diff --git a/Cargo.toml b/Cargo.toml
index b18ea9e..6f96dd2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -15,6 +15,8 @@ tinyvec_macros = { version = "0.1", optional = true }
 serde = { version = "1.0", optional = true, default-features = false }
 # Provides derived `Arbitrary` implementations
 arbitrary = { version = "1", optional = true }
+# Detects the available `rustc` version
+rustversion = "1.0.7"
 
 [features]
 default = []
@@ -29,17 +31,20 @@ std = ["alloc"]
 # "active" portion of an `ArrayVec` or `SliceVec`.
 grab_spare_slice = []
 
-# features that require rustc 1.40
+# formerly enabled features that require rustc 1.40
 # use Vec::append if possible in TinyVec::append - 1.37
 # DoubleEndedIterator::nth_back - 1.40
+# now these are automatically enabled if the listed rustc versions are detected
 rustc_1_40 = []
 
-# features that require rustc 1.55
+# formerly enabled features that require rustc 1.55
 # use const generics to implement Array for all array lengths
+# now that is automatically enabled if rustc 1.55+ is detected
 rustc_1_55 = ["rustc_1_40"]
 
-# features that require rustc 1.57
+# formerly enabled features that require rustc 1.57
 # add try_reserve functions to types that heap allocate.
+# now that is automatically enabled if rustc 1.57+ is detected
 rustc_1_57 = ["rustc_1_55"]
 
 # allow use of nightly feature `slice_partition_dedup`,
diff --git a/gen-array-impls.sh b/gen-array-impls.sh
index 5db5cd7..4139e55 100755
--- a/gen-array-impls.sh
+++ b/gen-array-impls.sh
@@ -3,6 +3,7 @@
 gen_impl() {
 	local len=$1
 	cat <<-END
+		#[rustversion::before(1.55)]
 		impl<T: Default> Array for [T; $len] {
 		  type Item = T;
 		  const CAPACITY: usize = $len;
@@ -43,6 +44,7 @@ cat <<-END
 	//     ./gen-array-impls.sh > src/array/generated_impl.rs
 	// from the repo root
 
+	#[rustversion::before(1.55)]
 	use super::Array;
 
 	$(for ((i = 0; i <= 33; i++)); do gen_impl $i; done)
diff --git a/src-backup/arrayset.rs b/src-backup/arrayset.rs
index 98e53f7..ca96da6 100644
--- a/src-backup/arrayset.rs
+++ b/src-backup/arrayset.rs
@@ -14,7 +14,8 @@ use core::{
 #[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub struct InsertError;
 
-// TODO(when std): impl std::error::Error for InsertError {}
+#[cfg(feature = "std")]
+impl std::error::Error for InsertError {}
 
 impl fmt::Display for InsertError {
   fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
diff --git a/src/array.rs b/src/array.rs
index 9a20984..e70767c 100644
--- a/src/array.rs
+++ b/src/array.rs
@@ -8,9 +8,10 @@
 ///
 /// You are generally **not** expected to need to implement this yourself. It is
 /// already implemented for all the major array lengths (`0..=32` and the powers
-/// of 2 up to 4,096), or for all array lengths with the feature `rustc_1_55`.
+/// of 2 up to 4,096), or for all array lengths in Rust versions 1.55 and newer.
 ///
-/// **Additional lengths can easily be added upon request.**
+/// **Additional lengths can easily be added upon request for Rust 1.54 and
+/// older.**
 ///
 /// ## Safety Reminder
 ///
@@ -41,8 +42,12 @@ pub trait Array {
   fn default() -> Self;
 }
 
-#[cfg(feature = "rustc_1_55")]
+// These `*_impl` modules implement `Array` for primitive arrays.
+//
+// NOTE(2022-07-09): The `#[rustversion::...]` conditional compilation
+// attributes are placed on the individual implementation blocks rather than on
+// the modules because using procedural attribute macros on non-inline modules
+// is unstable.  Even if doing so becomes stable, it would be incompatible with
+// `tinyvec`'s MSRV.
 mod const_generic_impl;
-
-#[cfg(not(feature = "rustc_1_55"))]
 mod generated_impl;
diff --git a/src/array/const_generic_impl.rs b/src/array/const_generic_impl.rs
index 2d9f1b1..695811d 100644
--- a/src/array/const_generic_impl.rs
+++ b/src/array/const_generic_impl.rs
@@ -1,5 +1,7 @@
+#[rustversion::since(1.55)]
 use super::Array;
 
