binding_type)

clippy_lints/src/default_numeric_fallback.rs

@@ -1,3 +1,6 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use if_chain::if_chain;
 use rustc_ast::ast::{LitFloatType, LitIntType, LitKind};
 use rustc_errors::Applicability;
 use rustc_hir::{
@@ -11,10 +14,6 @@ use rustc_middle::{
 };
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use if_chain::if_chain;
-
-use crate::utils::{snippet, span_lint_and_sugg};
-
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of unconstrained numeric literals which may cause default numeric fallback in type
     /// inference.

clippy_lints/src/dereference.rs

@@ -1,11 +1,14 @@
-use crate::utils::{get_parent_expr, implements_trait, snippet, span_lint_and_sugg};
+use clippy_utils::diagnostics::span_lint_and_sugg;
-use if_chain::if_chain;
+use clippy_utils::source::snippet_with_context;
-use rustc_ast::util::parser::{ExprPrecedence, PREC_POSTFIX, PREC_PREFIX};
+use clippy_utils::ty::peel_mid_ty_refs;
+use clippy_utils::{get_parent_node, in_macro, is_allowed};
+use rustc_ast::util::parser::PREC_PREFIX;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
+use rustc_hir::{BorrowKind, Expr, ExprKind, HirId, MatchSource, Mutability, Node, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_middle::ty::{self, Ty, TyCtxt, TyS, TypeckResults};
-use rustc_span::source_map::Span;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::{symbol::sym, Span};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for explicit `deref()` or `deref_mut()` method calls.
@@ -34,76 +37,265 @@ declare_clippy_lint! {
     "Explicit use of deref or deref_mut method while not in a method chain."
 }
 
-declare_lint_pass!(Dereferencing => [
+impl_lint_pass!(Dereferencing => [
-    EXPLICIT_DEREF_METHODS
+    EXPLICIT_DEREF_METHODS,
 ]);
 
+#[derive(Default)]
+pub struct Dereferencing {
+    state: Option<(State, StateData)>,
+
+    // While parsing a `deref` method call in ufcs form, the path to the function is itself an
+    // expression. This is to store the id of that expression so it can be skipped when
+    // `check_expr` is called for it.
+    skip_expr: Option<HirId>,
+}
+
+struct StateData {
+    /// Span of the top level expression
+    span: Span,
+    /// The required mutability
+    target_mut: Mutability,
+}
+
+enum State {
+    // Any number of deref method calls.
+    DerefMethod {
+        // The number of calls in a sequence which changed the referenced type
+        ty_changed_count: usize,
+        is_final_ufcs: bool,
+    },
+}
+
+// A reference operation considered by this lint pass
+enum RefOp {
+    Method(Mutability),
+    Deref,
+    AddrOf,
+}
+
 impl<'tcx> LateLintPass<'tcx> for Dereferencing {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) {
-        if_chain! {
+        // Skip path expressions from deref calls. e.g. `Deref::deref(e)`
-            if !expr.span.from_expansion();
+        if Some(expr.hir_id) == self.skip_expr.take() {
-            if let ExprKind::MethodCall(ref method_name, _, ref args, _) = &expr.kind;
+            return;
-            if args.len() == 1;
+        }
 
-            then {
+        // Stop processing sub expressions when a macro call is seen
-                if let Some(parent_expr) = get_parent_expr(cx, expr) {
+        if in_macro(expr.span) {
-                    // Check if we have the whole call chain here
+            if let Some((state, data)) = self.state.take() {
-                    if let ExprKind::MethodCall(..) = parent_expr.kind {
+                report(cx, expr, state, data);
-                        return;
-                    }
-                    // Check for Expr that we don't want to be linted
-                    let precedence = parent_expr.precedence();
-                    match precedence {
-                        // Lint a Call is ok though
-                        ExprPrecedence::Call | ExprPrecedence::AddrOf => (),
-                        _ => {
-                            if precedence.order() >= PREC_PREFIX && precedence.order() <= PREC_POSTFIX {
-                                return;
-                            }
-                        }
-                    }
-                }
-                let name = method_name.ident.as_str();
-                lint_deref(cx, &*name, &args[0], args[0].span, expr.span);
             }
+            return;
+        }
+
+        let typeck = cx.typeck_results();
+        let (kind, sub_expr) = if let Some(x) = try_parse_ref_op(cx.tcx, typeck, expr) {
+            x
+        } else {
+            // The whole chain of reference operations has been seen
+            if let Some((state, data)) = self.state.take() {
+                report(cx, expr, state, data);
+            }
+            return;
+        };
+
+        match (self.state.take(), kind) {
+            (None, kind) => {
+                let parent = get_parent_node(cx.tcx, expr.hir_id);
+                let expr_ty = typeck.expr_ty(expr);
+
+                match kind {
+                    RefOp::Method(target_mut)
+                        if !is_allowed(cx, EXPLICIT_DEREF_METHODS, expr.hir_id)
+                            && is_linted_explicit_deref_position(parent, expr.hir_id, expr.span) =>
+                    {
+                        self.state = Some((
+                            State::DerefMethod {
+                                ty_changed_count: if deref_method_same_type(expr_ty, typeck.expr_ty(sub_expr)) {
+                                    0
+                                } else {
+                                    1
+                                },
+                                is_final_ufcs: matches!(expr.kind, ExprKind::Call(..)),
+                            },
+                            StateData {
+                                span: expr.span,
+                                target_mut,
+                            },
+                        ));
+                    }
+                    _ => (),
+                }
+            },
+            (Some((State::DerefMethod { ty_changed_count, .. }, data)), RefOp::Method(_)) => {
+                self.state = Some((
+                    State::DerefMethod {
+                        ty_changed_count: if deref_method_same_type(typeck.expr_ty(expr), typeck.expr_ty(sub_expr)) {
+                            ty_changed_count
+                        } else {
+                            ty_changed_count + 1
+                        },
+                        is_final_ufcs: matches!(expr.kind, ExprKind::Call(..)),
+                    },
+                    data,
+                ));
+            },
+
+            (Some((state, data)), _) => report(cx, expr, state, data),
         }
     }
 }
 
