X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=clippy_lints%2Fsrc%2Feval_order_dependence.rs;h=41acf55dd7d572ec8a75994ec4e924ad4e0c70be;hb=4f3b49fffa13518aa6006762c0eb6851c0c0b2d5;hp=4240147f498db43a2742f0eb69171043f1ccd970;hpb=28f9b84042b7d0ffd1f913e8ba82348ebe23dd1b;p=rust.git diff --git a/clippy_lints/src/eval_order_dependence.rs b/clippy_lints/src/eval_order_dependence.rs index 4240147f498..41acf55dd7d 100644 --- a/clippy_lints/src/eval_order_dependence.rs +++ b/clippy_lints/src/eval_order_dependence.rs @@ -1,7 +1,8 @@ -use crate::utils::{get_parent_expr, span_lint, span_lint_and_note}; +use clippy_utils::diagnostics::{span_lint, span_lint_and_note}; +use clippy_utils::{get_parent_expr, path_to_local, path_to_local_id}; use if_chain::if_chain; use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor}; -use rustc_hir::{def, BinOpKind, Block, Expr, ExprKind, Guard, HirId, Local, Node, QPath, Stmt, StmtKind}; +use rustc_hir::{BinOpKind, Block, Expr, ExprKind, Guard, HirId, Local, Node, Stmt, StmtKind}; use rustc_lint::{LateContext, LateLintPass}; use rustc_middle::hir::map::Map; use rustc_middle::ty; @@ -70,35 +71,28 @@ impl<'tcx> LateLintPass<'tcx> for EvalOrderDependence { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { // Find a write to a local variable. - match expr.kind { - ExprKind::Assign(ref lhs, ..) | ExprKind::AssignOp(_, ref lhs, _) => { - if let ExprKind::Path(ref qpath) = lhs.kind { - if let QPath::Resolved(_, ref path) = *qpath { - if path.segments.len() == 1 { - if let def::Res::Local(var) = cx.qpath_res(qpath, lhs.hir_id) { - let mut visitor = ReadVisitor { - cx, - var, - write_expr: expr, - last_expr: expr, - }; - check_for_unsequenced_reads(&mut visitor); - } - } - } - } - }, - _ => {}, - } + let var = if_chain! { + if let ExprKind::Assign(lhs, ..) | ExprKind::AssignOp(_, lhs, _) = expr.kind; + if let Some(var) = path_to_local(lhs); + if expr.span.desugaring_kind().is_none(); + then { var } else { return; } + }; + let mut visitor = ReadVisitor { + cx, + var, + write_expr: expr, + last_expr: expr, + }; + check_for_unsequenced_reads(&mut visitor); } fn check_stmt(&mut self, cx: &LateContext<'tcx>, stmt: &'tcx Stmt<'_>) { match stmt.kind { - StmtKind::Local(ref local) => { - if let Local { init: Some(ref e), .. } = **local { + StmtKind::Local(local) => { + if let Local { init: Some(e), .. } = local { DivergenceVisitor { cx }.visit_expr(e); } }, - StmtKind::Expr(ref e) | StmtKind::Semi(ref e) => DivergenceVisitor { cx }.maybe_walk_expr(e), + StmtKind::Expr(e) | StmtKind::Semi(e) => DivergenceVisitor { cx }.maybe_walk_expr(e), StmtKind::Item(..) => {}, } } @@ -112,7 +106,7 @@ impl<'a, 'tcx> DivergenceVisitor<'a, 'tcx> { fn maybe_walk_expr(&mut self, e: &'tcx Expr<'_>) { match e.kind { ExprKind::Closure(..) => {}, - ExprKind::Match(ref e, arms, _) => { + ExprKind::Match(e, arms, _) => { self.visit_expr(e); for arm in arms { if let Some(Guard::If(if_expr)) = arm.guard { @@ -136,12 +130,12 @@ impl<'a, 'tcx> Visitor<'tcx> for DivergenceVisitor<'a, 'tcx> { fn visit_expr(&mut self, e: &'tcx Expr<'_>) { match e.kind { ExprKind::Continue(_) | ExprKind::Break(_, _) | ExprKind::Ret(_) => self.report_diverging_sub_expr(e), - ExprKind::Call(ref func, _) => { + ExprKind::Call(func, _) => { let typ = self.cx.typeck_results().expr_ty(func); match typ.kind() { ty::FnDef(..) | ty::FnPtr(_) => { let sig = typ.fn_sig(self.cx.tcx); - if let ty::Never = self.cx.tcx.erase_late_bound_regions(&sig).output().kind() { + if let ty::Never = self.cx.tcx.erase_late_bound_regions(sig).output().kind() { self.report_diverging_sub_expr(e); } }, @@ -272,14 +266,14 @@ fn check_expr<'a, 'tcx>(vis: &mut ReadVisitor<'a, 'tcx>, expr: &'tcx Expr<'_>) - fn check_stmt<'a, 'tcx>(vis: &mut ReadVisitor<'a, 'tcx>, stmt: &'tcx Stmt<'_>) -> StopEarly { match stmt.kind { - StmtKind::Expr(ref expr) | StmtKind::Semi(ref expr) => check_expr(vis, expr), + StmtKind::Expr(expr) | StmtKind::Semi(expr) => check_expr(vis, expr), // If the declaration is of a local variable, check its initializer // expression if it has one. Otherwise, keep going. - StmtKind::Local(ref local) => local + StmtKind::Local(local) => local .init .as_ref() .map_or(StopEarly::KeepGoing, |expr| check_expr(vis, expr)), - _ => StopEarly::KeepGoing, + StmtKind::Item(..) => StopEarly::KeepGoing, } } @@ -304,27 +298,20 @@ fn visit_expr(&mut self, expr: &'tcx Expr<'_>) { return; } - match expr.kind { - ExprKind::Path(ref qpath) => { - if_chain! { - if let QPath::Resolved(None, ref path) = *qpath; - if path.segments.len() == 1; - if let def::Res::Local(local_id) = self.cx.qpath_res(qpath, expr.hir_id); - if local_id == self.var; - // Check that this is a read, not a write. - if !is_in_assignment_position(self.cx, expr); - then { - span_lint_and_note( - self.cx, - EVAL_ORDER_DEPENDENCE, - expr.span, - "unsequenced read of a variable", - Some(self.write_expr.span), - "whether read occurs before this write depends on evaluation order" - ); - } - } + if path_to_local_id(expr, self.var) { + // Check that this is a read, not a write. + if !is_in_assignment_position(self.cx, expr) { + span_lint_and_note( + self.cx, + EVAL_ORDER_DEPENDENCE, + expr.span, + &format!("unsequenced read of `{}`", self.cx.tcx.hir().name(self.var)), + Some(self.write_expr.span), + "whether read occurs before this write depends on evaluation order", + ); } + } + match expr.kind { // We're about to descend a closure. Since we don't know when (or // if) the closure will be evaluated, any reads in it might not // occur here (or ever). Like above, bail to avoid false positives. @@ -356,7 +343,7 @@ fn nested_visit_map(&mut self) -> NestedVisitorMap { /// Returns `true` if `expr` is the LHS of an assignment, like `expr = ...`. fn is_in_assignment_position(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool { if let Some(parent) = get_parent_expr(cx, expr) { - if let ExprKind::Assign(ref lhs, ..) = parent.kind { + if let ExprKind::Assign(lhs, ..) = parent.kind { return lhs.hir_id == expr.hir_id; } }