The previous assumption that the wasm-code was compiled with rustc mi…

…ght be wrong now, that the code comes from the blockchain. Added Notes about that.

substrate/executor/src/wasm_executor.rs

@@ -490,6 +490,8 @@ impl WasmExecutor {
 		let memory = intermediate_instance
 			.not_started_instance()
 			.export_by_name("memory")
+			// TODO: with code coming from the blockchain it isn't strictly been compiled with rustc anymore.
+			// these assumptions are probably not true anymore
 			.expect("all modules compiled with rustc should have an export named 'memory'; qed")
 			.as_memory()
 			.expect("in module generated by rustc export named 'memory' should be a memory; qed")
@@ -537,7 +539,7 @@ impl CodeExecutor for WasmExecutor {
 		method: &str,
 		data: &[u8],
 	) -> Result<Vec<u8>> {
-		let module = Module::from_buffer(code).expect("all modules compiled with rustc are valid wasm code; qed");
+		let module = Module::from_buffer(code)?;
 		self.call_in_wasm_module(ext, &module, method, data)
 	}
 }