-fn lint_deref(cx: &LateContext<'_>, method_name: &str, call_expr: &Expr<'_>, var_span: Span, expr_span: Span) {
+fn try_parse_ref_op(
-    match method_name {
+    tcx: TyCtxt<'tcx>,
-        "deref" => {
+    typeck: &'tcx TypeckResults<'_>,
-            let impls_deref_trait = cx.tcx.lang_items().deref_trait().map_or(false, |id| {
+    expr: &'tcx Expr<'_>,
-                implements_trait(cx, cx.typeck_results().expr_ty(&call_expr), id, &[])
+) -> Option<(RefOp, &'tcx Expr<'tcx>)> {
-            });
+    let (def_id, arg) = match expr.kind {
-            if impls_deref_trait {
+        ExprKind::MethodCall(_, _, [arg], _) => (typeck.type_dependent_def_id(expr.hir_id)?, arg),
-                span_lint_and_sugg(
+        ExprKind::Call(
-                    cx,
+            Expr {
-                    EXPLICIT_DEREF_METHODS,
+                kind: ExprKind::Path(path),
-                    expr_span,
+                hir_id,
-                    "explicit deref method call",
+                ..
-                    "try this",
+            },
-                    format!("&*{}", &snippet(cx, var_span, "..")),
+            [arg],
-                    Applicability::MachineApplicable,
+        ) => (typeck.qpath_res(path, *hir_id).opt_def_id()?, arg),
-                );
+        ExprKind::Unary(UnOp::Deref, sub_expr) if !typeck.expr_ty(sub_expr).is_unsafe_ptr() => {
-            }
+            return Some((RefOp::Deref, sub_expr));
+        },
+        ExprKind::AddrOf(BorrowKind::Ref, _, sub_expr) => return Some((RefOp::AddrOf, sub_expr)),
+        _ => return None,
+    };
+    if tcx.is_diagnostic_item(sym::deref_method, def_id) {
+        Some((RefOp::Method(Mutability::Not), arg))
+    } else if tcx.trait_of_item(def_id)? == tcx.lang_items().deref_mut_trait()? {
+        Some((RefOp::Method(Mutability::Mut), arg))
+    } else {
+        None
+    }
+}
+
+// Checks whether the type for a deref call actually changed the type, not just the mutability of
+// the reference.
+fn deref_method_same_type(result_ty: Ty<'tcx>, arg_ty: Ty<'tcx>) -> bool {
+    match (result_ty.kind(), arg_ty.kind()) {
+        (ty::Ref(_, result_ty, _), ty::Ref(_, arg_ty, _)) => TyS::same_type(result_ty, arg_ty),
+
+        // The result type for a deref method is always a reference
+        // Not matching the previous pattern means the argument type is not a reference
+        // This means that the type did change
+        _ => false,
+    }
+}
+
+// Checks whether the parent node is a suitable context for switching from a deref method to the
+// deref operator.
+fn is_linted_explicit_deref_position(parent: Option<Node<'_>>, child_id: HirId, child_span: Span) -> bool {
+    let parent = match parent {
+        Some(Node::Expr(e)) if e.span.ctxt() == child_span.ctxt() => e,
+        _ => return true,
+    };
+    match parent.kind {
+        // Leave deref calls in the middle of a method chain.
+        // e.g. x.deref().foo()
+        ExprKind::MethodCall(_, _, [self_arg, ..], _) if self_arg.hir_id == child_id => false,
+
+        // Leave deref calls resulting in a called function
+        // e.g. (x.deref())()
+        ExprKind::Call(func_expr, _) if func_expr.hir_id == child_id => false,
+
+        // Makes an ugly suggestion
+        // e.g. *x.deref() => *&*x
+        ExprKind::Unary(UnOp::Deref, _)
+        // Postfix expressions would require parens
+        | ExprKind::Match(_, _, MatchSource::TryDesugar | MatchSource::AwaitDesugar)
+        | ExprKind::Field(..)
+        | ExprKind::Index(..)
+        | ExprKind::Err => false,
+
+        ExprKind::Box(..)
+        | ExprKind::ConstBlock(..)
+        | ExprKind::Array(_)
+        | ExprKind::Call(..)
+        | ExprKind::MethodCall(..)
+        | ExprKind::Tup(..)
+        | ExprKind::Binary(..)
+        | ExprKind::Unary(..)
+        | ExprKind::Lit(..)
+        | ExprKind::Cast(..)
+        | ExprKind::Type(..)
+        | ExprKind::DropTemps(..)
+        | ExprKind::If(..)
+        | ExprKind::Loop(..)
+        | ExprKind::Match(..)
+        | ExprKind::Closure(..)
+        | ExprKind::Block(..)
+        | ExprKind::Assign(..)
+        | ExprKind::AssignOp(..)
+        | ExprKind::Path(..)
+        | ExprKind::AddrOf(..)
+        | ExprKind::Break(..)
+        | ExprKind::Continue(..)
+        | ExprKind::Ret(..)
+        | ExprKind::InlineAsm(..)
+        | ExprKind::LlvmInlineAsm(..)
+        | ExprKind::Struct(..)
+        | ExprKind::Repeat(..)
+        | ExprKind::Yield(..) => true,
+    }
+}
+
+#[allow(clippy::needless_pass_by_value)]
+fn report(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>, state: State, data: StateData) {
+    match state {
+        State::DerefMethod {
+            ty_changed_count,
+            is_final_ufcs,
+        } => {
+            let mut app = Applicability::MachineApplicable;
+            let (expr_str, expr_is_macro_call) = snippet_with_context(cx, expr.span, data.span.ctxt(), "..", &mut app);
+            let ty = cx.typeck_results().expr_ty(expr);
+            let (_, ref_count) = peel_mid_ty_refs(ty);
+            let deref_str = if ty_changed_count >= ref_count && ref_count != 0 {
+                // a deref call changing &T -> &U requires two deref operators the first time
+                // this occurs. One to remove the reference, a second to call the deref impl.
+                "*".repeat(ty_changed_count + 1)
+            } else {
+                "*".repeat(ty_changed_count)
+            };
+            let addr_of_str = if ty_changed_count < ref_count {
+                // Check if a reborrow from &mut T -> &T is required.
+                if data.target_mut == Mutability::Not && matches!(ty.kind(), ty::Ref(_, _, Mutability::Mut)) {
+                    "&*"
+                } else {
+                    ""
+                }
+            } else if data.target_mut == Mutability::Mut {
+                "&mut "
+            } else {
+                "&"
+            };
+
+            let expr_str = if !expr_is_macro_call && is_final_ufcs && expr.precedence().order() < PREC_PREFIX {
+                format!("({})", expr_str)
+            } else {
+                expr_str.into_owned()
+            };
+
+            span_lint_and_sugg(
+                cx,
+                EXPLICIT_DEREF_METHODS,
+                data.span,
+                match data.target_mut {
+                    Mutability::Not => "explicit `deref` method call",
+                    Mutability::Mut => "explicit `deref_mut` method call",
+                },
+                "try this",
+                format!("{}{}{}", addr_of_str, deref_str, expr_str),
+                app,
+            );
         },
-        "deref_mut" => {
-            let impls_deref_mut_trait = cx.tcx.lang_items().deref_mut_trait().map_or(false, |id| {
-                implements_trait(cx, cx.typeck_results().expr_ty(&call_expr), id, &[])
-            });
-            if impls_deref_mut_trait {
-                span_lint_and_sugg(
-                    cx,
-                    EXPLICIT_DEREF_METHODS,
-                    expr_span,
-                    "explicit deref_mut method call",
-                    "try this",
-                    format!("&mut *{}", &snippet(cx, var_span, "..")),
-                    Applicability::MachineApplicable,
-                );
-            }
-        },
-        _ => (),
     }
 }

