1 use clippy_utils::diagnostics::span_lint;
2 use clippy_utils::{higher, is_direct_expn_of};
3 use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
4 use rustc_hir::{BorrowKind, Expr, ExprKind, MatchSource, Mutability};
5 use rustc_lint::{LateContext, LateLintPass};
6 use rustc_middle::hir::map::Map;
8 use rustc_session::{declare_lint_pass, declare_tool_lint};
11 declare_clippy_lint! {
12 /// **What it does:** Checks for function/method calls with a mutable
13 /// parameter in `debug_assert!`, `debug_assert_eq!` and `debug_assert_ne!` macros.
15 /// **Why is this bad?** In release builds `debug_assert!` macros are optimized out by the
17 /// Therefore mutating something in a `debug_assert!` macro results in different behaviour
18 /// between a release and debug build.
20 /// **Known problems:** None
24 /// debug_assert_eq!(vec![3].pop(), Some(3));
26 /// fn take_a_mut_parameter(_: &mut u32) -> bool { unimplemented!() }
27 /// debug_assert!(take_a_mut_parameter(&mut 5));
29 pub DEBUG_ASSERT_WITH_MUT_CALL,
31 "mutable arguments in `debug_assert{,_ne,_eq}!`"
34 declare_lint_pass!(DebugAssertWithMutCall => [DEBUG_ASSERT_WITH_MUT_CALL]);
36 const DEBUG_MACRO_NAMES: [&str; 3] = ["debug_assert", "debug_assert_eq", "debug_assert_ne"];
38 impl<'tcx> LateLintPass<'tcx> for DebugAssertWithMutCall {
39 fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
40 for dmn in &DEBUG_MACRO_NAMES {
41 if is_direct_expn_of(e.span, dmn).is_some() {
42 if let Some(macro_args) = higher::extract_assert_macro_args(e) {
43 for arg in macro_args {
44 let mut visitor = MutArgVisitor::new(cx);
45 visitor.visit_expr(arg);
46 if let Some(span) = visitor.expr_span() {
49 DEBUG_ASSERT_WITH_MUT_CALL,
51 &format!("do not call a function with mutable arguments inside of `{}!`", dmn),
61 struct MutArgVisitor<'a, 'tcx> {
62 cx: &'a LateContext<'tcx>,
63 expr_span: Option<Span>,
67 impl<'a, 'tcx> MutArgVisitor<'a, 'tcx> {
68 fn new(cx: &'a LateContext<'tcx>) -> Self {
76 fn expr_span(&self) -> Option<Span> {
77 if self.found { self.expr_span } else { None }
81 impl<'a, 'tcx> Visitor<'tcx> for MutArgVisitor<'a, 'tcx> {
84 fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
86 ExprKind::AddrOf(BorrowKind::Ref, Mutability::Mut, _) => {
94 ExprKind::Path(_) => {
95 if let Some(adj) = self.cx.typeck_results().adjustments().get(expr.hir_id) {
98 .any(|a| matches!(a.target.kind(), ty::Ref(_, _, Mutability::Mut)))
105 // Don't check await desugars
106 ExprKind::Match(_, _, MatchSource::AwaitDesugar) => return,
107 _ if !self.found => self.expr_span = Some(expr.span),
110 walk_expr(self, expr);
113 fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
114 NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())