Defer all code generation for with expressions, to avoid Babel validation errors for dynamically generated environment values

src/transformers/index.js

@@ -93,11 +93,11 @@ let trivial = {
 			let contextName = `$implicit${implicitContextCounter++}`;
 			setContext(null, "implicitContext", contextName);
 
+			return defer((node) => {
 			let setupCode = (hasParent)
 				? tmplImplicitContextNested({ environment: node.environment, parent: parentContext })
 				: tmplImplicitContextTop({ environment: node.environment });
 
-			return defer((node) => {
 				return tmplWithWrapper({
 					contextName: contextName,
 					setupCode: setupCode,