Auto merge of #92437 - flip1995:clippyup, r=Manishearth

Update Clippy

r? `@Manishearth`

src/tools/clippy/.github/workflows/clippy.yml

@@ -58,6 +58,10 @@ jobs:
       run: cargo test --features deny-warnings,internal-lints,metadata-collector-lint
       working-directory: clippy_lints
 
+    - name: Test clippy_utils
+      run: cargo test --features deny-warnings,internal-lints,metadata-collector-lint
+      working-directory: clippy_utils
+
     - name: Test rustc_tools_util
       run: cargo test --features deny-warnings
       working-directory: rustc_tools_util

src/tools/clippy/.github/workflows/clippy_bors.yml

@@ -121,6 +121,10 @@ jobs:
       run: cargo test --features deny-warnings,internal-lints,metadata-collector-lint
       working-directory: clippy_lints
 
+    - name: Test clippy_utils
+      run: cargo test --features deny-warnings,internal-lints,metadata-collector-lint
+      working-directory: clippy_utils
+
     - name: Test rustc_tools_util
       run: cargo test --features deny-warnings
       working-directory: rustc_tools_util

src/tools/clippy/CHANGELOG.md

@@ -6,13 +6,127 @@ document.
 
 ## Unreleased / In Rust Nightly
 
-[b7f3f7f...master](https://github.com/rust-lang/rust-clippy/compare/b7f3f7f...master)
+[e181011...master](https://github.com/rust-lang/rust-clippy/compare/e181011...master)
+
+## Rust 1.58 (beta)
+
+Current beta, release 2022-01-13
+
+[00e31fa...e181011](https://github.com/rust-lang/rust-clippy/compare/00e31fa...e181011)
+
+### New lints
+
+* [`transmute_num_to_bytes`]
+  [#7805](https://github.com/rust-lang/rust-clippy/pull/7805)
+* [`match_str_case_mismatch`]
+  [#7806](https://github.com/rust-lang/rust-clippy/pull/7806)
+* [`format_in_format_args`], [`to_string_in_format_args`]
+  [#7743](https://github.com/rust-lang/rust-clippy/pull/7743)
+* [`uninit_vec`]
+  [#7682](https://github.com/rust-lang/rust-clippy/pull/7682)
+* [`fn_to_numeric_cast_any`]
+  [#7705](https://github.com/rust-lang/rust-clippy/pull/7705)
+* [`undocumented_unsafe_blocks`]
+  [#7748](https://github.com/rust-lang/rust-clippy/pull/7748)
+* [`trailing_empty_array`]
+  [#7838](https://github.com/rust-lang/rust-clippy/pull/7838)
+* [`string_slice`]
+  [#7878](https://github.com/rust-lang/rust-clippy/pull/7878)
+
+### Moves or deprecations of lints
+
+* Move [`non_send_fields_in_send_ty`] to `suspicious`
+  [#7874](https://github.com/rust-lang/rust-clippy/pull/7874)
+* Move [`non_ascii_literal`] to `restriction`
+  [#7907](https://github.com/rust-lang/rust-clippy/pull/7907)
+
+### Changes that expand what code existing lints cover
+
+* [`question_mark`] now covers `Result`
+  [#7840](https://github.com/rust-lang/rust-clippy/pull/7840)
+* Make [`useless_format`] recognize bare `format!("")`
+  [#7801](https://github.com/rust-lang/rust-clippy/pull/7801)
+* Lint on underscored variables with no side effects in [`no_effect`]
+  [#7775](https://github.com/rust-lang/rust-clippy/pull/7775)
+* Expand [`match_ref_pats`] to check for multiple reference patterns
+  [#7800](https://github.com/rust-lang/rust-clippy/pull/7800)
+
+### False positive fixes
+
+* Fix false positive of [`implicit_saturating_sub`] with `else` clause
+  [#7832](https://github.com/rust-lang/rust-clippy/pull/7832)
+* Fix [`question_mark`] when there is call in conditional predicate
+  [#7860](https://github.com/rust-lang/rust-clippy/pull/7860)
+* [`mut_mut`] no longer lints when type is defined in external macros
+  [#7795](https://github.com/rust-lang/rust-clippy/pull/7795)
+* Avoid [`eq_op`] in test functions
+  [#7811](https://github.com/rust-lang/rust-clippy/pull/7811)
+* [`cast_possible_truncation`] no longer lints when cast is coming from `signum`
+  method call [#7850](https://github.com/rust-lang/rust-clippy/pull/7850)
+* [`match_str_case_mismatch`] no longer lints on uncased characters
+  [#7865](https://github.com/rust-lang/rust-clippy/pull/7865)
+* [`ptr_arg`] no longer lints references to type aliases
+  [#7890](https://github.com/rust-lang/rust-clippy/pull/7890)
+* [`missing_safety_doc`] now also accepts "implementation safety" headers
+  [#7856](https://github.com/rust-lang/rust-clippy/pull/7856)
+* [`missing_safety_doc`] no longer lints if any parent has `#[doc(hidden)]`
+  attribute [#7849](https://github.com/rust-lang/rust-clippy/pull/7849)
+* [`if_not_else`] now ignores else-if statements
+  [#7895](https://github.com/rust-lang/rust-clippy/pull/7895)
+* Avoid linting [`cast_possible_truncation`] on bit-reducing operations
+  [#7819](https://github.com/rust-lang/rust-clippy/pull/7819)
+* Avoid linting [`field_reassign_with_default`] when `Drop` and `Copy` are
+  involved [#7794](https://github.com/rust-lang/rust-clippy/pull/7794)
+* [`unnecessary_sort_by`] now checks if argument implements `Ord` trait
+  [#7824](https://github.com/rust-lang/rust-clippy/pull/7824)
+* Fix false positive in [`match_overlapping_arm`]
+  [#7847](https://github.com/rust-lang/rust-clippy/pull/7847)
+* Prevent [`needless_lifetimes`] false positive in `async` function definition
+  [#7901](https://github.com/rust-lang/rust-clippy/pull/7901)
+
+### Suggestion fixes/improvements
+
+* Keep an initial `::` when [`doc_markdown`] suggests to use ticks
+  [#7916](https://github.com/rust-lang/rust-clippy/pull/7916)
+* Add a machine applicable suggestion for the [`doc_markdown`] missing backticks
+  lint [#7904](https://github.com/rust-lang/rust-clippy/pull/7904)
+* [`equatable_if_let`] no longer expands macros in the suggestion
+  [#7788](https://github.com/rust-lang/rust-clippy/pull/7788)
+* Make [`shadow_reuse`] suggestion less verbose
+  [#7782](https://github.com/rust-lang/rust-clippy/pull/7782)
+
+### ICE fixes
+
+* Fix ICE in [`enum_variant_names`]
+  [#7873](https://github.com/rust-lang/rust-clippy/pull/7873)
+* Fix ICE in [`undocumented_unsafe_blocks`]
+  [#7891](https://github.com/rust-lang/rust-clippy/pull/7891)
+
+### Documentation improvements
+
+* Fixed naive doc formatting for `#[must_use]` lints ([`must_use_unit`],
+  [`double_must_use`], [`must_use_candidate`], [`let_underscore_must_use`])
+  [#7827](https://github.com/rust-lang/rust-clippy/pull/7827)
+* Fix typo in example for [`match_result_ok`]
+  [#7815](https://github.com/rust-lang/rust-clippy/pull/7815)
+
+### Others
+
+* Allow giving reasons for [`disallowed_types`]
+  [#7791](https://github.com/rust-lang/rust-clippy/pull/7791)
+* Fix [`manual_assert`] and [`match_wild_err_arm`] for `#![no_std]` and Rust
+  2021. [#7851](https://github.com/rust-lang/rust-clippy/pull/7851)
+* Fix regression in [`semicolon_if_nothing_returned`] on macros containing while
+  loops [#7789](https://github.com/rust-lang/rust-clippy/pull/7789)
+* Added a new configuration `literal-suffix-style` to enforce a certain style
+  writing [`unseparated_literal_suffix`]
+  [#7726](https://github.com/rust-lang/rust-clippy/pull/7726)
 
 ## Rust 1.57
 
-Current beta, release 2021-12-02
+Current stable, released 2021-12-02
 
-[7bfc26e...b7f3f7f](https://github.com/rust-lang/rust-clippy/compare/7bfc26e...b7f3f7f)
+[7bfc26e...00e31fa](https://github.com/rust-lang/rust-clippy/compare/7bfc26e...00e31fa)
 
 ### New Lints
 
@@ -161,7 +275,7 @@ Current beta, release 2021-12-02
 
 ## Rust 1.56
 
-Current stable, released 2021-10-21
+Released 2021-10-21
 
 [74d1561...7bfc26e](https://github.com/rust-lang/rust-clippy/compare/74d1561...7bfc26e)
 
@@ -2912,6 +3026,7 @@ Released 2018-09-13
 [`infinite_iter`]: https://rust-lang.github.io/rust-clippy/master/index.html#infinite_iter
 [`inherent_to_string`]: https://rust-lang.github.io/rust-clippy/master/index.html#inherent_to_string
 [`inherent_to_string_shadow_display`]: https://rust-lang.github.io/rust-clippy/master/index.html#inherent_to_string_shadow_display
+[`init_numbered_fields`]: https://rust-lang.github.io/rust-clippy/master/index.html#init_numbered_fields
 [`inline_always`]: https://rust-lang.github.io/rust-clippy/master/index.html#inline_always
 [`inline_asm_x86_att_syntax`]: https://rust-lang.github.io/rust-clippy/master/index.html#inline_asm_x86_att_syntax
 [`inline_asm_x86_intel_syntax`]: https://rust-lang.github.io/rust-clippy/master/index.html#inline_asm_x86_intel_syntax

src/tools/clippy/CONTRIBUTING.md

@@ -118,7 +118,7 @@ which `IntelliJ Rust` will be able to understand.
 Run `cargo dev setup intellij --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 `IntelliJ Rust` to understand most of the types that Clippy uses.
+Clippy's `Cargo.toml`s and should allow `IntelliJ Rust` to understand most of the types that Clippy uses.
 Just make sure to remove the dependencies again before finally making a pull request!
 
 [rustc_repo]: https://github.com/rust-lang/rust/
@@ -126,8 +126,8 @@ Just make sure to remove the dependencies again before finally making a pull req
 
 ### 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.`
+using `extern crate` when `package.metadata.rust-analyzer.rustc_private` is set to `true` in Clippy's `Cargo.toml.`
-You will required a `nightly` toolchain with the `rustc-dev` component installed.
+You will require a `nightly` toolchain with the `rustc-dev` component installed.
 Make sure that in the `rust-analyzer` configuration, you set
 ```
 { "rust-analyzer.rustcSource": "discover" }
@@ -228,7 +228,7 @@ about `subtree`s in the Rust repository see [Rust's `CONTRIBUTING.md`][subtree].
 
 ### Patching git-subtree to work with big repos
 
-Currently there's a bug in `git-subtree` that prevents it from working properly
+Currently, there's a bug in `git-subtree` that prevents it from working properly
 with the [`rust-lang/rust`] repo. There's an open PR to fix that, but it's stale.
 Before continuing with the following steps, we need to manually apply that fix to
 our local copy of `git-subtree`.

src/tools/clippy/README.md

@@ -144,7 +144,7 @@ line. (You can swap `clippy::all` with the specific lint category you are target
 ## Configuration
 
 Some lints can be configured in a TOML file named `clippy.toml` or `.clippy.toml`. It contains a basic `variable =
-value` mapping eg.
+value` mapping e.g.
 
 ```toml
 avoid-breaking-exported-api = false
@@ -155,6 +155,10 @@ cognitive-complexity-threshold = 30
 See the [list of lints](https://rust-lang.github.io/rust-clippy/master/index.html) for more information about which
 lints can be configured and the meaning of the variables.
 
+Note that configuration changes will not apply for code that has already been compiled and cached under `./target/`;
+for example, adding a new string to `doc-valid-idents` may still result in Clippy flagging that string. To be sure that
+any configuration changes are applied, you may want to run `cargo clean` and re-compile your crate from scratch.
+
 To deactivate the “for further information visit *lint-link*” message you can
 define the `CLIPPY_DISABLE_DOCS_LINKS` environment variable.
 
@@ -193,7 +197,7 @@ And to warn on `lint_name`, run
 cargo clippy -- -W clippy::lint_name
 ```
 
-This also works with lint groups. For example you
+This also works with lint groups. For example, you
 can run Clippy with warnings for all lints enabled:
 ```terminal
 cargo clippy -- -W clippy::pedantic
@@ -228,7 +232,7 @@ fn main() {
 You can also omit the patch version when specifying the MSRV, so `msrv = 1.30`
 is equivalent to `msrv = 1.30.0`.
 
-Note: `custom_inner_attributes` is an unstable feature so it has to be enabled explicitly.
+Note: `custom_inner_attributes` is an unstable feature, so it has to be enabled explicitly.
 
 Lints that recognize this configuration option can be found [here](https://rust-lang.github.io/rust-clippy/master/index.html#msrv)
 

src/tools/clippy/clippy_lints/src/approx_const.rs

@@ -87,7 +87,7 @@ impl ApproxConstant {
         let s = s.as_str();
         if s.parse::<f64>().is_ok() {
             for &(constant, name, min_digits, msrv) in &KNOWN_CONSTS {
-                if is_approx_const(constant, &s, min_digits)
+                if is_approx_const(constant, s, min_digits)
                     && msrv.as_ref().map_or(true, |msrv| meets_msrv(self.msrv.as_ref(), msrv))
                 {
                     span_lint_and_help(

src/tools/clippy/clippy_lints/src/attrs.rs

@@ -310,8 +310,10 @@ impl<'tcx> LateLintPass<'tcx> for Attributes {
                                             || is_word(lint, sym::deprecated)
                                             || is_word(lint, sym!(unreachable_pub))
                                             || is_word(lint, sym!(unused))
-                                            || extract_clippy_lint(lint).map_or(false, |s| s.as_str() == "wildcard_imports")
+                                            || extract_clippy_lint(lint)
-                                            || extract_clippy_lint(lint).map_or(false, |s| s.as_str() == "enum_glob_use")
+                                                .map_or(false, |s| s.as_str() == "wildcard_imports")
+                                            || extract_clippy_lint(lint)
+                                                .map_or(false, |s| s.as_str() == "enum_glob_use")
                                         {
                                             return;
                                         }

src/tools/clippy/clippy_lints/src/casts/unnecessary_cast.rs

@@ -49,8 +49,9 @@ pub(super) fn check(
                 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();
+                    if let Some(num_lit) = NumericLiteral::from_lit_kind(&src, &lit.node) {
-                    lint_unnecessary_cast(cx, expr, num_lit.integer, cast_from, cast_to);
+                        lint_unnecessary_cast(cx, expr, num_lit.integer, cast_from, cast_to);
+                    }
                 }
             },
             _ => {

src/tools/clippy/clippy_lints/src/enum_variants.rs

@@ -2,8 +2,8 @@
 
 use clippy_utils::diagnostics::{span_lint, span_lint_and_help};
 use clippy_utils::source::is_present_in_source;
-use clippy_utils::str_utils::{self, count_match_end, count_match_start};
+use clippy_utils::str_utils::{camel_case_split, count_match_end, count_match_start};
-use rustc_hir::{EnumDef, Item, ItemKind};
+use rustc_hir::{EnumDef, Item, ItemKind, Variant};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::source_map::Span;
@@ -18,6 +18,12 @@ declare_clippy_lint! {
     /// Enumeration variant names should specify their variant,
     /// not repeat the enumeration name.
     ///
+    /// ### Limitations
+    /// Characters with no casing will be considered when comparing prefixes/suffixes
+    /// This applies to numbers and non-ascii characters without casing
+    /// e.g. `Foo1` and `Foo2` is considered to have different prefixes
+    /// (the prefixes are `Foo1` and `Foo2` respectively), as also `Bar螃`, `Bar蟹`
+    ///
     /// ### Example
     /// ```rust
     /// enum Cake {
@@ -120,72 +126,73 @@ impl_lint_pass!(EnumVariantNames => [
     MODULE_INCEPTION
 ]);
 
-fn check_variant(
+fn check_enum_start(cx: &LateContext<'_>, item_name: &str, variant: &Variant<'_>) {
-    cx: &LateContext<'_>,
+    let name = variant.ident.name.as_str();
-    threshold: u64,
+    let item_name_chars = item_name.chars().count();
-    def: &EnumDef<'_>,
+
-    item_name: &str,
+    if count_match_start(item_name, name).char_count == item_name_chars
-    item_name_chars: usize,
+        && name.chars().nth(item_name_chars).map_or(false, |c| !c.is_lowercase())
-    span: Span,
+        && name.chars().nth(item_name_chars + 1).map_or(false, |c| !c.is_numeric())
-) {
+    {
+        span_lint(
+            cx,
+            ENUM_VARIANT_NAMES,
+            variant.span,
+            "variant name starts with the enum's name",
+        );
+    }
+}
+
+fn check_enum_end(cx: &LateContext<'_>, item_name: &str, variant: &Variant<'_>) {
+    let name = variant.ident.name.as_str();
+    let item_name_chars = item_name.chars().count();
+
+    if count_match_end(item_name, name).char_count == item_name_chars {
+        span_lint(
+            cx,
+            ENUM_VARIANT_NAMES,
+            variant.span,
+            "variant name ends with the enum's name",
+        );
+    }
+}
+
+fn check_variant(cx: &LateContext<'_>, threshold: u64, def: &EnumDef<'_>, item_name: &str, span: Span) {
     if (def.variants.len() as u64) < threshold {
         return;
     }
+
+    let first = &def.variants[0].ident.name.as_str();
+    let mut pre = camel_case_split(first);
+    let mut post = pre.clone();
+    post.reverse();
     for var in def.variants {
-        let name = var.ident.name.as_str();
+        check_enum_start(cx, item_name, var);
-        if count_match_start(item_name, &name).char_count == item_name_chars
+        check_enum_end(cx, item_name, var);
-            && name.chars().nth(item_name_chars).map_or(false, |c| !c.is_lowercase())
-            && name.chars().nth(item_name_chars + 1).map_or(false, |c| !c.is_numeric())
-        {
-            span_lint(
-                cx,
-                ENUM_VARIANT_NAMES,
-                var.span,
-                "variant name starts with the enum's name",
-            );
-        }
-        if count_match_end(item_name, &name).char_count == item_name_chars {
-            span_lint(
-                cx,
-                ENUM_VARIANT_NAMES,
-                var.span,
-                "variant name ends with the enum's name",
-            );
-        }
-    }
-    let first = def.variants[0].ident.name.as_str();
-    let mut pre = &first[..str_utils::camel_case_until(&*first).byte_index];
-    let mut post = &first[str_utils::camel_case_start(&*first).byte_index..];
-    for var in def.variants {
         let name = var.ident.name.as_str();
 
