var means the same as
dynamic in Dart.
In Dart 1.0,
var also means
However, in Dart 2.0,
auto, as in, take the type of the expression on the right hand side.
This means that code such as the following fails:
var widget = new Row(...); ... widget = new Container(...);
We should either make
dynamic or make
var get the type that is the common denominator of all the expressions that are assigned to the variable. Otherwise we are going to be putting up a barrier to entry for a large class of Flutter developers who do not care about types at all.