Update Clippy

src/tools/clippy/.github/PULL_REQUEST_TEMPLATE.md

@@ -3,7 +3,9 @@ Thank you for making Clippy better!
 We're collecting our changelog from pull request descriptions.
 If your PR only includes internal changes, you can just write
 `changelog: none`. Otherwise, please write a short comment
-explaining your change.
+explaining your change. Also, it's helpful for us that
+the lint name is put into brackets `[]` and backticks `` ` ` ``,
+e.g. ``[`lint_name`]``.
 
 If your PR fixes an issue, you can add "fixes #issue_number" into this
 PR description. This way the issue will be automatically closed when
@@ -29,4 +31,5 @@ Delete this line and everything above before opening your PR.
 ---
 
 *Please write a short comment explaining your change (or "none" for internal only changes)*
+
 changelog:

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

@@ -34,15 +34,16 @@ jobs:
       run: |
         MESSAGE=$(git log --format=%B -n 1)
         PR=$(echo "$MESSAGE" | grep -o "#[0-9]*" | head -1 | sed -e 's/^#//')
-        output=$(curl -H "Authorization: token ${{ secrets.GITHUB_TOKEN }}" -s "https://api.github.com/repos/rust-lang/rust-clippy/pulls/$PR" | \
-          python -c "import sys, json; print(json.load(sys.stdin)['body'])" | \
-          grep "^changelog: " | \
-          sed "s/changelog: //g")
-        if [[ -z "$output" ]]; then
+        body=$(curl -H "Authorization: token ${{ secrets.GITHUB_TOKEN }}" -s "https://api.github.com/repos/rust-lang/rust-clippy/pulls/$PR" | \
+          python -c "import sys, json; print(json.load(sys.stdin)['body'])")
+        output=$(grep "^changelog:\s*\S" <<< "$body" | sed "s/changelog:\s*//g") || {
           echo "ERROR: PR body must contain 'changelog: ...'"
           exit 1
-        elif [[ "$output" = "none" ]]; then
+        }
+        if [[ "$output" = "none" ]]; then
           echo "WARNING: changelog is 'none'"
+        else
+          echo "changelog: $output"
         fi
       env:
         PYTHONIOENCODING: 'utf-8'

src/tools/clippy/CHANGELOG.md

@@ -179,7 +179,7 @@ Current stable, released 2021-03-25
 
 * Replace [`find_map`] with [`manual_find_map`]
   [#6591](https://github.com/rust-lang/rust-clippy/pull/6591)
-* [`unknown_clippy_lints`] Now integrated in the `unknown_lints` rustc lint
+* `unknown_clippy_lints` Now integrated in the `unknown_lints` rustc lint
   [#6653](https://github.com/rust-lang/rust-clippy/pull/6653)
 
 ### Enhancements
@@ -280,7 +280,7 @@ Released 2021-02-11
 
 * Previously deprecated [`str_to_string`] and [`string_to_string`] have been un-deprecated
   as `restriction` lints [#6333](https://github.com/rust-lang/rust-clippy/pull/6333)
-* Deprecate [`panic_params`] lint. This is now available in rustc as `panic_fmt`
+* Deprecate `panic_params` lint. This is now available in rustc as `non_fmt_panic`
   [#6351](https://github.com/rust-lang/rust-clippy/pull/6351)
 * Move [`map_err_ignore`] to `restriction`
   [#6416](https://github.com/rust-lang/rust-clippy/pull/6416)
@@ -419,7 +419,7 @@ Released 2020-12-31
   [#6037](https://github.com/rust-lang/rust-clippy/pull/6037)
 * Rename `zero_width_space` to [`invisible_characters`]
   [#6105](https://github.com/rust-lang/rust-clippy/pull/6105)
-* Deprecate [`drop_bounds`] (uplifted)
+* Deprecate `drop_bounds` (uplifted)
   [#6111](https://github.com/rust-lang/rust-clippy/pull/6111)
 * Move [`string_lit_as_bytes`] to `nursery`
   [#6117](https://github.com/rust-lang/rust-clippy/pull/6117)
@@ -1018,7 +1018,7 @@ Released 2020-03-12
   [#5015](https://github.com/rust-lang/rust-clippy/pull/5015)
 * Move [`range_plus_one`] to pedantic group [#5057](https://github.com/rust-lang/rust-clippy/pull/5057)
 * Move [`debug_assert_with_mut_call`] to nursery group [#5106](https://github.com/rust-lang/rust-clippy/pull/5106)
-* Deprecate [`unused_label`] [#4930](https://github.com/rust-lang/rust-clippy/pull/4930)
+* Deprecate `unused_label` [#4930](https://github.com/rust-lang/rust-clippy/pull/4930)
 