-        let pre_match = count_match_start(pre, &name).byte_count;
+        let variant_split = camel_case_split(name);
-        pre = &pre[..pre_match];
-        let pre_camel = str_utils::camel_case_until(pre).byte_index;
-        pre = &pre[..pre_camel];
-        while let Some((next, last)) = name[pre.len()..].chars().zip(pre.chars().rev()).next() {
-            if next.is_numeric() {
-                return;
-            }
-            if next.is_lowercase() {
-                let last = pre.len() - last.len_utf8();
-                let last_camel = str_utils::camel_case_until(&pre[..last]);
-                pre = &pre[..last_camel.byte_index];
-            } else {
-                break;
-            }
-        }
 
-        let post_match = count_match_end(post, &name);
+        pre = pre
-        let post_end = post.len() - post_match.byte_count;
+            .iter()
-        post = &post[post_end..];
+            .zip(variant_split.iter())
-        let post_camel = str_utils::camel_case_start(post);
+            .take_while(|(a, b)| a == b)
-        post = &post[post_camel.byte_index..];
+            .map(|e| *e.0)
+            .collect();
+        post = post
+            .iter()
+            .zip(variant_split.iter().rev())
+            .take_while(|(a, b)| a == b)
+            .map(|e| *e.0)
+            .collect();
     }
     let (what, value) = match (pre.is_empty(), post.is_empty()) {
         (true, true) => return,
-        (false, _) => ("pre", pre),
+        (false, _) => ("pre", pre.join("")),
-        (true, false) => ("post", post),
+        (true, false) => {
+            post.reverse();
+            ("post", post.join(""))
+        },
     };
     span_lint_and_help(
         cx,
@@ -233,8 +240,7 @@ impl LateLintPass<'_> for EnumVariantNames {
     #[allow(clippy::similar_names)]
     fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
         let item_name = item.ident.name.as_str();
-        let item_name_chars = item_name.chars().count();
+        let item_camel = to_camel_case(item_name);
-        let item_camel = to_camel_case(&item_name);
         if !item.span.from_expansion() && is_present_in_source(cx, item.span) {
             if let Some(&(ref mod_name, ref mod_camel)) = self.modules.last() {
                 // constants don't have surrounding modules
@@ -283,7 +289,7 @@ impl LateLintPass<'_> for EnumVariantNames {
         }
         if let ItemKind::Enum(ref def, _) = item.kind {
             if !(self.avoid_breaking_exported_api && cx.access_levels.is_exported(item.def_id)) {
-                check_variant(cx, self.threshold, def, &item_name, item_name_chars, item.span);
+                check_variant(cx, self.threshold, def, item_name, item.span);
             }
         }
         self.modules.push((item.ident.name, item_camel));

src/tools/clippy/clippy_lints/src/float_literal.rs

@@ -73,7 +73,7 @@ impl<'tcx> LateLintPass<'tcx> for FloatLiteral {
                 // If its within the 2 decimal digits of being out of precision we
                 // check if the parsed representation is the same as the string
                 // since we'll need the truncated string anyway.
-                let digits = count_digits(&sym_str);
+                let digits = count_digits(sym_str);
                 let max = max_digits(fty);
                 let type_suffix = match lit_float_ty {
                     LitFloatType::Suffixed(ast::FloatTy::F32) => Some("f32"),

src/tools/clippy/clippy_lints/src/floating_point_arithmetic.rs

@@ -356,7 +356,7 @@ fn detect_hypot(cx: &LateContext<'_>, args: &[Expr<'_>]) -> Option<String> {
             if eq_expr_value(cx, lmul_lhs, lmul_rhs);
             if eq_expr_value(cx, rmul_lhs, rmul_rhs);
             then {
-                return Some(format!("{}.hypot({})", Sugg::hir(cx, lmul_lhs, ".."), Sugg::hir(cx, rmul_lhs, "..")));
+                return Some(format!("{}.hypot({})", Sugg::hir(cx, lmul_lhs, "..").maybe_par(), Sugg::hir(cx, rmul_lhs, "..")));
             }
         }
 
@@ -379,7 +379,7 @@ fn detect_hypot(cx: &LateContext<'_>, args: &[Expr<'_>]) -> Option<String> {
             if let Some((rvalue, _)) = constant(cx, cx.typeck_results(), rargs_1);
             if Int(2) == lvalue && Int(2) == rvalue;
             then {
-                return Some(format!("{}.hypot({})", Sugg::hir(cx, largs_0, ".."), Sugg::hir(cx, rargs_0, "..")));
+                return Some(format!("{}.hypot({})", Sugg::hir(cx, largs_0, "..").maybe_par(), Sugg::hir(cx, rargs_0, "..")));
             }
         }
     }
@@ -654,26 +654,52 @@ fn check_radians(cx: &LateContext<'_>, expr: &Expr<'_>) {
             if (F32(f32_consts::PI) == rvalue || F64(f64_consts::PI) == rvalue) &&
                (F32(180_f32) == lvalue || F64(180_f64) == lvalue)
             {
+                let mut proposal = format!("{}.to_degrees()", Sugg::hir(cx, mul_lhs, ".."));
+                if_chain! {
+                    if let ExprKind::Lit(ref literal) = mul_lhs.kind;
+                    if let ast::LitKind::Float(ref value, float_type) = literal.node;
+                    if float_type == ast::LitFloatType::Unsuffixed;
+                    then {
+                        if value.as_str().ends_with('.') {
+                            proposal = format!("{}0_f64.to_degrees()", Sugg::hir(cx, mul_lhs, ".."));
+                        } else {
+                            proposal = format!("{}_f64.to_degrees()", Sugg::hir(cx, mul_lhs, ".."));
+                        }
+                    }
+                }
                 span_lint_and_sugg(
                     cx,
                     SUBOPTIMAL_FLOPS,
                     expr.span,
                     "conversion to degrees can be done more accurately",
                     "consider using",
-                    format!("{}.to_degrees()", Sugg::hir(cx, mul_lhs, "..")),
+                    proposal,
                     Applicability::MachineApplicable,
                 );
             } else if
                 (F32(180_f32) == rvalue || F64(180_f64) == rvalue) &&
                 (F32(f32_consts::PI) == lvalue || F64(f64_consts::PI) == lvalue)
             {
+                let mut proposal = format!("{}.to_radians()", Sugg::hir(cx, mul_lhs, ".."));
+                if_chain! {
+                    if let ExprKind::Lit(ref literal) = mul_lhs.kind;
+                    if let ast::LitKind::Float(ref value, float_type) = literal.node;
+                    if float_type == ast::LitFloatType::Unsuffixed;
+                    then {
+                        if value.as_str().ends_with('.') {
+                            proposal = format!("{}0_f64.to_radians()", Sugg::hir(cx, mul_lhs, ".."));
+                        } else {
+                            proposal = format!("{}_f64.to_radians()", Sugg::hir(cx, mul_lhs, ".."));
+                        }
+                    }
+                }
                 span_lint_and_sugg(
                     cx,
                     SUBOPTIMAL_FLOPS,
                     expr.span,
                     "conversion to radians can be done more accurately",
                     "consider using",
-                    format!("{}.to_radians()", Sugg::hir(cx, mul_lhs, "..")),
+                    proposal,
                     Applicability::MachineApplicable,
                 );
             }

src/tools/clippy/clippy_lints/src/identity_op.rs

@@ -61,15 +61,18 @@ impl<'tcx> LateLintPass<'tcx> for IdentityOp {
 }
 
 fn is_allowed(cx: &LateContext<'_>, cmp: BinOp, left: &Expr<'_>, right: &Expr<'_>) -> bool {
-    // `1 << 0` is a common pattern in bit manipulation code
+    // This lint applies to integers
-    cmp.node == BinOpKind::Shl
+    !cx.typeck_results().expr_ty(left).peel_refs().is_integral()
-        && constant_simple(cx, cx.typeck_results(), right) == Some(Constant::Int(0))
+        || !cx.typeck_results().expr_ty(right).peel_refs().is_integral()
-        && constant_simple(cx, cx.typeck_results(), left) == Some(Constant::Int(1))
+        // `1 << 0` is a common pattern in bit manipulation code
+        || (cmp.node == BinOpKind::Shl
+            && constant_simple(cx, cx.typeck_results(), right) == Some(Constant::Int(0))
+            && constant_simple(cx, cx.typeck_results(), left) == Some(Constant::Int(1)))
 }
 
 fn check(cx: &LateContext<'_>, e: &Expr<'_>, m: i8, span: Span, arg: Span) {
-    if let Some(Constant::Int(v)) = constant_simple(cx, cx.typeck_results(), e) {
+    if let Some(Constant::Int(v)) = constant_simple(cx, cx.typeck_results(), e).map(Constant::peel_refs) {
-        let check = match *cx.typeck_results().expr_ty(e).kind() {
+        let check = match *cx.typeck_results().expr_ty(e).peel_refs().kind() {
             ty::Int(ity) => unsext(cx.tcx, -1_i128, ity),
             ty::Uint(uty) => clip(cx.tcx, !0, uty),
             _ => return,

src/tools/clippy/clippy_lints/src/implicit_saturating_sub.rs

@@ -96,7 +96,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitSaturatingSub {
                         if let LitKind::Int(0, _) = cond_lit.node {
                             if cx.typeck_results().expr_ty(cond_left).is_signed() {
                             } else {
-                                print_lint_and_sugg(cx, &var_name, expr);
+                                print_lint_and_sugg(cx, var_name, expr);
                             };
                         }
                     },
@@ -108,7 +108,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitSaturatingSub {
                             let mut int_ids = INT_TYPES.iter().filter_map(|&ty| cx.tcx.lang_items().require(ty).ok());
                             if int_ids.any(|int_id| int_id == impl_id);
                             then {
-                                print_lint_and_sugg(cx, &var_name, expr)
+                                print_lint_and_sugg(cx, var_name, expr)
                             }
                         }
                     },
@@ -121,7 +121,7 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitSaturatingSub {
                             let mut int_ids = INT_TYPES.iter().filter_map(|&ty| cx.tcx.lang_items().require(ty).ok());
                             if int_ids.any(|int_id| int_id == impl_id);
                             then {
-                                print_lint_and_sugg(cx, &var_name, expr)
+                                print_lint_and_sugg(cx, var_name, expr)
                             }
                         }
                     },

src/tools/clippy/clippy_lints/src/init_numbered_fields.rs

@@ -0,0 +1,80 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::in_macro;
+use clippy_utils::source::snippet_with_applicability;
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use std::borrow::Cow;
+use std::cmp::Reverse;
+use std::collections::BinaryHeap;
+
+declare_clippy_lint! {
+    /// ### What it does
+    /// Checks for tuple structs initialized with field syntax.
+    /// It will however not lint if a base initializer is present.
+    /// The lint will also ignore code in macros.
+    ///
+    /// ### Why is this bad?
+    /// This may be confusing to the uninitiated and adds no
+    /// benefit as opposed to tuple initializers
+    ///
+    /// ### Example
+    /// ```rust
+    /// struct TupleStruct(u8, u16);
+    ///
+    /// let _ = TupleStruct {
+    ///     0: 1,
+    ///     1: 23,
+    /// };
+    ///
+    /// // should be written as
+    /// let base = TupleStruct(1, 23);
+    ///
+    /// // This is OK however
+    /// let _ = TupleStruct { 0: 42, ..base };
+    /// ```
+    #[clippy::version = "1.59.0"]
+    pub INIT_NUMBERED_FIELDS,
+    style,
+    "numbered fields in tuple struct initializer"
+}
+
+declare_lint_pass!(NumberedFields => [INIT_NUMBERED_FIELDS]);
+
+impl<'tcx> LateLintPass<'tcx> for NumberedFields {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+        if let ExprKind::Struct(path, fields, None) = e.kind {
+            if !fields.is_empty()
+                && !in_macro(e.span)
+                && fields
+                    .iter()
+                    .all(|f| f.ident.as_str().as_bytes().iter().all(u8::is_ascii_digit))
+            {
+                let expr_spans = fields
+                    .iter()
+                    .map(|f| (Reverse(f.ident.as_str().parse::<usize>().unwrap()), f.expr.span))
+                    .collect::<BinaryHeap<_>>();
+                let mut appl = Applicability::MachineApplicable;
+                let snippet = format!(
+                    "{}({})",
+                    snippet_with_applicability(cx, path.span(), "..", &mut appl),
+                    expr_spans
+                        .into_iter_sorted()
+                        .map(|(_, span)| snippet_with_applicability(cx, span, "..", &mut appl))
+                        .intersperse(Cow::Borrowed(", "))
+                        .collect::<String>()
+                );
+                span_lint_and_sugg(
+                    cx,
+                    INIT_NUMBERED_FIELDS,
+                    e.span,
+                    "used a field initializer for a tuple struct",
+                    "try this instead",
+                    snippet,
+                    appl,
+                );
+            }
+        }
+    }
+}

src/tools/clippy/clippy_lints/src/len_zero.rs

@@ -441,7 +441,7 @@ fn is_empty_string(expr: &Expr<'_>) -> bool {
     if let ExprKind::Lit(ref lit) = expr.kind {
         if let LitKind::Str(lit, _) = lit.node {
             let lit = lit.as_str();
-            return lit == "";
+            return lit.is_empty();
         }
     }
     false

src/tools/clippy/clippy_lints/src/lib.register_all.rs

@@ -81,6 +81,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(infinite_iter::INFINITE_ITER),
     LintId::of(inherent_to_string::INHERENT_TO_STRING),
     LintId::of(inherent_to_string::INHERENT_TO_STRING_SHADOW_DISPLAY),
+    LintId::of(init_numbered_fields::INIT_NUMBERED_FIELDS),
     LintId::of(inline_fn_without_body::INLINE_FN_WITHOUT_BODY),
     LintId::of(int_plus_one::INT_PLUS_ONE),
     LintId::of(large_const_arrays::LARGE_CONST_ARRAYS),

src/tools/clippy/clippy_lints/src/lib.register_lints.rs

@@ -178,6 +178,7 @@ store.register_lints(&[
     inherent_impl::MULTIPLE_INHERENT_IMPL,
     inherent_to_string::INHERENT_TO_STRING,
     inherent_to_string::INHERENT_TO_STRING_SHADOW_DISPLAY,
+    init_numbered_fields::INIT_NUMBERED_FIELDS,
     inline_fn_without_body::INLINE_FN_WITHOUT_BODY,
     int_plus_one::INT_PLUS_ONE,
     integer_division::INTEGER_DIVISION,

src/tools/clippy/clippy_lints/src/lib.register_style.rs

@@ -29,6 +29,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![
     LintId::of(functions::MUST_USE_UNIT),
     LintId::of(functions::RESULT_UNIT_ERR),
     LintId::of(inherent_to_string::INHERENT_TO_STRING),
+    LintId::of(init_numbered_fields::INIT_NUMBERED_FIELDS),
     LintId::of(len_zero::COMPARISON_TO_EMPTY),
     LintId::of(len_zero::LEN_WITHOUT_IS_EMPTY),
     LintId::of(len_zero::LEN_ZERO),

src/tools/clippy/clippy_lints/src/lib.rs

@@ -1,13 +1,15 @@
 // error-pattern:cargo-clippy
 
+#![feature(binary_heap_into_iter_sorted)]
 #![feature(box_patterns)]
+#![feature(control_flow_enum)]
 #![feature(drain_filter)]
 #![feature(in_band_lifetimes)]
+#![feature(iter_intersperse)]
+#![feature(let_else)]
 #![feature(once_cell)]
 #![feature(rustc_private)]
 #![feature(stmt_expr_attributes)]
-#![feature(control_flow_enum)]
-#![feature(let_else)]
 #![recursion_limit = "512"]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
 #![allow(clippy::missing_docs_in_private_items, clippy::must_use_candidate)]
@@ -242,6 +244,7 @@ mod indexing_slicing;
 mod infinite_iter;
 mod inherent_impl;
 mod inherent_to_string;
+mod init_numbered_fields;
 mod inline_fn_without_body;
 mod int_plus_one;
 mod integer_division;
@@ -854,6 +857,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_early_pass(|| Box::new(octal_escapes::OctalEscapes));
     store.register_late_pass(|| Box::new(needless_late_init::NeedlessLateInit));
     store.register_late_pass(|| Box::new(return_self_not_must_use::ReturnSelfNotMustUse));
+    store.register_late_pass(|| Box::new(init_numbered_fields::NumberedFields));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }
 

src/tools/clippy/clippy_lints/src/loops/manual_memcpy.rs

@@ -12,6 +12,7 @@ use rustc_hir::{BinOpKind, Block, Expr, ExprKind, HirId, Pat, PatKind, StmtKind}
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::symbol::sym;
+use std::fmt::Display;
 use std::iter::Iterator;
 
 /// Checks for for loops that sequentially copy items from one slice-like
@@ -108,7 +109,7 @@ fn build_manual_memcpy_suggestion<'tcx>(
     src: &IndexExpr<'_>,
 ) -> String {
     fn print_offset(offset: MinifyingSugg<'static>) -> MinifyingSugg<'static> {
-        if offset.as_str() == "0" {
+        if offset.to_string() == "0" {
             sugg::EMPTY.into()
         } else {
             offset
@@ -123,7 +124,7 @@ fn build_manual_memcpy_suggestion<'tcx>(
             if let Some(arg) = len_args.get(0);
             if path_to_local(arg) == path_to_local(base);
             then {
-                if sugg.as_str() == end_str {
+                if sugg.to_string() == end_str {
                     sugg::EMPTY.into()
                 } else {
                     sugg
@@ -147,7 +148,7 @@ fn build_manual_memcpy_suggestion<'tcx>(
             print_offset(apply_offset(&start_str, &idx_expr.idx_offset)).into_sugg(),
             print_limit(
                 end,
-                end_str.as_str(),
+                end_str.to_string().as_str(),
                 idx_expr.base,
                 apply_offset(&end_str, &idx_expr.idx_offset),
             )
@@ -159,7 +160,7 @@ fn build_manual_memcpy_suggestion<'tcx>(
                 print_offset(apply_offset(&counter_start, &idx_expr.idx_offset)).into_sugg(),
                 print_limit(
                     end,
-                    end_str.as_str(),
+                    end_str.to_string().as_str(),
                     idx_expr.base,
                     apply_offset(&end_str, &idx_expr.idx_offset) + &counter_start - &start_str,
                 )
@@ -202,15 +203,13 @@ fn build_manual_memcpy_suggestion<'tcx>(
 #[derive(Clone)]
 struct MinifyingSugg<'a>(Sugg<'a>);
 
