You can build an expression tree which contains an addition assignment operation that does not have overflow checking using Expression.AddAssign method. For example, you have the following code.
int myInt;
myInt = 2;
myInt += 5;
Console.WriteLine(myInt);
Here is the code that is required to build the same functionality using expression tree.
ParameterExpression myIntVariableExpr = Expression.Variable(typeof(int), "myInt");
BlockExpression addAssignExpr = Expression.Block(
new ParameterExpression[] { myIntVariableExpr },
Expression.Assign(myIntVariableExpr, Expression.Constant(2)),
Expression.AddAssign(
myIntVariableExpr,
Expression.Constant(5)
)
);
Console.WriteLine(Expression.Lambda<Func<int>>(addAssignExpr).Compile()());