Update Clippy

src/tools/clippy/.gitignore

@@ -27,9 +27,11 @@ out
 # Generated by dogfood
 /target_recur/
 
+# Generated by lintcheck
+/lintcheck-logs
+
 # gh pages docs
 util/gh-pages/lints.json
-**/metadata_collection.json
 
 # rustfmt backups
 *.rs.bk

src/tools/clippy/CHANGELOG.md

@@ -3118,6 +3118,7 @@ Released 2018-09-13
 [`result_map_or_into_option`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_map_or_into_option
 [`result_map_unit_fn`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_map_unit_fn
 [`result_unit_err`]: https://rust-lang.github.io/rust-clippy/master/index.html#result_unit_err
+[`return_self_not_must_use`]: https://rust-lang.github.io/rust-clippy/master/index.html#return_self_not_must_use
 [`reversed_empty_ranges`]: https://rust-lang.github.io/rust-clippy/master/index.html#reversed_empty_ranges
 [`same_functions_in_if_condition`]: https://rust-lang.github.io/rust-clippy/master/index.html#same_functions_in_if_condition
 [`same_item_push`]: https://rust-lang.github.io/rust-clippy/master/index.html#same_item_push
@@ -3209,6 +3210,7 @@ Released 2018-09-13
 [`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_to_owned`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_to_owned
 [`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
 [`unneeded_field_pattern`]: https://rust-lang.github.io/rust-clippy/master/index.html#unneeded_field_pattern

src/tools/clippy/README.md

@@ -162,7 +162,8 @@ define the `CLIPPY_DISABLE_DOCS_LINKS` environment variable.
 
 You can add options to your code to `allow`/`warn`/`deny` Clippy lints:
 
-*   the whole set of `Warn` lints using the `clippy` lint group (`#![deny(clippy::all)]`)
+*   the whole set of `Warn` lints using the `clippy` lint group (`#![deny(clippy::all)]`).
+    Note that `rustc` has additional [lint groups](https://doc.rust-lang.org/rustc/lints/groups.html).
 
 *   all lints using both the `clippy` and `clippy::pedantic` lint groups (`#![deny(clippy::all)]`,
     `#![deny(clippy::pedantic)]`). Note that `clippy::pedantic` contains some very aggressive

src/tools/clippy/clippy_lints/src/asm_syntax.rs

@@ -65,13 +65,15 @@ declare_clippy_lint! {
     /// ```rust,no_run
     /// # #![feature(asm)]
     /// # unsafe { let ptr = "".as_ptr();
+    /// # use std::arch::asm;
     /// asm!("lea {}, [{}]", lateout(reg) _, in(reg) ptr);
     /// # }
     /// ```
     /// Use instead:
     /// ```rust,no_run
     /// # #![feature(asm)]
     /// # unsafe { let ptr = "".as_ptr();
+    /// # use std::arch::asm;
     /// asm!("lea ({}), {}", in(reg) ptr, lateout(reg) _, options(att_syntax));
     /// # }
     /// ```
@@ -102,13 +104,15 @@ declare_clippy_lint! {
     /// ```rust,no_run
     /// # #![feature(asm)]
     /// # unsafe { let ptr = "".as_ptr();
+    /// # use std::arch::asm;
     /// asm!("lea ({}), {}", in(reg) ptr, lateout(reg) _, options(att_syntax));
     /// # }
     /// ```
     /// Use instead:
     /// ```rust,no_run
     /// # #![feature(asm)]
     /// # unsafe { let ptr = "".as_ptr();
+    /// # use std::arch::asm;
     /// asm!("lea {}, [{}]", lateout(reg) _, in(reg) ptr);
     /// # }
     /// ```