 ### Enhancements
 
@@ -1046,7 +1046,7 @@ Released 2020-03-12
 * [`wildcard_enum_match_arm`] [#4934](https://github.com/rust-lang/rust-clippy/pull/4934)
 * [`cognitive_complexity`] [#4935](https://github.com/rust-lang/rust-clippy/pull/4935)
 * [`decimal_literal_representation`] [#4956](https://github.com/rust-lang/rust-clippy/pull/4956)
-* [`unknown_clippy_lints`] [#4963](https://github.com/rust-lang/rust-clippy/pull/4963)
+* `unknown_clippy_lints` [#4963](https://github.com/rust-lang/rust-clippy/pull/4963)
 * [`explicit_into_iter_loop`] [#4978](https://github.com/rust-lang/rust-clippy/pull/4978)
 * [`useless_attribute`] [#5022](https://github.com/rust-lang/rust-clippy/pull/5022)
 * [`if_let_some_result`] [#5032](https://github.com/rust-lang/rust-clippy/pull/5032)
@@ -1080,7 +1080,7 @@ Released 2020-01-30
   [Inside Rust Blog](https://blog.rust-lang.org/inside-rust/2019/11/04/Clippy-removes-plugin-interface.html) for
   details [#4714](https://github.com/rust-lang/rust-clippy/pull/4714)
 * Move [`use_self`] to nursery group [#4863](https://github.com/rust-lang/rust-clippy/pull/4863)
-* Deprecate [`into_iter_on_array`] [#4788](https://github.com/rust-lang/rust-clippy/pull/4788)
+* Deprecate `into_iter_on_array` [#4788](https://github.com/rust-lang/rust-clippy/pull/4788)
 * Expand [`string_lit_as_bytes`] to also trigger when literal has escapes
   [#4808](https://github.com/rust-lang/rust-clippy/pull/4808)
 * Fix false positive in `comparison_chain` [#4842](https://github.com/rust-lang/rust-clippy/pull/4842)
@@ -1282,7 +1282,7 @@ Released 2019-05-20
 
 [1fac380..37f5c1e](https://github.com/rust-lang/rust-clippy/compare/1fac380...37f5c1e)
 
-* New lint: [`drop_bounds`] to detect `T: Drop` bounds
+* New lint: `drop_bounds` to detect `T: Drop` bounds
 * Split [`redundant_closure`] into [`redundant_closure`] and [`redundant_closure_for_method_calls`] [#4110](https://github.com/rust-lang/rust-clippy/pull/4101)
 * Rename `cyclomatic_complexity` to [`cognitive_complexity`], start work on making lint more practical for Rust code
 * Move [`get_unwrap`] to the restriction category
@@ -1375,7 +1375,7 @@ Released 2019-01-17
 
 * New lints: [`slow_vector_initialization`], [`mem_discriminant_non_enum`],
   [`redundant_clone`], [`wildcard_dependencies`],
-  [`into_iter_on_ref`], [`into_iter_on_array`], [`deprecated_cfg_attr`],
+  [`into_iter_on_ref`], `into_iter_on_array`, [`deprecated_cfg_attr`],
   [`mem_discriminant_non_enum`], [`cargo_common_metadata`]
 * Add support for `u128` and `i128` to integer related lints
 * Add float support to `mistyped_literal_suffixes`
@@ -1649,7 +1649,7 @@ Released 2018-09-13
 
 ## 0.0.166
 * Rustup to *rustc 1.22.0-nightly (b7960878b 2017-10-18)*
-* New lints: [`explicit_write`], `identity_conversion`, [`implicit_hasher`], [`invalid_ref`], [`option_map_or_none`],
+* New lints: [`explicit_write`], `identity_conversion`, [`implicit_hasher`], `invalid_ref`, [`option_map_or_none`],
   [`range_minus_one`], [`range_plus_one`], [`transmute_int_to_bool`], [`transmute_int_to_char`],
   [`transmute_int_to_float`]
 
@@ -2037,7 +2037,7 @@ Released 2018-09-13
 
 ## 0.0.64 — 2016-04-26
 * Rustup to *rustc 1.10.0-nightly (645dd013a 2016-04-24)*
-* New lints: [`temporary_cstring_as_ptr`], [`unsafe_removed_from_name`], and [`mem_forget`]
+* New lints: `temporary_cstring_as_ptr`, [`unsafe_removed_from_name`], and [`mem_forget`]
 
