update the WASM runtime imports

substrate/wasm-runtime/polkadot/src/support/environment.rs

@@ -16,6 +16,7 @@
 
 //! Environment API: Allows certain information to be accessed throughout the runtime.
 
+use runtime_support::boxed::Box;
 use runtime_support::mem;
 use runtime_support::cell::RefCell;
 use runtime_support::rc::Rc;

substrate/wasm-runtime/support/src/lib.rs

@@ -8,11 +8,19 @@ extern crate alloc;
 
 pub use alloc::vec;
 pub use alloc::boxed;
-pub use alloc::rc::Rc;
+pub use alloc::rc;
 pub use core::mem;
 pub use core::slice;
 pub use core::cell;
 
+/// Common re-exports that are useful to have in scope.
+pub mod prelude {
+	pub use alloc::vec::Vec;
+	pub use alloc::boxed::Box;
+}
+
+use alloc::vec::Vec;
+
 extern crate pwasm_libc;
 extern crate pwasm_alloc;
 
@@ -68,7 +76,7 @@ pub fn chain_id() -> u64 {
 /// Conduct a 256-bit Blake2 hash.
 pub fn blake2_256(data: &[u8]) -> [u8; 32] {
 	unsafe {
-		let mut result: [u8; 32] = uninitialized();
+		let mut result: [u8; 32] = Default::default();
 		// guaranteed to write into result.
 		ext_blake2_256(&data[0], data.len() as u32, &mut result[0]);
 		result
@@ -78,7 +86,7 @@ pub fn blake2_256(data: &[u8]) -> [u8; 32] {
 /// Conduct four XX hashes to give a 256-bit result.
 pub fn twox_256(data: &[u8]) -> [u8; 32] {
 	unsafe {
-		let mut result: [u8; 32] = uninitialized();
+		let mut result: [u8; 32] = Default::default();
 		// guaranteed to write into result.
 		ext_twox_256(&data[0], data.len() as u32, &mut result[0]);
 		result
@@ -88,7 +96,7 @@ pub fn twox_256(data: &[u8]) -> [u8; 32] {
 /// Conduct two XX hashes to give a 256-bit result.
 pub fn twox_128(data: &[u8]) -> [u8; 16] {
 	unsafe {
-		let mut result: [u8; 16] = uninitialized();
+		let mut result: [u8; 16] = Default::default();
 		// guaranteed to write into result.
 		ext_twox_128(&data[0], data.len() as u32, &mut result[0]);
 		result
@@ -132,7 +140,7 @@ macro_rules! impl_stubs {
 				#[no_mangle]
 				pub fn $name(input_data: *mut u8, input_len: usize) -> u64 {
 					let input = unsafe {
-						$crate::Vec::from_raw_parts(input_data, input_len, input_len)
+						$crate::vec::Vec::from_raw_parts(input_data, input_len, input_len)
 					};
 
 					let output = super::$name(input);