bump MSRV to 1.55, drop generated Array impls

.github/workflows/rust.yml

@@ -11,7 +11,7 @@ jobs:
       matrix:
         os: [ubuntu-latest]
         rust:
-        - 1.47.0 # approximate MSRV is Stable -30
+        - 1.55.0 # approximate MSRV is Stable -30
         - stable
         - beta
         - nightly
@@ -28,11 +28,11 @@ jobs:
         toolchain: ${{ matrix.rust }}
     # On MSRV some dev-dependencies don't build so we can't run tests.
     - name: Check MSRV
-      if: matrix.rust == '1.47.0'
+      if: matrix.rust == '1.55.0'
       run: |
         cargo check --features=alloc,std,grab_spare_slice
     - name: Test non nightly
-      if: matrix.rust != '1.47.0' && matrix.rust != 'nightly'
+      if: matrix.rust != '1.55.0' && matrix.rust != 'nightly'
       run: |
         cargo test --features=alloc,std,grab_spare_slice,latest_stable_rust
     - name: Test on Nightly with All Features

Cargo.toml

@@ -38,13 +38,12 @@ grab_spare_slice = []
 # obsolete feature that has to stay for semver reasons
 rustc_1_40 = []
 
-# features that require rustc 1.55
-# use const generics to implement Array for all array lengths
-rustc_1_55 = ["rustc_1_40"]
+# obsolete feature that has to stay for semver reasons
+rustc_1_55 = []
 
 # features that require rustc 1.57
 # add try_reserve functions to types that heap allocate.
-rustc_1_57 = ["rustc_1_55"]
+rustc_1_57 = []
 
 # features that require rustc 1.61
 # add retain_mut function to TinyVec

src/array.rs

@@ -7,8 +7,7 @@
 /// * You can get a shared or mutable slice to the elements.
 ///
 /// 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`.
+/// already implemented for all array lengths.
 ///
 /// **Additional lengths can easily be added upon request.**
 ///
@@ -41,14 +40,7 @@ pub trait Array {
   fn default() -> Self;
 }
 
-#[cfg(all(feature = "generic-array", not(feature = "rustc_1_55")))]
-core::compile_error!("generic-array requires `rustc_1_55` feature");
-
-#[cfg(feature = "rustc_1_55")]
 mod const_generic_impl;
 
-#[cfg(not(feature = "rustc_1_55"))]
-mod generated_impl;
-
 #[cfg(feature = "generic-array")]
 mod generic_array_impl;

src/array/const_generic_impl.rs

@@ -5,13 +5,11 @@ impl<T: Default, const N: usize> Array for [T; N] {
   const CAPACITY: usize = N;
 
   #[inline(always)]
-  #[must_use]
   fn as_slice(&self) -> &[T] {
     &*self
   }
 
   #[inline(always)]
-  #[must_use]
   fn as_slice_mut(&mut self) -> &mut [T] {
     &mut *self
   }