void function() f = null;
f();

Calling a null function pointer results gives:
object.Error@(0): Access Violation
----------------
Program exited with code 1


void function() f = cast(void function())1;
f();

Calling a non-null function pointer gives:
object.Error@(0): Access Violation
----------------
0x00000001
0x00423FDB in _Dmain at D:\NX 1337\Projects\BlendUI\src\blendui\main.d(23)
0x00436353 in void rt.dmain2._d_run_main(int, char**, extern (C) int function(char[][])*).runAll().__lambda1()
0x004362D5 in void rt.dmain2._d_run_main(int, char**, extern (C) int function(char[][])*).runAll()
0x0043616F in _d_run_main
0x00424038 in main at D:\NX 1337\Projects\BlendUI\src\blendui\math\size.d(7)
0x00454FE9 in mainCRTStartup
0x76C28484 in BaseThreadInitThunk
0x771C302C in RtlValidSecurityDescriptor
0x771C2FFA in RtlValidSecurityDescriptor
Program exited with code 1


My quick glance at the trace handler source it seems like null is being used for determining length of a fixed size stack buffer. (sigh..) This is a rather frustrating bug and trivial to fix. I had to boot up linux and use gdb to just debug this nonsense.