Correctly unpack &mut [T] into *mut T and usize

wasi-common-cbindgen/tests/array_args.rs

@@ -0,0 +1,20 @@
+extern crate wasi_common_cbindgen;
+
+pub use wasi_common_cbindgen::wasi_common_cbindgen;
+
+#[wasi_common_cbindgen]
+fn array_args(a: &mut [u8]) {
+    a[0] = 1;
+}
+
+fn main() {
+    let mut expected: &mut [u8] = &mut [0, 0];
+    array_args(&mut expected);
+
+    let given: &mut [u8] = &mut [0, 0];
+    unsafe {
+        __wasi_array_args(given.as_mut_ptr(), given.len());
+    }
+
+    assert_eq!(given, expected);
+}

wasi-common-cbindgen/tests/mut_args.rs

@@ -17,4 +17,4 @@ fn main() {
         Box::from_raw(raw)
     };
     assert_eq!(*given, *expected);
-}
+}

wasi-common-cbindgen/tests/ref_args.rs

@@ -17,4 +17,4 @@ fn main() {
         res
     };
     assert_eq!(given, expected);
-}
+}

wasi-common-cbindgen/tests/test.rs

@@ -5,4 +5,5 @@ fn tests() {
     t.pass("tests/val_args.rs");
     t.pass("tests/ref_args.rs");
     t.pass("tests/mut_args.rs");
-}
+    t.pass("tests/array_args.rs");
+}

wasi-common-cbindgen/tests/val_args.rs

@@ -9,4 +9,4 @@ fn val_args(a: usize, b: usize) -> usize {
 
 fn main() {
     assert_eq!(unsafe { __wasi_val_args(1, 2) }, val_args(1, 2));
-}
+}