rust/clippy_lints/src/operators/duration_subsec.rs

44 lines
1.5 KiB
Rust

use clippy_utils::consts::{constant, Constant};
use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::source::snippet_with_applicability;
use clippy_utils::ty::is_type_diagnostic_item;
use rustc_errors::Applicability;
use rustc_hir::{BinOpKind, Expr, ExprKind};
use rustc_lint::LateContext;
use rustc_span::sym;
use super::DURATION_SUBSEC;
pub(crate) fn check<'tcx>(
cx: &LateContext<'tcx>,
expr: &'tcx Expr<'_>,
op: BinOpKind,
left: &'tcx Expr<'_>,
right: &'tcx Expr<'_>,
) {
if op == BinOpKind::Div
&& let ExprKind::MethodCall(method_path, self_arg, [], _) = left.kind
&& is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(self_arg).peel_refs(), sym::Duration)
&& let Some(Constant::Int(divisor)) = constant(cx, cx.typeck_results(), right)
{
let suggested_fn = match (method_path.ident.as_str(), divisor) {
("subsec_micros", 1_000) | ("subsec_nanos", 1_000_000) => "subsec_millis",
("subsec_nanos", 1_000) => "subsec_micros",
_ => return,
};
let mut applicability = Applicability::MachineApplicable;
span_lint_and_sugg(
cx,
DURATION_SUBSEC,
expr.span,
&format!("calling `{suggested_fn}()` is more concise than this calculation"),
"try",
format!(
"{}.{suggested_fn}()",
snippet_with_applicability(cx, self_arg.span, "_", &mut applicability)
),
applicability,
);
}
}