From e046315daa4392f175e197f7ef5cb5e290b63b15 Mon Sep 17 00:00:00 2001
From: Will Crichton <wcrichto@cs.stanford.edu>
Date: Mon, 2 Oct 2023 14:49:08 -0700
Subject: [PATCH] Implement Clone::clone_from for BitVec

---
 src/vec/tests/api.rs | 8 ++++++++
 src/vec/traits.rs    | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/src/vec/tests/api.rs b/src/vec/tests/api.rs
index ffd58f56..16359fc6 100644
--- a/src/vec/tests/api.rs
+++ b/src/vec/tests/api.rs
@@ -67,4 +67,12 @@ fn misc() {
 	let mut bv = bitvec![0, 0, 1, 1, 0, 0];
 	bv.extend_from_within(2 .. 4);
 	assert_eq!(bv, bits![0, 0, 1, 1, 0, 0, 1, 1]);
+
+	let mut bv = bitvec![0, 0, 1, 1];
+	let bv2 = bitvec![1, 1, 0, 0];
+	bv.clone_from(&bv2);
+	assert_eq!(bv, bv2);
+	let bv3 = bitvec![1, 0];
+	bv.clone_from(&bv3);
+	assert_eq!(bv, bv3);
 }
diff --git a/src/vec/traits.rs b/src/vec/traits.rs
index ec935b0a..97a2e2c4 100644
--- a/src/vec/traits.rs
+++ b/src/vec/traits.rs
@@ -71,6 +71,15 @@ where
 	fn clone(&self) -> Self {
 		Self::from_bitslice(self.as_bitslice())
 	}
+
+	#[inline]
+	fn clone_from(&mut self, other: &Self) {
+		if self.len() == other.len() {
+			self.copy_from_bitslice(other.as_bitslice());
+		} else {
+			*self = other.clone();
+		}
+	}
 }
 
 impl<T, O> Eq for BitVec<T, O>