This warning appears when a mandatory parameter is mentioned in a function definition after an optional parameter.
Make sure optional parameter is always mentioned at the end of the parameter list.
Example
[#Menu: Gateway Of Tally]
Add: Item: "MyFunc": Call: MyFunc
[Function: MyFunc]
000: Call: MyFunc2
[Function: MyFunc2]
Parameter: pVar1: String: "Var1"
Parameter: pVar2: String
In the example, the parameter pVar2 is a mandatory parameter which is mentioned after an optional parameter pVar1. Hence the message warning T0020: In the function 'MyFunc2', the mandatory parameter 'pVar1' is specified after optional parameter appears.
The code is corrected by adding the optional parameter at the end.
[#Menu: Gateway Of Tally]
Add: Item: "MyFunc": Call: MyFunc
[Function: MyFunc]
000: Call: MyFunc2: "Var2"
[Function: MyFunc2]
Parameter: pVar2: String
Parameter: pVar1: String: "Var1"