 ## 0.0.63 — 2016-04-08
 * Rustup to *rustc 1.9.0-nightly (7979dd608 2016-04-07)*
@@ -2091,7 +2091,7 @@ Released 2018-09-13
 
 ## 0.0.49 — 2016-03-09
 * Update to *rustc 1.9.0-nightly (eabfc160f 2016-03-08)*
-* New lints: [`overflow_check_conditional`], [`unused_label`], [`new_without_default`]
+* New lints: [`overflow_check_conditional`], `unused_label`, [`new_without_default`]
 
 ## 0.0.48 — 2016-03-07
 * Fixed: ICE in [`needless_range_loop`] with globals
@@ -2124,6 +2124,7 @@ Released 2018-09-13
 [`blacklisted_name`]: https://rust-lang.github.io/rust-clippy/master/index.html#blacklisted_name
 [`blanket_clippy_restriction_lints`]: https://rust-lang.github.io/rust-clippy/master/index.html#blanket_clippy_restriction_lints
 [`blocks_in_if_conditions`]: https://rust-lang.github.io/rust-clippy/master/index.html#blocks_in_if_conditions
+[`bool_assert_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_assert_comparison
 [`bool_comparison`]: https://rust-lang.github.io/rust-clippy/master/index.html#bool_comparison
 [`borrow_interior_mutable_const`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrow_interior_mutable_const
 [`borrowed_box`]: https://rust-lang.github.io/rust-clippy/master/index.html#borrowed_box
@@ -2148,6 +2149,7 @@ Released 2018-09-13
 [`clone_double_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#clone_double_ref
 [`clone_on_copy`]: https://rust-lang.github.io/rust-clippy/master/index.html#clone_on_copy
 [`clone_on_ref_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#clone_on_ref_ptr
+[`cloned_instead_of_copied`]: https://rust-lang.github.io/rust-clippy/master/index.html#cloned_instead_of_copied
 [`cmp_nan`]: https://rust-lang.github.io/rust-clippy/master/index.html#cmp_nan
 [`cmp_null`]: https://rust-lang.github.io/rust-clippy/master/index.html#cmp_null
 [`cmp_owned`]: https://rust-lang.github.io/rust-clippy/master/index.html#cmp_owned
@@ -2178,7 +2180,6 @@ Released 2018-09-13
 [`double_must_use`]: https://rust-lang.github.io/rust-clippy/master/index.html#double_must_use
 [`double_neg`]: https://rust-lang.github.io/rust-clippy/master/index.html#double_neg
 [`double_parens`]: https://rust-lang.github.io/rust-clippy/master/index.html#double_parens
-[`drop_bounds`]: https://rust-lang.github.io/rust-clippy/master/index.html#drop_bounds
 [`drop_copy`]: https://rust-lang.github.io/rust-clippy/master/index.html#drop_copy
 [`drop_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#drop_ref
 [`duplicate_underscore_argument`]: https://rust-lang.github.io/rust-clippy/master/index.html#duplicate_underscore_argument
@@ -2216,6 +2217,7 @@ Released 2018-09-13
 [`filter_next`]: https://rust-lang.github.io/rust-clippy/master/index.html#filter_next
 [`find_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#find_map
 [`flat_map_identity`]: https://rust-lang.github.io/rust-clippy/master/index.html#flat_map_identity
+[`flat_map_option`]: https://rust-lang.github.io/rust-clippy/master/index.html#flat_map_option
 [`float_arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#float_arithmetic
 [`float_cmp`]: https://rust-lang.github.io/rust-clippy/master/index.html#float_cmp
 [`float_cmp_const`]: https://rust-lang.github.io/rust-clippy/master/index.html#float_cmp_const
@@ -2264,10 +2266,9 @@ Released 2018-09-13
 [`int_plus_one`]: https://rust-lang.github.io/rust-clippy/master/index.html#int_plus_one
 [`integer_arithmetic`]: https://rust-lang.github.io/rust-clippy/master/index.html#integer_arithmetic
 [`integer_division`]: https://rust-lang.github.io/rust-clippy/master/index.html#integer_division
-[`into_iter_on_array`]: https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_array
 [`into_iter_on_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#into_iter_on_ref
 [`invalid_atomic_ordering`]: https://rust-lang.github.io/rust-clippy/master/index.html#invalid_atomic_ordering