clippy_lints/src/derive.rs

@@ -1,8 +1,7 @@
-use crate::utils::paths;
+use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_note, span_lint_and_then};
-use crate::utils::{
+use clippy_utils::paths;
-    get_trait_def_id, is_allowed, is_automatically_derived, is_copy, match_def_path, span_lint_and_help,
+use clippy_utils::ty::is_copy;
-    span_lint_and_note, span_lint_and_then,
+use clippy_utils::{get_trait_def_id, is_allowed, is_automatically_derived, match_def_path};
-};
 use if_chain::if_chain;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::{walk_expr, walk_fn, walk_item, FnKind, NestedVisitorMap, Visitor};

clippy_lints/src/disallowed_method.rs

@@ -1,4 +1,5 @@
-use crate::utils::{fn_def_id, span_lint};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::fn_def_id;
 
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::Expr;

clippy_lints/src/doc.rs

@@ -1,7 +1,6 @@
-use crate::utils::{
+use clippy_utils::diagnostics::{span_lint, span_lint_and_note};
-    implements_trait, is_entrypoint_fn, is_expn_of, is_type_diagnostic_item, match_panic_def_id, method_chain_args,
+use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
-    return_ty, span_lint, span_lint_and_note,
+use clippy_utils::{is_entrypoint_fn, is_expn_of, match_panic_def_id, method_chain_args, return_ty};
-};
 use if_chain::if_chain;
 use itertools::Itertools;
 use rustc_ast::ast::{Async, AttrKind, Attribute, FnKind, FnRetTy, ItemKind};
@@ -584,7 +583,7 @@ fn check_code(cx: &LateContext<'_>, text: &str, edition: Edition, span: Span) {
                                 let returns_nothing = match &sig.decl.output {
                                     FnRetTy::Default(..) => true,
                                     FnRetTy::Ty(ty) if ty.kind.is_unit() => true,
-                                    _ => false,
+                                    FnRetTy::Ty(_) => false,
                                 };
 
                                 if returns_nothing && !is_async && !block.stmts.is_empty() {

clippy_lints/src/double_comparison.rs

@@ -1,13 +1,14 @@
 //! Lint on unnecessary double comparisons. Some examples:
 
