diff --git a/src/any_value/mod.rs b/src/any_value/mod.rs
index cf44f7d..74b35e9 100644
--- a/src/any_value/mod.rs
+++ b/src/any_value/mod.rs
@@ -211,7 +211,7 @@ pub trait AnyValueCloneable: AnyValueSizeless {
     unsafe fn clone_into(&self, out: *mut u8);
 
     #[inline]
-    fn lazy_clone(&self) -> LazyClone<Self>
+    fn lazy_clone(&self) -> LazyClone<'_, Self>
         where Self: Sized
     {
         LazyClone::new(self)
diff --git a/src/any_vec.rs b/src/any_vec.rs
index 088d91d..9aaecfc 100644
--- a/src/any_vec.rs
+++ b/src/any_vec.rs
@@ -7,8 +7,8 @@ use core::ops::{Deref, DerefMut, Range, RangeBounds};
 use core::ptr::NonNull;
 use core::{fmt, ptr, slice};
 use core::slice::{from_raw_parts, from_raw_parts_mut};
-use crate::{AnyVecTyped, into_range, mem, ops};
-use crate::any_value::{AnyValue, AnyValueSizeless};
+use crate::{AnyVecTyped, into_range, mem, ops, assert_types_equal};
+use crate::any_value::{AnyValue, AnyValueSizeless, Unknown};
 use crate::any_vec_raw::{AnyVecRaw, DropFn};
 use crate::ops::{TempValue, Remove, SwapRemove, remove, swap_remove, Pop, pop};
 use crate::ops::{Drain, Splice, drain, splice};
@@ -423,7 +423,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     /// Returns [`AnyVecRef`] - typed view to const AnyVec,
     /// if container holds elements of type T, or None if it isn’t.
     #[inline]
-    pub fn downcast_ref<T: 'static>(&self) -> Option<AnyVecRef<T, M>> {
+    pub fn downcast_ref<T: 'static>(&self) -> Option<AnyVecRef<'_, T, M>> {
         if self.element_typeid() == TypeId::of::<T>() {
             unsafe{ Some(self.downcast_ref_unchecked()) }
         } else {
@@ -438,14 +438,14 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     /// The container elements must be of type `T`.
     /// Calling this method with the incorrect type is undefined behavior.
     #[inline]
-    pub unsafe fn downcast_ref_unchecked<T: 'static>(&self) -> AnyVecRef<T, M> {
+    pub unsafe fn downcast_ref_unchecked<T: 'static>(&self) -> AnyVecRef<'_, T, M> {
         AnyVecRef(AnyVecTyped::new(NonNull::from(&self.raw)))
     }
 
     /// Returns [`AnyVecMut`] - typed view to mut AnyVec,
     /// if container holds elements of type T, or None if it isn’t.
     #[inline]
-    pub fn downcast_mut<T: 'static>(&mut self) -> Option<AnyVecMut<T, M>> {
+    pub fn downcast_mut<T: 'static>(&mut self) -> Option<AnyVecMut<'_, T, M>> {
         if self.element_typeid() == TypeId::of::<T>() {
             unsafe{ Some(self.downcast_mut_unchecked()) }
         } else {
@@ -460,7 +460,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     /// The container elements must be of type `T`.
     /// Calling this method with the incorrect type is undefined behavior.
     #[inline]
-    pub unsafe fn downcast_mut_unchecked<T: 'static>(&mut self) -> AnyVecMut<T, M> {
+    pub unsafe fn downcast_mut_unchecked<T: 'static>(&mut self) -> AnyVecMut<'_, T, M> {
         AnyVecMut(AnyVecTyped::new(NonNull::from(&mut self.raw)))
     }
 
@@ -489,12 +489,12 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     }
 
     #[inline]
-    pub fn iter(&self) -> IterRef<Traits, M>{
+    pub fn iter(&self) -> IterRef<'_, Traits, M>{
         Iter::new(AnyVecPtr::from(self), 0, self.len())
     }
 
     #[inline]
-    pub fn iter_mut(&mut self) -> IterMut<Traits, M>{
+    pub fn iter_mut(&mut self) -> IterMut<'_, Traits, M>{
         let len = self.len();
         Iter::new(AnyVecPtr::from(self), 0, len)
     }
@@ -505,12 +505,12 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     ///
     /// * Panics if index is out of bounds.
     #[inline]
-    pub fn at(&self, index: usize) -> ElementRef<Traits, M>{
+    pub fn at(&self, index: usize) -> ElementRef<'_, Traits, M>{
         self.get(index).unwrap()
     }
 
     #[inline]
-    pub fn get(&self, index: usize) -> Option<ElementRef<Traits, M>>{
+    pub fn get(&self, index: usize) -> Option<ElementRef<'_, Traits, M>>{
         if index < self.len(){
             Some(unsafe{ self.get_unchecked(index) })
         } else {
@@ -519,7 +519,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     }
 
