% ./changed dontexist
panic: runtime error: invalid memory address or nil pointer dereference
[signal 0xb code=0x1 addr=0x20 pc=0x401f98]
goroutine 16 [running]:
runtime.panic(0x507e40, 0x5ce9d3)
/usr/lib/go/src/pkg/runtime/panic.c:279 +0xf5
main.func·001(0xc208046960, 0x19, 0x0, 0x0, 0x7f7cc98d6550, 0xc208024a80, 0x0, 0x0)
/home/username/sw/changed/changed.go:53 +0x68
path/filepath.Walk(0xc208046960, 0x19, 0x7f7cc9737d68, 0x0, 0x0)
/usr/lib/go/src/pkg/path/filepath/path.go:388 +0xa9
main.(*Walker).Walk(0x7f7cc9737de8, 0xc208046960, 0x19, 0x7f7cc9737dd8, 0x0, 0x0)
/home/username/sw/changed/changed.go:74 +0x76
main.buildLocalFileSet(0xc208046960, 0x19, 0xc20800f140, 0x4, 0x4, 0x0, 0x0, 0x0, 0xc208046920)
/home/username/sw/changed/changed.go:120 +0xe2
main.HasChanged(0xc208046960, 0x19, 0xc20800f140, 0x4, 0x4, 0x0, 0x0, 0x0, 0x543ab0)
/home/username/sw/changed/changed.go:162 +0xa3
main.main()
/home/username/sw/changed/changed.go:180 +0x24e
goroutine 17 [runnable]:
runtime.MHeap_Scavenger()
/usr/lib/go/src/pkg/runtime/mheap.c:507
runtime.goexit()
/usr/lib/go/src/pkg/runtime/proc.c:1445
goroutine 18 [runnable]:
bgsweep()
/usr/lib/go/src/pkg/runtime/mgc0.c:1976
runtime.goexit()
/usr/lib/go/src/pkg/runtime/proc.c:1445
goroutine 19 [runnable]:
runfinq()
/usr/lib/go/src/pkg/runtime/mgc0.c:2606
runtime.goexit()
/usr/lib/go/src/pkg/runtime/proc.c:1445