-impl<'a> MinifyingSugg<'a> {
+impl Display for MinifyingSugg<'a> {
-    fn as_str(&self) -> &str {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        // HACK: Don't sync to Clippy! Required because something with the `or_patterns` feature
+        self.0.fmt(f)
-        // changed and this would now require parentheses.
-        match &self.0 {
-            Sugg::NonParen(s) | Sugg::MaybeParen(s) | Sugg::BinOp(_, s) => s.as_ref(),
-        }
     }
+}
 
+impl<'a> MinifyingSugg<'a> {
     fn into_sugg(self) -> Sugg<'a> {
         self.0
     }
@@ -225,7 +224,7 @@ impl<'a> From<Sugg<'a>> for MinifyingSugg<'a> {
 impl std::ops::Add for &MinifyingSugg<'static> {
     type Output = MinifyingSugg<'static>;
     fn add(self, rhs: &MinifyingSugg<'static>) -> MinifyingSugg<'static> {
-        match (self.as_str(), rhs.as_str()) {
+        match (self.to_string().as_str(), rhs.to_string().as_str()) {
             ("0", _) => rhs.clone(),
             (_, "0") => self.clone(),
             (_, _) => (&self.0 + &rhs.0).into(),
@@ -236,7 +235,7 @@ impl std::ops::Add for &MinifyingSugg<'static> {
 impl std::ops::Sub for &MinifyingSugg<'static> {
     type Output = MinifyingSugg<'static>;
     fn sub(self, rhs: &MinifyingSugg<'static>) -> MinifyingSugg<'static> {
-        match (self.as_str(), rhs.as_str()) {
+        match (self.to_string().as_str(), rhs.to_string().as_str()) {
             (_, "0") => self.clone(),
             ("0", _) => (-rhs.0.clone()).into(),
             (x, y) if x == y => sugg::ZERO.into(),
@@ -248,7 +247,7 @@ impl std::ops::Sub for &MinifyingSugg<'static> {
 impl std::ops::Add<&MinifyingSugg<'static>> for MinifyingSugg<'static> {
     type Output = MinifyingSugg<'static>;
     fn add(self, rhs: &MinifyingSugg<'static>) -> MinifyingSugg<'static> {
-        match (self.as_str(), rhs.as_str()) {
+        match (self.to_string().as_str(), rhs.to_string().as_str()) {
             ("0", _) => rhs.clone(),
             (_, "0") => self,
             (_, _) => (self.0 + &rhs.0).into(),
@@ -259,7 +258,7 @@ impl std::ops::Add<&MinifyingSugg<'static>> for MinifyingSugg<'static> {
 impl std::ops::Sub<&MinifyingSugg<'static>> for MinifyingSugg<'static> {
     type Output = MinifyingSugg<'static>;
     fn sub(self, rhs: &MinifyingSugg<'static>) -> MinifyingSugg<'static> {
-        match (self.as_str(), rhs.as_str()) {
+        match (self.to_string().as_str(), rhs.to_string().as_str()) {
             (_, "0") => self,
             ("0", _) => (-rhs.0.clone()).into(),
             (x, y) if x == y => sugg::ZERO.into(),

src/tools/clippy/clippy_lints/src/macro_use.rs

@@ -1,4 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::in_macro;
 use clippy_utils::source::snippet;
 use hir::def::{DefKind, Res};
 use if_chain::if_chain;
@@ -8,7 +9,6 @@ use rustc_errors::Applicability;
 use rustc_hir as hir;
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
-use rustc_span::hygiene::ExpnKind;
 use rustc_span::{edition::Edition, sym, Span};
 
 declare_clippy_lint! {
@@ -213,7 +213,3 @@ impl<'tcx> LateLintPass<'tcx> for MacroUseImports {
         }
     }
 }
-
-fn in_macro(span: Span) -> bool {
-    span.from_expansion() && !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
-}

src/tools/clippy/clippy_lints/src/match_str_case_mismatch.rs

@@ -94,8 +94,8 @@ impl<'a, 'tcx> Visitor<'tcx> for MatchExprVisitor<'a, 'tcx> {
 
     fn visit_expr(&mut self, ex: &'tcx Expr<'_>) {
         match ex.kind {
-            ExprKind::MethodCall(segment, _, [receiver], _)
+            ExprKind::MethodCall(segment, _, [receiver], _) if self.case_altered(segment.ident.as_str(), receiver) => {
-                if self.case_altered(segment.ident.as_str(), receiver) => {},
+            },
             _ => walk_expr(self, ex),
         }
     }
@@ -142,7 +142,7 @@ fn verify_case<'a>(case_method: &'a CaseMethod, arms: &'a [Arm<'_>]) -> Option<(
                             }) = arm.pat.kind;
             if let LitKind::Str(symbol, _) = lit.node;
             let input = symbol.as_str();
-            if !case_check(&input);
+            if !case_check(input);
             then {
                 return Some((lit.span, symbol));
             }

src/tools/clippy/clippy_lints/src/methods/iter_skip_next.rs

@@ -1,8 +1,10 @@
-use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::is_trait_method;
+use clippy_utils::path_to_local;
 use clippy_utils::source::snippet;
 use rustc_errors::Applicability;
 use rustc_hir as hir;
+use rustc_hir::{BindingAnnotation, Node, PatKind};
 use rustc_lint::LateContext;
 use rustc_span::sym;
 
@@ -11,14 +13,34 @@ use super::ITER_SKIP_NEXT;
 pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) {
     // lint if caller of skip is an Iterator
     if is_trait_method(cx, expr, sym::Iterator) {
-        span_lint_and_sugg(
+        let mut application = Applicability::MachineApplicable;
+        span_lint_and_then(
             cx,
             ITER_SKIP_NEXT,
             expr.span.trim_start(recv.span).unwrap(),
             "called `skip(..).next()` on an iterator",
-            "use `nth` instead",
+            |diag| {
-            format!(".nth({})", snippet(cx, arg.span, "..")),
+                if_chain! {
-            Applicability::MachineApplicable,
+                    if let Some(id) = path_to_local(recv);
+                    if let Node::Binding(pat) = cx.tcx.hir().get(id);
+                    if let PatKind::Binding(ann, _, _, _)  = pat.kind;
+                    if ann != BindingAnnotation::Mutable;
+                    then {
+                        application = Applicability::Unspecified;
+                        diag.span_help(
+                            pat.span,
+                            &format!("for this change `{}` has to be mutable", snippet(cx, pat.span, "..")),
+                        );
+                    }
+                }
+
+                diag.span_suggestion(
+                    expr.span.trim_start(recv.span).unwrap(),
+                    "use `nth` instead",
+                    format!(".nth({})", snippet(cx, arg.span, "..")),
+                    application,
+                );
+            },
         );
     }
 }

src/tools/clippy/clippy_lints/src/methods/mod.rs

@@ -2112,7 +2112,7 @@ impl<'tcx> LateLintPass<'tcx> for Methods {
                 {
                     wrong_self_convention::check(
                         cx,
-                        &name,
+                        name,
                         self_ty,
                         first_arg_ty,
                         first_arg.pat.span,

src/tools/clippy/clippy_lints/src/methods/unwrap_or_else_default.rs

@@ -2,7 +2,8 @@
 
 use super::UNWRAP_OR_ELSE_DEFAULT;
 use clippy_utils::{
-    diagnostics::span_lint_and_sugg, is_trait_item, source::snippet_with_applicability, ty::is_type_diagnostic_item,
+    diagnostics::span_lint_and_sugg, is_default_equivalent_call, source::snippet_with_applicability,
+    ty::is_type_diagnostic_item,
 };
 use rustc_errors::Applicability;
 use rustc_hir as hir;
@@ -24,7 +25,7 @@ pub(super) fn check<'tcx>(
 
     if_chain! {
         if is_option || is_result;
-        if is_trait_item(cx, u_arg, sym::Default);
+        if is_default_equivalent_call(cx, u_arg);
         then {
             let mut applicability = Applicability::MachineApplicable;
 

src/tools/clippy/clippy_lints/src/methods/utils.rs

@@ -57,7 +57,7 @@ pub(super) fn get_hint_if_single_char_arg(
         let string = r.as_str();
         if string.chars().count() == 1;
         then {
-            let snip = snippet_with_applicability(cx, arg.span, &string, applicability);
+            let snip = snippet_with_applicability(cx, arg.span, string, applicability);
             let ch = if let ast::StrStyle::Raw(nhash) = style {
                 let nhash = nhash as usize;
                 // for raw string: r##"a"##

src/tools/clippy/clippy_lints/src/needless_bool.rs

@@ -187,14 +187,14 @@ impl<'tcx> LateLintPass<'tcx> for BoolComparison {
                 BinOpKind::Eq => {
                     let true_case = Some((|h| h, "equality checks against true are unnecessary"));
                     let false_case = Some((
-                        |h: Sugg<'_>| !h,
+                        |h: Sugg<'tcx>| !h,
                         "equality checks against false can be replaced by a negation",
                     ));
                     check_comparison(cx, e, true_case, false_case, true_case, false_case, ignore_no_literal);
                 },
                 BinOpKind::Ne => {
                     let true_case = Some((
-                        |h: Sugg<'_>| !h,
+                        |h: Sugg<'tcx>| !h,
                         "inequality checks against true can be replaced by a negation",
                     ));
                     let false_case = Some((|h| h, "inequality checks against false are unnecessary"));
@@ -206,12 +206,12 @@ impl<'tcx> LateLintPass<'tcx> for BoolComparison {
                     ignore_case,
                     Some((|h| h, "greater than checks against false are unnecessary")),
                     Some((
-                        |h: Sugg<'_>| !h,
+                        |h: Sugg<'tcx>| !h,
                         "less than comparison against true can be replaced by a negation",
                     )),
                     ignore_case,
                     Some((
-                        |l: Sugg<'_>, r: Sugg<'_>| (!l).bit_and(&r),
+                        |l: Sugg<'tcx>, r: Sugg<'tcx>| (!l).bit_and(&r),
                         "order comparisons between booleans can be simplified",
                     )),
                 ),
@@ -219,14 +219,14 @@ impl<'tcx> LateLintPass<'tcx> for BoolComparison {
                     cx,
                     e,
                     Some((
-                        |h: Sugg<'_>| !h,
+                        |h: Sugg<'tcx>| !h,
                         "less than comparison against true can be replaced by a negation",
                     )),
                     ignore_case,
                     ignore_case,
                     Some((|h| h, "greater than checks against false are unnecessary")),
                     Some((
-                        |l: Sugg<'_>, r: Sugg<'_>| l.bit_and(&(!r)),
+                        |l: Sugg<'tcx>, r: Sugg<'tcx>| l.bit_and(&(!r)),
                         "order comparisons between booleans can be simplified",
                     )),
                 ),

src/tools/clippy/clippy_lints/src/neg_multiply.rs

@@ -1,6 +1,8 @@
 use clippy_utils::consts::{self, Constant};
-use clippy_utils::diagnostics::span_lint;
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::source::snippet_with_applicability;
 use if_chain::if_chain;
+use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
@@ -18,12 +20,16 @@ declare_clippy_lint! {
     ///
     /// ### Example
     /// ```ignore
-    /// x * -1
+    /// // Bad
+    /// let a = x * -1;
+    ///
+    /// // Good
+    /// let b = -x;
     /// ```
     #[clippy::version = "pre 1.29.0"]
     pub NEG_MULTIPLY,
     style,
-    "multiplying integers with `-1`"
+    "multiplying integers by `-1`"
 }
 
 declare_lint_pass!(NegMultiply => [NEG_MULTIPLY]);
@@ -49,8 +55,19 @@ fn check_mul(cx: &LateContext<'_>, span: Span, lit: &Expr<'_>, exp: &Expr<'_>) {
         if let ExprKind::Lit(ref l) = lit.kind;
         if consts::lit_to_constant(&l.node, cx.typeck_results().expr_ty_opt(lit)) == Constant::Int(1);
         if cx.typeck_results().expr_ty(exp).is_integral();
+
         then {
-            span_lint(cx, NEG_MULTIPLY, span, "negation by multiplying with `-1`");
+            let mut applicability = Applicability::MachineApplicable;
+            let suggestion = format!("-{}", snippet_with_applicability(cx, exp.span, "..", &mut applicability));
+            span_lint_and_sugg(
+                    cx,
+                    NEG_MULTIPLY,
+                    span,
+                    "this multiplication by -1 can be written more succinctly",
+                    "consider using",
+                    suggestion,
+                    applicability,
+                );
         }
     }
 }

src/tools/clippy/clippy_lints/src/non_expressive_names.rs

@@ -218,20 +218,20 @@ impl<'a, 'tcx, 'b> SimilarNamesNameVisitor<'a, 'tcx, 'b> {
             return;
         }
         for existing_name in &self.0.names {
-            if allowed_to_be_similar(&interned_name, existing_name.exemptions) {
+            if allowed_to_be_similar(interned_name, existing_name.exemptions) {
                 continue;
             }
             match existing_name.len.cmp(&count) {
                 Ordering::Greater => {
                     if existing_name.len - count != 1
-                        || levenstein_not_1(&interned_name, existing_name.interned.as_str())
+                        || levenstein_not_1(interned_name, existing_name.interned.as_str())
                     {
                         continue;
                     }
                 },
                 Ordering::Less => {
                     if count - existing_name.len != 1
-                        || levenstein_not_1(existing_name.interned.as_str(), &interned_name)
+                        || levenstein_not_1(existing_name.interned.as_str(), interned_name)
                     {
                         continue;
                     }
@@ -298,7 +298,7 @@ impl<'a, 'tcx, 'b> SimilarNamesNameVisitor<'a, 'tcx, 'b> {
             return;
         }
         self.0.names.push(ExistingName {
-            exemptions: get_exemptions(&interned_name).unwrap_or(&[]),
+            exemptions: get_exemptions(interned_name).unwrap_or(&[]),
             interned: ident.name,
             span: ident.span,
             len: count,

src/tools/clippy/clippy_lints/src/ranges.rs

@@ -378,8 +378,8 @@ fn check_exclusive_range_plus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
                 span,
                 "an inclusive range would be more readable",
                 |diag| {
-                    let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").to_string());
+                    let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").maybe_par().to_string());
-                    let end = Sugg::hir(cx, y, "y");
+                    let end = Sugg::hir(cx, y, "y").maybe_par();
                     if let Some(is_wrapped) = &snippet_opt(cx, span) {
                         if is_wrapped.starts_with('(') && is_wrapped.ends_with(')') {
                             diag.span_suggestion(
@@ -415,8 +415,8 @@ fn check_inclusive_range_minus_one(cx: &LateContext<'_>, expr: &Expr<'_>) {
                 expr.span,
                 "an exclusive range would be more readable",
                 |diag| {
-                    let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").to_string());
+                    let start = start.map_or(String::new(), |x| Sugg::hir(cx, x, "x").maybe_par().to_string());
-                    let end = Sugg::hir(cx, y, "y");
+                    let end = Sugg::hir(cx, y, "y").maybe_par();
                     diag.span_suggestion(
                         expr.span,
                         "use",

src/tools/clippy/clippy_lints/src/return_self_not_must_use.rs

@@ -1,11 +1,12 @@
-use clippy_utils::{diagnostics::span_lint, must_use_attr, nth_arg, return_ty};
+use clippy_utils::ty::is_must_use_ty;
+use clippy_utils::{diagnostics::span_lint, nth_arg, return_ty};
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{Body, FnDecl, HirId, TraitItem, TraitItemKind};
 use rustc_lint::{LateContext, LateLintPass, LintContext};
 use rustc_middle::lint::in_external_macro;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::Span;
+use rustc_span::{sym, Span};
 
 declare_clippy_lint! {
     /// ### What it does
@@ -50,9 +51,9 @@ fn check_method(cx: &LateContext<'tcx>, decl: &'tcx FnDecl<'tcx>, fn_def: LocalD
         if decl.implicit_self.has_implicit_self();
         // We only show this warning for public exported methods.
         if cx.access_levels.is_exported(fn_def);
+        // We don't want to emit this lint if the `#[must_use]` attribute is already there.
+        if !cx.tcx.hir().attrs(hir_id).iter().any(|attr| attr.has_name(sym::must_use));
         if cx.tcx.visibility(fn_def.to_def_id()).is_public();
-        // No need to warn if the attribute is already present.
-        if must_use_attr(cx.tcx.hir().attrs(hir_id)).is_none();
         let ret_ty = return_ty(cx, hir_id);
         let self_arg = nth_arg(cx, hir_id, 0);
         // If `Self` has the same type as the returned type, then we want to warn.
@@ -60,6 +61,8 @@ fn check_method(cx: &LateContext<'tcx>, decl: &'tcx FnDecl<'tcx>, fn_def: LocalD
         // For this check, we don't want to remove the reference on the returned type because if
         // there is one, we shouldn't emit a warning!
         if self_arg.peel_refs() == ret_ty;
+        // If `Self` is already marked as `#[must_use]`, no need for the attribute here.
+        if !is_must_use_ty(cx, ret_ty);
 
         then {
             span_lint(

src/tools/clippy/clippy_lints/src/returns.rs

@@ -73,6 +73,7 @@ declare_clippy_lint! {
 enum RetReplacement {
     Empty,
     Block,
+    Unit,
 }
 
 declare_lint_pass!(Return => [LET_AND_RETURN, NEEDLESS_RETURN]);
@@ -212,7 +213,7 @@ fn check_final_expr<'tcx>(
         // (except for unit type functions) so we don't match it
         ExprKind::Match(_, arms, MatchSource::Normal) => {
             for arm in arms.iter() {
-                check_final_expr(cx, arm.body, Some(arm.body.span), RetReplacement::Block);
+                check_final_expr(cx, arm.body, Some(arm.body.span), RetReplacement::Unit);
             }
         },
         ExprKind::DropTemps(expr) => check_final_expr(cx, expr, None, RetReplacement::Empty),
@@ -259,6 +260,17 @@ fn emit_return_lint(cx: &LateContext<'_>, ret_span: Span, inner_span: Option<Spa
                     Applicability::MachineApplicable,
                 );
             },
+            RetReplacement::Unit => {
+                span_lint_and_sugg(
+                    cx,
+                    NEEDLESS_RETURN,
+                    ret_span,
+                    "unneeded `return` statement",
+                    "replace `return` with a unit value",
+                    "()".to_string(),
+                    Applicability::MachineApplicable,
+                );
+            },
         },
     }
 }

src/tools/clippy/clippy_lints/src/shadow.rs

@@ -5,7 +5,7 @@ use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def::Res;
 use rustc_hir::def_id::LocalDefId;
 use rustc_hir::hir_id::ItemLocalId;
-use rustc_hir::{Block, Body, BodyOwnerKind, Expr, ExprKind, HirId, Node, Pat, PatKind, QPath, UnOp};
+use rustc_hir::{Block, Body, BodyOwnerKind, Expr, ExprKind, HirId, Let, Node, Pat, PatKind, QPath, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_tool_lint, impl_lint_pass};
 use rustc_span::{Span, Symbol};
@@ -220,14 +220,14 @@ fn is_self_shadow(cx: &LateContext<'_>, pat: &Pat<'_>, mut expr: &Expr<'_>, hir_
     }
 }
 
