Minor fix of warning

com.oracle.truffle.r.nodes/src/com/oracle/truffle/r/nodes/qirinterface/QIRTranslateVisitor.java

@@ -85,7 +85,7 @@ public final class QIRTranslateVisitor implements RSyntaxNodeVisitor<QIRNode> {
                 final RNode value = ((WriteLocalFrameVariableNode) child).getRhs();
 
                 // If the assignment value reads an argument, then we translate to a lambda.
-                result = new QIRLambda(dummy, null, new QIRVariable(dummy, (String) ((WriteLocalFrameVariableNode) child).getName(), null), result, new FrameDescriptor());
+                result = new QIRLambda(dummy, null, new QIRVariable(dummy, ((WriteLocalFrameVariableNode) child).getName(), null), result, new FrameDescriptor());
                 // Else we apply STRAD-ASSIGN-ID normally
                 if (!(value instanceof AccessArgumentNode))
                     result = new QIRApply(dummy, result, value.asRSyntaxNode().accept(this));