diff options
Diffstat (limited to 'clippy_lints/src/operators/arithmetic_side_effects.rs')
| -rw-r--r-- | clippy_lints/src/operators/arithmetic_side_effects.rs | 110 |
1 files changed, 55 insertions, 55 deletions
diff --git a/clippy_lints/src/operators/arithmetic_side_effects.rs b/clippy_lints/src/operators/arithmetic_side_effects.rs index 8827daaa3ee..20b82d81a2a 100644 --- a/clippy_lints/src/operators/arithmetic_side_effects.rs +++ b/clippy_lints/src/operators/arithmetic_side_effects.rs @@ -1,5 +1,9 @@ use super::ARITHMETIC_SIDE_EFFECTS; -use clippy_utils::{consts::constant_simple, diagnostics::span_lint}; +use clippy_utils::{ + consts::{constant, constant_simple}, + diagnostics::span_lint, + peel_hir_expr_refs, +}; use rustc_ast as ast; use rustc_data_structures::fx::FxHashSet; use rustc_hir as hir; @@ -38,24 +42,6 @@ impl ArithmeticSideEffects { } } - /// Assuming that `expr` is a literal integer, checks operators (+=, -=, *, /) in a - /// non-constant environment that won't overflow. - fn has_valid_op(op: &Spanned<hir::BinOpKind>, expr: &hir::Expr<'_>) -> bool { - if let hir::ExprKind::Lit(ref lit) = expr.kind && - let ast::LitKind::Int(value, _) = lit.node - { - match (&op.node, value) { - (hir::BinOpKind::Div | hir::BinOpKind::Rem, 0) => false, - (hir::BinOpKind::Add | hir::BinOpKind::Sub, 0) - | (hir::BinOpKind::Div | hir::BinOpKind::Rem, _) - | (hir::BinOpKind::Mul, 0 | 1) => true, - _ => false, - } - } else { - false - } - } - /// Checks if the given `expr` has any of the inner `allowed` elements. fn is_allowed_ty(&self, ty: Ty<'_>) -> bool { self.allowed @@ -74,15 +60,14 @@ impl ArithmeticSideEffects { self.expr_span = Some(expr.span); } - /// If `expr` does not match any variant of `LiteralIntegerTy`, returns `None`. - fn literal_integer<'expr, 'tcx>(expr: &'expr hir::Expr<'tcx>) -> Option<LiteralIntegerTy<'expr, 'tcx>> { - if matches!(expr.kind, hir::ExprKind::Lit(_)) { - return Some(LiteralIntegerTy::Value(expr)); + /// If `expr` is not a literal integer like `1`, returns `None`. + fn literal_integer(expr: &hir::Expr<'_>) -> Option<u128> { + if let hir::ExprKind::Lit(ref lit) = expr.kind && let ast::LitKind::Int(n, _) = lit.node { + Some(n) } - if let hir::ExprKind::AddrOf(.., inn) = expr.kind && let hir::ExprKind::Lit(_) = inn.kind { - return Some(LiteralIntegerTy::Ref(inn)); + else { + None } - None } /// Manages when the lint should be triggered. Operations in constant environments, hard coded @@ -117,10 +102,20 @@ impl ArithmeticSideEffects { return; } let has_valid_op = if Self::is_integral(lhs_ty) && Self::is_integral(rhs_ty) { - match (Self::literal_integer(lhs), Self::literal_integer(rhs)) { - (None, Some(lit_int_ty)) | (Some(lit_int_ty), None) => Self::has_valid_op(op, lit_int_ty.into()), - (Some(LiteralIntegerTy::Value(_)), Some(LiteralIntegerTy::Value(_))) => true, - (None, None) | (Some(_), Some(_)) => false, + let (actual_lhs, lhs_ref_counter) = peel_hir_expr_refs(lhs); + let (actual_rhs, rhs_ref_counter) = peel_hir_expr_refs(rhs); + match (Self::literal_integer(actual_lhs), Self::literal_integer(actual_rhs)) { + (None, None) => false, + (None, Some(n)) | (Some(n), None) => match (&op.node, n) { + (hir::BinOpKind::Div | hir::BinOpKind::Rem, 0) => false, + (hir::BinOpKind::Add | hir::BinOpKind::Sub, 0) + | (hir::BinOpKind::Div | hir::BinOpKind::Rem, _) + | (hir::BinOpKind::Mul, 0 | 1) => true, + _ => false, + }, + (Some(_), Some(_)) => { + matches!((lhs_ref_counter, rhs_ref_counter), (0, 0)) + }, } } else { false @@ -129,21 +124,45 @@ impl ArithmeticSideEffects { self.issue_lint(cx, expr); } } + + fn manage_unary_ops<'tcx>( + &mut self, + cx: &LateContext<'tcx>, + expr: &hir::Expr<'tcx>, + un_expr: &hir::Expr<'tcx>, + un_op: hir::UnOp, + ) { + let hir::UnOp::Neg = un_op else { return; }; + if constant(cx, cx.typeck_results(), un_expr).is_some() { + return; + } + let ty = cx.typeck_results().expr_ty(expr).peel_refs(); + if self.is_allowed_ty(ty) { + return; + } + let actual_un_expr = peel_hir_expr_refs(un_expr).0; + if Self::literal_integer(actual_un_expr).is_some() { + return; + } + self.issue_lint(cx, expr); + } + + fn should_skip_expr(&mut self, expr: &hir::Expr<'_>) -> bool { + self.expr_span.is_some() || self.const_span.map_or(false, |sp| sp.contains(expr.span)) + } } impl<'tcx> LateLintPass<'tcx> for ArithmeticSideEffects { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &hir::Expr<'tcx>) { - if self.expr_span.is_some() || self.const_span.map_or(false, |sp| sp.contains(expr.span)) { + if self.should_skip_expr(expr) { return; } match &expr.kind { - hir::ExprKind::Binary(op, lhs, rhs) | hir::ExprKind::AssignOp(op, lhs, rhs) => { + hir::ExprKind::AssignOp(op, lhs, rhs) | hir::ExprKind::Binary(op, lhs, rhs) => { self.manage_bin_ops(cx, expr, op, lhs, rhs); }, - hir::ExprKind::Unary(hir::UnOp::Neg, _) => { - if constant_simple(cx, cx.typeck_results(), expr).is_none() { - self.issue_lint(cx, expr); - } + hir::ExprKind::Unary(un_op, un_expr) => { + self.manage_unary_ops(cx, expr, un_expr, *un_op); }, _ => {}, } @@ -177,22 +196,3 @@ impl<'tcx> LateLintPass<'tcx> for ArithmeticSideEffects { } } } - -/// Tells if an expression is a integer declared by value or by reference. -/// -/// If `LiteralIntegerTy::Ref`, then the contained value will be `hir::ExprKind::Lit` rather -/// than `hirExprKind::Addr`. -enum LiteralIntegerTy<'expr, 'tcx> { - /// For example, `&199` - Ref(&'expr hir::Expr<'tcx>), - /// For example, `1` or `i32::MAX` - Value(&'expr hir::Expr<'tcx>), -} - -impl<'expr, 'tcx> From<LiteralIntegerTy<'expr, 'tcx>> for &'expr hir::Expr<'tcx> { - fn from(from: LiteralIntegerTy<'expr, 'tcx>) -> Self { - match from { - LiteralIntegerTy::Ref(elem) | LiteralIntegerTy::Value(elem) => elem, - } - } -} |