-/// Finds the "init" expression for a pattern: `let <pat> = <init>;` or
+/// Finds the "init" expression for a pattern: `let <pat> = <init>;` (or `if let`) or
 /// `match <init> { .., <pat> => .., .. }`
 fn find_init<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Option<&'tcx Expr<'tcx>> {
     for (_, node) in cx.tcx.hir().parent_iter(hir_id) {
         let init = match node {
             Node::Arm(_) | Node::Pat(_) => continue,
             Node::Expr(expr) => match expr.kind {
-                ExprKind::Match(e, _, _) => Some(e),
+                ExprKind::Match(e, _, _) | ExprKind::Let(&Let { init: e, .. }) => Some(e),
                 _ => None,
             },
             Node::Local(local) => local.init,

src/tools/clippy/clippy_lints/src/tabs_in_doc_comments.rs

@@ -64,7 +64,7 @@ impl TabsInDocComments {
         if let ast::AttrKind::DocComment(_, comment) = attr.kind {
             let comment = comment.as_str();
 
-            for (lo, hi) in get_chunks_of_tabs(&comment) {
+            for (lo, hi) in get_chunks_of_tabs(comment) {
                 // +3 skips the opening delimiter
                 let new_span = Span::new(
                     attr.span.lo() + BytePos(3 + lo),

src/tools/clippy/clippy_lints/src/undocumented_unsafe_blocks.rs

@@ -15,7 +15,7 @@ use std::borrow::Cow;
 
 declare_clippy_lint! {
     /// ### What it does
-    /// Checks for `unsafe` blocks without a `// Safety: ` comment
+    /// Checks for `unsafe` blocks without a `// SAFETY: ` comment
     /// explaining why the unsafe operations performed inside
     /// the block are safe.
     ///
@@ -36,7 +36,7 @@ declare_clippy_lint! {
     /// use std::ptr::NonNull;
     /// let a = &mut 42;
     ///
-    /// // Safety: references are guaranteed to be non-null.
+    /// // SAFETY: references are guaranteed to be non-null.
     /// let ptr = unsafe { NonNull::new_unchecked(a) };
     /// ```
     #[clippy::version = "1.58.0"]
@@ -213,7 +213,7 @@ impl UndocumentedUnsafeBlocks {
             );
         } else {
             let block_indent = indent_of(cx, span);
-            let suggestion = format!("// Safety: ...\n{}", snippet(cx, span, ".."));
+            let suggestion = format!("// SAFETY: ...\n{}", snippet(cx, span, ".."));
 
             span_lint_and_sugg(
                 cx,

src/tools/clippy/clippy_lints/src/unsafe_removed_from_name.rs

@@ -60,7 +60,7 @@ fn check_use_tree(use_tree: &UseTree, cx: &EarlyContext<'_>, span: Span) {
 fn unsafe_to_safe_check(old_name: Ident, new_name: Ident, cx: &EarlyContext<'_>, span: Span) {
     let old_str = old_name.name.as_str();
     let new_str = new_name.name.as_str();
-    if contains_unsafe(&old_str) && !contains_unsafe(&new_str) {
+    if contains_unsafe(old_str) && !contains_unsafe(new_str) {
         span_lint(
             cx,
             UNSAFE_REMOVED_FROM_NAME,

src/tools/clippy/clippy_lints/src/unwrap.rs

@@ -161,7 +161,7 @@ fn collect_unwrap_info<'tcx>(
             if is_relevant_option_call(cx, ty, name) || is_relevant_result_call(cx, ty, name);
             then {
                 assert!(args.len() == 1);
-                let unwrappable = match name.as_ref() {
+                let unwrappable = match name {
                     "is_some" | "is_ok" => true,
                     "is_err" | "is_none" => false,
                     _ => unreachable!(),

src/tools/clippy/clippy_lints/src/upper_case_acronyms.rs

@@ -87,7 +87,7 @@ fn check_ident(cx: &LateContext<'_>, ident: &Ident, be_aggressive: bool) {
     if (ident.chars().all(|c| c.is_ascii_uppercase()) && ident.len() > 2)
     // otherwise, warn if we have SOmeTHING lIKE THIs but only warn with the aggressive
     // upper-case-acronyms-aggressive config option enabled
-    || (be_aggressive && ident != &corrected)
+    || (be_aggressive && ident != corrected)
     {
         span_lint_and_sugg(
             cx,

src/tools/clippy/clippy_lints/src/utils/internal_lints.rs

@@ -28,7 +28,7 @@ use rustc_middle::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::{Symbol, SymbolStr};
+use rustc_span::symbol::Symbol;
 use rustc_span::{sym, BytePos, Span};
 use rustc_typeck::hir_ty_to_ty;
 
@@ -344,11 +344,11 @@ impl EarlyLintPass for ClippyLintsInternal {
             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<SymbolStr> = None;
+                        let mut last_name: Option<&str> = None;
                         for item in items {
                             let name = item.ident.as_str();
-                            if let Some(ref last_name) = last_name {
+                            if let Some(last_name) = last_name {
-                                if **last_name > *name {
+                                if *last_name > *name {
                                     span_lint(
                                         cx,
                                         CLIPPY_LINTS_INTERNAL,
@@ -608,8 +608,7 @@ impl<'tcx> LateLintPass<'tcx> for OuterExpnDataPass {
         }
 
         let (method_names, arg_lists, spans) = method_calls(expr, 2);
-        let method_names: Vec<SymbolStr> = method_names.iter().map(|s| s.as_str()).collect();
+        let method_names: Vec<&str> = method_names.iter().map(Symbol::as_str).collect();
-        let method_names: Vec<&str> = method_names.iter().map(|s| &**s).collect();
         if_chain! {
             if let ["expn_data", "outer_expn"] = method_names.as_slice();
             let args = arg_lists[1];
@@ -839,7 +838,7 @@ impl<'tcx> LateLintPass<'tcx> for MatchTypeOnDiagItem {
             if is_expr_path_def_path(cx, fn_path, &["clippy_utils", "ty", "match_type"]);
             // Extract the path to the matched type
             if let Some(segments) = path_to_matched_type(cx, ty_path);
-            let segments: Vec<&str> = segments.iter().map(|sym| &**sym).collect();
+            let segments: Vec<&str> = segments.iter().map(Symbol::as_str).collect();
             if let Some(ty_did) = path_to_res(cx, &segments[..]).opt_def_id();
             // Check if the matched type is a diagnostic item
             if let Some(item_name) = cx.tcx.get_diagnostic_name(ty_did);
@@ -862,7 +861,7 @@ impl<'tcx> LateLintPass<'tcx> for MatchTypeOnDiagItem {
     }
 }
 
-fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Vec<SymbolStr>> {
+fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Vec<Symbol>> {
     use rustc_hir::ItemKind;
 
     match &expr.kind {
@@ -887,12 +886,12 @@ fn path_to_matched_type(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Ve
             _ => {},
         },
         ExprKind::Array(exprs) => {
-            let segments: Vec<SymbolStr> = exprs
+            let segments: Vec<Symbol> = exprs
                 .iter()
                 .filter_map(|expr| {
                     if let ExprKind::Lit(lit) = &expr.kind {
                         if let LitKind::Str(sym, _) = lit.node {
-                            return Some(sym.as_str());
+                            return Some(sym);
                         }
                     }
 
@@ -1076,7 +1075,6 @@ impl InterningDefinedSymbol {
             &paths::SYMBOL_TO_IDENT_STRING,
             &paths::TO_STRING_METHOD,
         ];
-        // SymbolStr might be de-referenced: `&*symbol.as_str()`
         let call = if_chain! {
             if let ExprKind::AddrOf(_, _, e) = expr.kind;
             if let ExprKind::Unary(UnOp::Deref, e) = e.kind;

src/tools/clippy/clippy_utils/src/consts.rs

@@ -168,6 +168,14 @@ impl Constant {
             None
         }
     }
+
+    #[must_use]
+    pub fn peel_refs(mut self) -> Self {
+        while let Constant::Ref(r) = self {
+            self = *r;
+        }
+        self
+    }
 }
 
 /// Parses a `LitKind` to a `Constant`.
@@ -320,7 +328,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                     let res = self.typeck_results.qpath_res(qpath, callee.hir_id);
                     if let Some(def_id) = res.opt_def_id();
                     let def_path = self.lcx.get_def_path(def_id);
-                    let def_path: Vec<&str> = def_path.iter().take(4).map(|s| s.as_str()).collect();
+                    let def_path: Vec<&str> = def_path.iter().take(4).map(Symbol::as_str).collect();
                     if let ["core", "num", int_impl, "max_value"] = *def_path;
                     then {
                        let value = match int_impl {

src/tools/clippy/clippy_utils/src/lib.rs

@@ -1,8 +1,9 @@
 #![feature(box_patterns)]
+#![feature(control_flow_enum)]
 #![feature(in_band_lifetimes)]
 #![feature(let_else)]
+#![feature(once_cell)]
 #![feature(rustc_private)]
-#![feature(control_flow_enum)]
 #![recursion_limit = "512"]
 #![cfg_attr(feature = "deny-warnings", deny(warnings))]
 #![allow(clippy::missing_errors_doc, clippy::missing_panics_doc, clippy::must_use_candidate)]
@@ -60,9 +61,12 @@ pub use self::hir_utils::{both, count_eq, eq_expr_value, over, SpanlessEq, Spanl
 
 use std::collections::hash_map::Entry;
 use std::hash::BuildHasherDefault;
+use std::lazy::SyncOnceCell;
+use std::sync::{Mutex, MutexGuard};
 
 use if_chain::if_chain;
 use rustc_ast::ast::{self, Attribute, LitKind};
+use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::unhash::UnhashMap;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
@@ -87,6 +91,7 @@ use rustc_middle::ty::binding::BindingMode;
 use rustc_middle::ty::{layout::IntegerExt, BorrowKind, DefIdTree, Ty, TyCtxt, TypeAndMut, TypeFoldable, UpvarCapture};
 use rustc_semver::RustcVersion;
 use rustc_session::Session;
+use rustc_span::def_id::LocalDefId;
 use rustc_span::hygiene::{ExpnKind, MacroKind};
 use rustc_span::source_map::original_sp;
 use rustc_span::sym;
@@ -142,6 +147,13 @@ macro_rules! extract_msrv_attr {
     };
 }
 
+/// Returns `true` if the span comes from a macro expansion, no matter if from a
+/// macro by example or from a procedural macro
+#[must_use]
+pub fn in_macro(span: Span) -> bool {
+    span.from_expansion() && !matches!(span.ctxt().outer_expn_data().kind, ExpnKind::Desugaring(..))
+}
+
 /// Returns `true` if the two spans come from differing expansions (i.e., one is
 /// from a macro and one isn't).
 #[must_use]
@@ -156,18 +168,18 @@ pub fn differing_macro_contexts(lhs: Span, rhs: Span) -> bool {
 /// instead.
 ///
 /// Examples:
-/// ```ignore
+/// ```
 /// let abc = 1;
 /// //        ^ output
 /// let def = abc;
-/// dbg!(def)
+/// dbg!(def);
 /// //   ^^^ input
 ///
 /// // or...
 /// let abc = 1;
 /// let def = abc + 2;
 /// //        ^^^^^^^ output
-/// dbg!(def)
+/// dbg!(def);
 /// //   ^^^ input
 /// ```
 pub fn expr_or_init<'a, 'b, 'tcx: 'b>(cx: &LateContext<'tcx>, mut expr: &'a Expr<'b>) -> &'a Expr<'b> {
@@ -664,6 +676,22 @@ fn is_default_equivalent_ctor(cx: &LateContext<'_>, def_id: DefId, path: &QPath<
     false
 }
 
+/// Return true if the expr is equal to `Default::default` when evaluated.
+pub fn is_default_equivalent_call(cx: &LateContext<'_>, repl_func: &Expr<'_>) -> bool {
+    if_chain! {
+        if let hir::ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
+        if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
+        if is_diag_trait_item(cx, repl_def_id, sym::Default)
+            || is_default_equivalent_ctor(cx, repl_def_id, repl_func_qpath);
+        then {
+            true
+        }
+        else {
+            false
+        }
+    }
+}
+
 /// Returns true if the expr is equal to `Default::default()` of it's type when evaluated.
 /// It doesn't cover all cases, for example indirect function calls (some of std
 /// functions are supported) but it is the best we have.
@@ -686,18 +714,7 @@ pub fn is_default_equivalent(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
                 false
             }
         },
-        ExprKind::Call(repl_func, _) => if_chain! {
+        ExprKind::Call(repl_func, _) => is_default_equivalent_call(cx, repl_func),
-            if let ExprKind::Path(ref repl_func_qpath) = repl_func.kind;
-            if let Some(repl_def_id) = cx.qpath_res(repl_func_qpath, repl_func.hir_id).opt_def_id();
-            if is_diag_trait_item(cx, repl_def_id, sym::Default)
-                || is_default_equivalent_ctor(cx, repl_def_id, repl_func_qpath);
-            then {
-                true
-            }
-            else {
-                false
-            }
-        },
         ExprKind::Path(qpath) => is_lang_ctor(cx, qpath, OptionNone),
         ExprKind::AddrOf(rustc_hir::BorrowKind::Ref, _, expr) => matches!(expr.kind, ExprKind::Array([])),
         _ => false,
@@ -1136,7 +1153,7 @@ pub fn find_macro_calls(names: &[&str], body: &Body<'_>) -> Vec<Span> {
 
 /// Extends the span to the beginning of the spans line, incl. whitespaces.
 ///
-/// ```rust,ignore
+/// ```rust
 ///        let x = ();
 /// //             ^^
 /// // will be converted to
@@ -1337,7 +1354,7 @@ pub fn is_adjusted(cx: &LateContext<'_>, e: &Expr<'_>) -> bool {
     cx.typeck_results().adjustments().get(e.hir_id).is_some()
 }
 
-/// Returns the pre-expansion span if is this comes from an expansion of the
+/// Returns the pre-expansion span if this comes from an expansion of the
 /// macro `name`.
 /// See also [`is_direct_expn_of`].
 #[must_use]
@@ -1364,7 +1381,8 @@ pub fn is_expn_of(mut span: Span, name: &str) -> Option<Span> {
 /// of the macro `name`.
 /// The difference with [`is_expn_of`] is that in
 /// ```rust
-/// # macro_rules! foo { ($e:tt) => { $e } }; macro_rules! bar { ($e:expr) => { $e } }
+/// # macro_rules! foo { ($name:tt!$args:tt) => { $name!$args } }
+/// # macro_rules! bar { ($e:expr) => { $e } }
 /// foo!(bar!(42));
 /// ```
 /// `42` is considered expanded from `foo!` and `bar!` by `is_expn_of` but only
@@ -1905,7 +1923,9 @@ pub fn is_no_core_crate(cx: &LateContext<'_>) -> bool {
 
 /// Check if parent of a hir node is a trait implementation block.
 /// For example, `f` in
-/// ```rust,ignore
+/// ```rust
+/// # struct S;
+/// # trait Trait { fn f(); }
 /// impl Trait for S {
 ///     fn f() {}
 /// }
@@ -2124,17 +2144,16 @@ pub fn is_hir_ty_cfg_dependant(cx: &LateContext<'_>, ty: &hir::Ty<'_>) -> bool {
     false
 }
 
-struct VisitConstTestStruct<'tcx> {
+struct TestItemNamesVisitor<'tcx> {
     tcx: TyCtxt<'tcx>,
     names: Vec<Symbol>,
-    found: bool,
 }
-impl<'hir> ItemLikeVisitor<'hir> for VisitConstTestStruct<'hir> {
+
+impl<'hir> ItemLikeVisitor<'hir> for TestItemNamesVisitor<'hir> {
     fn visit_item(&mut self, item: &Item<'_>) {
         if let ItemKind::Const(ty, _body) = item.kind {
             if let TyKind::Path(QPath::Resolved(_, path)) = ty.kind {
                 // We could also check for the type name `test::TestDescAndFn`
-                // and the `#[rustc_test_marker]` attribute?
                 if let Res::Def(DefKind::Struct, _) = path.res {
                     let has_test_marker = self
                         .tcx
@@ -2142,8 +2161,8 @@ impl<'hir> ItemLikeVisitor<'hir> for VisitConstTestStruct<'hir> {
                         .attrs(item.hir_id())
                         .iter()
                         .any(|a| a.has_name(sym::rustc_test_marker));
-                    if has_test_marker && self.names.contains(&item.ident.name) {
+                    if has_test_marker {
-                        self.found = true;
+                        self.names.push(item.ident.name);
                     }
                 }
             }
@@ -2154,32 +2173,42 @@ impl<'hir> ItemLikeVisitor<'hir> for VisitConstTestStruct<'hir> {
     fn visit_foreign_item(&mut self, _: &ForeignItem<'_>) {}
 }
 