+#[rustversion::since(1.55)]
 impl<T: Default, const N: usize> Array for [T; N] {
   type Item = T;
   const CAPACITY: usize = N;
diff --git a/src/array/generated_impl.rs b/src/array/generated_impl.rs
index e7979ac..5dea235 100644
--- a/src/array/generated_impl.rs
+++ b/src/array/generated_impl.rs
@@ -2,8 +2,10 @@
 //     ./gen-array-impls.sh > src/array/generated_impl.rs
 // from the repo root
 
+#[rustversion::before(1.55)]
 use super::Array;
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 0] {
   type Item = T;
   const CAPACITY: usize = 0;
@@ -26,6 +28,7 @@ impl<T: Default> Array for [T; 0] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 1] {
   type Item = T;
   const CAPACITY: usize = 1;
@@ -48,6 +51,7 @@ impl<T: Default> Array for [T; 1] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 2] {
   type Item = T;
   const CAPACITY: usize = 2;
@@ -70,6 +74,7 @@ impl<T: Default> Array for [T; 2] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 3] {
   type Item = T;
   const CAPACITY: usize = 3;
@@ -92,6 +97,7 @@ impl<T: Default> Array for [T; 3] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 4] {
   type Item = T;
   const CAPACITY: usize = 4;
@@ -114,6 +120,7 @@ impl<T: Default> Array for [T; 4] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 5] {
   type Item = T;
   const CAPACITY: usize = 5;
@@ -136,6 +143,7 @@ impl<T: Default> Array for [T; 5] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 6] {
   type Item = T;
   const CAPACITY: usize = 6;
@@ -165,6 +173,7 @@ impl<T: Default> Array for [T; 6] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 7] {
   type Item = T;
   const CAPACITY: usize = 7;
@@ -195,6 +204,7 @@ impl<T: Default> Array for [T; 7] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 8] {
   type Item = T;
   const CAPACITY: usize = 8;
@@ -226,6 +236,7 @@ impl<T: Default> Array for [T; 8] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 9] {
   type Item = T;
   const CAPACITY: usize = 9;
@@ -258,6 +269,7 @@ impl<T: Default> Array for [T; 9] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 10] {
   type Item = T;
   const CAPACITY: usize = 10;
@@ -291,6 +303,7 @@ impl<T: Default> Array for [T; 10] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 11] {
   type Item = T;
   const CAPACITY: usize = 11;
@@ -325,6 +338,7 @@ impl<T: Default> Array for [T; 11] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 12] {
   type Item = T;
   const CAPACITY: usize = 12;
@@ -360,6 +374,7 @@ impl<T: Default> Array for [T; 12] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 13] {
   type Item = T;
   const CAPACITY: usize = 13;
@@ -396,6 +411,7 @@ impl<T: Default> Array for [T; 13] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 14] {
   type Item = T;
   const CAPACITY: usize = 14;
@@ -433,6 +449,7 @@ impl<T: Default> Array for [T; 14] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 15] {
   type Item = T;
   const CAPACITY: usize = 15;
@@ -471,6 +488,7 @@ impl<T: Default> Array for [T; 15] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 16] {
   type Item = T;
   const CAPACITY: usize = 16;
@@ -510,6 +528,7 @@ impl<T: Default> Array for [T; 16] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 17] {
   type Item = T;
   const CAPACITY: usize = 17;
@@ -550,6 +569,7 @@ impl<T: Default> Array for [T; 17] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 18] {
   type Item = T;
   const CAPACITY: usize = 18;
