diff options
| -rw-r--r-- | CHANGELOG.md | 1 | ||||
| -rw-r--r-- | clippy_lints/src/lib.rs | 4 | ||||
| -rw-r--r-- | clippy_lints/src/undropped_manually_drops.rs | 49 | ||||
| -rw-r--r-- | src/lintlist/mod.rs | 7 | ||||
| -rw-r--r-- | tests/ui/undropped_manually_drops.rs | 18 |
5 files changed, 79 insertions, 0 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index d82f970b8bf..697e6166fdf 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -1979,6 +1979,7 @@ Released 2018-09-13 [`try_err`]: https://rust-lang.github.io/rust-clippy/master/index.html#try_err [`type_complexity`]: https://rust-lang.github.io/rust-clippy/master/index.html#type_complexity [`type_repetition_in_bounds`]: https://rust-lang.github.io/rust-clippy/master/index.html#type_repetition_in_bounds +[`undropped_manually_drops`]: https://rust-lang.github.io/rust-clippy/master/index.html#undropped_manually_drops [`unicode_not_nfc`]: https://rust-lang.github.io/rust-clippy/master/index.html#unicode_not_nfc [`unimplemented`]: https://rust-lang.github.io/rust-clippy/master/index.html#unimplemented [`uninit_assumed_init`]: https://rust-lang.github.io/rust-clippy/master/index.html#uninit_assumed_init diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index d4d2f92a6a6..49ff8ad366e 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -314,6 +314,7 @@ mod transmuting_null; mod trivially_copy_pass_by_ref; mod try_err; mod types; +mod undropped_manually_drops; mod unicode; mod unit_return_expecting_ord; mod unnamed_address; @@ -862,6 +863,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: &types::UNIT_CMP, &types::UNNECESSARY_CAST, &types::VEC_BOX, + &undropped_manually_drops::UNDROPPED_MANUALLY_DROPS, &unicode::INVISIBLE_CHARACTERS, &unicode::NON_ASCII_LITERAL, &unicode::UNICODE_NOT_NFC, @@ -1137,6 +1139,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: store.register_late_pass(move || box disallowed_method::DisallowedMethod::new(&disallowed_methods)); store.register_early_pass(|| box asm_syntax::InlineAsmX86AttSyntax); store.register_early_pass(|| box asm_syntax::InlineAsmX86IntelSyntax); + store.register_late_pass(|| box undropped_manually_drops::UndroppedManuallyDrops); store.register_group(true, "clippy::restriction", Some("clippy_restriction"), vec![ @@ -1790,6 +1793,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: LintId::of(&types::ABSURD_EXTREME_COMPARISONS), LintId::of(&types::CAST_REF_TO_MUT), LintId::of(&types::UNIT_CMP), + LintId::of(&undropped_manually_drops::UNDROPPED_MANUALLY_DROPS), LintId::of(&unicode::INVISIBLE_CHARACTERS), LintId::of(&unit_return_expecting_ord::UNIT_RETURN_EXPECTING_ORD), LintId::of(&unnamed_address::FN_ADDRESS_COMPARISONS), diff --git a/clippy_lints/src/undropped_manually_drops.rs b/clippy_lints/src/undropped_manually_drops.rs new file mode 100644 index 00000000000..48a050777b7 --- /dev/null +++ b/clippy_lints/src/undropped_manually_drops.rs @@ -0,0 +1,49 @@ +use rustc_lint::{LateLintPass, LateContext}; +use rustc_session::{declare_lint_pass, declare_tool_lint}; +use rustc_hir::*; +use crate::utils::{match_function_call, is_type_lang_item, paths, span_lint_and_help}; + +declare_clippy_lint! { + /// **What it does:** Prevents the safe `std::mem::drop` function from being called on `std::mem::ManuallyDrop`. + /// + /// **Why is this bad?** The safe `drop` function does not drop the inner value of a `ManuallyDrop`. + /// + /// **Known problems:** None. + /// + /// **Example:** + /// + /// ```rust + /// struct S; + /// drop(std::mem::ManuallyDrop::new(S)); + /// ``` + /// Use instead: + /// ```rust + /// struct S; + /// unsafe { + /// std::mem::ManuallyDrop::drop(std::mem::ManuallyDrop::new(S)); + /// } + /// ``` + pub UNDROPPED_MANUALLY_DROPS, + correctness, + "use of safe `std::mem::drop` function to drop a std::mem::ManuallyDrop, which will not drop the inner value" +} + +declare_lint_pass!(UndroppedManuallyDrops => [UNDROPPED_MANUALLY_DROPS]); + +impl LateLintPass<'tcx> for UndroppedManuallyDrops { + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { + if let Some(ref args) = match_function_call(cx, expr, &paths::DROP) { + let ty = cx.typeck_results().expr_ty(&args[0]); + if is_type_lang_item(cx, ty, lang_items::LangItem::ManuallyDrop) { + span_lint_and_help( + cx, + UNDROPPED_MANUALLY_DROPS, + expr.span, + "the inner value of this ManuallyDrop will not be dropped", + None, + "to drop a `ManuallyDrop<T>`, use std::mem::ManuallyDrop::drop" + ); + } + } + } +} \ No newline at end of file diff --git a/src/lintlist/mod.rs b/src/lintlist/mod.rs index 6301d623a2b..25a69e78c8f 100644 --- a/src/lintlist/mod.rs +++ b/src/lintlist/mod.rs @@ -2413,6 +2413,13 @@ vec for further information)", diff --git a/tests/ui/undropped_manually_drops.rs b/tests/ui/undropped_manually_drops.rs new file mode 100644 index 00000000000..bea62e1751e --- /dev/null +++ b/tests/ui/undropped_manually_drops.rs @@ -0,0 +1,18 @@ +#![warn(clippy::undropped_manually_drops)] + +struct S; + +fn main() { + let f = drop; + let manual = std::mem::ManuallyDrop::new(S); + + // These lines will not drop `S` + drop(std::mem::ManuallyDrop::new(S)); + f(manual); + + // These lines will + unsafe { + std::mem::ManuallyDrop::drop(std::mem::ManuallyDrop::new(S)); + std::mem::ManuallyDrop::drop(manual); + } +} |