+static TEST_ITEM_NAMES_CACHE: SyncOnceCell<Mutex<FxHashMap<LocalDefId, Vec<Symbol>>>> = SyncOnceCell::new();
+
+fn with_test_item_names(tcx: TyCtxt<'tcx>, module: LocalDefId, f: impl Fn(&[Symbol]) -> bool) -> bool {
+    let cache = TEST_ITEM_NAMES_CACHE.get_or_init(|| Mutex::new(FxHashMap::default()));
+    let mut map: MutexGuard<'_, FxHashMap<LocalDefId, Vec<Symbol>>> = cache.lock().unwrap();
+    match map.entry(module) {
+        Entry::Occupied(entry) => f(entry.get()),
+        Entry::Vacant(entry) => {
+            let mut visitor = TestItemNamesVisitor { tcx, names: Vec::new() };
+            tcx.hir().visit_item_likes_in_module(module, &mut visitor);
+            visitor.names.sort_unstable();
+            f(&*entry.insert(visitor.names))
+        },
+    }
+}
+
 /// Checks if the function containing the given `HirId` is a `#[test]` function
 ///
 /// Note: If you use this function, please add a `#[test]` case in `tests/ui_test`.
 pub fn is_in_test_function(tcx: TyCtxt<'_>, id: hir::HirId) -> bool {
-    let names: Vec<_> = tcx
+    with_test_item_names(tcx, tcx.parent_module(id), |names| {
-        .hir()
+        tcx.hir()
-        .parent_iter(id)
+            .parent_iter(id)
-        // Since you can nest functions we need to collect all until we leave
+            // Since you can nest functions we need to collect all until we leave
-        // function scope
+            // function scope
-        .filter_map(|(_id, node)| {
+            .any(|(_id, node)| {
-            if let Node::Item(item) = node {
+                if let Node::Item(item) = node {
-                if let ItemKind::Fn(_, _, _) = item.kind {
+                    if let ItemKind::Fn(_, _, _) = item.kind {
-                    return Some(item.ident.name);
+                        // Note that we have sorted the item names in the visitor,
+                        // so the binary_search gets the same as `contains`, but faster.
+                        return names.binary_search(&item.ident.name).is_ok();
+                    }
                 }
-            }
+                false
-            None
+            })
-        })
+    })
-        .collect();
-    let parent_mod = tcx.parent_module(id);
-    let mut vis = VisitConstTestStruct {
-        tcx,
-        names,
-        found: false,
-    };
-    tcx.hir().visit_item_likes_in_module(parent_mod, &mut vis);
-    vis.found
 }
 
 /// Checks whether item either has `test` attribute applied, or

src/tools/clippy/clippy_utils/src/str_utils.rs

@@ -15,6 +15,7 @@ impl StrIndex {
 /// Returns the index of the character after the first camel-case component of `s`.
 ///
 /// ```
+/// # use clippy_utils::str_utils::{camel_case_until, StrIndex};
 /// assert_eq!(camel_case_until("AbcDef"), StrIndex::new(6, 6));
 /// assert_eq!(camel_case_until("ABCD"), StrIndex::new(0, 0));
 /// assert_eq!(camel_case_until("AbcDD"), StrIndex::new(3, 3));
@@ -55,9 +56,10 @@ pub fn camel_case_until(s: &str) -> StrIndex {
     }
 }
 
-/// Returns index of the last camel-case component of `s`.
+/// Returns index of the first camel-case component of `s`.
 ///
 /// ```
+/// # use clippy_utils::str_utils::{camel_case_start, StrIndex};
 /// assert_eq!(camel_case_start("AbcDef"), StrIndex::new(0, 0));
 /// assert_eq!(camel_case_start("abcDef"), StrIndex::new(3, 3));
 /// assert_eq!(camel_case_start("ABCD"), StrIndex::new(4, 4));
@@ -66,19 +68,37 @@ pub fn camel_case_until(s: &str) -> StrIndex {
 /// ```
 #[must_use]
 pub fn camel_case_start(s: &str) -> StrIndex {
+    camel_case_start_from_idx(s, 0)
+}
+
+/// Returns `StrIndex` of the last camel-case component of `s[idx..]`.
+///
+/// ```
+/// # use clippy_utils::str_utils::{camel_case_start_from_idx, StrIndex};
+/// assert_eq!(camel_case_start_from_idx("AbcDef", 0), StrIndex::new(0, 0));
+/// assert_eq!(camel_case_start_from_idx("AbcDef", 1), StrIndex::new(3, 3));
+/// assert_eq!(camel_case_start_from_idx("AbcDefGhi", 0), StrIndex::new(0, 0));
+/// assert_eq!(camel_case_start_from_idx("AbcDefGhi", 1), StrIndex::new(3, 3));
+/// assert_eq!(camel_case_start_from_idx("Abcdefg", 1), StrIndex::new(7, 7));
+/// ```
+pub fn camel_case_start_from_idx(s: &str, start_idx: usize) -> StrIndex {
     let char_count = s.chars().count();
     let range = 0..char_count;
     let mut iter = range.rev().zip(s.char_indices().rev());
-    if let Some((char_index, (_, first))) = iter.next() {
+    if let Some((_, (_, first))) = iter.next() {
         if !first.is_lowercase() {
-            return StrIndex::new(char_index, s.len());
+            return StrIndex::new(char_count, s.len());
         }
     } else {
         return StrIndex::new(char_count, s.len());
     }
+
     let mut down = true;
     let mut last_index = StrIndex::new(char_count, s.len());
     for (char_index, (byte_index, c)) in iter {
+        if byte_index < start_idx {
+            break;
+        }
         if down {
             if c.is_uppercase() {
                 down = false;
@@ -96,9 +116,55 @@ pub fn camel_case_start(s: &str) -> StrIndex {
             return last_index;
         }
     }
+
     last_index
 }
 
+/// Get the indexes of camel case components of a string `s`
+///
+/// ```
+/// # use clippy_utils::str_utils::{camel_case_indices, StrIndex};
+/// assert_eq!(
+///     camel_case_indices("AbcDef"),
+///     vec![StrIndex::new(0, 0), StrIndex::new(3, 3), StrIndex::new(6, 6)]
+/// );
+/// assert_eq!(
+///     camel_case_indices("abcDef"),
+///     vec![StrIndex::new(3, 3), StrIndex::new(6, 6)]
+/// );
+/// ```
+pub fn camel_case_indices(s: &str) -> Vec<StrIndex> {
+    let mut result = Vec::new();
+    let mut str_idx = camel_case_start(s);
+
+    while str_idx.byte_index < s.len() {
+        let next_idx = str_idx.byte_index + 1;
+        result.push(str_idx);
+        str_idx = camel_case_start_from_idx(s, next_idx);
+    }
+    result.push(str_idx);
+
+    result
+}
+
+/// Split camel case string into a vector of its components
+///
+/// ```
+/// # use clippy_utils::str_utils::{camel_case_split, StrIndex};
+/// assert_eq!(camel_case_split("AbcDef"), vec!["Abc", "Def"]);
+/// ```
+pub fn camel_case_split(s: &str) -> Vec<&str> {
+    let mut offsets = camel_case_indices(s)
+        .iter()
+        .map(|e| e.byte_index)
+        .collect::<Vec<usize>>();
+    if offsets[0] != 0 {
+        offsets.insert(0, 0);
+    }
+
+    offsets.windows(2).map(|w| &s[w[0]..w[1]]).collect()
+}
+
 /// Dealing with sting comparison can be complicated, this struct ensures that both the
 /// character and byte count are provided for correct indexing.
 #[derive(Debug, Default, PartialEq, Eq)]
@@ -116,6 +182,7 @@ impl StrCount {
 /// Returns the number of chars that match from the start
 ///
 /// ```
+/// # use clippy_utils::str_utils::{count_match_start, StrCount};
 /// assert_eq!(count_match_start("hello_mouse", "hello_penguin"), StrCount::new(6, 6));
 /// assert_eq!(count_match_start("hello_clippy", "bye_bugs"), StrCount::new(0, 0));
 /// assert_eq!(count_match_start("hello_world", "hello_world"), StrCount::new(11, 11));
@@ -141,6 +208,7 @@ pub fn count_match_start(str1: &str, str2: &str) -> StrCount {
 /// Returns the number of chars and bytes that match from the end
 ///
 /// ```
+/// # use clippy_utils::str_utils::{count_match_end, StrCount};
 /// assert_eq!(count_match_end("hello_cat", "bye_cat"), StrCount::new(4, 4));
 /// assert_eq!(count_match_end("if_item_thing", "enum_value"), StrCount::new(0, 0));
 /// assert_eq!(count_match_end("Clippy", "Clippy"), StrCount::new(6, 6));
@@ -227,4 +295,31 @@ mod test {
     fn until_caps() {
         assert_eq!(camel_case_until("ABCD"), StrIndex::new(0, 0));
     }
+
+    #[test]
+    fn camel_case_start_from_idx_full() {
+        assert_eq!(camel_case_start_from_idx("AbcDef", 0), StrIndex::new(0, 0));
+        assert_eq!(camel_case_start_from_idx("AbcDef", 1), StrIndex::new(3, 3));
+        assert_eq!(camel_case_start_from_idx("AbcDef", 4), StrIndex::new(6, 6));
+        assert_eq!(camel_case_start_from_idx("AbcDefGhi", 0), StrIndex::new(0, 0));
+        assert_eq!(camel_case_start_from_idx("AbcDefGhi", 1), StrIndex::new(3, 3));
+        assert_eq!(camel_case_start_from_idx("Abcdefg", 1), StrIndex::new(7, 7));
+    }
+
+    #[test]
+    fn camel_case_indices_full() {
+        assert_eq!(camel_case_indices("Abc\u{f6}\u{f6}DD"), vec![StrIndex::new(7, 9)]);
+    }
+
+    #[test]
+    fn camel_case_split_full() {
+        assert_eq!(camel_case_split("A"), vec!["A"]);
+        assert_eq!(camel_case_split("AbcDef"), vec!["Abc", "Def"]);
+        assert_eq!(camel_case_split("Abc"), vec!["Abc"]);
+        assert_eq!(camel_case_split("abcDef"), vec!["abc", "Def"]);
+        assert_eq!(
+            camel_case_split("\u{f6}\u{f6}AabABcd"),
+            vec!["\u{f6}\u{f6}", "Aab", "A", "Bcd"]
+        );
+    }
 }

src/tools/clippy/clippy_utils/src/sugg.rs

@@ -1,9 +1,7 @@
 //! Contains utility functions to generate suggestions.
 #![deny(clippy::missing_docs_in_private_items)]
 
-use crate::source::{
+use crate::source::{snippet, snippet_opt, snippet_with_applicability, snippet_with_macro_callsite};
-    snippet, snippet_opt, snippet_with_applicability, snippet_with_context, snippet_with_macro_callsite,
-};
 use crate::{get_parent_expr_for_hir, higher};
 use rustc_ast::util::parser::AssocOp;
 use rustc_ast::{ast, token};
@@ -33,7 +31,7 @@ pub enum Sugg<'a> {
     MaybeParen(Cow<'a, str>),
     /// A binary operator expression, including `as`-casts and explicit type
     /// coercion.
-    BinOp(AssocOp, Cow<'a, str>),
+    BinOp(AssocOp, Cow<'a, str>, Cow<'a, str>),
 }
 
 /// Literal constant `0`, for convenience.
@@ -46,7 +44,8 @@ pub const EMPTY: Sugg<'static> = Sugg::NonParen(Cow::Borrowed(""));
 impl Display for Sugg<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> Result<(), std::fmt::Error> {
         match *self {
-            Sugg::NonParen(ref s) | Sugg::MaybeParen(ref s) | Sugg::BinOp(_, ref s) => s.fmt(f),
+            Sugg::NonParen(ref s) | Sugg::MaybeParen(ref s) => s.fmt(f),
+            Sugg::BinOp(op, ref lhs, ref rhs) => binop_to_string(op, lhs, rhs).fmt(f),
         }
     }
 }
@@ -55,10 +54,8 @@ impl Display for Sugg<'_> {
 impl<'a> Sugg<'a> {
     /// Prepare a suggestion from an expression.
     pub fn hir_opt(cx: &LateContext<'_>, expr: &hir::Expr<'_>) -> Option<Self> {
-        snippet_opt(cx, expr.span).map(|snippet| {
+        let get_snippet = |span| snippet(cx, span, "");
-            let snippet = Cow::Owned(snippet);
+        snippet_opt(cx, expr.span).map(|_| Self::hir_from_snippet(expr, get_snippet))
-            Self::hir_from_snippet(expr, snippet)
-        })
     }
 
     /// Convenience function around `hir_opt` for suggestions with a default
@@ -93,9 +90,8 @@ impl<'a> Sugg<'a> {
 
     /// Same as `hir`, but will use the pre expansion span if the `expr` was in a macro.
     pub fn hir_with_macro_callsite(cx: &LateContext<'_>, expr: &hir::Expr<'_>, default: &'a str) -> Self {
-        let snippet = snippet_with_macro_callsite(cx, expr.span, default);
+        let get_snippet = |span| snippet_with_macro_callsite(cx, span, default);
-
+        Self::hir_from_snippet(expr, get_snippet)
-        Self::hir_from_snippet(expr, snippet)
     }
 
     /// Same as `hir`, but first walks the span up to the given context. This will result in the
@@ -112,24 +108,26 @@ impl<'a> Sugg<'a> {
         default: &'a str,
         applicability: &mut Applicability,
     ) -> Self {
-        let (snippet, in_macro) = snippet_with_context(cx, expr.span, ctxt, default, applicability);
+        if expr.span.ctxt() == ctxt {
-
+            Self::hir_from_snippet(expr, |span| snippet(cx, span, default))
-        if in_macro {
-            Sugg::NonParen(snippet)
         } else {
-            Self::hir_from_snippet(expr, snippet)
+            let snip = snippet_with_applicability(cx, expr.span, default, applicability);
+            Sugg::NonParen(snip)
         }
     }
 
     /// Generate a suggestion for an expression with the given snippet. This is used by the `hir_*`
     /// function variants of `Sugg`, since these use different snippet functions.
-    fn hir_from_snippet(expr: &hir::Expr<'_>, snippet: Cow<'a, str>) -> Self {
+    fn hir_from_snippet(expr: &hir::Expr<'_>, get_snippet: impl Fn(Span) -> Cow<'a, str>) -> Self {
         if let Some(range) = higher::Range::hir(expr) {
             let op = match range.limits {
                 ast::RangeLimits::HalfOpen => AssocOp::DotDot,
                 ast::RangeLimits::Closed => AssocOp::DotDotEq,
             };
-            return Sugg::BinOp(op, snippet);
+            let start = range.start.map_or("".into(), |expr| get_snippet(expr.span));
+            let end = range.end.map_or("".into(), |expr| get_snippet(expr.span));
+
+            return Sugg::BinOp(op, start, end);
         }
 
         match expr.kind {
@@ -139,7 +137,7 @@ impl<'a> Sugg<'a> {
             | hir::ExprKind::Let(..)
             | hir::ExprKind::Closure(..)
             | hir::ExprKind::Unary(..)
-            | hir::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
+            | hir::ExprKind::Match(..) => Sugg::MaybeParen(get_snippet(expr.span)),
             hir::ExprKind::Continue(..)
             | hir::ExprKind::Yield(..)
             | hir::ExprKind::Array(..)
@@ -160,12 +158,20 @@ impl<'a> Sugg<'a> {
             | hir::ExprKind::Struct(..)
             | hir::ExprKind::Tup(..)
             | hir::ExprKind::DropTemps(_)
-            | hir::ExprKind::Err => Sugg::NonParen(snippet),
+            | hir::ExprKind::Err => Sugg::NonParen(get_snippet(expr.span)),
-            hir::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
+            hir::ExprKind::Assign(lhs, rhs, _) => {
-            hir::ExprKind::AssignOp(op, ..) => Sugg::BinOp(hirbinop2assignop(op), snippet),
+                Sugg::BinOp(AssocOp::Assign, get_snippet(lhs.span), get_snippet(rhs.span))
-            hir::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(op.node.into()), snippet),
+            },
-            hir::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet),
+            hir::ExprKind::AssignOp(op, lhs, rhs) => {
-            hir::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet),
+                Sugg::BinOp(hirbinop2assignop(op), get_snippet(lhs.span), get_snippet(rhs.span))
+            },
+            hir::ExprKind::Binary(op, lhs, rhs) => Sugg::BinOp(
+                AssocOp::from_ast_binop(op.node.into()),
+                get_snippet(lhs.span),
+                get_snippet(rhs.span),
+            ),
+            hir::ExprKind::Cast(lhs, ty) => Sugg::BinOp(AssocOp::As, get_snippet(lhs.span), get_snippet(ty.span)),
+            hir::ExprKind::Type(lhs, ty) => Sugg::BinOp(AssocOp::Colon, get_snippet(lhs.span), get_snippet(ty.span)),
         }
     }
 
@@ -173,10 +179,12 @@ impl<'a> Sugg<'a> {
     pub fn ast(cx: &EarlyContext<'_>, expr: &ast::Expr, default: &'a str) -> Self {
         use rustc_ast::ast::RangeLimits;
 
-        let snippet = if expr.span.from_expansion() {
+        let get_whole_snippet = || {
-            snippet_with_macro_callsite(cx, expr.span, default)
+            if expr.span.from_expansion() {
-        } else {
+                snippet_with_macro_callsite(cx, expr.span, default)
-            snippet(cx, expr.span, default)
+            } else {
+                snippet(cx, expr.span, default)
+            }
         };
 
         match expr.kind {
@@ -186,7 +194,7 @@ impl<'a> Sugg<'a> {
             | ast::ExprKind::If(..)
             | ast::ExprKind::Let(..)
             | ast::ExprKind::Unary(..)
-            | ast::ExprKind::Match(..) => Sugg::MaybeParen(snippet),
+            | ast::ExprKind::Match(..) => Sugg::MaybeParen(get_whole_snippet()),
             ast::ExprKind::Async(..)
             | ast::ExprKind::Block(..)
             | ast::ExprKind::Break(..)
@@ -215,14 +223,42 @@ impl<'a> Sugg<'a> {
             | ast::ExprKind::Array(..)
             | ast::ExprKind::While(..)
             | ast::ExprKind::Await(..)
-            | ast::ExprKind::Err => Sugg::NonParen(snippet),
+            | ast::ExprKind::Err => Sugg::NonParen(get_whole_snippet()),
-            ast::ExprKind::Range(.., RangeLimits::HalfOpen) => Sugg::BinOp(AssocOp::DotDot, snippet),
+            ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::HalfOpen) => Sugg::BinOp(
-            ast::ExprKind::Range(.., RangeLimits::Closed) => Sugg::BinOp(AssocOp::DotDotEq, snippet),
+                AssocOp::DotDot,
-            ast::ExprKind::Assign(..) => Sugg::BinOp(AssocOp::Assign, snippet),
+                lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)),
-            ast::ExprKind::AssignOp(op, ..) => Sugg::BinOp(astbinop2assignop(op), snippet),
+                rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)),
-            ast::ExprKind::Binary(op, ..) => Sugg::BinOp(AssocOp::from_ast_binop(op.node), snippet),
+            ),
-            ast::ExprKind::Cast(..) => Sugg::BinOp(AssocOp::As, snippet),
+            ast::ExprKind::Range(ref lhs, ref rhs, RangeLimits::Closed) => Sugg::BinOp(
-            ast::ExprKind::Type(..) => Sugg::BinOp(AssocOp::Colon, snippet),
+                AssocOp::DotDotEq,
+                lhs.as_ref().map_or("".into(), |lhs| snippet(cx, lhs.span, default)),
+                rhs.as_ref().map_or("".into(), |rhs| snippet(cx, rhs.span, default)),
+            ),
+            ast::ExprKind::Assign(ref lhs, ref rhs, _) => Sugg::BinOp(
+                AssocOp::Assign,
+                snippet(cx, lhs.span, default),
+                snippet(cx, rhs.span, default),
+            ),
+            ast::ExprKind::AssignOp(op, ref lhs, ref rhs) => Sugg::BinOp(
+                astbinop2assignop(op),
+                snippet(cx, lhs.span, default),
+                snippet(cx, rhs.span, default),
+            ),
+            ast::ExprKind::Binary(op, ref lhs, ref rhs) => Sugg::BinOp(
+                AssocOp::from_ast_binop(op.node),
+                snippet(cx, lhs.span, default),
+                snippet(cx, rhs.span, default),
+            ),
+            ast::ExprKind::Cast(ref lhs, ref ty) => Sugg::BinOp(
+                AssocOp::As,
+                snippet(cx, lhs.span, default),
+                snippet(cx, ty.span, default),
+            ),
+            ast::ExprKind::Type(ref lhs, ref ty) => Sugg::BinOp(
+                AssocOp::Colon,
+                snippet(cx, lhs.span, default),
+                snippet(cx, ty.span, default),
+            ),
         }
     }
 
