Rollup merge of #81038 - flip1995:clippyup, r=Manishearth

Update Clippy

Biweekly Clippy update

r? ``@Manishearth``

Author: KodrAus

src/tools/clippy/CHANGELOG.md

@@ -6,11 +6,138 @@ document.
 
 ## Unreleased / In Rust Nightly
 
-[b20d4c1...master](https://github.com/rust-lang/rust-clippy/compare/b20d4c1...master)
+[4911ab1...master](https://github.com/rust-lang/rust-clippy/compare/4911ab1...master)
+
+## Rust 1.50
+
+Current beta, release 2021-02-11
+
+[b20d4c1...4911ab1](https://github.com/rust-lang/rust-clippy/compare/b20d4c1...4911ab1)
+
+### New Lints
+
+* [`suspicious_operation_groupings`] [#6086](https://github.com/rust-lang/rust-clippy/pull/6086)
+* [`size_of_in_element_count`] [#6394](https://github.com/rust-lang/rust-clippy/pull/6394)
+* [`unnecessary_wraps`] [#6070](https://github.com/rust-lang/rust-clippy/pull/6070)
+* [`let_underscore_drop`] [#6305](https://github.com/rust-lang/rust-clippy/pull/6305)
+* [`collapsible_match`] [#6402](https://github.com/rust-lang/rust-clippy/pull/6402)
+* [`redundant_else`] [#6330](https://github.com/rust-lang/rust-clippy/pull/6330)
+* [`zero_sized_map_values`] [#6218](https://github.com/rust-lang/rust-clippy/pull/6218)
+* [`print_stderr`] [#6367](https://github.com/rust-lang/rust-clippy/pull/6367)
+* [`string_from_utf8_as_bytes`] [#6134](https://github.com/rust-lang/rust-clippy/pull/6134)
+
+### Moves and Deprecations
+
+* 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`
+  [#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)
+* Move [`await_holding_refcell_ref`] to `pedantic`
+  [#6354](https://github.com/rust-lang/rust-clippy/pull/6354)
+* Move [`await_holding_lock`] to `pedantic`
+  [#6354](https://github.com/rust-lang/rust-clippy/pull/6354)
+
+### Enhancements
+
+* Add the `unreadable-literal-lint-fractions` configuration to disable
+  the `unreadable_literal` lint for fractions
+  [#6421](https://github.com/rust-lang/rust-clippy/pull/6421)
+* [`clone_on_copy`]: Now shows the type in the lint message
+  [#6443](https://github.com/rust-lang/rust-clippy/pull/6443)
+* [`redundant_pattern_matching`]: Now also lints on `std::task::Poll`
+  [#6339](https://github.com/rust-lang/rust-clippy/pull/6339)
+* [`redundant_pattern_matching`]: Additionally also lints on `std::net::IpAddr`
+  [#6377](https://github.com/rust-lang/rust-clippy/pull/6377)
+* [`search_is_some`]: Now suggests `contains` instead of `find(foo).is_some()`
+  [#6119](https://github.com/rust-lang/rust-clippy/pull/6119)
+* [`clone_double_ref`]: Now prints the reference type in the lint message
+  [#6442](https://github.com/rust-lang/rust-clippy/pull/6442)
+* [`modulo_one`]: Now also lints on -1.
+  [#6360](https://github.com/rust-lang/rust-clippy/pull/6360)
+* [`empty_loop`]: Now lints no_std crates, too
+  [#6205](https://github.com/rust-lang/rust-clippy/pull/6205)
+* [`or_fun_call`]: Now also lints when indexing `HashMap` or `BTreeMap`
+  [#6267](https://github.com/rust-lang/rust-clippy/pull/6267)
+* [`wrong_self_convention`]: Now also lints in trait definitions
+  [#6316](https://github.com/rust-lang/rust-clippy/pull/6316)
+* [`needless_borrow`]: Print the type in the lint message
+  [#6449](https://github.com/rust-lang/rust-clippy/pull/6449)
+
+[msrv_readme]: https://github.com/rust-lang/rust-clippy#specifying-the-minimum-supported-rust-version
+
+### False Positive Fixes
+
+* [`manual_range_contains`]: No longer lints in `const fn`