@@ -591,6 +611,7 @@ impl<T: Default> Array for [T; 18] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 19] {
   type Item = T;
   const CAPACITY: usize = 19;
@@ -633,6 +654,7 @@ impl<T: Default> Array for [T; 19] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 20] {
   type Item = T;
   const CAPACITY: usize = 20;
@@ -676,6 +698,7 @@ impl<T: Default> Array for [T; 20] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 21] {
   type Item = T;
   const CAPACITY: usize = 21;
@@ -720,6 +743,7 @@ impl<T: Default> Array for [T; 21] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 22] {
   type Item = T;
   const CAPACITY: usize = 22;
@@ -765,6 +789,7 @@ impl<T: Default> Array for [T; 22] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 23] {
   type Item = T;
   const CAPACITY: usize = 23;
@@ -811,6 +836,7 @@ impl<T: Default> Array for [T; 23] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 24] {
   type Item = T;
   const CAPACITY: usize = 24;
@@ -858,6 +884,7 @@ impl<T: Default> Array for [T; 24] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 25] {
   type Item = T;
   const CAPACITY: usize = 25;
@@ -906,6 +933,7 @@ impl<T: Default> Array for [T; 25] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 26] {
   type Item = T;
   const CAPACITY: usize = 26;
@@ -955,6 +983,7 @@ impl<T: Default> Array for [T; 26] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 27] {
   type Item = T;
   const CAPACITY: usize = 27;
@@ -1005,6 +1034,7 @@ impl<T: Default> Array for [T; 27] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 28] {
   type Item = T;
   const CAPACITY: usize = 28;
@@ -1056,6 +1086,7 @@ impl<T: Default> Array for [T; 28] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 29] {
   type Item = T;
   const CAPACITY: usize = 29;
@@ -1108,6 +1139,7 @@ impl<T: Default> Array for [T; 29] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 30] {
   type Item = T;
   const CAPACITY: usize = 30;
@@ -1161,6 +1193,7 @@ impl<T: Default> Array for [T; 30] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 31] {
   type Item = T;
   const CAPACITY: usize = 31;
@@ -1215,6 +1248,7 @@ impl<T: Default> Array for [T; 31] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 32] {
   type Item = T;
   const CAPACITY: usize = 32;
@@ -1270,6 +1304,7 @@ impl<T: Default> Array for [T; 32] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 33] {
   type Item = T;
   const CAPACITY: usize = 33;
@@ -1326,6 +1361,7 @@ impl<T: Default> Array for [T; 33] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 64] {
   type Item = T;
   const CAPACITY: usize = 64;
@@ -1413,6 +1449,7 @@ impl<T: Default> Array for [T; 64] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 128] {
   type Item = T;
   const CAPACITY: usize = 128;
@@ -1564,6 +1601,7 @@ impl<T: Default> Array for [T; 128] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 256] {
   type Item = T;
   const CAPACITY: usize = 256;
@@ -1843,6 +1881,7 @@ impl<T: Default> Array for [T; 256] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 512] {
   type Item = T;
   const CAPACITY: usize = 512;
@@ -2378,6 +2417,7 @@ impl<T: Default> Array for [T; 512] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 1024] {
   type Item = T;
   const CAPACITY: usize = 1024;
@@ -3425,6 +3465,7 @@ impl<T: Default> Array for [T; 1024] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 2048] {
   type Item = T;
   const CAPACITY: usize = 2048;
@@ -5496,6 +5537,7 @@ impl<T: Default> Array for [T; 2048] {
   }
 }
 
