mulFromInteger was called on null

Question

i have strange errors got from my flutter pages do some math computation with null value. or i assume it was makes errors happening.

in my case i do computation such as (120 * null) inside stateful widget init section. when i build in release mode. I have debug view which means it read background in my apps and shows:

NoSuchMethodError: The method '_mulFromInteger' was called on null.
Receiver: null
Tried Calling:_mulFromInteger(134)

is multiply operations (*) have method behind of it? or can anyone explain what is _mulFromInteger?

Answer 1

This implementation of int in dart is provided by the class _IntegerImplementation. In this class you can see:

num operator *(num other) => other._mulFromInteger(this);

You can see that the implementation of the operator * calls _mulFromInteger on the argument. That's why you get this error.