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Auto merge of #7174 - camsteffen:eval-order-async, r=flip1995

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Fix eval_order_dependence async false positive

changelog: Fix [`eval_order_dependence`] false positive in async code

Fixes #6925
This commit is contained in:
bors 2021-05-05 21:18:05 +00:00
commit 93fe3562d0
3 changed files with 33 additions and 27 deletions
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30
clippy_lints/src/eval_order_dependence.rs
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@ -1,5 +1,6 @@
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::{BinOpKind, Block, Expr, ExprKind, Guard, HirId, Local, Node, Stmt, StmtKind};
use rustc_lint::{LateContext, LateLintPass};
@ -70,20 +71,19 @@ declare_lint_pass!(EvalOrderDependence => [EVAL_ORDER_DEPENDENCE, DIVERGING_SUB_
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(lhs, ..) | ExprKind::AssignOp(_, lhs, _) => {
if let Some(var) = path_to_local(lhs) {
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 {
@ -305,7 +305,7 @@ impl<'a, 'tcx> Visitor<'tcx> for ReadVisitor<'a, 'tcx> {
self.cx,
EVAL_ORDER_DEPENDENCE,
expr.span,
"unsequenced read of a variable",
&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",
);