segfault in auto string method generated for []&int{len:1} (does not check for 0 pointers)

[spytheman]

V doctor:

OS: linux, Ubuntu 20.04.3 LTS
Processor: 2 cpus, 64bit, little endian, Intel(R) Core(TM) i3-3225 CPU @ 3.30GHz
CC version: cc (Ubuntu 10.3.0-1ubuntu1~20.04) 10.3.0

getwd: /v/cleanv
vmodules: /home/delian/.vmodules
vroot: /v/cleanv
vexe: /v/cleanv/v
vexe mtime: 2022-06-19 06:36:55
is vroot writable: true
is vmodules writable: true
V full version: V 0.2.4 1d46213.e031096

Git version: git version 2.25.1
Git vroot status: weekly.2022.24-27-ge0310964
.git/config present: true
thirdparty/tcc status: thirdparty-linux-amd64 eee03626

What did you do?
v -g -o vdbg cmd/v && vdbg auto_str_method_not_checking_for_null_pointers.v

fn main() {
	a := []&int{len: 1}
	println(a)
}

What did you expect to see?

[ nil ] or some other representation of an array containing 1 zero pointer ([&0] would be ambigous though with an element pointing to an actual int 0 value)

What did you see instead?

signal 11: segmentation fault
/tmp/v_1000/auto_str_method_not_checking_for_null_pointers.3793111048561402845.tmp.c:7070: at print_backtrace: Backtrace
/tmp/v_1000/auto_str_method_not_checking_for_null_pointers.3793111048561402845.tmp.c:7141: by v_segmentation_fault_handler
7ffff7dcc0c0 : by ???
/tmp/v_1000/auto_str_method_not_checking_for_null_pointers.3793111048561402845.tmp.c:2014: by Array_int_ptr_str
/tmp/v_1000/auto_str_method_not_checking_for_null_pointers.3793111048561402845.tmp.c:12079: by main__main
/tmp/v_1000/auto_str_method_not_checking_for_null_pointers.3793111048561402845.tmp.c:12449: by main

[medvednikov]

Just like with struct inits requiring reference initialization, we should require such arrays to contain valid references (unless in unsafe).