     #[inline]
-    pub unsafe fn get_unchecked(&self, index: usize) -> ElementRef<Traits, M>{
+    pub unsafe fn get_unchecked(&self, index: usize) -> ElementRef<'_, Traits, M>{
         let element_ptr = self.raw.get_unchecked(index) as *mut u8;
         ElementRef(
             ManuallyDrop::new(ElementPointer::new(
@@ -535,12 +535,12 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     ///
     /// * Panics if index is out of bounds.
     #[inline]
-    pub fn at_mut(&mut self, index: usize) -> ElementMut<Traits, M>{
+    pub fn at_mut(&mut self, index: usize) -> ElementMut<'_, Traits, M>{
         self.get_mut(index).unwrap()
     }
 
     #[inline]
-    pub fn get_mut(&mut self, index: usize) -> Option<ElementMut<Traits, M>>{
+    pub fn get_mut(&mut self, index: usize) -> Option<ElementMut<'_, Traits, M>>{
         if index < self.len(){
             Some(unsafe{ self.get_unchecked_mut(index) })
         } else {
@@ -549,7 +549,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     }
 
     #[inline]
-    pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> ElementMut<Traits, M> {
+    pub unsafe fn get_unchecked_mut(&mut self, index: usize) -> ElementMut<'_, Traits, M> {
         let element_ptr = self.raw.get_unchecked_mut(index);
         ElementMut(
             ManuallyDrop::new(ElementPointer::new(
@@ -625,7 +625,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     /// [`mem::forget`]: core::mem::forget
     ///
     #[inline]
-    pub fn pop(&mut self) -> Option<Pop<Traits, M>> {
+    pub fn pop(&mut self) -> Option<Pop<'_, Traits, M>> {
         if self.is_empty(){
             None
         } else {
@@ -648,7 +648,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     /// [`mem::forget`]: core::mem::forget
     ///
     #[inline]
-    pub fn remove(&mut self, index: usize) -> Remove<Traits, M> {
+    pub fn remove(&mut self, index: usize) -> Remove<'_, Traits, M> {
         self.raw.index_check(index);
         TempValue::new(remove::Remove::new(
             AnyVecPtr::from(self),
@@ -669,13 +669,31 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     /// [`mem::forget`]: core::mem::forget
     ///
     #[inline]
-    pub fn swap_remove(&mut self, index: usize) -> SwapRemove<Traits, M> {
+    pub fn swap_remove(&mut self, index: usize) -> SwapRemove<'_, Traits, M> {
         self.raw.index_check(index);
         TempValue::new(swap_remove::SwapRemove::new(
             AnyVecPtr::from(self),
             index
         ))
     }
+    
+    /// Moves all the elements of `other` into `self`, leaving `other` empty.
+    /// 
+    /// # Panics
+    /// 
+    /// * Panics if types mismatch.
+    /// * Panics if out of memory.
+    pub fn append<OtherTraits, OtherM>(
+        &mut self, other: &mut AnyVec<OtherTraits, OtherM>
+    ) where
+        OtherTraits: ?Sized + Trait, 
+        OtherM: MemBuilder
+    {
+        assert_types_equal(other.element_typeid(), self.element_typeid());
+        unsafe{
+            self.raw.append_unchecked::<Unknown, _>(&mut other.raw);
+        }
+    }
 
     /// Removes the specified range from the vector in bulk, returning all removed
     /// elements as an iterator. If the iterator is dropped before being fully consumed,
@@ -697,7 +715,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     /// [`mem::forget`]: core::mem::forget
     ///
     #[inline]
-    pub fn drain(&mut self, range: impl RangeBounds<usize>) -> Drain<Traits, M> {
+    pub fn drain(&mut self, range: impl RangeBounds<usize>) -> Drain<'_, Traits, M> {
         let Range{start, end} = into_range(self.len(), range);
         ops::Iter(drain::Drain::new(
             AnyVecPtr::from(self),
@@ -729,7 +747,7 @@ impl<Traits: ?Sized + Trait, M: MemBuilder> AnyVec<Traits, M>
     ///
     #[inline]
     pub fn splice<I: IntoIterator>(&mut self, range: impl RangeBounds<usize>, replace_with: I)
-        -> Splice<Traits, M, I::IntoIter>
+        -> Splice<'_, Traits, M, I::IntoIter>
     where
         I::IntoIter: ExactSizeIterator,
         I::Item: AnyValue
diff --git a/src/any_vec_raw.rs b/src/any_vec_raw.rs
index d75d3c5..7f77cc6 100644
--- a/src/any_vec_raw.rs
+++ b/src/any_vec_raw.rs
@@ -209,6 +209,38 @@ impl<M: MemBuilder> AnyVecRaw<M> {
 
