fix warning

Author: RalfJung

src/eval.rs

@@ -40,7 +40,7 @@ pub fn create_ecx<'mir, 'tcx: 'mir>(
         MemoryExtra::new(StdRng::seed_from_u64(config.seed.unwrap_or(0)), config.validate),
     );
     // Complete initialization.
-    EnvVars::init(&mut ecx, config.communicate);
+    EnvVars::init(&mut ecx);
 
     // Setup first stack-frame
     let main_instance = ty::Instance::mono(ecx.tcx.tcx, main_id);

src/shims/env.rs

@@ -13,9 +13,8 @@ pub struct EnvVars {
 impl EnvVars {
     pub(crate) fn init<'mir, 'tcx>(
         ecx: &mut InterpCx<'mir, 'tcx, Evaluator<'tcx>>,
-        communicate: bool,
     ) {
-        if communicate {
+        if ecx.machine.communicate {
             for (name, value) in std::env::vars() {
                 let value = alloc_env_value(value.as_bytes(), ecx.memory_mut());
                 ecx.machine.env_vars.map.insert(name.into_bytes(), value);