+  [#6382](https://github.com/rust-lang/rust-clippy/pull/6382)
+* [`unnecessary_lazy_evaluations`]: No longer lints if closure argument is used
+  [#6370](https://github.com/rust-lang/rust-clippy/pull/6370)
+* [`match_single_binding`]: Now ignores cases with `#[cfg()]` macros
+  [#6435](https://github.com/rust-lang/rust-clippy/pull/6435)
+* [`match_like_matches_macro`]: No longer lints on arms with attributes
+  [#6290](https://github.com/rust-lang/rust-clippy/pull/6290)
+* [`map_clone`]: No longer lints with deref and clone
+  [#6269](https://github.com/rust-lang/rust-clippy/pull/6269)
+* [`map_clone`]: No longer lints in the case of &mut
+  [#6301](https://github.com/rust-lang/rust-clippy/pull/6301)
+* [`needless_update`]: Now ignores `non_exhaustive` structs
+  [#6464](https://github.com/rust-lang/rust-clippy/pull/6464)
+* [`needless_collect`]: No longer lints when a collect is needed multiple times
+  [#6313](https://github.com/rust-lang/rust-clippy/pull/6313)
+* [`unnecessary_cast`] No longer lints cfg-dependent types
+  [#6369](https://github.com/rust-lang/rust-clippy/pull/6369)
+* [`declare_interior_mutable_const`] and [`borrow_interior_mutable_const`]:
+  Both now ignore enums with frozen variants
+  [#6110](https://github.com/rust-lang/rust-clippy/pull/6110)
+
+
+### Suggestion Fixes/Improvements
+
+* [`vec_box`]: Provide correct type scope suggestion
+  [#6271](https://github.com/rust-lang/rust-clippy/pull/6271)
+* [`manual_range_contains`]: Give correct suggestion when using floats
+  [#6320](https://github.com/rust-lang/rust-clippy/pull/6320)
+* [`unnecessary_lazy_evaluations`]: Don't always mark suggestion as MachineApplicable
+  [#6272](https://github.com/rust-lang/rust-clippy/pull/6272)
+* [`manual_async_fn`]: Improve suggestion formatting
+  [#6294](https://github.com/rust-lang/rust-clippy/pull/6294)
+* [`unnecessary_cast`]: Fix incorrectly formatted float literal suggestion
+  [#6362](https://github.com/rust-lang/rust-clippy/pull/6362)
+
+### ICE Fixes
+
+* Fix a crash in [`from_iter_instead_of_collect`]
+  [#6304](https://github.com/rust-lang/rust-clippy/pull/6304)
+* Fix a silent crash when parsing doc comments in [`needless_doctest_main`]
+  [#6458](https://github.com/rust-lang/rust-clippy/pull/6458)
+
+### Documentation Improvements
+
+* The lint website search has been improved ([#6477](https://github.com/rust-lang/rust-clippy/pull/6477)):
+  * Searching for lints with dashes and spaces is possible now. For example
+    `missing-errors-doc` and `missing errors doc` are now valid aliases for lint names
+  * Improved fuzzy search in lint descriptions
+* Various README improvements
+  [#6287](https://github.com/rust-lang/rust-clippy/pull/6287)
+* Add known problems to [`comparison_chain`] documentation
+  [#6390](https://github.com/rust-lang/rust-clippy/pull/6390)
+* Fix example used in [`cargo_common_metadata`]
+  [#6293](https://github.com/rust-lang/rust-clippy/pull/6293)
+* Improve [`map_clone`] documentation
+  [#6340](https://github.com/rust-lang/rust-clippy/pull/6340)
+
+### Others
+
+* You can now tell Clippy about the MSRV your project supports. Please refer to
+  the specific README section to learn more about MSRV support [here][msrv_readme]
+  [#6201](https://github.com/rust-lang/rust-clippy/pull/6201)
+* Add `--no-deps` option to avoid running on path dependencies in workspaces
+  [#6188](https://github.com/rust-lang/rust-clippy/pull/6188)
 