+#[rustversion::before(1.55)]
 impl<T: Default> Array for [T; 4096] {
   type Item = T;
   const CAPACITY: usize = 4096;
diff --git a/src/arrayvec.rs b/src/arrayvec.rs
index 42ed134..cdfaf69 100644
--- a/src/arrayvec.rs
+++ b/src/arrayvec.rs
@@ -1398,7 +1398,7 @@ impl<A: Array> DoubleEndedIterator for ArrayVecIterator<A> {
     self.tail -= 1;
     return Some(take(item));
   }
-  #[cfg(feature = "rustc_1_40")]
+  #[rustversion::since(1.40)]
   #[inline]
   fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
     let base = self.base as usize;
@@ -1753,7 +1753,8 @@ where
 #[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 
-#[cfg(all(feature = "alloc", feature = "rustc_1_57"))]
+#[cfg(feature = "alloc")]
+#[rustversion::since(1.57)]
 use alloc::collections::TryReserveError;
 
 #[cfg(feature = "alloc")]
@@ -1790,7 +1791,7 @@ impl<A: Array> ArrayVec<A> {
   /// assert_eq!(v, &[1, 2, 3]);
   /// assert_eq!(v.capacity(), 13);
   /// ```
-  #[cfg(feature = "rustc_1_57")]
+  #[rustversion::since(1.57)]
   pub fn try_drain_to_vec_and_reserve(
     &mut self, n: usize,
   ) -> Result<Vec<A::Item>, TryReserveError> {
@@ -1831,7 +1832,7 @@ impl<A: Array> ArrayVec<A> {
   /// // Vec may reserve more than necessary in order to prevent more future allocations.
   /// assert!(v.capacity() >= 3);
   /// ```
-  #[cfg(feature = "rustc_1_57")]
+  #[rustversion::since(1.57)]
   pub fn try_drain_to_vec(&mut self) -> Result<Vec<A::Item>, TryReserveError> {
     self.try_drain_to_vec_and_reserve(0)
   }
diff --git a/src/arrayvec_drain.rs b/src/arrayvec_drain.rs
index 8721b7e..42b0400 100644
--- a/src/arrayvec_drain.rs
+++ b/src/arrayvec_drain.rs
@@ -60,7 +60,7 @@ impl<'a, T: 'a + Default> DoubleEndedIterator for ArrayVecDrain<'a, T> {
     self.iter.next_back().map(take)
   }
 
-  #[cfg(feature = "rustc_1_40")]
+  #[rustversion::since(1.40)]
   fn nth_back(&mut self, n: usize) -> Option<Self::Item> {
     self.iter.nth_back(n).map(take)
   }
diff --git a/src/lib.rs b/src/lib.rs
index 68a7036..a4c81be 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -36,8 +36,6 @@
 //! ## Other Features
 //! * `grab_spare_slice` lets you get access to the "inactive" portions of an
 //!   ArrayVec.
-//! * `rustc_1_40` makes the crate assume a minimum rust version of `1.40.0`,
-//!   which allows some better internal optimizations.
 //! * `serde` provides a `Serialize` and `Deserialize` implementation for
 //!   [`TinyVec`] and [`ArrayVec`] types, provided the inner item also has an
 //!   implementation.
@@ -100,8 +98,33 @@ mod tinyvec;
 #[cfg(feature = "alloc")]
 pub use crate::tinyvec::*;
 
-// TODO MSRV(1.40.0): Just call the normal `core::mem::take`
-#[inline(always)]
+#[rustversion::since(1.40)]
+use core::mem::take;
+
+/// Reimplement `core::mem::take` for Rust versions that lack it.
+#[rustversion::before(1.40)]
+#[inline]
 fn take<T: Default>(from: &mut T) -> T {
   replace(from, T::default())
 }
+
+#[cfg(feature = "rustc_1_57")]
+#[rustversion::before(1.57)]
+compile_error!(
+  "The crate feature `rustc_1_57` of `tinyvec` is enabled but the available \
+  Rust version is older than 1.57."
+);
+
+#[cfg(feature = "rustc_1_55")]
+#[rustversion::before(1.55)]
+compile_error!(
+  "The crate feature `rustc_1_55` of `tinyvec` is enabled but the available \
+  Rust version is older than 1.55."
+);
+
+#[cfg(feature = "rustc_1_40")]
+#[rustversion::before(1.40)]
+compile_error!(
+  "The crate feature `rustc_1_40` of `tinyvec` is enabled but the available \
+  Rust version is older than 1.40."
+);
diff --git a/src/tinyvec.rs b/src/tinyvec.rs
index df3c80e..3972047 100644
--- a/src/tinyvec.rs
+++ b/src/tinyvec.rs
@@ -6,7 +6,7 @@ use alloc::vec::{self, Vec};
 use core::convert::TryFrom;
 use tinyvec_macros::impl_mirrored;
 
-#[cfg(feature = "rustc_1_57")]
+#[rustversion::since(1.57)]
 use alloc::collections::TryReserveError;
 