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

@@ -2,7 +2,7 @@ use clippy_utils::consts::{constant, Constant};
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::higher;
 use clippy_utils::source::snippet_opt;
-use clippy_utils::{is_direct_expn_of, is_expn_of, match_panic_call};
+use clippy_utils::{is_direct_expn_of, is_expn_of, match_panic_call, peel_blocks};
 use if_chain::if_chain;
 use rustc_hir::{Expr, ExprKind, UnOp};
 use rustc_lint::{LateContext, LateLintPass};
@@ -122,15 +122,7 @@ fn match_assert_with_message<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>)
         if let ExprKind::Unary(UnOp::Not, expr) = cond.kind;
         // bind the first argument of the `assert!` macro
         if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.typeck_results(), expr);
-        // block
-        if let ExprKind::Block(block, _) = then.kind;
-        if block.stmts.is_empty();
-        if let Some(block_expr) = &block.expr;
-        // inner block is optional. unwrap it if it exists, or use the expression as is otherwise.
-        if let Some(begin_panic_call) = match block_expr.kind {
-            ExprKind::Block(inner_block, _) => &inner_block.expr,
-            _ => &block.expr,
-        };
+        let begin_panic_call = peel_blocks(then);
         // function call
         if let Some(arg) = match_panic_call(cx, begin_panic_call);
         // bind the second argument of the `assert!` macro if it exists

src/tools/clippy/clippy_lints/src/blocks_in_if_conditions.rs

@@ -73,9 +73,11 @@ impl<'a, 'tcx> Visitor<'tcx> for ExVisitor<'a, 'tcx> {
 
             let body = self.cx.tcx.hir().body(eid);
             let ex = &body.value;
-            if matches!(ex.kind, ExprKind::Block(_, _)) && !body.value.span.from_expansion() {
-                self.found_block = Some(ex);
-                return;
+            if let ExprKind::Block(block, _) = ex.kind {
+                if !body.value.span.from_expansion() && !block.stmts.is_empty() {
+                    self.found_block = Some(ex);
+                    return;
+                }
             }
         }
         walk_expr(self, expr);

src/tools/clippy/clippy_lints/src/bytecount.rs

@@ -2,7 +2,7 @@ use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::source::snippet_with_applicability;
 use clippy_utils::ty::match_type;
 use clippy_utils::visitors::is_local_used;
-use clippy_utils::{path_to_local_id, paths, peel_ref_operators, remove_blocks, strip_pat_refs};
+use clippy_utils::{path_to_local_id, paths, peel_blocks, peel_ref_operators, strip_pat_refs};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, PatKind};
@@ -42,7 +42,7 @@ impl<'tcx> LateLintPass<'tcx> for ByteCount {
     fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
         if_chain! {
             if let ExprKind::MethodCall(count, _, [count_recv], _) = expr.kind;
-            if count.ident.name == sym!(count);
+            if count.ident.name == sym::count;
             if let ExprKind::MethodCall(filter, _, [filter_recv, filter_arg], _) = count_recv.kind;
             if filter.ident.name == sym!(filter);
             if let ExprKind::Closure(_, _, body_id, _, _) = filter_arg.kind;
@@ -55,7 +55,7 @@ impl<'tcx> LateLintPass<'tcx> for ByteCount {
                        cx.typeck_results().expr_ty(filter_recv).peel_refs(),
                        &paths::SLICE_ITER);
             let operand_is_arg = |expr| {
-                let expr = peel_ref_operators(cx, remove_blocks(expr));
+                let expr = peel_ref_operators(cx, peel_blocks(expr));
                 path_to_local_id(expr, arg_id)
             };
             let needle = if operand_is_arg(l) {

src/tools/clippy/clippy_lints/src/collapsible_match.rs

@@ -1,10 +1,10 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::higher::IfLetOrMatch;
 use clippy_utils::visitors::is_local_used;
-use clippy_utils::{is_lang_ctor, is_unit_expr, path_to_local, peel_ref_operators, SpanlessEq};
+use clippy_utils::{is_lang_ctor, is_unit_expr, path_to_local, peel_blocks_with_stmt, peel_ref_operators, SpanlessEq};
 use if_chain::if_chain;
 use rustc_hir::LangItem::OptionNone;
-use rustc_hir::{Arm, Expr, ExprKind, Guard, HirId, Pat, PatKind, StmtKind};
+use rustc_hir::{Arm, Expr, Guard, HirId, Pat, PatKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::{MultiSpan, Span};
@@ -75,7 +75,7 @@ fn check_arm<'tcx>(
     outer_guard: Option<&'tcx Guard<'tcx>>,
     outer_else_body: Option<&'tcx Expr<'tcx>>,
 ) {
-    let inner_expr = strip_singleton_blocks(outer_then_body);
+    let inner_expr = peel_blocks_with_stmt(outer_then_body);
     if_chain! {
         if let Some(inner) = IfLetOrMatch::parse(cx, inner_expr);
         if let Some((inner_scrutinee, inner_then_pat, inner_else_body)) = match inner {
@@ -138,20 +138,6 @@ fn check_arm<'tcx>(
     }
 }
 
