diff --git a/clippy_lints/src/if_not_else.rs b/clippy_lints/src/if_not_else.rs index 4dc1ff83771..2f6daeeb90d 100644 --- a/clippy_lints/src/if_not_else.rs +++ b/clippy_lints/src/if_not_else.rs @@ -56,44 +56,33 @@ fn is_zero_const(expr: &Expr<'_>, cx: &LateContext<'_>) -> bool { } impl LateLintPass<'_> for IfNotElse { - fn check_expr(&mut self, cx: &LateContext<'_>, item: &Expr<'_>) { - // While loops will be desugared to ExprKind::If. This will cause the lint to fire. - // To fix this, return early if this span comes from a macro or desugaring. - if item.span.from_expansion() { - return; - } - if let ExprKind::If(cond, _, Some(els)) = item.kind { - if let ExprKind::Block(..) = els.kind { - // Disable firing the lint in "else if" expressions. - if is_else_clause(cx.tcx, item) { - return; - } + fn check_expr(&mut self, cx: &LateContext<'_>, e: &Expr<'_>) { + if let ExprKind::If(cond, _, Some(els)) = e.kind + && let ExprKind::DropTemps(cond) = cond.kind + && let ExprKind::Block(..) = els.kind + { + let (msg, help) = match cond.kind { + ExprKind::Unary(UnOp::Not, _) => ( + "unnecessary boolean `not` operation", + "remove the `!` and swap the blocks of the `if`/`else`", + ), + // Don't lint on `… != 0`, as these are likely to be bit tests. + // For example, `if foo & 0x0F00 != 0 { … } else { … }` is already in the "proper" order. + ExprKind::Binary(op, _, rhs) if op.node == BinOpKind::Ne && !is_zero_const(rhs, cx) => ( + "unnecessary `!=` operation", + "change to `==` and swap the blocks of the `if`/`else`", + ), + _ => return, + }; - match cond.peel_drop_temps().kind { - ExprKind::Unary(UnOp::Not, _) => { - span_lint_and_help( - cx, - IF_NOT_ELSE, - item.span, - "unnecessary boolean `not` operation", - None, - "remove the `!` and swap the blocks of the `if`/`else`", - ); - }, - ExprKind::Binary(ref kind, _, lhs) if kind.node == BinOpKind::Ne && !is_zero_const(lhs, cx) => { - // Disable firing the lint on `… != 0`, as these are likely to be bit tests. - // For example, `if foo & 0x0F00 != 0 { … } else { … }` already is in the "proper" order. - span_lint_and_help( - cx, - IF_NOT_ELSE, - item.span, - "unnecessary `!=` operation", - None, - "change to `==` and swap the blocks of the `if`/`else`", - ); - }, - _ => (), - } + // `from_expansion` will also catch `while` loops which appear in the HIR as: + // ```rust + // loop { + // if cond { ... } else { break; } + // } + // ``` + if !e.span.from_expansion() && !is_else_clause(cx.tcx, e) { + span_lint_and_help(cx, IF_NOT_ELSE, e.span, msg, None, help); } } }