Extended Relational Patterns in Switch statement's cases: Allowing Local Variables and Fields

[explorest]

Current relational patterns in switch statement cases (e.g. case > 10) are limited to constant expressions. This proposal extends them to allow local variables, parameters, and fields, reducing verbosity and improving readability in switch statements/expressions.
Currently we can only use constants in relational patterns. Like so :

int x = 10;
int y = 20;
switch (x)
{
    case  > 0  :  return "x>0";    
    case <  0  :  return "x<0";        

}

If we need to use variables , the current syntax requires type patterns with when guard.

 int x = 10;
 int y = 20;
 switch (x)  
 {
    case int when x > y: return "x > y";
    case int when x < y: return "x < y";
    case int when x == y: return "x == y";
 }

This is needlessly verbose. Matching on the type int makes no sense for this use case.
Proposed (Concise) syntax :

  int x = 10;
  int y = 20;
  switch (x)
 {
    case > y: return "x > y";
    case < y: return "x < y";
    case == y: return "x == y";
  }

[huoyaoyuan]

#6947 #7736