@@ -8,8 +8,9 @@
 import polemy._common;
 import polemy.failure;
 import polemy.lex;
 import polemy.ast;
+import polemy.layer;
 
 /// Parse a string and return its AST
 /// Throws: ParseException, LexException, UnexpectedEOF
 
@@ -101,11 +102,11 @@
 			auto e = tryEat("(")
 				? parseLambdaAfterOpenParen(pos)  // let var ( ...
 				: (eat("=", "after "~kwd), E(0)); // let var = ...
 			if( moreDeclarationExists() )
-				return new LetExpression(pos, var, "(system)", e, Body());
+				return new LetExpression(pos, var, SystemLayer, e, Body());
 			else
-				return new LetExpression(pos, var, "(system)", e, new VarExpression(pos, var));
+				return new LetExpression(pos, var, SystemLayer, e, new VarExpression(pos, var));
 		}
 		else
 		{
 			string kwd = layer;
@@ -474,9 +475,9 @@
 			var("foo"))
 	);
 
 	assert_eq(parseString(`@@type ( x ) { x }`),
-		let("@type", "(system)", fun(["x"], var("x")), var("@type")) );
+		let("@type", SystemLayer, fun(["x"], var("x")), var("@type")) );
 
 	assert_eq(parseString(`{}`), call(var("{}")));
 	assert_eq(parseString(`{foo:1,"bar":2}`),
 		call(var(".="), call(var(".="), call(var("{}")), strl("foo"), intl(1)), strl("bar"), intl(2)));