Auto merge of #96745 - ehuss:even-more-attribute-validation, r=cjgillot

[rust.git] / clippy_lints / src / mem_forget.rs

diff --git a/clippy_lints/src/mem_forget.rs b/clippy_lints/src/mem_forget.rs
index 3f314d332823e468488677b55a77d23613864e5b..d6c235b5a693a96975c006c3f5ee123f17a82fa5 100644 (file)
--- a/clippy_lints/src/mem_forget.rs
+++ b/clippy_lints/src/mem_forget.rs
@@ -1,21 +1,25 @@
-use crate::utils::{match_def_path, paths, span_lint};
-use rustc::hir::{Expr, ExprKind};
-use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
-use rustc::{declare_lint_pass, declare_tool_lint};
+use clippy_utils::diagnostics::span_lint;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+use rustc_span::sym;
 
 declare_clippy_lint! {
-    /// **What it does:** Checks for usage of `std::mem::forget(t)` where `t` is
+    /// ### 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
+    /// ### Why is this bad?
+    /// `std::mem::forget(t)` prevents `t` from running its
     /// destructor, possibly causing leaks.
     ///
-    /// **Known problems:** None.
-    ///
-    /// **Example:**
+    /// ### Example
     /// ```rust
+    /// # use std::mem;
+    /// # use std::rc::Rc;
     /// mem::forget(Rc::new(55))
     /// ```
+    #[clippy::version = "pre 1.29.0"]
     pub MEM_FORGET,
     restriction,
     "`mem::forget` usage on `Drop` types, likely to cause memory leaks"
@@ -23,16 +27,16 @@
 
 declare_lint_pass!(MemForget => [MEM_FORGET]);
 
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for MemForget {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
-        if let ExprKind::Call(ref path_expr, ref args) = e.node {
-            if let ExprKind::Path(ref qpath) = path_expr.node {
-                if let Some(def_id) = cx.tables.qpath_res(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]);
+impl<'tcx> LateLintPass<'tcx> for MemForget {
+    fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+        if let ExprKind::Call(path_expr, [ref first_arg, ..]) = e.kind {
+            if let ExprKind::Path(ref qpath) = path_expr.kind {
+                if let Some(def_id) = cx.qpath_res(qpath, path_expr.hir_id).opt_def_id() {
+                    if cx.tcx.is_diagnostic_item(sym::mem_forget, def_id) {
+                        let forgot_ty = cx.typeck_results().expr_ty(first_arg);
 
                         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");
+                            span_lint(cx, MEM_FORGET, e.span, "usage of `mem::forget` on `Drop` type");
                         }
                     }
                 }