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::eq_expr_value;
+use clippy_utils::source::snippet_with_applicability;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
-use crate::utils::{eq_expr_value, snippet_with_applicability, span_lint_and_sugg};
-
 declare_clippy_lint! {
     /// **What it does:** Checks for double comparisons that could be simplified to a single expression.
     ///

clippy_lints/src/double_parens.rs

@@ -1,4 +1,4 @@
-use crate::utils::span_lint;
+use clippy_utils::diagnostics::span_lint;
 use rustc_ast::ast::{Expr, ExprKind};
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};

clippy_lints/src/drop_forget_ref.rs

@@ -1,4 +1,6 @@
-use crate::utils::{is_copy, match_def_path, paths, span_lint_and_note};
+use clippy_utils::diagnostics::span_lint_and_note;
+use clippy_utils::ty::is_copy;
+use clippy_utils::{match_def_path, paths};
 use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/duration_subsec.rs

@@ -1,3 +1,5 @@
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::match_type;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind};
@@ -6,8 +8,8 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Spanned;
 
 use crate::consts::{constant, Constant};
-use crate::utils::paths;
+use clippy_utils::diagnostics::span_lint_and_sugg;
-use crate::utils::{match_type, snippet_with_applicability, span_lint_and_sugg};
+use clippy_utils::paths;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for calculation of subsecond microseconds or milliseconds

clippy_lints/src/else_if_without_else.rs

@@ -1,12 +1,11 @@
 //! Lint on if expressions with an else if, but without a final else branch.
 
+use clippy_utils::diagnostics::span_lint_and_help;
 use rustc_ast::ast::{Expr, ExprKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use crate::utils::span_lint_and_help;
-
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of if expressions with an `else if` branch,
     /// but without a final `else` branch.

clippy_lints/src/empty_enum.rs

@@ -1,6 +1,6 @@
 //! lint when there is an enum with no variants
 
-use crate::utils::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_and_help;
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};

clippy_lints/src/entry.rs

@@ -1,6 +1,8 @@
-use crate::utils::SpanlessEq;
+use clippy_utils::diagnostics::span_lint_and_then;
-use crate::utils::{get_item_name, is_type_diagnostic_item, match_type, paths, snippet, snippet_opt};
+use clippy_utils::source::{snippet, snippet_opt, snippet_with_applicability};
-use crate::utils::{snippet_with_applicability, span_lint_and_then};
+use clippy_utils::ty::{is_type_diagnostic_item, match_type};
+use clippy_utils::SpanlessEq;
+use clippy_utils::{get_item_name, paths};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};

clippy_lints/src/enum_clike.rs

@@ -2,7 +2,7 @@
 //! don't fit into an `i32`
 
 use crate::consts::{miri_to_const, Constant};
-use crate::utils::span_lint;
+use clippy_utils::diagnostics::span_lint;
 use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::util::IntTypeExt;

clippy_lints/src/enum_variants.rs

@@ -1,7 +1,8 @@
 //! lint on enum variants that are prefixed or suffixed by the same characters
 
-use crate::utils::{camel_case, is_present_in_source};
+use clippy_utils::camel_case;
-use crate::utils::{span_lint, span_lint_and_help};
+use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
+use clippy_utils::source::is_present_in_source;
 use rustc_ast::ast::{EnumDef, Item, ItemKind, VisibilityKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, Lint};
 use rustc_session::{declare_tool_lint, impl_lint_pass};

clippy_lints/src/eq_op.rs

@@ -1,7 +1,7 @@
-use crate::utils::{
+use clippy_utils::diagnostics::{multispan_sugg, span_lint, span_lint_and_then};
-    ast_utils::is_useless_with_eq_exprs, eq_expr_value, higher, implements_trait, in_macro, is_copy, is_expn_of,
+use clippy_utils::source::snippet;
-    multispan_sugg, snippet, span_lint, span_lint_and_then,
+use clippy_utils::ty::{implements_trait, is_copy};
-};
+use clippy_utils::{ast_utils::is_useless_with_eq_exprs, eq_expr_value, higher, in_macro, is_expn_of};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, StmtKind};

clippy_lints/src/erasing_op.rs

@@ -1,10 +1,10 @@
+use clippy_utils::diagnostics::span_lint;
 use rustc_hir::{BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
 use crate::consts::{constant_simple, Constant};
-use crate::utils::span_lint;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for erasing operations, e.g., `x * 0`.

clippy_lints/src/escape.rs

@@ -1,3 +1,5 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::ty::contains_ty;
 use rustc_hir::intravisit;
 use rustc_hir::{self, AssocItemKind, Body, FnDecl, HirId, HirIdSet, Impl, ItemKind, Node};
 use rustc_infer::infer::TyCtxtInferExt;
@@ -11,8 +13,6 @@ use rustc_target::abi::LayoutOf;
 use rustc_target::spec::abi::Abi;
 use rustc_typeck::expr_use_visitor::{ConsumeMode, Delegate, ExprUseVisitor, PlaceBase, PlaceWithHirId};
 
-use crate::utils::{contains_ty, span_lint};
-
 #[derive(Copy, Clone)]
 pub struct BoxedLocal {
     pub too_large_for_stack: u64,
@@ -186,7 +186,7 @@ impl<'a, 'tcx> Delegate<'tcx> for EscapeDelegate<'a, 'tcx> {
         }
     }
 
