diff options
| -rw-r--r-- | clippy_lints/src/lib.register_all.rs | 2 | ||||
| -rw-r--r-- | clippy_lints/src/lib.register_lints.rs | 2 | ||||
| -rw-r--r-- | clippy_lints/src/lib.register_style.rs | 2 | ||||
| -rw-r--r-- | clippy_lints/src/lib.rs | 2 | ||||
| -rw-r--r-- | clippy_lints/src/methods/mod.rs | 41 | ||||
| -rw-r--r-- | clippy_lints/src/methods/mut_mutex_lock.rs | 30 | ||||
| -rw-r--r-- | clippy_lints/src/mut_mutex_lock.rs | 70 |
7 files changed, 74 insertions, 75 deletions
diff --git a/clippy_lints/src/lib.register_all.rs b/clippy_lints/src/lib.register_all.rs index c496fd289bb..1151cd42e59 100644 --- a/clippy_lints/src/lib.register_all.rs +++ b/clippy_lints/src/lib.register_all.rs @@ -182,6 +182,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![ LintId::of(methods::MAP_COLLECT_RESULT_UNIT), LintId::of(methods::MAP_FLATTEN), LintId::of(methods::MAP_IDENTITY), + LintId::of(methods::MUT_MUTEX_LOCK), LintId::of(methods::NEEDLESS_OPTION_AS_DEREF), LintId::of(methods::NEEDLESS_OPTION_TAKE), LintId::of(methods::NEEDLESS_SPLITN), @@ -226,7 +227,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![ LintId::of(misc_early::ZERO_PREFIXED_LITERAL), LintId::of(mixed_read_write_in_expression::DIVERGING_SUB_EXPRESSION), LintId::of(mut_key::MUTABLE_KEY_TYPE), - LintId::of(mut_mutex_lock::MUT_MUTEX_LOCK), LintId::of(mut_reference::UNNECESSARY_MUT_PASSED), LintId::of(needless_arbitrary_self_type::NEEDLESS_ARBITRARY_SELF_TYPE), LintId::of(needless_bool::BOOL_COMPARISON), diff --git a/clippy_lints/src/lib.register_lints.rs b/clippy_lints/src/lib.register_lints.rs index 67fb0d50931..2ae93b49737 100644 --- a/clippy_lints/src/lib.register_lints.rs +++ b/clippy_lints/src/lib.register_lints.rs @@ -329,6 +329,7 @@ store.register_lints(&[ methods::MAP_FLATTEN, methods::MAP_IDENTITY, methods::MAP_UNWRAP_OR, + methods::MUT_MUTEX_LOCK, methods::NAIVE_BYTECOUNT, methods::NEEDLESS_OPTION_AS_DEREF, methods::NEEDLESS_OPTION_TAKE, @@ -389,7 +390,6 @@ store.register_lints(&[ module_style::SELF_NAMED_MODULE_FILES, mut_key::MUTABLE_KEY_TYPE, mut_mut::MUT_MUT, - mut_mutex_lock::MUT_MUTEX_LOCK, mut_reference::UNNECESSARY_MUT_PASSED, mutable_debug_assertion::DEBUG_ASSERT_WITH_MUT_CALL, mutex_atomic::MUTEX_ATOMIC, diff --git a/clippy_lints/src/lib.register_style.rs b/clippy_lints/src/lib.register_style.rs index 52bf019c82e..d34aadd1d37 100644 --- a/clippy_lints/src/lib.register_style.rs +++ b/clippy_lints/src/lib.register_style.rs @@ -70,6 +70,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![ LintId::of(methods::MANUAL_SATURATING_ARITHMETIC), LintId::of(methods::MAP_CLONE), LintId::of(methods::MAP_COLLECT_RESULT_UNIT), + LintId::of(methods::MUT_MUTEX_LOCK), LintId::of(methods::NEW_RET_NO_SELF), LintId::of(methods::OBFUSCATED_IF_ELSE), LintId::of(methods::OK_EXPECT), @@ -89,7 +90,6 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![ LintId::of(misc_early::DUPLICATE_UNDERSCORE_ARGUMENT), LintId::of(misc_early::MIXED_CASE_HEX_LITERALS), LintId::of(misc_early::REDUNDANT_PATTERN), - LintId::of(mut_mutex_lock::MUT_MUTEX_LOCK), LintId::of(mut_reference::UNNECESSARY_MUT_PASSED), LintId::of(needless_late_init::NEEDLESS_LATE_INIT), LintId::of(needless_parens_on_range_literals::NEEDLESS_PARENS_ON_RANGE_LITERALS), diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index 