"Extract Method" handles variables defined from pattern matching poorly

[Meowtimer]

Version Used:
5.0.0-1.25319.11

Steps to Reproduce:

1. Have some statements/expressions doing pattern matching and extracting variables
2. Select said code and invoke extract method refactoring

Original code:

static void PatternMatchingUsage()
{
  var t = (1, 2);
  // selection start
  switch (t)
  {
    case (var x, 2):
      Console.WriteLine(x);
      break;
  }
  // selection end
}

Expected Behavior:

Extract method treats extracted variables as belonging to the scope they are extracted in and does not introduce out parameters, extra declarations etc.

Actual Behavior:

Extracted method has extra declaration of extracted variable.

static void PatternMatchingUsage()
{
  var t = (1, 2);
  NewMethod(t);
}

private static void NewMethod((int, int) t)
{
  int x;
  switch (t)
  {
    case (var x, 2) when x % 2 is 0:
      Console.WriteLine(x);
      break;
  }
}

With more involved examples Extract method might introduce out parameters which then also produce actual compiler errors, not just warnings of unused variable declarations like in the example.

[William-Banquier]

Hello, can I work on this issue?

[CyrusNajmabadi]

Absolutely @William-Banquier

[Tapo16]

static void PatternMatchingUsage()
{
var t = (1, 2);
NewMethod(t);
}

private static void NewMethod((int, int) t)
{
int x;
switch (t)
{
case (var x, 2) when x % 2 is 0:
Console.WriteLine(x);
break;
}
} this syntax is not supported in the ver 7 and 8 but when i used this static void PatternMatchingUsage()
{
var t = (1, 2);
NewMethod(t);
}

private static void NewMethod((int, int) t)
{
int x;
switch (t)
{
case (var x, 2) when x % 2 is 0:
Console.WriteLine(x);
break;
}
} then it is fine

[William-Banquier]

Absolutely @William-Banquier

Awesome, thank you, will try to get a PR ready with the fix over the next couple days