#861 From inside a non static member procedure, ThreadCall allows to start as a thread a non static member Sub()

[fxm (freebasic.net)]

Compiler bug (see forum at https://www.freebasic.net/forum/viewtopic.php?f=3&t=25865):

From inside a non static member procedure, ThreadCall allows to start as a thread a non static member Sub (without any parameters), which crashes only if attempting to access a non static member field (same execution behavior than calling a non static member procedure on a null pointer).

In the following example, the two syntaxes should be disallowed by the compiler and induce a compiler error message:

Type UDT
   Dim As Integer value
   Declare Sub thread ()
   Declare Sub thread_start ()
end type

Sub UDT.thread ()
   Do
      Print "IT WORKS!"  ', value  '' program crashes when accessing to value
   Loop Until Inkey <> ""
End Sub

Sub UDT.thread_start ()
   'Threadcall This.thread()  '' compiler error => OK
   Threadcall UDT.thread()   '' no compiler error => NOK
   Threadcall thread()       '' no compiler error => NOK
End Sub

Dim As UDT u
u.thread_start

Sleep

[fxm (freebasic.net)]

As soon as the Sub() thread has a parameter to pass, the compiler outputs an error message, but that: "error 24: Invalid data types".