2019-10-16 06:25:42 -05:00
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use crate::utils::{is_direct_expn_of, span_lint};
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use if_chain::if_chain;
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2020-01-09 01:13:22 -06:00
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use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
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2020-01-29 08:46:38 -06:00
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use rustc_hir::{BorrowKind, Expr, ExprKind, MatchSource, Mutability, StmtKind, UnOp};
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2020-01-12 00:08:41 -06:00
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use rustc_lint::{LateContext, LateLintPass};
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2020-03-30 04:02:14 -05:00
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use rustc_middle::hir::map::Map;
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use rustc_middle::ty;
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2020-01-11 05:37:08 -06:00
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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2019-12-30 18:17:56 -06:00
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use rustc_span::Span;
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2019-10-16 06:25:42 -05:00
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declare_clippy_lint! {
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/// **What it does:** Checks for function/method calls with a mutable
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/// parameter in `debug_assert!`, `debug_assert_eq!` and `debug_assert_ne!` macros.
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///
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/// **Why is this bad?** In release builds `debug_assert!` macros are optimized out by the
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/// compiler.
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/// Therefore mutating something in a `debug_assert!` macro results in different behaviour
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/// between a release and debug build.
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///
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/// **Known problems:** None
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///
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/// **Example:**
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/// ```rust,ignore
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/// debug_assert_eq!(vec![3].pop(), Some(3));
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/// // or
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/// fn take_a_mut_parameter(_: &mut u32) -> bool { unimplemented!() }
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/// debug_assert!(take_a_mut_parameter(&mut 5));
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/// ```
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pub DEBUG_ASSERT_WITH_MUT_CALL,
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2020-01-31 03:42:31 -06:00
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nursery,
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2019-10-16 06:25:42 -05:00
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"mutable arguments in `debug_assert{,_ne,_eq}!`"
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}
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declare_lint_pass!(DebugAssertWithMutCall => [DEBUG_ASSERT_WITH_MUT_CALL]);
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const DEBUG_MACRO_NAMES: [&str; 3] = ["debug_assert", "debug_assert_eq", "debug_assert_ne"];
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for DebugAssertWithMutCall {
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2019-12-27 01:12:26 -06:00
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) {
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2019-10-16 06:25:42 -05:00
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for dmn in &DEBUG_MACRO_NAMES {
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if is_direct_expn_of(e.span, dmn).is_some() {
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if let Some(span) = extract_call(cx, e) {
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span_lint(
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cx,
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DEBUG_ASSERT_WITH_MUT_CALL,
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span,
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&format!("do not call a function with mutable arguments inside of `{}!`", dmn),
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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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//HACK(hellow554): remove this when #4694 is implemented
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#[allow(clippy::cognitive_complexity)]
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2019-12-27 01:12:26 -06:00
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fn extract_call<'a, 'tcx>(cx: &'a LateContext<'a, 'tcx>, e: &'tcx Expr<'_>) -> Option<Span> {
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2019-10-16 06:25:42 -05:00
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if_chain! {
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if let ExprKind::Block(ref block, _) = e.kind;
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if block.stmts.len() == 1;
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if let StmtKind::Semi(ref matchexpr) = block.stmts[0].kind;
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then {
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2020-01-29 08:45:42 -06:00
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// debug_assert
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2019-10-16 06:25:42 -05:00
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if_chain! {
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if let ExprKind::Match(ref ifclause, _, _) = matchexpr.kind;
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if let ExprKind::DropTemps(ref droptmp) = ifclause.kind;
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if let ExprKind::Unary(UnOp::UnNot, ref condition) = droptmp.kind;
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then {
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let mut visitor = MutArgVisitor::new(cx);
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visitor.visit_expr(condition);
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return visitor.expr_span();
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2020-01-29 08:45:42 -06:00
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}
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}
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// debug_assert_{eq,ne}
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if_chain! {
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if let ExprKind::Block(ref matchblock, _) = matchexpr.kind;
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if let Some(ref matchheader) = matchblock.expr;
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if let ExprKind::Match(ref headerexpr, _, _) = matchheader.kind;
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if let ExprKind::Tup(ref conditions) = headerexpr.kind;
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if conditions.len() == 2;
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then {
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if let ExprKind::AddrOf(BorrowKind::Ref, _, ref lhs) = conditions[0].kind {
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let mut visitor = MutArgVisitor::new(cx);
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visitor.visit_expr(lhs);
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if let Some(span) = visitor.expr_span() {
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return Some(span);
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}
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}
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if let ExprKind::AddrOf(BorrowKind::Ref, _, ref rhs) = conditions[1].kind {
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let mut visitor = MutArgVisitor::new(cx);
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visitor.visit_expr(rhs);
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if let Some(span) = visitor.expr_span() {
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return Some(span);
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2019-10-16 06:25:42 -05:00
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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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None
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}
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struct MutArgVisitor<'a, 'tcx> {
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cx: &'a LateContext<'a, 'tcx>,
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expr_span: Option<Span>,
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found: bool,
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}
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impl<'a, 'tcx> MutArgVisitor<'a, 'tcx> {
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fn new(cx: &'a LateContext<'a, 'tcx>) -> Self {
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Self {
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cx,
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expr_span: None,
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found: false,
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}
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}
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fn expr_span(&self) -> Option<Span> {
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if self.found {
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self.expr_span
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} else {
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None
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}
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}
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}
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impl<'a, 'tcx> Visitor<'tcx> for MutArgVisitor<'a, 'tcx> {
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2020-01-09 01:13:22 -06:00
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type Map = Map<'tcx>;
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2019-12-27 01:12:26 -06:00
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fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
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2019-10-16 06:25:42 -05:00
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match expr.kind {
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2019-12-21 12:38:45 -06:00
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ExprKind::AddrOf(BorrowKind::Ref, Mutability::Mut, _) => {
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2019-10-16 06:25:42 -05:00
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self.found = true;
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return;
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},
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ExprKind::Path(_) => {
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if let Some(adj) = self.cx.tables.adjustments().get(expr.hir_id) {
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if adj
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.iter()
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2019-12-21 12:38:45 -06:00
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.any(|a| matches!(a.target.kind, ty::Ref(_, _, Mutability::Mut)))
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2019-10-16 06:25:42 -05:00
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{
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self.found = true;
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return;
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}
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}
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},
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2020-01-29 08:46:38 -06:00
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// Don't check await desugars
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ExprKind::Match(_, _, MatchSource::AwaitDesugar) => return,
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2019-10-16 06:25:42 -05:00
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_ if !self.found => self.expr_span = Some(expr.span),
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_ => return,
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}
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walk_expr(self, expr)
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}
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2020-03-15 17:41:20 -05:00
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fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
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NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
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2019-10-16 06:25:42 -05:00
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}
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}
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