diff --git a/src/consensus/encode.rs b/src/consensus/encode.rs
index bdda57c7..05004055 100644
--- a/src/consensus/encode.rs
+++ b/src/consensus/encode.rs
@@ -249,7 +249,7 @@ macro_rules! decoder_fn {
     ($name:ident, $val_type:ty, $readfn:ident, $byte_len: expr) => {
         #[inline]
         fn $name(&mut self) -> Result<$val_type, Error> {
-            assert_eq!(::std::mem::size_of::<$val_type>(), $byte_len); // size_of isn't a constfn in 1.22
+            debug_assert_eq!(::std::mem::size_of::<$val_type>(), $byte_len); // size_of isn't a constfn in 1.22
             let mut val = [0; $byte_len];
             self.read_exact(&mut val[..]).map_err(Error::Io)?;
             Ok(endian::$readfn(&val))
diff --git a/src/util/endian.rs b/src/util/endian.rs
index 37b59a19..d4ae5ec4 100644
--- a/src/util/endian.rs
+++ b/src/util/endian.rs
@@ -28,7 +28,7 @@ macro_rules! define_be_to_array {
     ($name: ident, $type: ty, $byte_len: expr) => {
         #[inline]
         pub fn $name(val: $type) -> [u8; $byte_len] {
-            assert_eq!(::std::mem::size_of::<$type>(), $byte_len); // size_of isn't a constfn in 1.22
+            debug_assert_eq!(::std::mem::size_of::<$type>(), $byte_len); // size_of isn't a constfn in 1.22
             let mut res = [0; $byte_len];
             for i in 0..$byte_len {
                 res[i] = ((val >> ($byte_len - i - 1)*8) & 0xff) as u8;
@@ -41,7 +41,7 @@ macro_rules! define_le_to_array {
     ($name: ident, $type: ty, $byte_len: expr) => {
         #[inline]
         pub fn $name(val: $type) -> [u8; $byte_len] {
-            assert_eq!(::std::mem::size_of::<$type>(), $byte_len); // size_of isn't a constfn in 1.22
+            debug_assert_eq!(::std::mem::size_of::<$type>(), $byte_len); // size_of isn't a constfn in 1.22
             let mut res = [0; $byte_len];
             for i in 0..$byte_len {
                 res[i] = ((val >> i*8) & 0xff) as u8;