rayon parallel feature w/o nightly features on old compilers

.github/workflows/nalgebra-ci-build.yml

@@ -61,7 +61,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - name: test
-        run: cargo test --features arbitrary,rand,serde-serialize,sparse,debug,io,compare,libm,proptest-support,slow-tests,rkyv-safe-deser,rayon;
+        run: cargo test --features arbitrary,rand,serde-serialize,sparse,debug,io,compare,libm,proptest-support,slow-tests,rkyv-safe-deser,rayon-par;
   test-nalgebra-glm:
     runs-on: ubuntu-latest
     steps:

Cargo.toml

@@ -33,7 +33,7 @@ libm    = [ "simba/libm" ]
 libm-force = [ "simba/libm_force" ]
 macros = [ "nalgebra-macros" ]
 cuda   = [ "cust_core", "simba/cuda" ]
-rayon  = [ "std", "dep:rayon" ]
+rayon-par  = [ "std", "rayon" ]
 
 # Conversion
 convert-mint = [ "mint" ]

tests/lib.rs

@@ -10,8 +10,8 @@ compile_error!(
 );
 
 // make sure to test the parallel iterators for all builds that do not require no_std
-#[cfg(all(feature = "std", not(feature = "rayon")))]
-compile_error!("Please additionally enable the `rayon` feature to compile and run the tests");
+#[cfg(all(feature = "std", not(feature = "rayon-par")))]
+compile_error!("Please additionally enable the `rayon-par` feature to compile and run the tests");
 
 #[cfg(all(feature = "debug", feature = "compare", feature = "rand"))]
 #[macro_use]