-    fn fake_read(&mut self, _: rustc_typeck::expr_use_visitor::Place<'tcx>, _: FakeReadCause, _: HirId) { }
+    fn fake_read(&mut self, _: rustc_typeck::expr_use_visitor::Place<'tcx>, _: FakeReadCause, _: HirId) {}
 }
 
 impl<'a, 'tcx> EscapeDelegate<'a, 'tcx> {

clippy_lints/src/eta_reduction.rs

@@ -1,3 +1,9 @@
+use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
+use clippy_utils::higher;
+use clippy_utils::higher::VecArgs;
+use clippy_utils::source::snippet_opt;
+use clippy_utils::ty::{implements_trait, type_is_unsafe_function};
+use clippy_utils::{is_adjusted, iter_input_pats};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{def_id, Expr, ExprKind, Param, PatKind, QPath};
@@ -6,13 +12,6 @@ use rustc_middle::lint::in_external_macro;
 use rustc_middle::ty::{self, Ty};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use crate::utils::{
-    implements_trait, is_adjusted, iter_input_pats, snippet_opt, span_lint_and_sugg, span_lint_and_then,
-    type_is_unsafe_function,
-};
-use clippy_utils::higher;
-use clippy_utils::higher::VecArgs;
-
 declare_clippy_lint! {
     /// **What it does:** Checks for closures which just call another function where
     /// the function can be called directly. `unsafe` functions or calls where types

clippy_lints/src/eval_order_dependence.rs

@@ -1,4 +1,5 @@
-use crate::utils::{get_parent_expr, path_to_local, path_to_local_id, span_lint, span_lint_and_note};
+use clippy_utils::diagnostics::{span_lint, span_lint_and_note};
+use clippy_utils::{get_parent_expr, path_to_local, path_to_local_id};
 use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
 use rustc_hir::{BinOpKind, Block, Expr, ExprKind, Guard, HirId, Local, Node, Stmt, StmtKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -272,7 +273,7 @@ fn check_stmt<'a, 'tcx>(vis: &mut ReadVisitor<'a, 'tcx>, stmt: &'tcx Stmt<'_>) -
             .init
             .as_ref()
             .map_or(StopEarly::KeepGoing, |expr| check_expr(vis, expr)),
-        _ => StopEarly::KeepGoing,
+        StmtKind::Item(..) => StopEarly::KeepGoing,
     }
 }
 

clippy_lints/src/excessive_bools.rs

@@ -1,7 +1,6 @@
-use crate::utils::{attr_by_name, in_macro, match_path_ast, span_lint_and_help};
+use clippy_utils::diagnostics::span_lint_and_help;
-use rustc_ast::ast::{
+use clippy_utils::{attr_by_name, in_macro, match_path_ast};
-    AssocItemKind, Extern, FnKind, FnSig, ImplKind, Item, ItemKind, TraitKind, Ty, TyKind,
+use rustc_ast::ast::{AssocItemKind, Extern, FnKind, FnSig, ImplKind, Item, ItemKind, TraitKind, Ty, TyKind};
-};
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::Span;

clippy_lints/src/exhaustive_items.rs

@@ -1,4 +1,5 @@
-use crate::utils::{indent_of, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::indent_of;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{Item, ItemKind};

clippy_lints/src/exit.rs

@@ -1,4 +1,5 @@
-use crate::utils::{is_entrypoint_fn, match_def_path, paths, span_lint};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::{is_entrypoint_fn, match_def_path, paths};
 use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind, Item, ItemKind, Node};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/explicit_write.rs

@@ -1,4 +1,5 @@
-use crate::utils::{is_expn_of, match_function_call, paths, span_lint, span_lint_and_sugg};
+use clippy_utils::diagnostics::{span_lint, span_lint_and_sugg};
+use clippy_utils::{is_expn_of, match_function_call, paths};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;

clippy_lints/src/fallible_impl_from.rs

@@ -1,4 +1,6 @@
-use crate::utils::{is_expn_of, is_type_diagnostic_item, match_panic_def_id, method_chain_args, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::{is_expn_of, match_panic_def_id, method_chain_args};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/float_equality_without_abs.rs

@@ -1,4 +1,5 @@
-use crate::utils::{match_def_path, paths, span_lint_and_then, sugg};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::{match_def_path, paths, sugg};
 use if_chain::if_chain;
 use rustc_ast::util::parser::AssocOp;
 use rustc_errors::Applicability;

clippy_lints/src/float_literal.rs

@@ -1,4 +1,5 @@
-use crate::utils::{numeric_literal, span_lint_and_sugg};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::numeric_literal;
 use if_chain::if_chain;
 use rustc_ast::ast::{self, LitFloatType, LitKind};
 use rustc_errors::Applicability;

clippy_lints/src/floating_point_arithmetic.rs

@@ -2,7 +2,8 @@ use crate::consts::{
     constant, constant_simple, Constant,
     Constant::{Int, F32, F64},
 };
-use crate::utils::{eq_expr_value, get_parent_expr, numeric_literal, span_lint_and_sugg, sugg};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::{eq_expr_value, get_parent_expr, numeric_literal, sugg};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, PathSegment, UnOp};

clippy_lints/src/format.rs

@@ -1,8 +1,8 @@
-use crate::utils::paths;
+use clippy_utils::diagnostics::span_lint_and_then;
-use crate::utils::{
+use clippy_utils::paths;
-    is_expn_of, is_type_diagnostic_item, last_path_segment, match_def_path, match_function_call, snippet, snippet_opt,
+use clippy_utils::source::{snippet, snippet_opt};
-    span_lint_and_then,
+use clippy_utils::ty::is_type_diagnostic_item;
-};
+use clippy_utils::{is_expn_of, last_path_segment, match_def_path, match_function_call};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;

