Why do I get an error when I use DumpMachine in q#? - q#

Question

Here is my code:
using (q = Qubit()) {
Message("Input:");
Message("q = ∣0❭, index = 1");
Message("Requaired Output:");
Message("∣0❭: 0.707107 + 0.000000 i");
Message("∣1❭: 0.000000 + -0.707107 i");
Task12(q, 1);
Message("Your Output:");
DumpMachine();
Reset(q);
}
But I get this error:
The type or namespace name '_2e502c3cdee5457783e1ea9b1f54eb1b_DumpMachine' does not exist in the namespace 'Microsoft.Quantum.Diagnostics' (are you missing an assembly reference?)
Does anyone have an idea why?

Answer 1

Can you verify if you have open Microsoft.Quantum.Diagnostics; listed?
I copied your code and added the functions, it works for me, I use .NET Core 3.1 & VisualStudio 2019, here is my code, I also added it to GitHub https://github.com/nahidf-adventures/qsharp-adventures/tree/master/src/QbitSample:
namespace QbitSample {
open Microsoft.Quantum.Canon;
open Microsoft.Quantum.Intrinsic;
open Microsoft.Quantum.Measurement;
open Microsoft.Quantum.Diagnostics;
#EntryPoint()
operation HelloQ() : Unit {
using (q = Qubit()) {
Message("Input:");
Message("q = ∣0❭, index = 1");
Message("Requaired Output:");
Message("∣0❭: 0.707107 + 0.000000 i");
Message("∣1❭: 0.000000 + -0.707107 i");
Task12(q, 1);
Message("Your Output:");
DumpMachine();
Reset(q);
}
}
operation Task12(q: Qubit, count : Int) : Unit {
}
}