-fn strip_singleton_blocks<'hir>(mut expr: &'hir Expr<'hir>) -> &'hir Expr<'hir> {
-    while let ExprKind::Block(block, _) = expr.kind {
-        match (block.stmts, block.expr) {
-            ([stmt], None) => match stmt.kind {
-                StmtKind::Expr(e) | StmtKind::Semi(e) => expr = e,
-                _ => break,
-            },
-            ([], Some(e)) => expr = e,
-            _ => break,
-        }
-    }
-    expr
-}
-
 /// A "wild-like" arm has a wild (`_`) or `None` pattern and no guard. Such arms can be "collapsed"
 /// into a single wild arm without any significant loss in semantics or readability.
 fn arm_is_wild_like(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {

src/tools/clippy/clippy_lints/src/derivable_impls.rs

@@ -1,5 +1,5 @@
 use clippy_utils::diagnostics::span_lint_and_help;
-use clippy_utils::{is_automatically_derived, is_default_equivalent, remove_blocks};
+use clippy_utils::{is_automatically_derived, is_default_equivalent, peel_blocks};
 use rustc_hir::{
     def::{DefKind, Res},
     Body, Expr, ExprKind, GenericArg, Impl, ImplItemKind, Item, ItemKind, Node, PathSegment, QPath, TyKind,
@@ -95,7 +95,7 @@ impl<'tcx> LateLintPass<'tcx> for DerivableImpls {
                         }
                     }
                 }
-                let should_emit = match remove_blocks(func_expr).kind {
+                let should_emit = match peel_blocks(func_expr).kind {
                     ExprKind::Tup(fields) => fields.iter().all(|e| is_default_equivalent(cx, e)),
                     ExprKind::Call(callee, args)
                         if is_path_self(callee) => args.iter().all(|e| is_default_equivalent(cx, e)),

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

@@ -4,7 +4,7 @@ use clippy_utils::consts::{
 };
 use clippy_utils::diagnostics::span_lint_and_sugg;
 use clippy_utils::higher;
-use clippy_utils::{eq_expr_value, get_parent_expr, in_constant, numeric_literal, sugg};
+use clippy_utils::{eq_expr_value, get_parent_expr, in_constant, numeric_literal, peel_blocks, sugg};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::{BinOpKind, Expr, ExprKind, PathSegment, UnOp};
@@ -546,13 +546,9 @@ fn are_negated<'a>(cx: &LateContext<'_>, expr1: &'a Expr<'a>, expr2: &'a Expr<'a
 
 fn check_custom_abs(cx: &LateContext<'_>, expr: &Expr<'_>) {
     if_chain! {
-        if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr);
-        if let ExprKind::Block(block, _) = then.kind;
-        if block.stmts.is_empty();
-        if let Some(if_body_expr) = block.expr;
-        if let Some(ExprKind::Block(else_block, _)) = r#else.map(|el| &el.kind);
-        if else_block.stmts.is_empty();
-        if let Some(else_body_expr) = else_block.expr;
+        if let Some(higher::If { cond, then, r#else: Some(r#else) }) = higher::If::hir(expr);
+        let if_body_expr = peel_blocks(then);
+        let else_body_expr = peel_blocks(r#else);
         if let Some((if_expr_positive, body)) = are_negated(cx, if_body_expr, else_body_expr);
         then {
             let positive_abs_sugg = (