179d630089f..9f6ea1266d5 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -291,7 +291,6 @@ mod mixed_read_write_in_expression; mod module_style; mod mut_key; mod mut_mut; -mod mut_mutex_lock; mod mut_reference; mod mutable_debug_assertion; mod mutex_atomic; @@ -815,7 +814,6 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: store.register_late_pass(|| Box::new(if_let_mutex::IfLetMutex)); store.register_late_pass(|| Box::new(if_not_else::IfNotElse)); store.register_late_pass(|| Box::new(equatable_if_let::PatternEquality)); - store.register_late_pass(|| Box::new(mut_mutex_lock::MutMutexLock)); store.register_late_pass(|| Box::new(manual_async_fn::ManualAsyncFn)); store.register_late_pass(|| Box::new(vec_resize_to_zero::VecResizeToZero)); store.register_late_pass(|| Box::new(panic_in_result_fn::PanicInResultFn)); diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index e327bdcf578..6ad32ae09d7 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -51,6 +51,7 @@ mod map_err_ignore; mod map_flatten; mod map_identity; mod map_unwrap_or; +mod mut_mutex_lock; mod needless_option_as_deref; mod needless_option_take; mod no_effect_replace; @@ -2642,6 +2643,42 @@ declare_clippy_lint! { "`map_err` should not ignore the original error" } +declare_clippy_lint! { + /// ### What it does + /// Checks for `&mut Mutex::lock` calls + /// + /// ### Why is this bad? + /// `Mutex::lock` is less efficient than + /// calling `Mutex::get_mut`. In addition you also have a statically + /// guarantee that the mutex isn't locked, instead of just a runtime + /// guarantee. + /// + /// ### Example + /// ```rust + /// use std::sync::{Arc, Mutex}; + /// + /// let mut value_rc = Arc::new(Mutex::new(42_u8)); + /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap(); + /// + /// let mut value = value_mutex.lock().unwrap(); + /// *value += 1; + /// ``` + /// Use instead: + /// ```rust + /// use std::sync::{Arc, Mutex}; + /// + /// let mut value_rc = Arc::new(Mutex::new(42_u8)); + /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap(); + /// + /// let value = value_mutex.get_mut().unwrap(); + /// *value += 1; + /// ``` + #[clippy::version = "1.49.0"] + pub MUT_MUTEX_LOCK, + style, + "`&mut Mutex::lock` does unnecessary locking" +} + pub struct Methods { avoid_breaking_exported_api: bool, msrv: Option<RustcVersion>, @@ -2753,6 +2790,7 @@ impl_lint_pass!(Methods => [ MANUAL_OK_OR, MAP_CLONE, MAP_ERR_IGNORE, + MUT_MUTEX_LOCK, ]); /// Extracts a method call name, args, and `Span` of the method name. @@ -3081,6 +3119,9 @@ impl Methods { } } }, + ("lock", []) => { + mut_mutex_lock::check(cx, expr, recv, span); + }, (name @ ("map" | "map_err"), [m_arg]) => { if name == "map" { map_clone::check(cx, expr, recv, m_arg, self.msrv); diff --git a/clippy_lints/src/methods/mut_mutex_lock.rs b/clippy_lints/src/methods/mut_mutex_lock.rs new file mode 100644 index 00000000000..bd8458a222e --- /dev/null +++ b/clippy_lints/src/methods/mut_mutex_lock.rs @@ -0,0 +1,30 @@ +use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::ty::is_type_diagnostic_item; +use