-[`invalid_ref`]: https://rust-lang.github.io/rust-clippy/master/index.html#invalid_ref
+[`invalid_null_ptr_usage`]: https://rust-lang.github.io/rust-clippy/master/index.html#invalid_null_ptr_usage
 [`invalid_regex`]: https://rust-lang.github.io/rust-clippy/master/index.html#invalid_regex
 [`invalid_upcast_comparisons`]: https://rust-lang.github.io/rust-clippy/master/index.html#invalid_upcast_comparisons
 [`invisible_characters`]: https://rust-lang.github.io/rust-clippy/master/index.html#invisible_characters
@@ -2402,7 +2403,6 @@ Released 2018-09-13
 [`overflow_check_conditional`]: https://rust-lang.github.io/rust-clippy/master/index.html#overflow_check_conditional
 [`panic`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic
 [`panic_in_result_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_in_result_fn
-[`panic_params`]: https://rust-lang.github.io/rust-clippy/master/index.html#panic_params
 [`panicking_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#panicking_unwrap
 [`partialeq_ne_impl`]: https://rust-lang.github.io/rust-clippy/master/index.html#partialeq_ne_impl
 [`path_buf_push_overwrite`]: https://rust-lang.github.io/rust-clippy/master/index.html#path_buf_push_overwrite
@@ -2488,7 +2488,6 @@ Released 2018-09-13
 [`suspicious_unary_op_formatting`]: https://rust-lang.github.io/rust-clippy/master/index.html#suspicious_unary_op_formatting
 [`tabs_in_doc_comments`]: https://rust-lang.github.io/rust-clippy/master/index.html#tabs_in_doc_comments
 [`temporary_assignment`]: https://rust-lang.github.io/rust-clippy/master/index.html#temporary_assignment
-[`temporary_cstring_as_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#temporary_cstring_as_ptr
 [`to_digit_is_some`]: https://rust-lang.github.io/rust-clippy/master/index.html#to_digit_is_some
 [`to_string_in_display`]: https://rust-lang.github.io/rust-clippy/master/index.html#to_string_in_display
 [`todo`]: https://rust-lang.github.io/rust-clippy/master/index.html#todo
@@ -2517,13 +2516,13 @@ Released 2018-09-13
 [`unit_arg`]: https://rust-lang.github.io/rust-clippy/master/index.html#unit_arg
 [`unit_cmp`]: https://rust-lang.github.io/rust-clippy/master/index.html#unit_cmp
 [`unit_return_expecting_ord`]: https://rust-lang.github.io/rust-clippy/master/index.html#unit_return_expecting_ord
-[`unknown_clippy_lints`]: https://rust-lang.github.io/rust-clippy/master/index.html#unknown_clippy_lints
 [`unnecessary_cast`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast
 [`unnecessary_filter_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_filter_map
 [`unnecessary_fold`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_fold
 [`unnecessary_lazy_evaluations`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_lazy_evaluations
 [`unnecessary_mut_passed`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_mut_passed
 [`unnecessary_operation`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_operation
+[`unnecessary_self_imports`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_self_imports
 [`unnecessary_sort_by`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_sort_by
 [`unnecessary_unwrap`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_unwrap
 [`unnecessary_wraps`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_wraps
@@ -2541,7 +2540,6 @@ Released 2018-09-13
 [`unstable_as_slice`]: https://rust-lang.github.io/rust-clippy/master/index.html#unstable_as_slice
 [`unused_collect`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_collect
 [`unused_io_amount`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_io_amount
-[`unused_label`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_label
 [`unused_self`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_self
 [`unused_unit`]: https://rust-lang.github.io/rust-clippy/master/index.html#unused_unit
 [`unusual_byte_groupings`]: https://rust-lang.github.io/rust-clippy/master/index.html#unusual_byte_groupings

