MutableOperandRange getArgOperandsMutable() {
      return getArgsMutable();
    }

    // Return the callee of this operation.
    CallInterfaceCallable getCallableForCallee() { return getCalleeAttr(); }
    // Sets the callee from the callable
    void setCalleeFromCallable(CallInterfaceCallable callee);
  }];

  let assemblyFormat = [{
    $callee `(` $args `)` attr-dict `:` functional-type($args, results)

//===----------------------------------------------------------------------===//

void CallOp::setCalleeFromCallable(CallInterfaceCallable callee) {
  // Direct call.
  if (FlatSymbolRefAttr calleeAttr = getCalleeAttr()) {
    auto symRef = callee.get<SymbolRefAttr>();
    return setCalleeAttr(cast<FlatSymbolRefAttr>(symRef));
  }
  // Indirect call, callee Value is the first operand.
  return setOperand(0, callee.get<Value>());