 ## Rust 1.49
 
-Current beta, release 2020-12-31
+Current stable, released 2020-12-31
 
 [e636b88...b20d4c1](https://github.com/rust-lang/rust-clippy/compare/e636b88...b20d4c1)
 
@@ -116,7 +243,7 @@ Current beta, release 2020-12-31
 
 ## Rust 1.48
 
-Current stable, released 2020-11-19
+Released 2020-11-19
 
 [09bd400...e636b88](https://github.com/rust-lang/rust-clippy/compare/09bd400...e636b88)
 
@@ -1769,6 +1896,7 @@ Released 2018-09-13
 [`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
 [`cognitive_complexity`]: https://rust-lang.github.io/rust-clippy/master/index.html#cognitive_complexity
+[`collapsible_else_if`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_else_if
 [`collapsible_if`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
 [`collapsible_match`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_match
 [`comparison_chain`]: https://rust-lang.github.io/rust-clippy/master/index.html#comparison_chain
@@ -1973,6 +2101,7 @@ Released 2018-09-13
 [`needless_doctest_main`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_doctest_main
 [`needless_lifetimes`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes
 [`needless_pass_by_value`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_value
+[`needless_question_mark`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_question_mark
 [`needless_range_loop`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_range_loop
 [`needless_return`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_return
 [`needless_update`]: https://rust-lang.github.io/rust-clippy/master/index.html#needless_update
@@ -2012,6 +2141,7 @@ Released 2018-09-13
 [`print_with_newline`]: https://rust-lang.github.io/rust-clippy/master/index.html#print_with_newline
 [`println_empty_string`]: https://rust-lang.github.io/rust-clippy/master/index.html#println_empty_string
 [`ptr_arg`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_arg
+[`ptr_as_ptr`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr
 [`ptr_eq`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_eq
 [`ptr_offset_with_cast`]: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_offset_with_cast
 [`pub_enum_variant_names`]: https://rust-lang.github.io/rust-clippy/master/index.html#pub_enum_variant_names
@@ -2152,6 +2282,7 @@ Released 2018-09-13
 [`useless_transmute`]: https://rust-lang.github.io/rust-clippy/master/index.html#useless_transmute
 [`useless_vec`]: https://rust-lang.github.io/rust-clippy/master/index.html#useless_vec
 [`vec_box`]: https://rust-lang.github.io/rust-clippy/master/index.html#vec_box
+[`vec_init_then_push`]: https://rust-lang.github.io/rust-clippy/master/index.html#vec_init_then_push
 [`vec_resize_to_zero`]: https://rust-lang.github.io/rust-clippy/master/index.html#vec_resize_to_zero
 [`verbose_bit_mask`]: https://rust-lang.github.io/rust-clippy/master/index.html#verbose_bit_mask
 [`verbose_file_reads`]: https://rust-lang.github.io/rust-clippy/master/index.html#verbose_file_reads

src/tools/clippy/clippy_dev/src/bless.rs

@@ -5,7 +5,7 @@ use std::env;
 use std::ffi::OsStr;
 use std::fs;
 use std::lazy::SyncLazy;
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 use walkdir::WalkDir;
 
 use crate::clippy_project_root;
@@ -16,27 +16,41 @@ pub static CARGO_TARGET_DIR: SyncLazy<PathBuf> = SyncLazy::new(|| match env::var
     None => env::current_dir().unwrap().join("target"),
 });
 