clippy_lints/src/formatting.rs

@@ -1,4 +1,6 @@
-use crate::utils::{differing_macro_contexts, snippet_opt, span_lint_and_help, span_lint_and_note};
+use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_note};
+use clippy_utils::differing_macro_contexts;
+use clippy_utils::source::snippet_opt;
 use if_chain::if_chain;
 use rustc_ast::ast::{BinOpKind, Block, Expr, ExprKind, StmtKind, UnOp};
 use rustc_lint::{EarlyContext, EarlyLintPass};

clippy_lints/src/from_over_into.rs

@@ -1,5 +1,6 @@
-use crate::utils::paths::INTO;
+use clippy_utils::diagnostics::span_lint_and_help;
-use crate::utils::{match_def_path, meets_msrv, span_lint_and_help};
+use clippy_utils::paths::INTO;
+use clippy_utils::{match_def_path, meets_msrv};
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass, LintContext};

clippy_lints/src/from_str_radix_10.rs

@@ -1,3 +1,6 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::sugg::Sugg;
+use clippy_utils::ty::is_type_diagnostic_item;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{def, Expr, ExprKind, PrimTy, QPath, TyKind};
@@ -6,10 +9,6 @@ use rustc_middle::ty::Ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::sym;
 
-use crate::utils::is_type_diagnostic_item;
-use crate::utils::span_lint_and_sugg;
-use crate::utils::sugg::Sugg;
-
 declare_clippy_lint! {
     /// **What it does:**
     /// Checks for function invocations of the form `primitive::from_str_radix(s, 10)`

clippy_lints/src/functions.rs

@@ -1,7 +1,9 @@
-use crate::utils::{
+use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_then};
-    attr_by_name, attrs::is_proc_macro, is_must_use_ty, is_trait_impl_item, is_type_diagnostic_item, iter_input_pats,
+use clippy_utils::source::{snippet, snippet_opt};
-    match_def_path, must_use_attr, path_to_local, return_ty, snippet, snippet_opt, span_lint, span_lint_and_help,
+use clippy_utils::ty::{is_must_use_ty, is_type_diagnostic_item, type_is_unsafe_function};
-    span_lint_and_then, trait_ref_of_method, type_is_unsafe_function,
+use clippy_utils::{
+    attr_by_name, attrs::is_proc_macro, is_trait_impl_item, iter_input_pats, match_def_path, must_use_attr,
+    path_to_local, return_ty, trait_ref_of_method,
 };
 use if_chain::if_chain;
 use rustc_ast::ast::Attribute;

clippy_lints/src/future_not_send.rs

@@ -1,4 +1,5 @@
-use crate::utils;
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::return_ty;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Body, FnDecl, HirId};
 use rustc_infer::infer::TyCtxtInferExt;
@@ -61,7 +62,7 @@ impl<'tcx> LateLintPass<'tcx> for FutureNotSend {
         if let FnKind::Closure = kind {
             return;
         }
-        let ret_ty = utils::return_ty(cx, hir_id);
+        let ret_ty = return_ty(cx, hir_id);
         if let Opaque(id, subst) = *ret_ty.kind() {
             let preds = cx.tcx.explicit_item_bounds(id);
             let mut is_future = false;
@@ -84,7 +85,7 @@ impl<'tcx> LateLintPass<'tcx> for FutureNotSend {
                     fulfillment_cx.select_all_or_error(&infcx)
                 });
                 if let Err(send_errors) = send_result {
-                    utils::span_lint_and_then(
+                    span_lint_and_then(
                         cx,
                         FUTURE_NOT_SEND,
                         span,

clippy_lints/src/get_last_with_len.rs

@@ -1,6 +1,9 @@
 //! lint on using `x.get(x.len() - 1)` instead of `x.last()`
 
-use crate::utils::{is_type_diagnostic_item, snippet_with_applicability, span_lint_and_sugg, SpanlessEq};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::SpanlessEq;
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;

clippy_lints/src/identity_op.rs

@@ -1,3 +1,4 @@
+use clippy_utils::source::snippet;
 use if_chain::if_chain;
 use rustc_hir::{BinOp, BinOpKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
@@ -6,7 +7,8 @@ use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::source_map::Span;
 
 use crate::consts::{constant_simple, Constant};
-use crate::utils::{clip, snippet, span_lint, unsext};
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::{clip, unsext};
 
 declare_clippy_lint! {
     /// **What it does:** Checks for identity operations, e.g., `x + 0`.

clippy_lints/src/if_let_mutex.rs

@@ -1,4 +1,6 @@
-use crate::utils::{is_type_diagnostic_item, span_lint_and_help, SpanlessEq};
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::SpanlessEq;
 use if_chain::if_chain;
 use rustc_hir::intravisit::{self as visit, NestedVisitorMap, Visitor};
 use rustc_hir::{Expr, ExprKind, MatchSource};

clippy_lints/src/if_let_some_result.rs

@@ -1,4 +1,7 @@
-use crate::utils::{is_type_diagnostic_item, method_chain_args, snippet_with_applicability, span_lint_and_sugg};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::method_chain_args;
+use clippy_utils::source::snippet_with_applicability;
+use clippy_utils::ty::is_type_diagnostic_item;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{Expr, ExprKind, MatchSource, PatKind, QPath};

clippy_lints/src/if_not_else.rs

@@ -1,13 +1,12 @@
 //! lint on if branches that could be swapped so no `!` operation is necessary
 //! on the condition
 
+use clippy_utils::diagnostics::span_lint_and_help;
 use rustc_ast::ast::{BinOpKind, Expr, ExprKind, UnOp};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use crate::utils::span_lint_and_help;
-
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of `!` or `!=` in an if condition with an
     /// else branch.

