public void SwitchUpdateDoesntRepeatEnumeration()
{
SwitchExpression sw = Expression.Switch(
Expression.Constant(0),
Expression.Constant(0),
Expression.SwitchCase(Expression.Constant(1), Expression.Constant(1)),
Expression.SwitchCase(Expression.Constant(2), Expression.Constant(2))
);
IEnumerable <SwitchCase> newCases =
new RunOnceEnumerable <SwitchCase>(
new SwitchCase[]
{
Expression.SwitchCase(Expression.Constant(1), Expression.Constant(1)),
Expression.SwitchCase(Expression.Constant(2), Expression.Constant(2))
});
Assert.NotSame(sw, sw.Update(sw.SwitchValue, newCases, sw.DefaultBody));
}
public void UpdateDoesntRepeatEnumeration()
{
MethodInfo meth = typeof(List <int>).GetMethod("Add");
ElementInit[] inits = new[]
{
Expression.ElementInit(meth, Expression.Constant(1)),
Expression.ElementInit(meth, Expression.Constant(2)),
Expression.ElementInit(meth, Expression.Constant(3))
};
ListInitExpression init = Expression.ListInit(Expression.New(typeof(List <int>)), inits);
IEnumerable <ElementInit> newInits = new RunOnceEnumerable <ElementInit>(
new[]
{
Expression.ElementInit(meth, Expression.Constant(1)),
Expression.ElementInit(meth, Expression.Constant(2)),
Expression.ElementInit(meth, Expression.Constant(3))
});
Assert.NotSame(init, init.Update(init.NewExpression, newInits));
}
private static void VerifyUpdateDifferentParamsReturnsDifferent <TDelegate>(Expression <TDelegate> lamda, ParameterExpression[] pars)
{
// Should try to create new lambda, but should fail as should have wrong number of arguments.
Assert.Throws <ArgumentException>(() => lamda.Update(lamda.Body, pars.Append(Expression.Parameter(typeof(int)))));
if (pars.Length != 0)
{
Assert.Throws <ArgumentException>(() => lamda.Update(lamda.Body, null));
for (int i = 0; i != pars.Length; ++i)
{
ParameterExpression[] newPars = new ParameterExpression[pars.Length];
pars.CopyTo(newPars, 0);
newPars[i] = Expression.Parameter(typeof(int));
Assert.NotSame(lamda, lamda.Update(lamda.Body, newPars));
}
IEnumerable <ParameterExpression> diffPars = new RunOnceEnumerable <ParameterExpression>(
Enumerable.Range(0, lamda.Parameters.Count) // Trigger Parameters collection build.
.Select(_ => Expression.Parameter(typeof(int))));
Assert.NotSame(lamda, lamda.Update(lamda.Body, diffPars));
}
}
