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[WIP] Trigger absurd_extreme_comparisons if Duration is less than zero #14817

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[WIP] Trigger absurd_extreme_comparisons if Duration is less than zero #14817

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76 changes: 74 additions & 2 deletions clippy_lints/src/operators/absurd_extreme_comparisons.rs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
use rustc_hir::{BinOpKind, Expr, ExprKind};
use rustc_hir::{BinOpKind, Expr, ExprKind, QPath};
use rustc_lint::LateContext;
use rustc_middle::ty;

Expand All @@ -7,7 +7,7 @@ use clippy_utils::consts::{ConstEvalCtxt, Constant};
use clippy_utils::diagnostics::span_lint_and_help;
use clippy_utils::source::snippet;
use clippy_utils::ty::is_isize_or_usize;
use clippy_utils::{clip, int_bits, unsext};
use clippy_utils::{clip, int_bits, sym, unsext};

use super::ABSURD_EXTREME_COMPARISONS;

Expand Down Expand Up @@ -121,6 +121,78 @@ fn detect_absurd_comparison<'tcx>(
fn detect_extreme_expr<'tcx>(cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) -> Option<ExtremeExpr<'tcx>> {
let ty = cx.typeck_results().expr_ty(expr);

// Detect Duration zero values
if let ty::Adt(adt_def, _) = *ty.kind()
&& cx.tcx.is_diagnostic_item(sym::Duration, adt_def.did())
{
if let ExprKind::Call(func, args) = &expr.kind {
if let ExprKind::Path(qpath) = &func.kind {
let method_name = match qpath {
QPath::Resolved(_, path) => path.segments.last().map(|seg| seg.ident.name.as_str()),
QPath::TypeRelative(_, seg) => Some(seg.ident.name.as_str()),
_ => None,
};

// Handle constructors like from_secs(0), from_millis(0), etc.
if args.len() == 1 {
let int_methods = ["from_secs", "from_millis", "from_micros", "from_nanos"];
if int_methods.iter().any(|&m| Some(m) == method_name) {
if let Some(Constant::Int(0)) = ConstEvalCtxt::new(cx).eval(&args[0]) {
return Some(ExtremeExpr {
which: ExtremeType::Minimum,
expr,
});
}
}

// Handle float constructors
let float_methods = ["from_secs_f32", "from_secs_f64"];
if float_methods.iter().any(|&m| Some(m) == method_name) {
if let ExprKind::Lit(lit) = &args[0].kind {
let lit_str = snippet(cx, lit.span, "");
if lit_str == "0.0" || lit_str == "0" {
return Some(ExtremeExpr {
which: ExtremeType::Minimum,
expr,
});
}
}
}
}
// Handle new(0, 0)
else if args.len() == 2 && method_name == Some("new") {
let first_arg_const = ConstEvalCtxt::new(cx).eval(&args[0]);
let second_arg_const = ConstEvalCtxt::new(cx).eval(&args[1]);

if let (Some(Constant::Int(0)), Some(Constant::Int(0))) = (first_arg_const, second_arg_const) {
return Some(ExtremeExpr {
which: ExtremeType::Minimum,
expr,
});
}

if let (ExprKind::Path(_), ExprKind::Path(_)) = (&args[0].kind, &args[1].kind) {
if snippet(cx, args[0].span, "").contains("zero")
&& snippet(cx, args[1].span, "").contains("zero")
{
return Some(ExtremeExpr {
which: ExtremeType::Minimum,
expr,
});
}
}
}
// Handle constructor default()
else if args.is_empty() && method_name == Some("default") {
return Some(ExtremeExpr {
which: ExtremeType::Minimum,
expr,
});
}
}
}
}

let cv = ConstEvalCtxt::new(cx).eval(expr)?;

let which = match (ty.kind(), cv) {
Expand Down
67 changes: 67 additions & 0 deletions tests/ui/absurd-extreme-comparisons.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,8 @@
clippy::needless_pass_by_value
)]

use std::time::Duration;

#[rustfmt::skip]
fn main() {
const Z: u32 = 0;
Expand Down Expand Up @@ -69,7 +71,68 @@ fn main() {
() < {};
//~^ unit_cmp

Duration::from_secs(0) > Duration::new(5, 0);
//~^ absurd_extreme_comparisons
Duration::new(5, 0) < Duration::from_secs(0);
//~^ absurd_extreme_comparisons
Duration::from_secs(0) < Duration::new(5, 0); // ok

let d = Duration::new(5, 0);

d < Duration::from_secs(0);
//~^ absurd_extreme_comparisons
Duration::from_secs(0) > d;
//~^ absurd_extreme_comparisons

d < Duration::from_millis(0);
//~^ absurd_extreme_comparisons
Duration::from_micros(0) > d;
//~^ absurd_extreme_comparisons

d <= Duration::from_nanos(0);
//~^ absurd_extreme_comparisons
Duration::from_nanos(0) >= d;
//~^ absurd_extreme_comparisons

d < Duration::default();
//~^ absurd_extreme_comparisons
Duration::default() > d;
//~^ absurd_extreme_comparisons

d < Duration::from_secs_f32(0.0);
//~^ absurd_extreme_comparisons
Duration::from_secs_f64(0.0) > d;
//~^ absurd_extreme_comparisons

let zero_secs: u64 = 0;
let zero_nanos: u32 = 0;
d < Duration::new(zero_secs, zero_nanos);
//~^ absurd_extreme_comparisons
Duration::new(zero_secs, zero_nanos) > d;
//~^ absurd_extreme_comparisons

d > Duration::from_secs(0); // OK
Duration::from_secs(0) < d; // OK
d == Duration::from_secs(0); // OK

let d = Duration::new(5, 0);
d < one_second_plus(0); // OK
one_second_plus(0) > d; // OK

let n = 0;
d < one_second_plus(n); // OK

d < Duration::from_secs(0);
//~^ absurd_extreme_comparisons
Duration::from_secs(0) > d;
//~^ absurd_extreme_comparisons


let d_zero = Duration::from_secs(0);
let d_one = one_second_plus(0);
d_zero < d_one; // OK
d_one > d_zero; // OK
d_zero < d_zero; // OK
}

use std::cmp::{Ordering, PartialEq, PartialOrd};
Expand All @@ -96,3 +159,7 @@ pub fn bar(len: u64) -> bool {
// This is OK as we are casting from target sized to fixed size
len >= usize::MAX as u64
}

fn one_second_plus(n: u64) -> Duration {
Duration::from_secs(n + 1)
}
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