47 lines
1.6 KiB
Rust
47 lines
1.6 KiB
Rust
use clippy_utils::diagnostics::span_lint;
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use clippy_utils::{match_def_path, paths};
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use rustc_hir::{Expr, ExprKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for usage of `std::mem::forget(t)` where `t` is
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/// `Drop`.
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///
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/// ### Why is this bad?
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/// `std::mem::forget(t)` prevents `t` from running its
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/// destructor, possibly causing leaks.
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///
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/// ### Example
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/// ```rust
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/// # use std::mem;
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/// # use std::rc::Rc;
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/// mem::forget(Rc::new(55))
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/// ```
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#[clippy::version = "pre 1.29.0"]
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pub MEM_FORGET,
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restriction,
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"`mem::forget` usage on `Drop` types, likely to cause memory leaks"
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}
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declare_lint_pass!(MemForget => [MEM_FORGET]);
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impl<'tcx> LateLintPass<'tcx> for MemForget {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
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if let ExprKind::Call(path_expr, [ref first_arg, ..]) = e.kind {
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if let ExprKind::Path(ref qpath) = path_expr.kind {
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if let Some(def_id) = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id() {
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if match_def_path(cx, def_id, &paths::MEM_FORGET) {
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let forgot_ty = cx.typeck_results().expr_ty(first_arg);
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if forgot_ty.ty_adt_def().map_or(false, |def| def.has_dtor(cx.tcx)) {
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span_lint(cx, MEM_FORGET, e.span, "usage of `mem::forget` on `Drop` type");
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}
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}
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}
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}
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}
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}
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}
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