src/tools/clippy/CONTRIBUTING.md

@@ -21,10 +21,10 @@ All contributors are expected to follow the [Rust Code of Conduct].
     - [IntelliJ Rust](#intellij-rust)
     - [Rust Analyzer](#rust-analyzer)
   - [How Clippy works](#how-clippy-works)
-  - [Syncing changes between Clippy and [`rust-lang/rust`]](#syncing-changes-between-clippy-and-rust-langrust)
+  - [Syncing changes between Clippy and `rust-lang/rust`](#syncing-changes-between-clippy-and-rust-langrust)
     - [Patching git-subtree to work with big repos](#patching-git-subtree-to-work-with-big-repos)
-    - [Performing the sync from [`rust-lang/rust`] to Clippy](#performing-the-sync-from-rust-langrust-to-clippy)
-    - [Performing the sync from Clippy to [`rust-lang/rust`]](#performing-the-sync-from-clippy-to-rust-langrust)
+    - [Performing the sync from `rust-lang/rust` to Clippy](#performing-the-sync-from-rust-langrust-to-clippy)
+    - [Performing the sync from Clippy to `rust-lang/rust`](#performing-the-sync-from-clippy-to-rust-langrust)
     - [Defining remotes](#defining-remotes)
   - [Issue and PR triage](#issue-and-pr-triage)
   - [Bors and Homu](#bors-and-homu)

src/tools/clippy/clippy_lints/src/assertions_on_constants.rs

@@ -127,10 +127,9 @@ fn match_assert_with_message<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>)
             _ => &block.expr,
         };
         // function call
-        if let Some(args) = match_panic_call(cx, begin_panic_call);
-        if args.len() == 1;
+        if let Some(arg) = match_panic_call(cx, begin_panic_call);
         // bind the second argument of the `assert!` macro if it exists
-        if let panic_message = snippet_opt(cx, args[0].span);
+        if let panic_message = snippet_opt(cx, arg.span);
         // second argument of begin_panic is irrelevant
         // as is the second match arm
         then {

src/tools/clippy/clippy_lints/src/bool_assert_comparison.rs

@@ -0,0 +1,75 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::{ast_utils, is_direct_expn_of};
+use rustc_ast::ast::{Expr, ExprKind, Lit, LitKind};
+use rustc_errors::Applicability;
+use rustc_lint::{EarlyContext, EarlyLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// **What it does:** This lint warns about boolean comparisons in assert-like macros.
+    ///
+    /// **Why is this bad?** It is shorter to use the equivalent.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust
+    /// // Bad
+    /// assert_eq!("a".is_empty(), false);
+    /// assert_ne!("a".is_empty(), true);
+    ///
+    /// // Good
+    /// assert!(!"a".is_empty());
+    /// ```
+    pub BOOL_ASSERT_COMPARISON,
+    style,
+    "Using a boolean as comparison value in an assert_* macro when there is no need"
+}
+
+declare_lint_pass!(BoolAssertComparison => [BOOL_ASSERT_COMPARISON]);
+
+fn is_bool_lit(e: &Expr) -> bool {
+    matches!(
+        e.kind,
+        ExprKind::Lit(Lit {
+            kind: LitKind::Bool(_),
+            ..
+        })
+    ) && !e.span.from_expansion()
+}
+
+impl EarlyLintPass for BoolAssertComparison {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, e: &Expr) {
+        let macros = ["assert_eq", "debug_assert_eq"];
+        let inverted_macros = ["assert_ne", "debug_assert_ne"];
+
+        for mac in macros.iter().chain(inverted_macros.iter()) {
+            if let Some(span) = is_direct_expn_of(e.span, mac) {
+                if let Some([a, b]) = ast_utils::extract_assert_macro_args(e) {
+                    let nb_bool_args = is_bool_lit(a) as usize + is_bool_lit(b) as usize;
+
+                    if nb_bool_args != 1 {
+                        // If there are two boolean arguments, we definitely don't understand
+                        // what's going on, so better leave things as is...
+                        //
+                        // Or there is simply no boolean and then we can leave things as is!
+                        return;
+                    }
+
+                    let non_eq_mac = &mac[..mac.len() - 3];
+                    span_lint_and_sugg(
+                        cx,
+                        BOOL_ASSERT_COMPARISON,
+                        span,
+                        &format!("used `{}!` with a literal bool", mac),
+                        "replace it with",
+                        format!("{}!(..)", non_eq_mac),
+                        Applicability::MaybeIncorrect,
+                    );
+                    return;
+                }
+            }
+        }
+    }
+}

src/tools/clippy/clippy_lints/src/booleans.rs

@@ -261,7 +261,7 @@ fn simplify_not(cx: &LateContext<'_>, expr: &Expr<'_>) -> Option<String> {
             }
             METHODS_WITH_NEGATION
                 .iter()
-                .cloned()
+                .copied()
                 .flat_map(|(a, b)| vec![(a, b), (b, a)])
                 .find(|&(a, _)| {
                     let path: &str = &path.ident.name.as_str();