Contracts: Enabled signed extension

frame/contracts/fixtures/sign_extension.wat

@@ -0,0 +1,9 @@
+(module
+	(import "env" "memory" (memory 1 1))
+	(func (export "deploy"))
+	(func (export "call"))
+	(func (param i32) (result i32)
+		local.get 0
+		i32.extend8_s
+	)
+)

frame/contracts/src/tests.rs

@@ -5633,3 +5633,27 @@ fn root_cannot_instantiate() {
 		);
 	});
 }
+
+#[test]
+fn sign_extension_works() {
+	let (code, _) = compile_module::<Test>("sign_extension").unwrap();
+
+	ExtBuilder::default().build().execute_with(|| {
+		let _ = Balances::deposit_creating(&ALICE, 1_000_000);
+
+		assert_ok!(
+			Contracts::bare_instantiate(
+				ALICE,
+				0,
+				GAS_LIMIT,
+				None,
+				Code::Upload(code),
+				vec![],
+				vec![],
+				DebugInfo::Skip,
+				CollectEvents::Skip,
+			)
+			.result
+		);
+	});
+}

frame/contracts/src/wasm/prepare.rs

@@ -64,7 +64,7 @@ impl LoadedModule {
 		config
 			.wasm_multi_value(false)
 			.wasm_mutable_global(false)
-			.wasm_sign_extension(false)
+			.wasm_sign_extension(true)
 			.wasm_bulk_memory(false)
 			.wasm_reference_types(false)
 			.wasm_tail_call(false)