1 files changed, 44 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/casts/cast_abs_to_unsigned.rs b/src/tools/clippy/clippy_lints/src/casts/cast_abs_to_unsigned.rs
new file mode 100644
index 000000000..64ea326b7
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/casts/cast_abs_to_unsigned.rs
@@ -0,0 +1,44 @@
+use clippy_utils::diagnostics::span_lint_and_sugg;
+use clippy_utils::sugg::Sugg;
+use clippy_utils::{meets_msrv, msrvs};
+use rustc_errors::Applicability;
+use rustc_hir::{Expr, ExprKind};
+use rustc_lint::LateContext;
+use rustc_middle::ty::{self, Ty};
+use rustc_semver::RustcVersion;
+
+use super::CAST_ABS_TO_UNSIGNED;
+
+pub(super) fn check(
+    cx: &LateContext<'_>,
+    expr: &Expr<'_>,
+    cast_expr: &Expr<'_>,
+    cast_from: Ty<'_>,
+    cast_to: Ty<'_>,
+    msrv: Option<RustcVersion>,
+) {
+    if meets_msrv(msrv, msrvs::UNSIGNED_ABS)
+        && let ty::Int(from) = cast_from.kind()
+        && let ty::Uint(to) = cast_to.kind()
+        && let ExprKind::MethodCall(method_path, args, _) = cast_expr.kind
+        && method_path.ident.name.as_str() == "abs"
+    {
+        let span = if from.bit_width() == to.bit_width() {
+            expr.span
+        } else {
+            // if the result of `.unsigned_abs` would be a different type, keep the cast
+            // e.g. `i64 -> usize`, `i16 -> u8`
+            cast_expr.span
+        };
+
+        span_lint_and_sugg(
+            cx,
+            CAST_ABS_TO_UNSIGNED,
+            span,
+            &format!("casting the result of `{cast_from}::abs()` to {cast_to}"),
+            "replace with",
+            format!("{}.unsigned_abs()", Sugg::hir(cx, &args[0], "..")),
+            Applicability::MachineApplicable,
+        );
+    }
+}