Strange problem with if-else

Question

I remember this tip in if-else lesson:
"When only one line of code is in the if block, the curly braces can be omitted."
So let's test this :
// Suppose that everything is okay and the condition is true.
(Edited)

using System;

namespace Test
{
class Program
{
static void Main(string[] args)
{
string Value2 = "Hello";
if (true)
var Value1 = Value2; // Error : Embedded statement cannot be a declaration or labeled statement
}
}
}
So we're not able to omitt curly braces in this situation.
Tested in visual studio 2015
Any idea about why such a thing is not possible?

Answer 1

What's around that IF statement? What does "something" consist of?

Answer 2

@Jamie
Thanks for your great answer.

Answer 3

show us the whole code, what is something

Answer 4

OK let me make it clearly.

using System;

namespace Test
{
class Program
{
static void Main(string[] args)
{
string Value2 = "Hello";
if (true)
var Value1 = Value2; // Error: Embedded statement cannot be a declaration or labeled statement.
}
}
}