         self.len += 1;
     }
+    
+    /// # Safety
+    ///
+    /// Type is not checked.
+    pub unsafe fn append_unchecked<T: 'static, OtherM: MemBuilder>(
+        &mut self, other: &mut AnyVecRaw<OtherM>
+    ) {
+        self.reserve(other.len);
+        
+        // copy
+        unsafe { 
+            if !Unknown::is::<T>(){
+                ptr::copy_nonoverlapping(
+                    other.mem.as_ptr().cast::<T>(),
+                    self.mem.as_mut_ptr().cast::<T>().add(self.len), 
+                    other.len
+                );
+            } else {
+                let element_size = self.element_layout().size();
+                ptr::copy_nonoverlapping(
+                    other.mem.as_ptr(), 
+                    self.mem.as_mut_ptr().add(self.len*element_size), 
+                    other.len*element_size
+                );
+            }
+        }
+        
+        // update len(s)
+        self.len += other.len;
+        other.len = 0;        
+        
+    }
 
     #[inline]
     pub fn clear(&mut self){
diff --git a/src/any_vec_typed.rs b/src/any_vec_typed.rs
index d2b2f84..1d81957 100644
--- a/src/any_vec_typed.rs
+++ b/src/any_vec_typed.rs
@@ -147,6 +147,19 @@ impl<'a, T: 'static, M: MemBuilder + 'a> AnyVecTyped<'a, T, M>{
         }
     }
 
+    /// Moves all the elements of `other` into `self`, leaving `other` empty.
+    /// 
+    /// # Panics
+    /// 
+    /// * Panics if out of memory.
+    pub fn append<OtherM: MemBuilder>(
+        &mut self, other: &mut AnyVecTyped<T, OtherM>
+    ) {
+        unsafe{
+            self.this_mut().append_unchecked::<T, _>(other.this_mut());
+        }
+    }    
+
     #[inline]
     pub fn drain(&mut self, range: impl RangeBounds<usize>)
         -> impl ElementIterator<Item = T> + 'a
diff --git a/tests/any_vec.rs b/tests/any_vec.rs
index dcd85ab..411d754 100644
--- a/tests/any_vec.rs
+++ b/tests/any_vec.rs
@@ -271,6 +271,33 @@ fn any_vec_splice_test() {
     ]);
 }
 
+#[test]
+fn append_test() {
+    let mut any_vec: AnyVec = AnyVec::new::<String>();
+    any_vec.push(AnyValueWrapper::new(String::from("0")));
+    any_vec.push(AnyValueWrapper::new(String::from("1")));
+    any_vec.push(AnyValueWrapper::new(String::from("2")));
+    any_vec.push(AnyValueWrapper::new(String::from("3")));
+    any_vec.push(AnyValueWrapper::new(String::from("4")));
+    
+    let mut any_vec2: AnyVec = AnyVec::new::<String>();
+    any_vec2.push(AnyValueWrapper::new(String::from("100")));
+    any_vec2.push(AnyValueWrapper::new(String::from("200")));
+    
+    any_vec.append(&mut any_vec2);
+    
+    assert_equal(any_vec.downcast_ref::<String>().unwrap().as_slice(), &[
+        String::from("0"),
+        String::from("1"),
+        String::from("2"),
+        String::from("3"),
+        String::from("4"),
+        String::from("100"),
+        String::from("200"),
+    ]);    
+    assert!(any_vec2.is_empty());
+}
+
 #[test]
 fn any_vec_insert_front(){
     let mut any_vec: AnyVec = AnyVec::new::<usize>();
diff --git a/tests/any_vec_typed.rs b/tests/any_vec_typed.rs
index 6fa7047..3bd5758 100644
--- a/tests/any_vec_typed.rs
+++ b/tests/any_vec_typed.rs
@@ -196,6 +196,35 @@ fn any_vec_debug() {
     assert_eq!(format!("{vec:?}"), format!("{control_vec:?}"));
 }
 
+#[test]
+fn append_test() {
+    let mut any_vec: AnyVec = AnyVec::new::<String>();
+    let mut vec = any_vec.downcast_mut::<String>().unwrap();
+    vec.push(String::from("0"));
+    vec.push(String::from("1"));
+    vec.push(String::from("2"));
+    vec.push(String::from("3"));
+    vec.push(String::from("4"));
+    
+    let mut any_vec2: AnyVec = AnyVec::new::<String>();
+    let mut vec2 = any_vec2.downcast_mut::<String>().unwrap();
+    vec2.push(String::from("100"));
+    vec2.push(String::from("200"));
+    
+    vec.append(&mut vec2);
+    
+    assert_equal(any_vec.downcast_ref::<String>().unwrap().as_slice(), &[
+        String::from("0"),
+        String::from("1"),
+        String::from("2"),
+        String::from("3"),
+        String::from("4"),
+        String::from("100"),
+        String::from("200"),
+    ]);    
+    assert!(any_vec2.is_empty());
+}
+
 /*
 #[test]
 fn any_vec_index_test() {