Remove support for saturating shifts

The implementation in stdlib has been removed as part of stabilizing
rust-lang/rust#87920. Support for saturating
shifts will be added back once rust-lang/libs-team#230
is fixed.

Author: mauricelam

.github/workflows/rust.yml

@@ -21,7 +21,7 @@ jobs:
     - name: Run tests
       run: cargo test --verbose
     - run: rustup install nightly
-    - run: cargo +nightly test --verbose --features saturating_int_impl
+    - run: cargo +nightly test --verbose
 
   build-windows:
 
@@ -34,4 +34,4 @@ jobs:
     - name: Run tests
       run: cargo test --verbose
     - run: rustup install nightly
-    - run: cargo +nightly test --verbose --features saturating_int_impl
+    - run: cargo +nightly test --verbose

.vscode/settings.json

@@ -1,5 +1,4 @@
 {
     "rust-analyzer.cargo.features": [
-        "saturating_int_impl"
     ]
 }

Cargo.toml

@@ -8,7 +8,6 @@ proc-macro = true
 
 [features]
 default = []
-saturating_int_impl = [] # Requires nightly and the lang-feature of the same name
 
 [dependencies]
 anyhow = "1.0.75"

README.md

@@ -17,10 +17,8 @@ wrapping! { 1_i32 + 2_i32 - 3_i32 };
 * Sub `-`
 * Mul `*`
 * Div `/`
-* Shl `<<` (except `saturating`, which is only supported with the feature
-  `saturating_int_impl`, and requires nightly)
-* Shr `>>` (except `saturating`, which is only supported with the feature
-  `saturating_int_impl`, and requires nightly)
+* Shl `<<` (except `saturating`, due to https://github.com/rust-lang/libs-team/issues/230)
+* Shr `>>` (except `saturating`, due to https://github.com/rust-lang/libs-team/issues/230)
 ## Known issues
 * For most operations, constraining the numeric literals are required (e.g.
   `2_i32` instead of `2`), due to

src/lib.rs

@@ -19,10 +19,8 @@
 //! * Sub `-`
 //! * Mul `*`
 //! * Div `/`
-//! * Shl `<<` (except `saturating`, which is only supported with the feature
-//!   `saturating_int_impl`, and requires nightly)
-//! * Shr `>>` (except `saturating`, which is only supported with the feature
-//!   `saturating_int_impl`, and requires nightly)
+//! * Shl `<<` (except `saturating`, due to https://github.com/rust-lang/libs-team/issues/230)
+//! * Shr `>>` (except `saturating`, due to https://github.com/rust-lang/libs-team/issues/230)
 //!
 //! ## Known issues
 //! * For most operations, constraining the numeric literals are required (e.g.
@@ -175,26 +173,10 @@ fn saturating_impl(item: TokenStream) -> anyhow::Result<TokenStream> {
                     syn::BinOp::Div(_) => quote! { (#new_left).saturating_div(#new_right) },
                     syn::BinOp::Rem(_) => quote! { (#new_left).saturating_rem(#new_right) },
                     syn::BinOp::Shl(_) => {
-                        #[cfg(feature = "saturating_int_impl")]
-                        {
-                            quote! { (::core::num::Saturating(#new_left) #op (#new_right)).0 }
-                        }
-
-                        #[cfg(not(feature = "saturating_int_impl"))]
-                        {
-                            bail!("Saturating bit shifts are not supported (https://github.com/rust-lang/libs-team/issues/230)")
-                        }
+                        bail!("Saturating bit shifts are not supported (https://github.com/rust-lang/libs-team/issues/230)")
                     }
                     syn::BinOp::Shr(_) => {
-                        #[cfg(feature = "saturating_int_impl")]
-                        {
-                            quote! { (::core::num::Saturating(#new_left) #op (#new_right)).0 }
-                        }
-
-                        #[cfg(not(feature = "saturating_int_impl"))]
-                        {
-                            bail!("Saturating bit shifts are not supported (https://github.com/rust-lang/libs-team/issues/230)")
-                        }
+                        bail!("Saturating bit shifts are not supported (https://github.com/rust-lang/libs-team/issues/230)")
                     }
                     syn::BinOp::And(_)
                     | syn::BinOp::Or(_)

src/tests.rs

@@ -122,16 +122,7 @@ fn test_bitshift() {
     });
 }
 
-#[cfg_attr(feature = "saturating_int_impl", ignore)]
 #[test]
 fn test_bitshift_no_saturating() {
     saturating_impl(quote! { 1 << 2 >> 3 }).unwrap_err();
 }
-
-#[test]
-#[cfg_attr(not(feature = "saturating_int_impl"), ignore)]
-fn test_bitshift_saturating() {
-    assert_expansion!(saturating_impl! { 1 << 2 >> 3 }.unwrap(), {
-        (::core::num::Saturating((::core::num::Saturating(1) << (2)).0) >> (3)).0
-    });
-}

tests/test.rs

@@ -1,5 +1,4 @@
 #![no_std]
-#![cfg_attr(feature="saturating_int_impl", feature(saturating_int_impl))]
 #![allow(clippy::precedence)]
 
 use arithmetic_mode::{checked, panicking, saturating, wrapping};
@@ -74,15 +73,6 @@ fn test_checked_operator_precedence() {
     assert_eq!(Some(11), checked! { 1_u8 + 2_u8 * 3_u8 + 4_u8 });
 }
 
-#[cfg(feature="saturating_int_impl")]
-#[test]
-fn test_saturating_shift() {
-    // Looks like the implementation of shift is just wrapping_shl / shr
-    // https://doc.rust-lang.org/src/core/num/saturating.rs.html#146
-    assert_eq!(2, saturating! { 1_u8 << 9_usize });
-    assert_eq!(127, saturating! { 255_u8 >> 9_usize });
-}
-
 macro_rules! test_unchanging {
     ($ident:ident, $expr:expr) => {
         ::paste::paste! {