#717 Create dynamic array of UDT with only a destructor induces a bad data member initialization of array elements

[fxm (freebasic.net)]

When we create a dynamic array of UDT with only a destructor (without implicit or explicit constructor), the first element(s) or more of the array is(are) badly initialized (relating their member data values per default)!

Example:

Type UDT
  I As Integer
  Declare destructor ()
End Type
Destructor UDT ()
End Destructor

Dim u1(3 to 7) As UDT
Print u1(3).I, u1(4).I, u1(5).I, u1(6).I, u1(7).I

Dim N As Integer = 7

Dim u2(3 to N) As UDT
Print u2(3).I, u2(4).I, u2(5).I, u2(6).I, u2(7).I

Redim u3(3 to N) As UDT
Print u3(3).I, u3(4).I, u3(5).I, u3(6).I, u3(7).I

Dim pu As UDT Ptr = New UDT[5]
Print pu[0].I, pu[1].I, pu[2].I, pu[3].I, pu[4].I

Sleep

Result:

 0             0             0             0             0
 3342792       3342792       1129469263    1346196293    1767332922
 3342760       3342760       1180130387    1378775925    1996510021
 0             0             0             0             0

If we suppress the destructor, or if we add a constructor (implicitly by an initializer, or by including an object with constructor, or even with an explicit empty constructor), the fault disappears!

[fxm (freebasic.net)]

This bug is already present from fbc version 0.17 (the first version which supports UDT destructor).
From fbc version 0.18.2 up to fbc version 0.20.0, this even induces an "Aborting due to runtime error 12 ("segmentation violation" signal)" from the compiler.

[Ebben]

The example works properly here with git HEAD on linux.

[dkl]

Fixed by [7ec04a]

The simple example showed only zeroes for me aswell, but valgrind reported the accesses to uninitialized memory.