Records with internal readonly fields/properties derived from constructor should initialise within the constructor

[Jeltz191]

I often use a record construct to pre-calculate variables that are used multiple times within the records methods (see example below). Currently line 4 is disallowed (CS0236), but if placed in a traditional constructor it becomes perfectly acceptable. Changing the initializer to a lambda method defeats the efficiency improvements, and changing to an old-style constructer just bloats the code.

public record test(int j1, int j2)
{
private readonly int q2 = 2 * j1 + j2 * j2; //pre-calculate
private readonly int q3=q2*j1; //currently not allowed!!!!
// private readonly int q3=(2 * j1 + j2 * j2)j // allowed but inefficient and less readable
// private readonly int q3=>q2j1; //allowed but defeats the purpose of improving efficiency.
public (int, int) Method(int j3) //Method made more efficient due to pre-calculation
{
return (q2 + j2 * j3, q2 * j3 + j2);
}
}