src/tools/clippy/clippy_lints/src/if_then_some_else_none.rs

@@ -1,6 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_help;
 use clippy_utils::source::snippet_with_macro_callsite;
-use clippy_utils::{contains_return, higher, is_else_clause, is_lang_ctor, meets_msrv, msrvs};
+use clippy_utils::{contains_return, higher, is_else_clause, is_lang_ctor, meets_msrv, msrvs, peel_blocks};
 use if_chain::if_chain;
 use rustc_hir::LangItem::{OptionNone, OptionSome};
 use rustc_hir::{Expr, ExprKind, Stmt, StmtKind};
@@ -77,10 +77,7 @@ impl LateLintPass<'_> for IfThenSomeElseNone {
             if let ExprKind::Call(then_call, [then_arg]) = then_expr.kind;
             if let ExprKind::Path(ref then_call_qpath) = then_call.kind;
             if is_lang_ctor(cx, then_call_qpath, OptionSome);
-            if let ExprKind::Block(els_block, _) = els.kind;
-            if els_block.stmts.is_empty();
-            if let Some(els_expr) = els_block.expr;
-            if let ExprKind::Path(ref qpath) = els_expr.kind;
+            if let ExprKind::Path(ref qpath) = peel_blocks(els).kind;
             if is_lang_ctor(cx, qpath, OptionNone);
             if !stmts_contains_early_return(then_block.stmts);
             then {

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

@@ -1,10 +1,9 @@
 use clippy_utils::diagnostics::span_lint_and_sugg;
-use clippy_utils::higher;
-use clippy_utils::SpanlessEq;
+use clippy_utils::{higher, peel_blocks_with_stmt, SpanlessEq};
 use if_chain::if_chain;
 use rustc_ast::ast::LitKind;
 use rustc_errors::Applicability;
-use rustc_hir::{lang_items::LangItem, BinOpKind, Expr, ExprKind, QPath, StmtKind};
+use rustc_hir::{lang_items::LangItem, BinOpKind, Expr, ExprKind, QPath};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
@@ -52,13 +51,8 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitSaturatingSub {
             // Ensure that the binary operator is >, != and <
             if BinOpKind::Ne == cond_op.node || BinOpKind::Gt == cond_op.node || BinOpKind::Lt == cond_op.node;
 
-            // Check if the true condition block has only one statement
-            if let ExprKind::Block(block, _) = then.kind;
-            if block.stmts.len() == 1 && block.expr.is_none();
-
             // Check if assign operation is done
-            if let StmtKind::Semi(e) = block.stmts[0].kind;
-            if let Some(target) = subtracts_one(cx, e);
+            if let Some(target) = subtracts_one(cx, then);
 
             // Extracting out the variable name
             if let ExprKind::Path(QPath::Resolved(_, ares_path)) = target.kind;
@@ -138,8 +132,8 @@ impl<'tcx> LateLintPass<'tcx> for ImplicitSaturatingSub {
     }
 }
 
-fn subtracts_one<'a>(cx: &LateContext<'_>, expr: &Expr<'a>) -> Option<&'a Expr<'a>> {
-    match expr.kind {
+fn subtracts_one<'a>(cx: &LateContext<'_>, expr: &'a Expr<'a>) -> Option<&'a Expr<'a>> {
+    match peel_blocks_with_stmt(expr).kind {
         ExprKind::AssignOp(ref op1, target, value) => {
             if_chain! {
                 if BinOpKind::Sub == op1.node;

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

@@ -181,6 +181,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(methods::UNNECESSARY_FILTER_MAP),
     LintId::of(methods::UNNECESSARY_FOLD),
     LintId::of(methods::UNNECESSARY_LAZY_EVALUATIONS),
+    LintId::of(methods::UNNECESSARY_TO_OWNED),
     LintId::of(methods::UNWRAP_OR_ELSE_DEFAULT),
     LintId::of(methods::USELESS_ASREF),
     LintId::of(methods::WRONG_SELF_CONVENTION),
@@ -220,7 +221,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(non_copy_const::DECLARE_INTERIOR_MUTABLE_CONST),
     LintId::of(non_expressive_names::JUST_UNDERSCORES_AND_DIGITS),
     LintId::of(non_octal_unix_permissions::NON_OCTAL_UNIX_PERMISSIONS),
-    LintId::of(non_send_fields_in_send_ty::NON_SEND_FIELDS_IN_SEND_TY),
     LintId::of(octal_escapes::OCTAL_ESCAPES),
     LintId::of(open_options::NONSENSICAL_OPEN_OPTIONS),
     LintId::of(option_env_unwrap::OPTION_ENV_UNWRAP),
@@ -246,6 +246,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(reference::REF_IN_DEREF),
     LintId::of(regex::INVALID_REGEX),
     LintId::of(repeat_once::REPEAT_ONCE),
+    LintId::of(return_self_not_must_use::RETURN_SELF_NOT_MUST_USE),
     LintId::of(returns::LET_AND_RETURN),
     LintId::of(returns::NEEDLESS_RETURN),
     LintId::of(self_assignment::SELF_ASSIGNMENT),