@@ -306,17 +342,51 @@ impl<'a> Sugg<'a> {
                     Sugg::NonParen(format!("({})", sugg).into())
                 }
             },
-            Sugg::BinOp(_, sugg) => {
+            Sugg::BinOp(op, lhs, rhs) => {
-                if has_enclosing_paren(&sugg) {
+                let sugg = binop_to_string(op, &lhs, &rhs);
-                    Sugg::NonParen(sugg)
+                Sugg::NonParen(format!("({})", sugg).into())
-                } else {
-                    Sugg::NonParen(format!("({})", sugg).into())
-                }
             },
         }
     }
 }
 
+/// Generates a string from the operator and both sides.
+fn binop_to_string(op: AssocOp, lhs: &str, rhs: &str) -> String {
+    match op {
+        AssocOp::Add
+        | AssocOp::Subtract
+        | AssocOp::Multiply
+        | AssocOp::Divide
+        | AssocOp::Modulus
+        | AssocOp::LAnd
+        | AssocOp::LOr
+        | AssocOp::BitXor
+        | AssocOp::BitAnd
+        | AssocOp::BitOr
+        | AssocOp::ShiftLeft
+        | AssocOp::ShiftRight
+        | AssocOp::Equal
+        | AssocOp::Less
+        | AssocOp::LessEqual
+        | AssocOp::NotEqual
+        | AssocOp::Greater
+        | AssocOp::GreaterEqual => format!(
+            "{} {} {}",
+            lhs,
+            op.to_ast_binop().expect("Those are AST ops").to_string(),
+            rhs
+        ),
+        AssocOp::Assign => format!("{} = {}", lhs, rhs),
+        AssocOp::AssignOp(op) => {
+            format!("{} {}= {}", lhs, token_kind_to_string(&token::BinOp(op)), rhs)
+        },
+        AssocOp::As => format!("{} as {}", lhs, rhs),
+        AssocOp::DotDot => format!("{}..{}", lhs, rhs),
+        AssocOp::DotDotEq => format!("{}..={}", lhs, rhs),
+        AssocOp::Colon => format!("{}: {}", lhs, rhs),
+    }
+}
+
 /// Return `true` if `sugg` is enclosed in parenthesis.
 fn has_enclosing_paren(sugg: impl AsRef<str>) -> bool {
     let mut chars = sugg.as_ref().chars();
@@ -391,10 +461,25 @@ impl Neg for Sugg<'_> {
     }
 }
 
-impl Not for Sugg<'_> {
+impl Not for Sugg<'a> {
-    type Output = Sugg<'static>;
+    type Output = Sugg<'a>;
-    fn not(self) -> Sugg<'static> {
+    fn not(self) -> Sugg<'a> {
-        make_unop("!", self)
+        use AssocOp::{Equal, Greater, GreaterEqual, Less, LessEqual, NotEqual};
+
+        if let Sugg::BinOp(op, lhs, rhs) = self {
+            let to_op = match op {
+                Equal => NotEqual,
+                NotEqual => Equal,
+                Less => GreaterEqual,
+                GreaterEqual => Less,
+                Greater => LessEqual,
+                LessEqual => Greater,
+                _ => return make_unop("!", Sugg::BinOp(op, lhs, rhs)),
+            };
+            Sugg::BinOp(to_op, lhs, rhs)
+        } else {
+            make_unop("!", self)
+        }
     }
 }
 
@@ -463,53 +548,21 @@ pub fn make_assoc(op: AssocOp, lhs: &Sugg<'_>, rhs: &Sugg<'_>) -> Sugg<'static>
             || is_shift(other) && is_arith(op)
     }
 
-    let lhs_paren = if let Sugg::BinOp(lop, _) = *lhs {
+    let lhs_paren = if let Sugg::BinOp(lop, _, _) = *lhs {
         needs_paren(op, lop, Associativity::Left)
     } else {
         false
     };
 
-    let rhs_paren = if let Sugg::BinOp(rop, _) = *rhs {
+    let rhs_paren = if let Sugg::BinOp(rop, _, _) = *rhs {
         needs_paren(op, rop, Associativity::Right)
     } else {
         false
     };
 
-    let lhs = ParenHelper::new(lhs_paren, lhs);
+    let lhs = ParenHelper::new(lhs_paren, lhs).to_string();
-    let rhs = ParenHelper::new(rhs_paren, rhs);
+    let rhs = ParenHelper::new(rhs_paren, rhs).to_string();
-    let sugg = match op {
+    Sugg::BinOp(op, lhs.into(), rhs.into())
-        AssocOp::Add
-        | AssocOp::BitAnd
-        | AssocOp::BitOr
-        | AssocOp::BitXor
-        | AssocOp::Divide
-        | AssocOp::Equal
-        | AssocOp::Greater
-        | AssocOp::GreaterEqual
-        | AssocOp::LAnd
-        | AssocOp::LOr
-        | AssocOp::Less
-        | AssocOp::LessEqual
-        | AssocOp::Modulus
-        | AssocOp::Multiply
-        | AssocOp::NotEqual
-        | AssocOp::ShiftLeft
-        | AssocOp::ShiftRight
-        | AssocOp::Subtract => format!(
-            "{} {} {}",
-            lhs,
-            op.to_ast_binop().expect("Those are AST ops").to_string(),
-            rhs
-        ),
-        AssocOp::Assign => format!("{} = {}", lhs, rhs),
-        AssocOp::AssignOp(op) => format!("{} {}= {}", lhs, token_kind_to_string(&token::BinOp(op)), rhs),
-        AssocOp::As => format!("{} as {}", lhs, rhs),
-        AssocOp::DotDot => format!("{}..{}", lhs, rhs),
-        AssocOp::DotDotEq => format!("{}..={}", lhs, rhs),
-        AssocOp::Colon => format!("{}: {}", lhs, rhs),
-    };
-
-    Sugg::BinOp(op, sugg.into())
 }
 
 /// Convenience wrapper around `make_assoc` and `AssocOp::from_ast_binop`.
@@ -1007,10 +1060,32 @@ mod test {
 
     #[test]
     fn binop_maybe_par() {
-        let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1)".into());
+        let sugg = Sugg::BinOp(AssocOp::Add, "1".into(), "1".into());
         assert_eq!("(1 + 1)", sugg.maybe_par().to_string());
 
-        let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1) + (1 + 1)".into());
+        let sugg = Sugg::BinOp(AssocOp::Add, "(1 + 1)".into(), "(1 + 1)".into());
         assert_eq!("((1 + 1) + (1 + 1))", sugg.maybe_par().to_string());
     }
+    #[test]
+    fn not_op() {
+        use AssocOp::{Add, Equal, Greater, GreaterEqual, LAnd, LOr, Less, LessEqual, NotEqual};
+
+        fn test_not(op: AssocOp, correct: &str) {
+            let sugg = Sugg::BinOp(op, "x".into(), "y".into());
+            assert_eq!((!sugg).to_string(), correct);
+        }
+
+        // Invert the comparison operator.
+        test_not(Equal, "x != y");
+        test_not(NotEqual, "x == y");
+        test_not(Less, "x >= y");
+        test_not(LessEqual, "x > y");
+        test_not(Greater, "x <= y");
+        test_not(GreaterEqual, "x < y");
+
+        // Other operators are inverted like !(..).
+        test_not(Add, "!(x + y)");
+        test_not(LAnd, "!(x && y)");
+        test_not(LOr, "!(x || y)");
+    }
 }

src/tools/clippy/rust-toolchain

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "nightly-2021-12-17"
+channel = "nightly-2021-12-30"
 components = ["cargo", "llvm-tools-preview", "rust-src", "rust-std", "rustc", "rustc-dev", "rustfmt"]

src/tools/clippy/tests/ui/crashes/ice-7868.stderr

@@ -7,7 +7,7 @@ LL |     unsafe { 0 };
    = note: `-D clippy::undocumented-unsafe-blocks` implied by `-D warnings`
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL ~     unsafe { 0 };
    |
 

src/tools/clippy/tests/ui/enum_variants.rs

@@ -145,4 +145,10 @@ enum HIDataRequest {
     DeleteUnpubHIData(String),
 }
 
+enum North {
+    Normal,
+    NoLeft,
+    NoRight,
+}
+
 fn main() {}

src/tools/clippy/tests/ui/enum_variants.stderr

@@ -6,6 +6,18 @@ LL |     cFoo,
    |
    = note: `-D clippy::enum-variant-names` implied by `-D warnings`
 
+error: all variants have the same prefix: `c`
+  --> $DIR/enum_variants.rs:14:1
+   |
+LL | / enum Foo {
+LL | |     cFoo,
+LL | |     cBar,
+LL | |     cBaz,
+LL | | }
+   | |_^
+   |
+   = help: remove the prefixes and use full paths to the variants instead of glob imports
+
 error: variant name starts with the enum's name
   --> $DIR/enum_variants.rs:26:5
    |
@@ -60,6 +72,18 @@ LL | | }
    |
    = help: remove the prefixes and use full paths to the variants instead of glob imports
 
+error: all variants have the same prefix: `C`
+  --> $DIR/enum_variants.rs:59:1
+   |
+LL | / enum Something {
+LL | |     CCall,
+LL | |     CCreate,
+LL | |     CCryogenize,
+LL | | }
+   | |_^
+   |
+   = help: remove the prefixes and use full paths to the variants instead of glob imports
+
 error: all variants have the same prefix: `WithOut`
   --> $DIR/enum_variants.rs:81:1
    |
@@ -72,18 +96,6 @@ LL | | }
    |
    = help: remove the prefixes and use full paths to the variants instead of glob imports
 
-error: all variants have the same prefix: `Prefix`
-  --> $DIR/enum_variants.rs:87:1
-   |
-LL | / enum NonCaps {
-LL | |     Prefix的,
-LL | |     PrefixTea,
-LL | |     PrefixCake,
-LL | | }
-   | |_^
-   |
-   = help: remove the prefixes and use full paths to the variants instead of glob imports
-
 error: all variants have the same postfix: `IData`
   --> $DIR/enum_variants.rs:136:1
    |
@@ -108,5 +120,5 @@ LL | | }
    |
    = help: remove the postfixes and use full paths to the variants instead of glob imports
 
-error: aborting due to 11 previous errors
+error: aborting due to 12 previous errors
 

src/tools/clippy/tests/ui/floating_point_rad.fixed

@@ -11,7 +11,12 @@ pub const fn const_context() {
 fn main() {
     let x = 3f32;
     let _ = x.to_degrees();
+    let _ = 90.0_f64.to_degrees();
+    let _ = 90.5_f64.to_degrees();
     let _ = x.to_radians();
+    let _ = 90.0_f64.to_radians();
+    let _ = 90.5_f64.to_radians();
+    // let _ = 90.5 * 80. * std::f32::consts::PI / 180f32;
     // Cases where the lint shouldn't be applied
     let _ = x * 90f32 / std::f32::consts::PI;
     let _ = x * std::f32::consts::PI / 90f32;

src/tools/clippy/tests/ui/floating_point_rad.rs

@@ -11,7 +11,12 @@ pub const fn const_context() {
 fn main() {
     let x = 3f32;
     let _ = x * 180f32 / std::f32::consts::PI;
+    let _ = 90. * 180f64 / std::f64::consts::PI;
+    let _ = 90.5 * 180f64 / std::f64::consts::PI;
     let _ = x * std::f32::consts::PI / 180f32;
+    let _ = 90. * std::f32::consts::PI / 180f32;
+    let _ = 90.5 * std::f32::consts::PI / 180f32;
+    // let _ = 90.5 * 80. * std::f32::consts::PI / 180f32;
     // Cases where the lint shouldn't be applied
     let _ = x * 90f32 / std::f32::consts::PI;
     let _ = x * std::f32::consts::PI / 90f32;

src/tools/clippy/tests/ui/floating_point_rad.stderr

@@ -6,11 +6,35 @@ LL |     let _ = x * 180f32 / std::f32::consts::PI;
    |
    = note: `-D clippy::suboptimal-flops` implied by `-D warnings`
 
-error: conversion to radians can be done more accurately
+error: conversion to degrees can be done more accurately
   --> $DIR/floating_point_rad.rs:14:13
    |
+LL |     let _ = 90. * 180f64 / std::f64::consts::PI;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.0_f64.to_degrees()`
+
+error: conversion to degrees can be done more accurately
+  --> $DIR/floating_point_rad.rs:15:13
+   |
+LL |     let _ = 90.5 * 180f64 / std::f64::consts::PI;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.5_f64.to_degrees()`
+
+error: conversion to radians can be done more accurately
+  --> $DIR/floating_point_rad.rs:16:13
+   |
 LL |     let _ = x * std::f32::consts::PI / 180f32;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `x.to_radians()`
 
-error: aborting due to 2 previous errors
+error: conversion to radians can be done more accurately
+  --> $DIR/floating_point_rad.rs:17:13
+   |
+LL |     let _ = 90. * std::f32::consts::PI / 180f32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.0_f64.to_radians()`
+
+error: conversion to radians can be done more accurately
+  --> $DIR/floating_point_rad.rs:18:13
+   |
+LL |     let _ = 90.5 * std::f32::consts::PI / 180f32;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using: `90.5_f64.to_radians()`
+
+error: aborting due to 6 previous errors
 

src/tools/clippy/tests/ui/identity_op.rs

@@ -2,10 +2,20 @@ const ONE: i64 = 1;
 const NEG_ONE: i64 = -1;
 const ZERO: i64 = 0;
 
+struct A(String);
+
+impl std::ops::Shl<i32> for A {
+    type Output = A;
+    fn shl(mut self, other: i32) -> Self {
+        self.0.push_str(&format!("{}", other));
+        self
+    }
+}
 #[allow(
     clippy::eq_op,
     clippy::no_effect,
     clippy::unnecessary_operation,
+    clippy::op_ref,
     clippy::double_parens
 )]
 #[warn(clippy::identity_op)]
@@ -38,4 +48,9 @@ fn main() {
     42 << 0;
     1 >> 0;
     42 >> 0;
+    &x >> 0;
+    x >> &0;
+
+    let mut a = A("".into());
+    let b = a << 0; // no error: non-integer
 }

src/tools/clippy/tests/ui/identity_op.stderr

@@ -1,5 +1,5 @@
 error: the operation is ineffective. Consider reducing it to `x`
-  --> $DIR/identity_op.rs:16:5
+  --> $DIR/identity_op.rs:26:5
    |
 LL |     x + 0;
    |     ^^^^^
@@ -7,64 +7,76 @@ LL |     x + 0;
    = note: `-D clippy::identity-op` implied by `-D warnings`
 
 error: the operation is ineffective. Consider reducing it to `x`
-  --> $DIR/identity_op.rs:17:5
+  --> $DIR/identity_op.rs:27:5
    |
 LL |     x + (1 - 1);
    |     ^^^^^^^^^^^
 
 error: the operation is ineffective. Consider reducing it to `x`
-  --> $DIR/identity_op.rs:19:5
+  --> $DIR/identity_op.rs:29:5
    |
 LL |     0 + x;
    |     ^^^^^
 
 error: the operation is ineffective. Consider reducing it to `x`
-  --> $DIR/identity_op.rs:22:5
+  --> $DIR/identity_op.rs:32:5
    |
 LL |     x | (0);
    |     ^^^^^^^
 
 error: the operation is ineffective. Consider reducing it to `x`
-  --> $DIR/identity_op.rs:25:5
+  --> $DIR/identity_op.rs:35:5
    |
 LL |     x * 1;
    |     ^^^^^
 
 error: the operation is ineffective. Consider reducing it to `x`
-  --> $DIR/identity_op.rs:26:5
+  --> $DIR/identity_op.rs:36:5
    |
 LL |     1 * x;
    |     ^^^^^
 
 error: the operation is ineffective. Consider reducing it to `x`
-  --> $DIR/identity_op.rs:32:5
+  --> $DIR/identity_op.rs:42:5
    |
 LL |     -1 & x;
    |     ^^^^^^
 
 error: the operation is ineffective. Consider reducing it to `u`
-  --> $DIR/identity_op.rs:35:5
+  --> $DIR/identity_op.rs:45:5
    |
 LL |     u & 255;
    |     ^^^^^^^
 
 error: the operation is ineffective. Consider reducing it to `42`
-  --> $DIR/identity_op.rs:38:5
+  --> $DIR/identity_op.rs:48:5
    |
 LL |     42 << 0;
    |     ^^^^^^^
 
 error: the operation is ineffective. Consider reducing it to `1`
-  --> $DIR/identity_op.rs:39:5
+  --> $DIR/identity_op.rs:49:5
    |
 LL |     1 >> 0;
    |     ^^^^^^
 
 error: the operation is ineffective. Consider reducing it to `42`
-  --> $DIR/identity_op.rs:40:5
+  --> $DIR/identity_op.rs:50:5
    |
 LL |     42 >> 0;
    |     ^^^^^^^
 
-error: aborting due to 11 previous errors
+error: the operation is ineffective. Consider reducing it to `&x`
+  --> $DIR/identity_op.rs:51:5
+   |
+LL |     &x >> 0;
+   |     ^^^^^^^
+
+error: the operation is ineffective. Consider reducing it to `x`
+  --> $DIR/identity_op.rs:52:5
+   |
+LL |     x >> &0;
+   |     ^^^^^^^
+
+error: aborting due to 13 previous errors
 

src/tools/clippy/tests/ui/iter_skip_next.fixed

@@ -4,6 +4,7 @@
 #![warn(clippy::iter_skip_next)]
 #![allow(clippy::blacklisted_name)]
 #![allow(clippy::iter_nth)]
+#![allow(unused_mut, dead_code)]
 
 extern crate option_helpers;
 
