Rust Remove SafeSliceAccess for Arrays, and fix miri.

rust/flatbuffers/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "flatbuffers"
-version = "0.8.4"
+version = "0.8.5"
 edition = "2018"
 authors = ["Robert Winslow <hello@rwinslow.com>", "FlatBuffers Maintainers"]
 license = "Apache-2.0"

rust/flatbuffers/src/array.rs

@@ -52,6 +52,9 @@ impl<'a, T: 'a, const N: usize> Array<'a, T, N> {
     pub fn len(&self) -> usize {
         N
     }
+    pub fn as_ptr(&self) -> *const u8 {
+        self.0.as_ptr()
+    }
 }
 
 impl<'a, T: Follow<'a> + 'a, const N: usize> Array<'a, T, N> {
@@ -75,14 +78,7 @@ impl<'a, T: Follow<'a> + Debug, const N: usize> Into<[T::Inner; N]> for Array<'a
     }
 }
 
-impl<'a, T: SafeSliceAccess + 'a, const N: usize> Array<'a, T, N> {
-    pub fn safe_slice(self) -> &'a [T] {
-        let sz = size_of::<T>();
-        debug_assert!(sz > 0);
-        let ptr = self.0.as_ptr() as *const T;
-        unsafe { from_raw_parts(ptr, N) }
-    }
-}
+// TODO(caspern): Implement some future safe version of SafeSliceAccess.
 
 /// Implement Follow for all possible Arrays that have Follow-able elements.
 impl<'a, T: Follow<'a> + 'a, const N: usize> Follow<'a> for Array<'a, T, N> {
@@ -98,12 +94,16 @@ pub fn emplace_scalar_array<T: EndianScalar, const N: usize>(
     loc: usize,
     src: &[T; N],
 ) {
-    let mut buf_ptr = buf[loc..].as_mut_ptr() as *mut T;
+    let mut buf_ptr = buf[loc..].as_mut_ptr();
     for item in src.iter() {
         let item_le = item.to_little_endian();
         unsafe {
-            buf_ptr.write(item_le);
-            buf_ptr = buf_ptr.add(1);
+            core::ptr::copy_nonoverlapping(
+                &item_le as *const T as *const u8,
+                buf_ptr,
+                size_of::<T>(),
+            );
+            buf_ptr = buf_ptr.add(size_of::<T>());
         }
     }
 }

tests/RustTest.sh

@@ -63,5 +63,5 @@ fi
 # RUST_NIGHTLY environment variable set in dockerfile.
 if [[ $RUST_NIGHTLY == 1 ]]; then
   rustup +nightly component add miri
-  cargo +nightly miri test -- -Zmiri-disable-isolation
+  MIRIFLAGS="-Zmiri-disable-isolation" cargo +nightly miri test
 fi

tests/rust_usage_test/tests/arrays_test.rs

@@ -225,8 +225,8 @@ fn verify_struct_array_alignment() {
     let array_table = root_as_array_table(buf).unwrap();
     let array_struct = array_table.a().unwrap();
     let struct_start_ptr = array_struct.0.as_ptr() as usize;
-    let b_start_ptr = array_struct.b().safe_slice().as_ptr() as usize;
-    let d_start_ptr = array_struct.d().safe_slice().as_ptr() as usize;
+    let b_start_ptr = array_struct.b().as_ptr() as usize;
+    let d_start_ptr = array_struct.d().as_ptr() as usize;
     // The T type of b
     let b_aln = ::std::mem::align_of::<i32>();
     assert_eq!((b_start_ptr - struct_start_ptr) % b_aln, 0);
@@ -272,8 +272,6 @@ mod array_fuzz {
                 let arr: flatbuffers::Array<$ty, ARRAY_SIZE> = flatbuffers::Array::follow(&test_buf, 0);
                 let got: [$ty; ARRAY_SIZE] = arr.into();
                 assert_eq!(got, xs.0);
-                #[cfg(target_endian = "little")]
-                assert_eq!(arr.safe_slice(), xs.0);
             }
             #[test]
             fn $test_name() { 
@@ -317,13 +315,10 @@ mod array_fuzz {
         let arr: flatbuffers::Array<NestedStruct, ARRAY_SIZE> = flatbuffers::Array::follow(&test_buf, 0);
         let got: [&NestedStruct; ARRAY_SIZE] = arr.into();
         assert_eq!(got, native_struct_array);
-        let arr_slice = arr.safe_slice();
-        for i in 0..ARRAY_SIZE {
-            assert_eq!(arr_slice[i], *native_struct_array[i]);
-        }
     }
 
     #[test]
+    #[cfg(not(miri))]  // slow.
     fn test_struct() { 
         quickcheck::QuickCheck::new().max_tests(MAX_TESTS).quickcheck(prop_struct as fn(FakeArray<NestedStructWrapper, ARRAY_SIZE>));
     }

tests/rust_usage_test/tests/integration_test.rs

@@ -1115,6 +1115,7 @@ mod roundtrip_byteswap {
     // fn fuzz_f64() { quickcheck::QuickCheck::new().max_tests(N).quickcheck(prop_f64 as fn(f64)); }
 }
 
+#[cfg(not(miri))]
 quickcheck! {
   fn struct_of_structs(
     a_id: u32,