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

@@ -315,6 +315,7 @@ store.register_lints(&[
     methods::UNNECESSARY_FILTER_MAP,
     methods::UNNECESSARY_FOLD,
     methods::UNNECESSARY_LAZY_EVALUATIONS,
+    methods::UNNECESSARY_TO_OWNED,
     methods::UNWRAP_OR_ELSE_DEFAULT,
     methods::UNWRAP_USED,
     methods::USELESS_ASREF,
@@ -422,6 +423,7 @@ store.register_lints(&[
     regex::INVALID_REGEX,
     regex::TRIVIAL_REGEX,
     repeat_once::REPEAT_ONCE,
+    return_self_not_must_use::RETURN_SELF_NOT_MUST_USE,
     returns::LET_AND_RETURN,
     returns::NEEDLESS_RETURN,
     same_name_method::SAME_NAME_METHOD,

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

@@ -18,6 +18,7 @@ store.register_group(true, "clippy::nursery", Some("clippy_nursery"), vec![
     LintId::of(missing_const_for_fn::MISSING_CONST_FOR_FN),
     LintId::of(mutable_debug_assertion::DEBUG_ASSERT_WITH_MUT_CALL),
     LintId::of(mutex_atomic::MUTEX_INTEGER),
+    LintId::of(non_send_fields_in_send_ty::NON_SEND_FIELDS_IN_SEND_TY),
     LintId::of(nonstandard_macro_braces::NONSTANDARD_MACRO_BRACES),
     LintId::of(option_if_let_else::OPTION_IF_LET_ELSE),
     LintId::of(path_buf_push_overwrite::PATH_BUF_PUSH_OVERWRITE),

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

@@ -17,6 +17,7 @@ store.register_group(true, "clippy::perf", Some("clippy_perf"), vec![
     LintId::of(methods::MANUAL_STR_REPEAT),
     LintId::of(methods::OR_FUN_CALL),
     LintId::of(methods::SINGLE_CHAR_PATTERN),
+    LintId::of(methods::UNNECESSARY_TO_OWNED),
     LintId::of(misc::CMP_OWNED),
     LintId::of(mutex_atomic::MUTEX_ATOMIC),
     LintId::of(redundant_clone::REDUNDANT_CLONE),

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

@@ -15,8 +15,8 @@ store.register_group(true, "clippy::suspicious", Some("clippy_suspicious"), vec!
     LintId::of(loops::MUT_RANGE_BOUND),
     LintId::of(methods::SUSPICIOUS_MAP),
     LintId::of(mut_key::MUTABLE_KEY_TYPE),
-    LintId::of(non_send_fields_in_send_ty::NON_SEND_FIELDS_IN_SEND_TY),
     LintId::of(octal_escapes::OCTAL_ESCAPES),
+    LintId::of(return_self_not_must_use::RETURN_SELF_NOT_MUST_USE),
     LintId::of(suspicious_trait_impl::SUSPICIOUS_ARITHMETIC_IMPL),
     LintId::of(suspicious_trait_impl::SUSPICIOUS_OP_ASSIGN_IMPL),
 ])

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

@@ -340,6 +340,7 @@ mod ref_option_ref;
 mod reference;
 mod regex;
 mod repeat_once;
+mod return_self_not_must_use;
 mod returns;
 mod same_name_method;
 mod self_assignment;
@@ -852,6 +853,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_late_pass(|| Box::new(trailing_empty_array::TrailingEmptyArray));
     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));
     // add lints here, do not remove this comment, it's used in `new_lint`
 }
 

src/tools/clippy/clippy_lints/src/lifetimes.rs

@@ -29,7 +29,7 @@ declare_clippy_lint! {
     ///
     /// ### Known problems
     /// - We bail out if the function has a `where` clause where lifetimes
-    /// are mentioned due to potenial false positives.
+    /// are mentioned due to potential false positives.
     /// - Lifetime bounds such as `impl Foo + 'a` and `T: 'a` must be elided with the
     /// placeholder notation `'_` because the fully elided notation leaves the type bound to `'static`.
     ///