-pub fn bless() {
-    let test_dirs = [
+static CLIPPY_BUILD_TIME: SyncLazy<Option<std::time::SystemTime>> = SyncLazy::new(|| {
+    let profile = env::var("PROFILE").unwrap_or_else(|_| "debug".to_string());
+    let mut path = PathBuf::from(&**CARGO_TARGET_DIR);
+    path.push(profile);
+    path.push("cargo-clippy");
+    fs::metadata(path).ok()?.modified().ok()
+});
+
+pub fn bless(ignore_timestamp: bool) {
+    let test_suite_dirs = [
         clippy_project_root().join("tests").join("ui"),
+        clippy_project_root().join("tests").join("ui-internal"),
         clippy_project_root().join("tests").join("ui-toml"),
         clippy_project_root().join("tests").join("ui-cargo"),
     ];
-    for test_dir in &test_dirs {
-        WalkDir::new(test_dir)
+    for test_suite_dir in &test_suite_dirs {
+        WalkDir::new(test_suite_dir)
             .into_iter()
             .filter_map(Result::ok)
             .filter(|f| f.path().extension() == Some(OsStr::new("rs")))
             .for_each(|f| {
-                update_reference_file(f.path().with_extension("stdout"));
-                update_reference_file(f.path().with_extension("stderr"));
-                update_reference_file(f.path().with_extension("fixed"));
+                let test_name = f.path().strip_prefix(test_suite_dir).unwrap();
+                for &ext in &["stdout", "stderr", "fixed"] {
+                    update_reference_file(
+                        f.path().with_extension(ext),
+                        test_name.with_extension(ext),
+                        ignore_timestamp,
+                    );
+                }
             });
     }
 }
 
-fn update_reference_file(reference_file_path: PathBuf) {
-    let test_output_path = build_dir().join(PathBuf::from(reference_file_path.file_name().unwrap()));
+fn update_reference_file(reference_file_path: PathBuf, test_name: PathBuf, ignore_timestamp: bool) {
+    let test_output_path = build_dir().join(test_name);
     let relative_reference_file_path = reference_file_path.strip_prefix(clippy_project_root()).unwrap();
 
     // If compiletest did not write any changes during the test run,
@@ -45,6 +59,11 @@ fn update_reference_file(reference_file_path: PathBuf) {
         return;
     }
 
+    // If the test output was not updated since the last clippy build, it may be outdated
+    if !ignore_timestamp && !updated_since_clippy_build(&test_output_path).unwrap_or(true) {
+        return;
+    }
+
     let test_output_file = fs::read(&test_output_path).expect("Unable to read test output file");
     let reference_file = fs::read(&reference_file_path).unwrap_or_default();
 
@@ -64,6 +83,12 @@ fn update_reference_file(reference_file_path: PathBuf) {
     }
 }
 
+fn updated_since_clippy_build(path: &Path) -> Option<bool> {
+    let clippy_build_time = (*CLIPPY_BUILD_TIME)?;
+    let modified = fs::metadata(path).ok()?.modified().ok()?;
+    Some(modified >= clippy_build_time)
+}
+
 fn build_dir() -> PathBuf {
     let profile = env::var("PROFILE").unwrap_or_else(|_| "debug".to_string());
     let mut path = PathBuf::new();

src/tools/clippy/clippy_dev/src/main.rs

@@ -7,8 +7,8 @@ fn main() {
     let matches = get_clap_config();
 
     match matches.subcommand() {
-        ("bless", Some(_)) => {
-            bless::bless();
+        ("bless", Some(matches)) => {
+            bless::bless(matches.is_present("ignore-timestamp"));
         },
         ("fmt", Some(matches)) => {
             fmt::run(matches.is_present("check"), matches.is_present("verbose"));
@@ -47,7 +47,15 @@ fn main() {
 
 fn get_clap_config<'a>() -> ArgMatches<'a> {
     App::new("Clippy developer tooling")
-        .subcommand(SubCommand::with_name("bless").about("bless the test output changes"))
+        .subcommand(
+            SubCommand::with_name("bless")
+                .about("bless the test output changes")
+                .arg(
+                    Arg::with_name("ignore-timestamp")
+                        .long("ignore-timestamp")
+                        .help("Include files updated before clippy was built"),
+                ),
+        )
         .subcommand(
             SubCommand::with_name("fmt")
                 .about("Run rustfmt on all projects and tests")