clippy_lints/src/if_then_some_else_none.rs

@@ -0,0 +1,117 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::source::snippet_with_macro_callsite;
+use clippy_utils::{match_qpath, meets_msrv, parent_node_is_if_expr};
+use if_chain::if_chain;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass, LintContext};
+use rustc_middle::lint::in_external_macro;
+use rustc_semver::RustcVersion;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+
+const IF_THEN_SOME_ELSE_NONE_MSRV: RustcVersion = RustcVersion::new(1, 50, 0);
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for if-else that could be written to `bool::then`.
+    ///
+    /// **Why is this bad?** Looks a little redundant. Using `bool::then` helps it have less lines of code.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust
+    /// # let v = vec![0];
+    /// let a = if v.is_empty() {
+    ///     println!("true!");
+    ///     Some(42)
+    /// } else {
+    ///     None
+    /// };
+    /// ```
+    ///
+    /// Could be written:
+    ///
+    /// ```rust
+    /// # let v = vec![0];
+    /// let a = v.is_empty().then(|| {
+    ///     println!("true!");
+    ///     42
+    /// });
+    /// ```
+    pub IF_THEN_SOME_ELSE_NONE,
+    restriction,
+    "Finds if-else that could be written using `bool::then`"
+}
+
+pub struct IfThenSomeElseNone {
+    msrv: Option<RustcVersion>,
+}
+
+impl IfThenSomeElseNone {
+    #[must_use]
+    pub fn new(msrv: Option<RustcVersion>) -> Self {
+        Self { msrv }
+    }
+}
+
+impl_lint_pass!(IfThenSomeElseNone => [IF_THEN_SOME_ELSE_NONE]);
+
+impl LateLintPass<'_> for IfThenSomeElseNone {
+    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &'tcx Expr<'_>) {
+        if !meets_msrv(self.msrv.as_ref(), &IF_THEN_SOME_ELSE_NONE_MSRV) {
+            return;
+        }
+
+        if in_external_macro(cx.sess(), expr.span) {
+            return;
+        }
+
+        // We only care about the top-most `if` in the chain
+        if parent_node_is_if_expr(expr, cx) {
+            return;
+        }
+
+        if_chain! {
+            if let ExprKind::If(ref cond, ref then, Some(ref els)) = expr.kind;
+            if let ExprKind::Block(ref then_block, _) = then.kind;
+            if let Some(ref then_expr) = then_block.expr;
+            if let ExprKind::Call(ref then_call, [then_arg]) = then_expr.kind;
+            if let ExprKind::Path(ref then_call_qpath) = then_call.kind;
+            if match_qpath(then_call_qpath, &clippy_utils::paths::OPTION_SOME);
+            if let ExprKind::Block(ref els_block, _) = els.kind;
+            if els_block.stmts.is_empty();
+            if let Some(ref els_expr) = els_block.expr;
+            if let ExprKind::Path(ref els_call_qpath) = els_expr.kind;
+            if match_qpath(els_call_qpath, &clippy_utils::paths::OPTION_NONE);
+            then {
+                let cond_snip = snippet_with_macro_callsite(cx, cond.span, "[condition]");
+                let cond_snip = if matches!(cond.kind, ExprKind::Unary(_, _) | ExprKind::Binary(_, _, _)) {
+                    format!("({})", cond_snip)
+                } else {
+                    cond_snip.into_owned()
+                };
+                let arg_snip = snippet_with_macro_callsite(cx, then_arg.span, "");
+                let closure_body = if then_block.stmts.is_empty() {
+                    arg_snip.into_owned()
+                } else {
+                    format!("{{ /* snippet */ {} }}", arg_snip)
+                };
+                let help = format!(
+                    "consider using `bool::then` like: `{}.then(|| {})`",
+                    cond_snip,
+                    closure_body,
+                );
+                span_lint_and_help(
+                    cx,
+                    IF_THEN_SOME_ELSE_NONE,
+                    expr.span,
+                    "this could be simplified with `bool::then`",
+                    None,
+                    &help,
+                );
+            }
+        }
+    }
+
+    extract_msrv_attr!(LateContext);
+}

clippy_lints/src/implicit_return.rs

@@ -1,4 +1,6 @@
-use crate::utils::{match_panic_def_id, snippet_opt, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::match_panic_def_id;
+use clippy_utils::source::snippet_opt;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::intravisit::FnKind;

clippy_lints/src/implicit_saturating_sub.rs

@@ -1,4 +1,5 @@
-use crate::utils::{in_macro, match_qpath, span_lint_and_sugg, SpanlessEq};
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::{in_macro, match_qpath, SpanlessEq};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;

clippy_lints/src/inconsistent_struct_constructor.rs

@@ -1,3 +1,6 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet;
+use if_chain::if_chain;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::Applicability;
 use rustc_hir::{self as hir, ExprKind};
@@ -5,13 +8,10 @@ use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::symbol::Symbol;
 
