diff --git a/polkadot/parachain/test-chains/basic_add/Cargo.toml b/polkadot/parachain/test-chains/basic_add/Cargo.toml
index afc9e9f131..dd0fc4050d 100644
--- a/polkadot/parachain/test-chains/basic_add/Cargo.toml
+++ b/polkadot/parachain/test-chains/basic_add/Cargo.toml
@@ -9,7 +9,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 polkadot-parachain = { path = "../../", default-features = false }
-wee_alloc = "0.2.0"
+wee_alloc = "0.4.0"
 tiny-keccak = "1.4"
 pwasm-libc = "0.2"
 
diff --git a/polkadot/parachain/test-chains/basic_add/src/lib.rs b/polkadot/parachain/test-chains/basic_add/src/lib.rs
index 3f877b16d1..be21a8dec8 100644
--- a/polkadot/parachain/test-chains/basic_add/src/lib.rs
+++ b/polkadot/parachain/test-chains/basic_add/src/lib.rs
@@ -17,7 +17,7 @@
 //! Basic parachain that adds a number as part of its state.
 
 #![cfg_attr(not(feature = "std"), no_std)]
-#![cfg_attr(not(feature = "std"), feature(alloc, core_intrinsics, global_allocator, lang_items))]
+#![cfg_attr(not(feature = "std"), feature(alloc, core_intrinsics, global_allocator, lang_items, panic_implementation))]
 
 #[cfg(not(feature = "std"))]
 extern crate alloc;
diff --git a/polkadot/parachain/test-chains/basic_add/src/wasm.rs b/polkadot/parachain/test-chains/basic_add/src/wasm.rs
index fa1bf64f43..3af2dd39a9 100644
--- a/polkadot/parachain/test-chains/basic_add/src/wasm.rs
+++ b/polkadot/parachain/test-chains/basic_add/src/wasm.rs
@@ -16,19 +16,23 @@
 
 //! Defines WASM module logic.
 
+use core::intrinsics;
+
 use parachain::{self, ValidationResult};
 use parachain::codec::Slicable;
 use super::{HeadData, BlockData};
 
-#[lang = "panic_fmt"]
+#[panic_implementation]
 #[no_mangle]
-pub extern fn panic_fmt(
-	_args: ::core::fmt::Arguments,
-	_file: &'static str,
-	_line: u32,
-	_col: u32,
-) -> ! {
-	use core::intrinsics;
+pub fn rust_begin_panic(_info: &::core::panic::PanicInfo) -> ! {
+	unsafe {
+		intrinsics::abort()
+	}
+}
+
+#[lang = "oom"]
+#[no_mangle]
+pub fn oom() -> ! {
 	unsafe {
 		intrinsics::abort();
 	}
diff --git a/polkadot/parachain/test-chains/build.sh b/polkadot/parachain/test-chains/build.sh
new file mode 100755
index 0000000000..2b876634e8
--- /dev/null
+++ b/polkadot/parachain/test-chains/build.sh
@@ -0,0 +1,13 @@
+#!/bin/sh
+set -e
+
+rm -rf ./target
+for i in */
+do
+  i=${i%/}
+  cd $i
+
+  RUSTFLAGS="-C link-arg=--import-memory" cargo +nightly build --target=wasm32-unknown-unknown --release --no-default-features
+  wasm-gc target/wasm32-unknown-unknown/release/$i.wasm ../../tests/res/$i.wasm
+  cd ..
+done
diff --git a/polkadot/parachain/test-chains/build_test_chains.sh b/polkadot/parachain/test-chains/build_test_chains.sh
deleted file mode 100755
index 6523e46f14..0000000000
--- a/polkadot/parachain/test-chains/build_test_chains.sh
+++ /dev/null
@@ -1,14 +0,0 @@
-#!/bin/sh
-set -e
-
-rm -rf ./target
-for i in */
-do
-  i=${i%/}
-  cd $i
-
-  # TODO: stop using exact nightly when wee-alloc works on normal nightly.
-  RUSTFLAGS="-C link-arg=--import-memory" cargo +nightly-2018-03-07 build --target=wasm32-unknown-unknown --release --no-default-features
-  wasm-gc target/wasm32-unknown-unknown/release/$i.wasm ../../tests/res/$i.wasm
-  cd ..
-done
diff --git a/polkadot/parachain/tests/res/basic_add.wasm b/polkadot/parachain/tests/res/basic_add.wasm
index 83f52db817..709c111d27 100755
Binary files a/polkadot/parachain/tests/res/basic_add.wasm and b/polkadot/parachain/tests/res/basic_add.wasm differ