diff --git a/stdlib/public/core/Array.swift b/stdlib/public/core/Array.swift
index 667ccf932e51d..443d2227eeaa7 100644
--- a/stdlib/public/core/Array.swift
+++ b/stdlib/public/core/Array.swift
@@ -1378,9 +1378,16 @@ extension Array: RangeReplaceableCollection {
     if !keepCapacity {
       _buffer = _Buffer()
     }
-    else {
+    else if _buffer.isMutableAndUniquelyReferenced() {
       self.replaceSubrange(indices, with: EmptyCollection())
     }
+    else {
+      let buffer = _ContiguousArrayBuffer<Element>(
+        _uninitializedCount: 0,
+        minimumCapacity: capacity
+      )
+      _buffer = _Buffer(_buffer: buffer, shiftedToStartIndex: startIndex)
+    }
   }
 
   //===--- algorithms -----------------------------------------------------===//
diff --git a/stdlib/public/core/ArraySlice.swift b/stdlib/public/core/ArraySlice.swift
index be6363e3a9483..369f42dd8301d 100644
--- a/stdlib/public/core/ArraySlice.swift
+++ b/stdlib/public/core/ArraySlice.swift
@@ -195,11 +195,7 @@ extension ArraySlice {
   func _checkSubscript(
     _ index: Int, wasNativeTypeChecked: Bool
   ) -> _DependenceToken {
-#if _runtime(_ObjC)
     _buffer._checkValidSubscript(index)
-#else
-    _buffer._checkValidSubscript(index)
-#endif
     return _DependenceToken()
   }
 
@@ -1071,9 +1067,16 @@ extension ArraySlice: RangeReplaceableCollection {
     if !keepCapacity {
       _buffer = _Buffer()
     }
-    else {
+    else if _buffer.isMutableAndUniquelyReferenced() {
       self.replaceSubrange(indices, with: EmptyCollection())
     }
+    else {
+      let buffer = _ContiguousArrayBuffer<Element>(
+        _uninitializedCount: 0,
+        minimumCapacity: capacity
+      )
+      _buffer = _Buffer(_buffer: buffer, shiftedToStartIndex: startIndex)
+    }
   }
 
   //===--- algorithms -----------------------------------------------------===//
diff --git a/stdlib/public/core/ContiguousArray.swift b/stdlib/public/core/ContiguousArray.swift
index 0d41e4b0f1592..c06d55c61ed7f 100644
--- a/stdlib/public/core/ContiguousArray.swift
+++ b/stdlib/public/core/ContiguousArray.swift
@@ -975,9 +975,12 @@ extension ContiguousArray: RangeReplaceableCollection {
     if !keepCapacity {
       _buffer = _Buffer()
     }
-    else {
+    else if _buffer.isMutableAndUniquelyReferenced() {
       self.replaceSubrange(indices, with: EmptyCollection())
     }
+    else {
+      _buffer = _Buffer(_uninitializedCount: 0, minimumCapacity: capacity)
+    }
   }
 
   //===--- algorithms -----------------------------------------------------===//