 #[cfg(feature = "serde")]
@@ -317,7 +317,7 @@ impl<A: Array> TinyVec<A> {
   /// assert_eq!(Ok(()), tv.try_move_to_the_heap());
   /// assert!(tv.is_heap());
   /// ```
-  #[cfg(feature = "rustc_1_57")]
+  #[rustversion::since(1.57)]
   pub fn try_move_to_the_heap(&mut self) -> Result<(), TryReserveError> {
     let arr = match self {
       TinyVec::Heap(_) => return Ok(()),
@@ -364,7 +364,7 @@ impl<A: Array> TinyVec<A> {
   /// assert!(tv.is_heap());
   /// assert!(tv.capacity() >= 35);
   /// ```
-  #[cfg(feature = "rustc_1_57")]
+  #[rustversion::since(1.57)]
   pub fn try_move_to_the_heap_and_reserve(
     &mut self, n: usize,
   ) -> Result<(), TryReserveError> {
@@ -418,7 +418,7 @@ impl<A: Array> TinyVec<A> {
   /// assert!(tv.is_heap());
   /// assert!(tv.capacity() >= 5);
   /// ```
-  #[cfg(feature = "rustc_1_57")]
+  #[rustversion::since(1.57)]
   pub fn try_reserve(&mut self, n: usize) -> Result<(), TryReserveError> {
     let arr = match self {
       TinyVec::Heap(h) => return h.try_reserve(n),
@@ -487,7 +487,7 @@ impl<A: Array> TinyVec<A> {
   /// assert!(tv.is_heap());
   /// assert!(tv.capacity() >= 5);
   /// ```
-  #[cfg(feature = "rustc_1_57")]
+  #[rustversion::since(1.57)]
   pub fn try_reserve_exact(&mut self, n: usize) -> Result<(), TryReserveError> {
     let arr = match self {
       TinyVec::Heap(h) => return h.try_reserve_exact(n),
@@ -530,7 +530,7 @@ impl<A: Array> TinyVec<A> {
 
 impl<A: Array> TinyVec<A> {
   /// Move all values from `other` into this vec.
-  #[cfg(feature = "rustc_1_40")]
+  #[rustversion::since(1.37)]
   #[inline]
   pub fn append(&mut self, other: &mut Self) {
     self.reserve(other.len());
@@ -544,7 +544,7 @@ impl<A: Array> TinyVec<A> {
   }
 
   /// Move all values from `other` into this vec.
-  #[cfg(not(feature = "rustc_1_40"))]
+  #[rustversion::before(1.37)]
   #[inline]
   pub fn append(&mut self, other: &mut Self) {
     match other {
@@ -1101,7 +1101,7 @@ impl<'p, A: Array> DoubleEndedIterator for TinyVecDrain<'p, A> {
     #[inline]
     fn next_back(self: &mut Self) -> Option<Self::Item>;
 
-    #[cfg(feature = "rustc_1_40")]
+    #[rustversion::since(1.40)]
     #[inline]
     fn nth_back(self: &mut Self, n: usize) -> Option<Self::Item>;
   }
@@ -1380,7 +1380,7 @@ impl<A: Array> DoubleEndedIterator for TinyVecIterator<A> {
     #[inline]
     fn next_back(self: &mut Self) -> Option<Self::Item>;
 
-    #[cfg(feature = "rustc_1_40")]
+    #[rustversion::since(1.40)]
     #[inline]
     fn nth_back(self: &mut Self, n: usize) -> Option<Self::Item>;
   }
diff --git a/tests/arrayvec.rs b/tests/arrayvec.rs
index ad21770..565a2b2 100644
--- a/tests/arrayvec.rs
+++ b/tests/arrayvec.rs
@@ -387,7 +387,7 @@ fn iter_last_nth() {
 }
 
 #[test]
-#[cfg(feature = "rustc_1_40")]
+#[rustversion::since(1.40)]
 fn reviter() {
   let mut av: ArrayVec<[i32; 10]> = Default::default();
   av.push(1);
diff --git a/tests/tinyvec.rs b/tests/tinyvec.rs
index 32e2a01..c79ee5a 100644
--- a/tests/tinyvec.rs
+++ b/tests/tinyvec.rs
@@ -304,7 +304,7 @@ fn TinyVec_reserve() {
   assert!(tv.capacity() >= 10);
 }
 
-#[cfg(feature = "rustc_1_57")]
+#[rustversion::since(1.57)]
 #[test]
 fn TinyVec_try_reserve() {
   let mut tv: TinyVec<[i32; 4]> = Default::default();
@@ -336,7 +336,7 @@ fn TinyVec_reserve_exact() {
   assert!(tv.capacity() >= 10);
 }
 
-#[cfg(feature = "rustc_1_57")]
+#[rustversion::since(1.57)]
 #[test]
 fn TinyVec_try_reserve_exact() {
   let mut tv: TinyVec<[i32; 4]> = Default::default();
@@ -374,7 +374,7 @@ fn TinyVec_move_to_heap_and_shrink() {
   assert_eq!(tv.as_slice(), [1, 2, 3, 4]);
 }
 
-#[cfg(feature = "rustc_1_57")]
+#[rustversion::since(1.57)]
 #[test]
 fn TinyVec_try_move_to_heap_and_shrink() {
   let mut tv: TinyVec<[i32; 4]> = Default::default();