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

@@ -370,7 +370,7 @@ fn extract_clippy_lint(lint: &NestedMetaItem) -> Option<SymbolStr> {
         if let Some(meta_item) = lint.meta_item();
         if meta_item.path.segments.len() > 1;
         if let tool_name = meta_item.path.segments[0].ident;
-        if tool_name.as_str() == "clippy";
+        if tool_name.name == sym::clippy;
         let lint_name = meta_item.path.segments.last().unwrap().ident.name;
         then {
             return Some(lint_name.as_str());

src/tools/clippy/clippy_lints/src/collapsible_if.rs

@@ -23,9 +23,7 @@ use rustc_errors::Applicability;
 
 declare_clippy_lint! {
     /// **What it does:** Checks for nested `if` statements which can be collapsed
-    /// by `&&`-combining their conditions and for `else { if ... }` expressions
-    /// that
-    /// can be collapsed to `else if ...`.
+    /// by `&&`-combining their conditions.
     ///
     /// **Why is this bad?** Each `if`-statement adds one level of nesting, which
     /// makes code look more complex than it really is.
@@ -40,7 +38,31 @@ declare_clippy_lint! {
     ///     }
     /// }
     ///
-    /// // or
+    /// ```
+    ///
+    /// Should be written:
+    ///
+    /// ```rust.ignore
+    /// if x && y {
+    ///     …
+    /// }
+    /// ```
+    pub COLLAPSIBLE_IF,
+    style,
+    "nested `if`s that can be collapsed (e.g., `if x { if y { ... } }`"
+}
+
+declare_clippy_lint! {
+    /// **What it does:** Checks for collapsible `else { if ... }` expressions
+    /// that can be collapsed to `else if ...`.
+    ///
+    /// **Why is this bad?** Each `if`-statement adds one level of nesting, which
+    /// makes code look more complex than it really is.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust,ignore
     ///
     /// if x {
     ///     …
@@ -54,24 +76,18 @@ declare_clippy_lint! {
     /// Should be written:
     ///
     /// ```rust.ignore
-    /// if x && y {
-    ///     …
-    /// }
-    ///
-    /// // or
-    ///
     /// if x {
     ///     …
     /// } else if y {
     ///     …
     /// }
     /// ```
-    pub COLLAPSIBLE_IF,
+    pub COLLAPSIBLE_ELSE_IF,
     style,
-    "`if`s that can be collapsed (e.g., `if x { if y { ... } }` and `else { if x { ... } }`)"
+    "nested `else`-`if` expressions that can be collapsed (e.g., `else { if x { ... } }`)"
 }
 
-declare_lint_pass!(CollapsibleIf => [COLLAPSIBLE_IF]);
+declare_lint_pass!(CollapsibleIf => [COLLAPSIBLE_IF, COLLAPSIBLE_ELSE_IF]);
 
 impl EarlyLintPass for CollapsibleIf {
     fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) {
@@ -112,7 +128,7 @@ fn check_collapsible_maybe_if_let(cx: &EarlyContext<'_>, else_: &ast::Expr) {
             let mut applicability = Applicability::MachineApplicable;
             span_lint_and_sugg(
                 cx,
-                COLLAPSIBLE_IF,
+                COLLAPSIBLE_ELSE_IF,
                 block.span,
                 "this `else { if .. }` block can be collapsed",
                 "collapse nested if block",

src/tools/clippy/clippy_lints/src/comparison_chain.rs

@@ -13,7 +13,7 @@ declare_clippy_lint! {
     /// repetitive
     ///
     /// **Known problems:** The match statement may be slower due to the compiler
-    /// not inlining the call to cmp. See issue #5354
+    /// not inlining the call to cmp. See issue [#5354](https://github.com/rust-lang/rust-clippy/issues/5354)
     ///
     /// **Example:**
     /// ```rust,ignore