if_chain::if_chain; +use rustc_errors::Applicability; +use rustc_hir::{Expr, Mutability}; +use rustc_lint::LateContext; +use rustc_middle::ty; +use rustc_span::{sym, Span}; + +use super::MUT_MUTEX_LOCK; + +pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, ex: &'tcx Expr<'tcx>, recv: &'tcx Expr<'tcx>, name_span: Span) { + if_chain! { + if let ty::Ref(_, _, Mutability::Mut) = cx.typeck_results().expr_ty(recv).kind(); + if let Some(method_id) = cx.typeck_results().type_dependent_def_id(ex.hir_id); + if let Some(impl_id) = cx.tcx.impl_of_method(method_id); + if is_type_diagnostic_item(cx, cx.tcx.type_of(impl_id), sym::Mutex); + then { + span_lint_and_sugg( + cx, + MUT_MUTEX_LOCK, + name_span, + "calling `&mut Mutex::lock` unnecessarily locks an exclusive (mutable) reference", + "change this to", + "get_mut".to_owned(), + Applicability::MaybeIncorrect, + ); + } + } +} diff --git a/clippy_lints/src/mut_mutex_lock.rs b/clippy_lints/src/mut_mutex_lock.rs deleted file mode 100644 index b7f981faa2d..00000000000 --- a/clippy_lints/src/mut_mutex_lock.rs +++ /dev/null @@ -1,70 +0,0 @@ -use clippy_utils::diagnostics::span_lint_and_sugg; -use clippy_utils::ty::is_type_diagnostic_item; -use if_chain::if_chain; -use rustc_errors::Applicability; -use rustc_hir::{Expr, ExprKind, Mutability}; -use rustc_lint::{LateContext, LateLintPass}; -use rustc_middle::ty; -use rustc_session::{declare_lint_pass, declare_tool_lint}; -use rustc_span::sym; - -declare_clippy_lint! { - /// ### What it does - /// Checks for `&mut Mutex::lock` calls - /// - /// ### Why is this bad? - /// `Mutex::lock` is less efficient than - /// calling `Mutex::get_mut`. In addition you also have a statically - /// guarantee that the mutex isn't locked, instead of just a runtime - /// guarantee. - /// - /// ### Example - /// ```rust - /// use std::sync::{Arc, Mutex}; - /// - /// let mut value_rc = Arc::new(Mutex::new(42_u8)); - /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap(); - /// - /// let mut value = value_mutex.lock().unwrap(); - /// *value += 1; - /// ``` - /// Use instead: - /// ```rust - /// use std::sync::{Arc, Mutex}; - /// - /// let mut value_rc = Arc::new(Mutex::new(42_u8)); - /// let value_mutex = Arc::get_mut(&mut value_rc).unwrap(); - /// - /// let value = value_mutex.get_mut().unwrap(); - /// *value += 1; - /// ``` - #[clippy::version = "1.49.0"] - pub MUT_MUTEX_LOCK, - style, - "`&mut Mutex::lock` does unnecessary locking" -} - -declare_lint_pass!(MutMutexLock => [MUT_MUTEX_LOCK]); - -impl<'tcx> LateLintPass<'tcx> for MutMutexLock { - fn check_expr(&mut self, cx: &LateContext<'tcx>, ex: &'tcx Expr<'tcx>) { - if_chain! { - if let ExprKind::MethodCall(path, [self_arg, ..], _) = &ex.kind; - if path.ident.name == sym!(lock); - let ty = cx.typeck_results().expr_ty(self_arg); - if let ty::Ref(_, inner_ty, Mutability::Mut) = ty.kind(); - if is_type_diagnostic_item(cx, *inner_ty, sym::Mutex); - then { - span_lint_and_sugg( - cx, - MUT_MUTEX_LOCK, - path.ident.span, - "calling `&mut Mutex::lock` unnecessarily locks an exclusive (mutable) reference", - "change this to", - "get_mut".to_owned(), - Applicability::MaybeIncorrect, - ); - } - } - } -} |