-use if_chain::if_chain;
-
-use crate::utils::{snippet, span_lint_and_sugg};
-
 declare_clippy_lint! {
-    /// **What it does:** Checks for struct constructors where the order of the field init
+    /// **What it does:** Checks for struct constructors where all fields are shorthand and
-    /// shorthand in the constructor is inconsistent with the order in the struct definition.
+    /// the order of the field init shorthand in the constructor is inconsistent
+    /// with the order in the struct definition.
     ///
     /// **Why is this bad?** Since the order of fields in a constructor doesn't affect the
     /// resulted instance as the below example indicates,
@@ -25,11 +25,11 @@ declare_clippy_lint! {
     /// let x = 1;
     /// let y = 2;
     ///
-    /// // This assertion never fails.
+    /// // This assertion never fails:
     /// assert_eq!(Foo { x, y }, Foo { y, x });
     /// ```
     ///
-    /// inconsistent order means nothing and just decreases readability and consistency.
+    /// inconsistent order can be confusing and decreases readability and consistency.
     ///
     /// **Known problems:** None.
     ///
@@ -42,6 +42,7 @@ declare_clippy_lint! {
     /// }
     /// let x = 1;
     /// let y = 2;
+    ///
     /// Foo { y, x };
     /// ```
     ///
@@ -107,7 +108,7 @@ impl LateLintPass<'_> for InconsistentStructConstructor {
                     cx,
                     INCONSISTENT_STRUCT_CONSTRUCTOR,
                     expr.span,
-                    "inconsistent struct constructor",
+                    "struct constructor field order is inconsistent with struct definition field order",
                     "try",
                     sugg,
                     Applicability::MachineApplicable,

clippy_lints/src/indexing_slicing.rs

@@ -1,7 +1,8 @@
 //! lint on indexing and slicing operations
 
 use crate::consts::{constant, Constant};
-use crate::utils::{higher, span_lint, span_lint_and_help};
+use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
+use clippy_utils::higher;
 use rustc_ast::ast::RangeLimits;
 use rustc_hir::{Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/infinite_iter.rs

@@ -1,9 +1,10 @@
+use clippy_utils::diagnostics::span_lint;
+use clippy_utils::ty::{implements_trait, match_type};
+use clippy_utils::{get_trait_def_id, higher, match_qpath, paths};
 use rustc_hir::{BorrowKind, Expr, ExprKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use crate::utils::{get_trait_def_id, higher, implements_trait, match_qpath, match_type, paths, span_lint};
-
 declare_clippy_lint! {
     /// **What it does:** Checks for iteration that is guaranteed to be infinite.
     ///

clippy_lints/src/inherent_impl.rs

@@ -1,6 +1,7 @@
 //! lint on inherent implementations
 
-use crate::utils::{in_macro, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::in_macro;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::{def_id, Crate, Impl, Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/inherent_to_string.rs

@@ -1,14 +1,12 @@
+use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::ty::{implements_trait, is_type_diagnostic_item};
+use clippy_utils::{get_trait_def_id, paths, return_ty, trait_ref_of_method};
 use if_chain::if_chain;
 use rustc_hir::{ImplItem, ImplItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
 
-use crate::utils::{
-    get_trait_def_id, implements_trait, is_type_diagnostic_item, paths, return_ty, span_lint_and_help,
-    trait_ref_of_method,
-};
-
 declare_clippy_lint! {
     /// **What it does:** Checks for the definition of inherent methods with a signature of `to_string(&self) -> String`.
     ///

clippy_lints/src/inline_fn_without_body.rs

@@ -1,7 +1,7 @@
 //! checks for `#[inline]` on trait methods without bodies
 
-use crate::utils::span_lint_and_then;
+use clippy_utils::diagnostics::span_lint_and_then;
-use crate::utils::sugg::DiagnosticBuilderExt;
+use clippy_utils::sugg::DiagnosticBuilderExt;
 use rustc_ast::ast::Attribute;
 use rustc_errors::Applicability;
 use rustc_hir::{TraitFn, TraitItem, TraitItemKind};

clippy_lints/src/int_plus_one.rs

@@ -1,12 +1,12 @@
 //! lint on blocks unnecessarily using >= with a + 1 or - 1
 
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_opt;
 use rustc_ast::ast::{BinOpKind, Expr, ExprKind, Lit, LitKind};
 use rustc_errors::Applicability;
 use rustc_lint::{EarlyContext, EarlyLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
-use crate::utils::{snippet_opt, span_lint_and_sugg};
-
 declare_clippy_lint! {
     /// **What it does:** Checks for usage of `x >= y + 1` or `x - 1 >= y` (and `<=`) in a block
     ///

clippy_lints/src/integer_division.rs

@@ -1,4 +1,4 @@
-use crate::utils::span_lint_and_help;
+use clippy_utils::diagnostics::span_lint_and_help;
 use if_chain::if_chain;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass};

clippy_lints/src/items_after_statements.rs

@@ -1,6 +1,6 @@
 //! lint when items are used after statements
 
-use crate::utils::span_lint;
+use clippy_utils::diagnostics::span_lint;
 use rustc_ast::ast::{Block, ItemKind, StmtKind};
 use rustc_lint::{EarlyContext, EarlyLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;

clippy_lints/src/large_const_arrays.rs

@@ -1,5 +1,5 @@
 use crate::rustc_target::abi::LayoutOf;
-use crate::utils::span_lint_and_then;
+use clippy_utils::diagnostics::span_lint_and_then;
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{Item, ItemKind};

clippy_lints/src/large_enum_variant.rs

@@ -1,6 +1,7 @@
 //! lint when there is a large size difference between variants on an enum
 
-use crate::utils::{snippet_opt, span_lint_and_then};
+use clippy_utils::diagnostics::span_lint_and_then;
+use clippy_utils::source::snippet_opt;
 use rustc_errors::Applicability;
 use rustc_hir::{Item, ItemKind, VariantData};
 use rustc_lint::{LateContext, LateLintPass};