@@ -19,4 +20,18 @@ fn main() {
     let foo = IteratorFalsePositives { foo: 0 };
     let _ = foo.skip(42).next();
     let _ = foo.filter().skip(42).next();
+
+    // fix #8128
+    let test_string = "1|1 2";
+    let mut sp = test_string.split('|').map(|s| s.trim());
+    let _: Vec<&str> = sp.nth(1).unwrap().split(' ').collect();
+    if let Some(mut s) = Some(test_string.split('|').map(|s| s.trim())) {
+        let _: Vec<&str> = s.nth(1).unwrap().split(' ').collect();
+    };
+    fn check<T>(mut s: T)
+    where
+        T: Iterator<Item = String>,
+    {
+        let _: Vec<&str> = s.nth(1).unwrap().split(' ').collect();
+    }
 }

src/tools/clippy/tests/ui/iter_skip_next.rs

@@ -4,6 +4,7 @@
 #![warn(clippy::iter_skip_next)]
 #![allow(clippy::blacklisted_name)]
 #![allow(clippy::iter_nth)]
+#![allow(unused_mut, dead_code)]
 
 extern crate option_helpers;
 
@@ -19,4 +20,18 @@ fn main() {
     let foo = IteratorFalsePositives { foo: 0 };
     let _ = foo.skip(42).next();
     let _ = foo.filter().skip(42).next();
+
+    // fix #8128
+    let test_string = "1|1 2";
+    let mut sp = test_string.split('|').map(|s| s.trim());
+    let _: Vec<&str> = sp.skip(1).next().unwrap().split(' ').collect();
+    if let Some(mut s) = Some(test_string.split('|').map(|s| s.trim())) {
+        let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+    };
+    fn check<T>(mut s: T)
+    where
+        T: Iterator<Item = String>,
+    {
+        let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+    }
 }

src/tools/clippy/tests/ui/iter_skip_next.stderr

@@ -1,5 +1,5 @@
 error: called `skip(..).next()` on an iterator
-  --> $DIR/iter_skip_next.rs:15:28
+  --> $DIR/iter_skip_next.rs:16:28
    |
 LL |     let _ = some_vec.iter().skip(42).next();
    |                            ^^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(42)`
@@ -7,22 +7,40 @@ LL |     let _ = some_vec.iter().skip(42).next();
    = note: `-D clippy::iter-skip-next` implied by `-D warnings`
 
 error: called `skip(..).next()` on an iterator
-  --> $DIR/iter_skip_next.rs:16:36
+  --> $DIR/iter_skip_next.rs:17:36
    |
 LL |     let _ = some_vec.iter().cycle().skip(42).next();
    |                                    ^^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(42)`
 
 error: called `skip(..).next()` on an iterator
-  --> $DIR/iter_skip_next.rs:17:20
+  --> $DIR/iter_skip_next.rs:18:20
    |
 LL |     let _ = (1..10).skip(10).next();
    |                    ^^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(10)`
 
 error: called `skip(..).next()` on an iterator
-  --> $DIR/iter_skip_next.rs:18:33
+  --> $DIR/iter_skip_next.rs:19:33
    |
 LL |     let _ = &some_vec[..].iter().skip(3).next();
    |                                 ^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(3)`
 
-error: aborting due to 4 previous errors
+error: called `skip(..).next()` on an iterator
+  --> $DIR/iter_skip_next.rs:27:26
+   |
+LL |     let _: Vec<&str> = sp.skip(1).next().unwrap().split(' ').collect();
+   |                          ^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(1)`
+
+error: called `skip(..).next()` on an iterator
+  --> $DIR/iter_skip_next.rs:29:29
+   |
+LL |         let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+   |                             ^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(1)`
+
+error: called `skip(..).next()` on an iterator
+  --> $DIR/iter_skip_next.rs:35:29
+   |
+LL |         let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+   |                             ^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(1)`
+
+error: aborting due to 7 previous errors
 

src/tools/clippy/tests/ui/iter_skip_next_unfixable.rs

@@ -0,0 +1,19 @@
+#![warn(clippy::iter_skip_next)]
+#![allow(dead_code)]
+
+/// Checks implementation of `ITER_SKIP_NEXT` lint
+fn main() {
+    // fix #8128
+    let test_string = "1|1 2";
+    let sp = test_string.split('|').map(|s| s.trim());
+    let _: Vec<&str> = sp.skip(1).next().unwrap().split(' ').collect();
+    if let Some(s) = Some(test_string.split('|').map(|s| s.trim())) {
+        let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+    };
+    fn check<T>(s: T)
+    where
+        T: Iterator<Item = String>,
+    {
+        let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+    }
+}

src/tools/clippy/tests/ui/iter_skip_next_unfixable.stderr

@@ -0,0 +1,39 @@
+error: called `skip(..).next()` on an iterator
+  --> $DIR/iter_skip_next_unfixable.rs:9:26
+   |
+LL |     let _: Vec<&str> = sp.skip(1).next().unwrap().split(' ').collect();
+   |                          ^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(1)`
+   |
+   = note: `-D clippy::iter-skip-next` implied by `-D warnings`
+help: for this change `sp` has to be mutable
+  --> $DIR/iter_skip_next_unfixable.rs:8:9
+   |
+LL |     let sp = test_string.split('|').map(|s| s.trim());
+   |         ^^
+
+error: called `skip(..).next()` on an iterator
+  --> $DIR/iter_skip_next_unfixable.rs:11:29
+   |
+LL |         let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+   |                             ^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(1)`
+   |
+help: for this change `s` has to be mutable
+  --> $DIR/iter_skip_next_unfixable.rs:10:17
+   |
+LL |     if let Some(s) = Some(test_string.split('|').map(|s| s.trim())) {
+   |                 ^
+
+error: called `skip(..).next()` on an iterator
+  --> $DIR/iter_skip_next_unfixable.rs:17:29
+   |
+LL |         let _: Vec<&str> = s.skip(1).next().unwrap().split(' ').collect();
+   |                             ^^^^^^^^^^^^^^^ help: use `nth` instead: `.nth(1)`
+   |
+help: for this change `s` has to be mutable
+  --> $DIR/iter_skip_next_unfixable.rs:13:17
+   |
+LL |     fn check<T>(s: T)
+   |                 ^
+
+error: aborting due to 3 previous errors
+

src/tools/clippy/tests/ui/manual_memcpy/with_loop_counters.stderr

@@ -43,7 +43,7 @@ LL | /     for i in 3..(3 + src.len()) {
 LL | |         dst[i] = src[count];
 LL | |         count += 1;
 LL | |     }
-   | |_____^ help: try replacing the loop by: `dst[3..(3 + src.len())].clone_from_slice(&src[..((3 + src.len()) - 3)]);`
+   | |_____^ help: try replacing the loop by: `dst[3..(3 + src.len())].clone_from_slice(&src[..(3 + src.len() - 3)]);`
 
 error: it looks like you're manually copying between slices
   --> $DIR/with_loop_counters.rs:35:5

src/tools/clippy/tests/ui/needless_bool/fixable.fixed

@@ -41,6 +41,15 @@ fn main() {
     x;
     !x;
     !(x && y);
+    let a = 0;
+    let b = 1;
+
+    a != b;
+    a == b;
+    a >= b;
+    a > b;
+    a <= b;
+    a < b;
     if x {
         x
     } else {

src/tools/clippy/tests/ui/needless_bool/fixable.rs

@@ -53,6 +53,39 @@ fn main() {
     } else {
         true
     };
+    let a = 0;
+    let b = 1;
+
+    if a == b {
+        false
+    } else {
+        true
+    };
+    if a != b {
+        false
+    } else {
+        true
+    };
+    if a < b {
+        false
+    } else {
+        true
+    };
+    if a <= b {
+        false
+    } else {
+        true
+    };
+    if a > b {
+        false
+    } else {
+        true
+    };
+    if a >= b {
+        false
+    } else {
+        true
+    };
     if x {
         x
     } else {

src/tools/clippy/tests/ui/needless_bool/fixable.stderr

@@ -31,7 +31,67 @@ LL | |     };
    | |_____^ help: you can reduce it to: `!(x && y)`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:72:5
+  --> $DIR/fixable.rs:59:5
+   |
+LL | /     if a == b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a != b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:64:5
+   |
+LL | /     if a != b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a == b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:69:5
+   |
+LL | /     if a < b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a >= b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:74:5
+   |
+LL | /     if a <= b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a > b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:79:5
+   |
+LL | /     if a > b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a <= b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:84:5
+   |
+LL | /     if a >= b {
+LL | |         false
+LL | |     } else {
+LL | |         true
+LL | |     };
+   | |_____^ help: you can reduce it to: `a < b`
+
+error: this if-then-else expression returns a bool literal
+  --> $DIR/fixable.rs:105:5
    |
 LL | /     if x {
 LL | |         return true;
@@ -41,7 +101,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return x`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:80:5
+  --> $DIR/fixable.rs:113:5
    |
 LL | /     if x {
 LL | |         return false;
@@ -51,7 +111,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return !x`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:88:5
+  --> $DIR/fixable.rs:121:5
    |
 LL | /     if x && y {
 LL | |         return true;
@@ -61,7 +121,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return x && y`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:96:5
+  --> $DIR/fixable.rs:129:5
    |
 LL | /     if x && y {
 LL | |         return false;
@@ -71,7 +131,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `return !(x && y)`
 
 error: equality checks against true are unnecessary
-  --> $DIR/fixable.rs:104:8
+  --> $DIR/fixable.rs:137:8
    |
 LL |     if x == true {};
    |        ^^^^^^^^^ help: try simplifying it as shown: `x`
@@ -79,25 +139,25 @@ LL |     if x == true {};
    = note: `-D clippy::bool-comparison` implied by `-D warnings`
 
 error: equality checks against false can be replaced by a negation
-  --> $DIR/fixable.rs:108:8
+  --> $DIR/fixable.rs:141:8
    |
 LL |     if x == false {};
    |        ^^^^^^^^^^ help: try simplifying it as shown: `!x`
 
 error: equality checks against true are unnecessary
-  --> $DIR/fixable.rs:118:8
+  --> $DIR/fixable.rs:151:8
    |
 LL |     if x == true {};
    |        ^^^^^^^^^ help: try simplifying it as shown: `x`
 
 error: equality checks against false can be replaced by a negation
-  --> $DIR/fixable.rs:119:8
+  --> $DIR/fixable.rs:152:8
    |
 LL |     if x == false {};
    |        ^^^^^^^^^^ help: try simplifying it as shown: `!x`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:128:12
+  --> $DIR/fixable.rs:161:12
    |
 LL |       } else if returns_bool() {
    |  ____________^
@@ -108,7 +168,7 @@ LL | |     };
    | |_____^ help: you can reduce it to: `{ !returns_bool() }`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:141:5
+  --> $DIR/fixable.rs:174:5
    |
 LL | /     if unsafe { no(4) } & 1 != 0 {
 LL | |         true
@@ -118,16 +178,16 @@ LL | |     };
    | |_____^ help: you can reduce it to: `(unsafe { no(4) } & 1 != 0)`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:146:30
+  --> $DIR/fixable.rs:179:30
    |
 LL |     let _brackets_unneeded = if unsafe { no(4) } & 1 != 0 { true } else { false };
    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: you can reduce it to: `unsafe { no(4) } & 1 != 0`
 
 error: this if-then-else expression returns a bool literal
-  --> $DIR/fixable.rs:149:9
+  --> $DIR/fixable.rs:182:9
    |
 LL |         if unsafe { no(4) } & 1 != 0 { true } else { false }
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: you can reduce it to: `(unsafe { no(4) } & 1 != 0)`
 
-error: aborting due to 15 previous errors
+error: aborting due to 21 previous errors
 

src/tools/clippy/tests/ui/needless_return.fixed

@@ -71,7 +71,18 @@ fn test_void_if_fun(b: bool) {
 fn test_void_match(x: u32) {
     match x {
         0 => (),
-        _ => {},
+        _ => (),
+    }
+}
+
+fn test_nested_match(x: u32) {
+    match x {
+        0 => (),
+        1 => {
+            let _ = 42;
+            
+        },
+        _ => (),
     }
 }
 
@@ -182,7 +193,7 @@ async fn async_test_void_if_fun(b: bool) {
 async fn async_test_void_match(x: u32) {
     match x {
         0 => (),
-        _ => {},
+        _ => (),
     }
 }
 

src/tools/clippy/tests/ui/needless_return.rs

@@ -75,6 +75,17 @@ fn test_void_match(x: u32) {
     }
 }
 
+fn test_nested_match(x: u32) {
+    match x {
+        0 => (),
+        1 => {
+            let _ = 42;
+            return;
+        },
+        _ => return,
+    }
+}
+
 fn read_line() -> String {
     use std::io::BufRead;
     let stdin = ::std::io::stdin();

src/tools/clippy/tests/ui/needless_return.stderr

@@ -70,127 +70,139 @@ error: unneeded `return` statement
   --> $DIR/needless_return.rs:74:14
    |
 LL |         _ => return,
-   |              ^^^^^^ help: replace `return` with an empty block: `{}`
+   |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:89:9
+  --> $DIR/needless_return.rs:83:13
-   |
-LL |         return String::from("test");
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::from("test")`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:91:9
-   |
-LL |         return String::new();
-   |         ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::new()`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:113:32
-   |
-LL |         bar.unwrap_or_else(|_| return)
-   |                                ^^^^^^ help: replace `return` with an empty block: `{}`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:118:13
    |
 LL |             return;
    |             ^^^^^^^ help: remove `return`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:120:20
+  --> $DIR/needless_return.rs:85:14
-   |
-LL |         let _ = || return;
-   |                    ^^^^^^ help: replace `return` with an empty block: `{}`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:126:32
-   |
-LL |         res.unwrap_or_else(|_| return Foo)
-   |                                ^^^^^^^^^^ help: remove `return`: `Foo`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:135:5
-   |
-LL |     return true;
-   |     ^^^^^^^^^^^^ help: remove `return`: `true`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:139:5
-   |
-LL |     return true;
-   |     ^^^^^^^^^^^^ help: remove `return`: `true`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:144:9
-   |
-LL |         return true;
-   |         ^^^^^^^^^^^^ help: remove `return`: `true`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:146:9
-   |
-LL |         return false;
-   |         ^^^^^^^^^^^^^ help: remove `return`: `false`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:152:17
-   |
-LL |         true => return false,
-   |                 ^^^^^^^^^^^^ help: remove `return`: `false`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:154:13
-   |
-LL |             return true;
-   |             ^^^^^^^^^^^^ help: remove `return`: `true`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:161:9
-   |
-LL |         return true;
-   |         ^^^^^^^^^^^^ help: remove `return`: `true`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:163:16
-   |
-LL |     let _ = || return true;
-   |                ^^^^^^^^^^^ help: remove `return`: `true`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:171:5
-   |
-LL |     return;
-   |     ^^^^^^^ help: remove `return`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:176:9
-   |
-LL |         return;
-   |         ^^^^^^^ help: remove `return`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:178:9
-   |
-LL |         return;
-   |         ^^^^^^^ help: remove `return`
-
-error: unneeded `return` statement
-  --> $DIR/needless_return.rs:185:14
    |
 LL |         _ => return,
-   |              ^^^^^^ help: replace `return` with an empty block: `{}`
+   |              ^^^^^^ help: replace `return` with a unit value: `()`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:200:9
+  --> $DIR/needless_return.rs:100:9
    |
 LL |         return String::from("test");
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::from("test")`
 
 error: unneeded `return` statement
-  --> $DIR/needless_return.rs:202:9
+  --> $DIR/needless_return.rs:102:9
    |
 LL |         return String::new();
    |         ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::new()`
 
-error: aborting due to 32 previous errors
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:124:32
+   |
+LL |         bar.unwrap_or_else(|_| return)
+   |                                ^^^^^^ help: replace `return` with an empty block: `{}`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:129:13
+   |
+LL |             return;
+   |             ^^^^^^^ help: remove `return`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:131:20
+   |
+LL |         let _ = || return;
+   |                    ^^^^^^ help: replace `return` with an empty block: `{}`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:137:32
+   |
+LL |         res.unwrap_or_else(|_| return Foo)
+   |                                ^^^^^^^^^^ help: remove `return`: `Foo`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:146:5
+   |
+LL |     return true;
+   |     ^^^^^^^^^^^^ help: remove `return`: `true`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:150:5
+   |
+LL |     return true;
+   |     ^^^^^^^^^^^^ help: remove `return`: `true`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:155:9
+   |
+LL |         return true;
+   |         ^^^^^^^^^^^^ help: remove `return`: `true`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:157:9
+   |
+LL |         return false;
+   |         ^^^^^^^^^^^^^ help: remove `return`: `false`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:163:17
+   |
+LL |         true => return false,
+   |                 ^^^^^^^^^^^^ help: remove `return`: `false`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:165:13
+   |
+LL |             return true;
+   |             ^^^^^^^^^^^^ help: remove `return`: `true`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:172:9
+   |
+LL |         return true;
+   |         ^^^^^^^^^^^^ help: remove `return`: `true`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:174:16
+   |
+LL |     let _ = || return true;
+   |                ^^^^^^^^^^^ help: remove `return`: `true`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:182:5
+   |
+LL |     return;
+   |     ^^^^^^^ help: remove `return`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:187:9
+   |
+LL |         return;
+   |         ^^^^^^^ help: remove `return`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:189:9
+   |
+LL |         return;
+   |         ^^^^^^^ help: remove `return`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:196:14
+   |
+LL |         _ => return,
+   |              ^^^^^^ help: replace `return` with a unit value: `()`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:211:9
+   |
+LL |         return String::from("test");
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::from("test")`
+
+error: unneeded `return` statement
+  --> $DIR/needless_return.rs:213:9
+   |
+LL |         return String::new();
+   |         ^^^^^^^^^^^^^^^^^^^^^ help: remove `return`: `String::new()`
+
+error: aborting due to 34 previous errors
 

src/tools/clippy/tests/ui/neg_multiply.fixed

@@ -0,0 +1,45 @@
+// run-rustfix
+#![warn(clippy::neg_multiply)]
+#![allow(clippy::no_effect, clippy::unnecessary_operation, clippy::precedence)]
+#![allow(unused)]
+
+use std::ops::Mul;
+
+struct X;
+
+impl Mul<isize> for X {
+    type Output = X;
+
+    fn mul(self, _r: isize) -> Self {
+        self
+    }
+}
+
+impl Mul<X> for isize {
+    type Output = X;
+
+    fn mul(self, _r: X) -> X {
+        X
+    }
+}
+
+fn main() {
+    let x = 0;
+
+    -x;
+
+    -x;
+
+    100 + -x;
+
+    -(100 + x);
+
+    -17;
+
+    0xcafe | -0xff00;
+
+    -1 * -1; // should be ok
+
+    X * -1; // should be ok
+    -1 * X; // should also be ok
+}

src/tools/clippy/tests/ui/neg_multiply.rs

@@ -1,5 +1,7 @@
+// run-rustfix
 #![warn(clippy::neg_multiply)]
-#![allow(clippy::no_effect, clippy::unnecessary_operation)]
+#![allow(clippy::no_effect, clippy::unnecessary_operation, clippy::precedence)]
+#![allow(unused)]
 
 use std::ops::Mul;
 
