| use crate::utils::{match_def_path, paths, qpath_res, span_lint}; |
| use rustc_hir::{Expr, ExprKind}; |
| use rustc_lint::{LateContext, LateLintPass}; |
| use rustc_session::{declare_lint_pass, declare_tool_lint}; |
| |
| declare_clippy_lint! { |
| /// **What it does:** Checks for usage of `std::mem::forget(t)` where `t` is |
| /// `Drop`. |
| /// |
| /// **Why is this bad?** `std::mem::forget(t)` prevents `t` from running its |
| /// destructor, possibly causing leaks. |
| /// |
| /// **Known problems:** None. |
| /// |
| /// **Example:** |
| /// ```rust |
| /// # use std::mem; |
| /// # use std::rc::Rc; |
| /// mem::forget(Rc::new(55)) |
| /// ``` |
| pub MEM_FORGET, |
| restriction, |
| "`mem::forget` usage on `Drop` types, likely to cause memory leaks" |
| } |
| |
| declare_lint_pass!(MemForget => [MEM_FORGET]); |
| |
| impl<'tcx> LateLintPass<'tcx> for MemForget { |
| fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) { |
| if let ExprKind::Call(ref path_expr, ref args) = e.kind { |
| if let ExprKind::Path(ref qpath) = path_expr.kind { |
| if let Some(def_id) = qpath_res(cx, qpath, path_expr.hir_id).opt_def_id() { |
| if match_def_path(cx, def_id, &paths::MEM_FORGET) { |
| let forgot_ty = cx.tables().expr_ty(&args[0]); |
| |
| if forgot_ty.ty_adt_def().map_or(false, |def| def.has_dtor(cx.tcx)) { |
| span_lint(cx, MEM_FORGET, e.span, "usage of `mem::forget` on `Drop` type"); |
| } |
| } |
| } |
| } |
| } |
| } |
| } |