@@ -28,6 +30,14 @@ fn main() {
 
     -1 * x;
 
+    100 + x * -1;
+
+    (100 + x) * -1;
+
+    -1 * 17;
+
+    0xcafe | 0xff00 * -1;
+
     -1 * -1; // should be ok
 
     X * -1; // should be ok

src/tools/clippy/tests/ui/neg_multiply.stderr

@@ -1,16 +1,40 @@
-error: negation by multiplying with `-1`
+error: this multiplication by -1 can be written more succinctly
-  --> $DIR/neg_multiply.rs:27:5
+  --> $DIR/neg_multiply.rs:29:5
    |
 LL |     x * -1;
-   |     ^^^^^^
+   |     ^^^^^^ help: consider using: `-x`
    |
    = note: `-D clippy::neg-multiply` implied by `-D warnings`
 
-error: negation by multiplying with `-1`
+error: this multiplication by -1 can be written more succinctly
-  --> $DIR/neg_multiply.rs:29:5
+  --> $DIR/neg_multiply.rs:31:5
    |
 LL |     -1 * x;
-   |     ^^^^^^
+   |     ^^^^^^ help: consider using: `-x`
 
-error: aborting due to 2 previous errors
+error: this multiplication by -1 can be written more succinctly
+  --> $DIR/neg_multiply.rs:33:11
+   |
+LL |     100 + x * -1;
+   |           ^^^^^^ help: consider using: `-x`
+
+error: this multiplication by -1 can be written more succinctly
+  --> $DIR/neg_multiply.rs:35:5
+   |
+LL |     (100 + x) * -1;
+   |     ^^^^^^^^^^^^^^ help: consider using: `-(100 + x)`
+
+error: this multiplication by -1 can be written more succinctly
+  --> $DIR/neg_multiply.rs:37:5
+   |
+LL |     -1 * 17;
+   |     ^^^^^^^ help: consider using: `-17`
+
+error: this multiplication by -1 can be written more succinctly
+  --> $DIR/neg_multiply.rs:39:14
+   |
+LL |     0xcafe | 0xff00 * -1;
+   |              ^^^^^^^^^^^ help: consider using: `-0xff00`
+
+error: aborting due to 6 previous errors
 

src/tools/clippy/tests/ui/numbered_fields.fixed

@@ -0,0 +1,33 @@
+//run-rustfix
+#![warn(clippy::init_numbered_fields)]
+
+#[derive(Default)]
+struct TupleStruct(u32, u32, u8);
+
+// This shouldn't lint because it's in a macro
+macro_rules! tuple_struct_init {
+    () => {
+        TupleStruct { 0: 0, 1: 1, 2: 2 }
+    };
+}
+
+fn main() {
+    let tuple_struct = TupleStruct::default();
+
+    // This should lint
+    let _ = TupleStruct(1u32, 42, 23u8);
+
+    // This should also lint and order the fields correctly
+    let _ = TupleStruct(1u32, 3u32, 2u8);
+
+    // Ok because of default initializer
+    let _ = TupleStruct { 0: 42, ..tuple_struct };
+
+    let _ = TupleStruct {
+        1: 23,
+        ..TupleStruct::default()
+    };
+
+    // Ok because it's in macro
+    let _ = tuple_struct_init!();
+}

src/tools/clippy/tests/ui/numbered_fields.rs

@@ -0,0 +1,41 @@
+//run-rustfix
+#![warn(clippy::init_numbered_fields)]
+
+#[derive(Default)]
+struct TupleStruct(u32, u32, u8);
+
+// This shouldn't lint because it's in a macro
+macro_rules! tuple_struct_init {
+    () => {
+        TupleStruct { 0: 0, 1: 1, 2: 2 }
+    };
+}
+
+fn main() {
+    let tuple_struct = TupleStruct::default();
+
+    // This should lint
+    let _ = TupleStruct {
+        0: 1u32,
+        1: 42,
+        2: 23u8,
+    };
+
+    // This should also lint and order the fields correctly
+    let _ = TupleStruct {
+        0: 1u32,
+        2: 2u8,
+        1: 3u32,
+    };
+
+    // Ok because of default initializer
+    let _ = TupleStruct { 0: 42, ..tuple_struct };
+
+    let _ = TupleStruct {
+        1: 23,
+        ..TupleStruct::default()
+    };
+
+    // Ok because it's in macro
+    let _ = tuple_struct_init!();
+}

src/tools/clippy/tests/ui/numbered_fields.stderr

@@ -0,0 +1,26 @@
+error: used a field initializer for a tuple struct
+  --> $DIR/numbered_fields.rs:18:13
+   |
+LL |       let _ = TupleStruct {
+   |  _____________^
+LL | |         0: 1u32,
+LL | |         1: 42,
+LL | |         2: 23u8,
+LL | |     };
+   | |_____^ help: try this instead: `TupleStruct(1u32, 42, 23u8)`
+   |
+   = note: `-D clippy::init-numbered-fields` implied by `-D warnings`
+
+error: used a field initializer for a tuple struct
+  --> $DIR/numbered_fields.rs:25:13
+   |
+LL |       let _ = TupleStruct {
+   |  _____________^
+LL | |         0: 1u32,
+LL | |         2: 2u8,
+LL | |         1: 3u32,
+LL | |     };
+   | |_____^ help: try this instead: `TupleStruct(1u32, 3u32, 2u8)`
+
+error: aborting due to 2 previous errors
+

src/tools/clippy/tests/ui/return_self_not_must_use.rs

@@ -5,12 +5,12 @@ pub struct Bar;
 
 pub trait Whatever {
     fn what(&self) -> Self;
-    // There should be no warning here!
+    // There should be no warning here! (returns a reference)
     fn what2(&self) -> &Self;
 }
 
 impl Bar {
-    // There should be no warning here!
+    // There should be no warning here! (note taking a self argument)
     pub fn not_new() -> Self {
         Self
     }
@@ -20,23 +20,38 @@ impl Bar {
     pub fn bar(self) -> Self {
         self
     }
-    // There should be no warning here!
+    // There should be no warning here! (private method)
     fn foo2(&self) -> Self {
         Self
     }
-    // There should be no warning here!
+    // There should be no warning here! (returns a reference)
     pub fn foo3(&self) -> &Self {
         self
     }
+    // There should be no warning here! (already a `must_use` attribute)
+    #[must_use]
+    pub fn foo4(&self) -> Self {
+        Self
+    }
 }
 
 impl Whatever for Bar {
-    // There should be no warning here!
+    // There should be no warning here! (comes from the trait)
     fn what(&self) -> Self {
         self.foo2()
     }
-    // There should be no warning here!
+    // There should be no warning here! (comes from the trait)
     fn what2(&self) -> &Self {
         self
     }
 }
+
+#[must_use]
+pub struct Foo;
+
+impl Foo {
+    // There should be no warning here! (`Foo` already implements `#[must_use]`)
+    fn foo(&self) -> Self {
+        Self
+    }
+}

src/tools/clippy/tests/ui/shadow.rs

@@ -47,6 +47,8 @@ fn syntax() {
     let _ = |[x]: [u32; 1]| {
         let x = 1;
     };
+    let y = Some(1);
+    if let Some(y) = y {}
 }
 
 fn negative() {

src/tools/clippy/tests/ui/shadow.stderr

@@ -241,17 +241,29 @@ note: previous binding is here
 LL |     let _ = |[x]: [u32; 1]| {
    |               ^
 
+error: `y` is shadowed
+  --> $DIR/shadow.rs:51:17
+   |
+LL |     if let Some(y) = y {}
+   |                 ^
+   |
+note: previous binding is here
+  --> $DIR/shadow.rs:50:9
+   |
+LL |     let y = Some(1);
+   |         ^
+
 error: `_b` shadows a previous, unrelated binding
-  --> $DIR/shadow.rs:85:9
+  --> $DIR/shadow.rs:87:9
    |
 LL |     let _b = _a;
    |         ^^
    |
 note: previous binding is here
-  --> $DIR/shadow.rs:84:28
+  --> $DIR/shadow.rs:86:28
    |
 LL | pub async fn foo2(_a: i32, _b: i64) {
    |                            ^^
 
-error: aborting due to 21 previous errors
+error: aborting due to 22 previous errors
 

src/tools/clippy/tests/ui/short_circuit_statement.fixed

@@ -6,7 +6,7 @@
 fn main() {
     if f() { g(); }
     if !f() { g(); }
-    if !(1 == 2) { g(); }
+    if 1 != 2 { g(); }
 }
 
 fn f() -> bool {

src/tools/clippy/tests/ui/short_circuit_statement.stderr

@@ -16,7 +16,7 @@ error: boolean short circuit operator in statement may be clearer using an expli
   --> $DIR/short_circuit_statement.rs:9:5
    |
 LL |     1 == 2 || g();
-   |     ^^^^^^^^^^^^^^ help: replace it with: `if !(1 == 2) { g(); }`
+   |     ^^^^^^^^^^^^^^ help: replace it with: `if 1 != 2 { g(); }`
 
 error: aborting due to 3 previous errors
 

src/tools/clippy/tests/ui/undocumented_unsafe_blocks.rs

@@ -5,7 +5,7 @@
 fn nested_local() {
     let _ = {
         let _ = {
-            // Safety:
+            // SAFETY:
             let _ = unsafe {};
         };
     };
@@ -14,7 +14,7 @@ fn nested_local() {
 fn deep_nest() {
     let _ = {
         let _ = {
-            // Safety:
+            // SAFETY:
             let _ = unsafe {};
 
             // Safety:
@@ -28,7 +28,7 @@ fn deep_nest() {
                                 // Safety:
                                 let _ = unsafe {};
 
-                                // Safety:
+                                // SAFETY:
                                 unsafe {};
                             };
                         };
@@ -44,7 +44,7 @@ fn deep_nest() {
         unsafe {};
     };
 
-    // Safety:
+    // SAFETY:
     unsafe {};
 }
 
@@ -59,7 +59,7 @@ fn line_comment() {
 }
 
 fn line_comment_newlines() {
-    // Safety:
+    // SAFETY:
 
     unsafe {}
 }
@@ -84,7 +84,7 @@ fn block_comment() {
 }
 
 fn block_comment_newlines() {
-    /* Safety: */
+    /* SAFETY: */
 
     unsafe {}
 }
@@ -96,7 +96,7 @@ fn inline_block_comment() {
 
 fn block_comment_with_extras() {
     /* This is a description
-     * Safety:
+     * SAFETY:
      */
     unsafe {}
 }
@@ -122,7 +122,7 @@ fn buried_safety() {
 }
 
 fn safety_with_prepended_text() {
-    // This is a test. Safety:
+    // This is a test. safety:
     unsafe {}
 }
 
@@ -132,7 +132,7 @@ fn local_line_comment() {
 }
 
 fn local_block_comment() {
-    /* Safety: */
+    /* SAFETY: */
     let _ = unsafe {};
 }
 
@@ -142,18 +142,18 @@ fn comment_array() {
 }
 
 fn comment_tuple() {
-    // Safety:
+    // sAFETY:
     let _ = (42, unsafe {}, "test", unsafe {});
 }
 
 fn comment_unary() {
-    // Safety:
+    // SAFETY:
     let _ = *unsafe { &42 };
 }
 
 #[allow(clippy::match_single_binding)]
 fn comment_match() {
-    // Safety:
+    // SAFETY:
     let _ = match unsafe {} {
         _ => {},
     };
@@ -177,7 +177,7 @@ fn comment_macro_call() {
     }
 
     t!(
-        // Safety:
+        // SAFETY:
         unsafe {}
     );
 }
@@ -194,18 +194,18 @@ fn comment_macro_def() {
 }
 
 fn non_ascii_comment() {
-    // ॐ᧻໒ Safety: ௵∰
+    // ॐ᧻໒ SaFeTy: ௵∰
     unsafe {};
 }
 
 fn local_commented_block() {
     let _ =
-        // Safety:
+        // safety:
         unsafe {};
 }
 
 fn local_nest() {
-    // Safety:
+    // safety:
     let _ = [(42, unsafe {}, unsafe {}), (52, unsafe {}, unsafe {})];
 }
 
@@ -267,17 +267,17 @@ fn no_comment_macro_def() {
 }
 
 fn trailing_comment() {
-    unsafe {} // Safety:
+    unsafe {} // SAFETY:
 }
 
 fn internal_comment() {
     unsafe {
-        // Safety:
+        // SAFETY:
     }
 }
 
 fn interference() {
-    // Safety
+    // SAFETY
 
     let _ = 42;
 

src/tools/clippy/tests/ui/undocumented_unsafe_blocks.stderr

@@ -7,7 +7,7 @@ LL |     unsafe {}
    = note: `-D clippy::undocumented-unsafe-blocks` implied by `-D warnings`
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     unsafe {}
    |
 
@@ -19,7 +19,7 @@ LL |     let _ = [unsafe { 14 }, unsafe { 15 }, 42, unsafe { 16 }];
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     let _ = [unsafe { 14 }, unsafe { 15 }, 42, unsafe { 16 }];
    |
 
@@ -31,7 +31,7 @@ LL |     let _ = (42, unsafe {}, "test", unsafe {});
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     let _ = (42, unsafe {}, "test", unsafe {});
    |
 
@@ -43,7 +43,7 @@ LL |     let _ = *unsafe { &42 };
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     let _ = *unsafe { &42 };
    |
 
@@ -55,7 +55,7 @@ LL |     let _ = match unsafe {} {
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     let _ = match unsafe {} {
    |
 
@@ -67,7 +67,7 @@ LL |     let _ = &unsafe {};
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     let _ = &unsafe {};
    |
 
@@ -79,7 +79,7 @@ LL |     let _ = [unsafe {}; 5];
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     let _ = [unsafe {}; 5];
    |
 
@@ -91,7 +91,7 @@ LL |     let _ = unsafe {};
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     let _ = unsafe {};
    |
 
@@ -103,7 +103,7 @@ LL |     t!(unsafe {});
    |
 help: consider adding a safety comment
    |
-LL ~     t!(// Safety: ...
+LL ~     t!(// SAFETY: ...
 LL ~     unsafe {});
    |
 
@@ -122,13 +122,13 @@ LL |     t!();
 error: unsafe block missing a safety comment
   --> $DIR/undocumented_unsafe_blocks.rs:270:5
    |
-LL |     unsafe {} // Safety:
+LL |     unsafe {} // SAFETY:
    |     ^^^^^^^^^
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
-LL ~     unsafe {} // Safety:
+LL ~     unsafe {} // SAFETY:
    |
 
 error: unsafe block missing a safety comment
@@ -139,7 +139,7 @@ LL |     unsafe {
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL +     unsafe {
    |
 
@@ -151,7 +151,7 @@ LL |     unsafe {};
    |
 help: consider adding a safety comment
    |
-LL ~     // Safety: ...
+LL ~     // SAFETY: ...
 LL ~     unsafe {};
    |
 
@@ -163,7 +163,7 @@ LL |     println!("{}", unsafe { String::from_utf8_unchecked(vec![]) });
    |
 help: consider adding a safety comment
    |
-LL ~     println!("{}", // Safety: ...
+LL ~     println!("{}", // SAFETY: ...
 LL ~     unsafe { String::from_utf8_unchecked(vec![]) });
    |
 

src/tools/clippy/tests/ui/unwrap_or_else_default.fixed

@@ -45,7 +45,7 @@ fn unwrap_or_else_default() {
     with_enum.unwrap_or_else(Enum::A);
 
     let with_new = Some(vec![1]);
-    with_new.unwrap_or_else(Vec::new);
+    with_new.unwrap_or_default();
 
     let with_err: Result<_, ()> = Ok(vec![1]);
     with_err.unwrap_or_else(make);
@@ -66,6 +66,9 @@ fn unwrap_or_else_default() {
 
     let with_default_type = Some(1);
     with_default_type.unwrap_or_default();
+
+    let with_default_type: Option<Vec<u64>> = None;
+    with_default_type.unwrap_or_default();
 }
 
 fn main() {}

src/tools/clippy/tests/ui/unwrap_or_else_default.rs

@@ -66,6 +66,9 @@ fn unwrap_or_else_default() {
 
     let with_default_type = Some(1);
     with_default_type.unwrap_or_else(u64::default);
+
+    let with_default_type: Option<Vec<u64>> = None;
+    with_default_type.unwrap_or_else(Vec::new);
 }
 
 fn main() {}

src/tools/clippy/tests/ui/unwrap_or_else_default.stderr

@@ -1,10 +1,16 @@
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:48:5
+   |
+LL |     with_new.unwrap_or_else(Vec::new);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `with_new.unwrap_or_default()`
+   |
+   = note: `-D clippy::unwrap-or-else-default` implied by `-D warnings`
+
 error: use of `.unwrap_or_else(..)` to construct default value
   --> $DIR/unwrap_or_else_default.rs:62:5
    |
 LL |     with_real_default.unwrap_or_else(<HasDefaultAndDuplicate as Default>::default);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `with_real_default.unwrap_or_default()`
-   |
-   = note: `-D clippy::unwrap-or-else-default` implied by `-D warnings`
 
 error: use of `.unwrap_or_else(..)` to construct default value
   --> $DIR/unwrap_or_else_default.rs:65:5
@@ -18,5 +24,11 @@ error: use of `.unwrap_or_else(..)` to construct default value
 LL |     with_default_type.unwrap_or_else(u64::default);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `with_default_type.unwrap_or_default()`
 
-error: aborting due to 3 previous errors
+error: use of `.unwrap_or_else(..)` to construct default value
+  --> $DIR/unwrap_or_else_default.rs:71:5
+   |
+LL |     with_default_type.unwrap_or_else(Vec::new);
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `with_default_type.unwrap_or_default()`
+
+error: aborting due to 5 previous errors