Nilaway does not catch panic when using reflect.TypeOf function

[zsaurabhsabharwal]

reflect package states that TypeOf function will return a nil pointer if a nil interface is passed to as an argument (https://cs.opensource.google/go/go/+/refs/tags/go1.21.6:src/reflect/type.go;l=1151)

In the below example, I've passed a nil interface value to this function and tried to call a pointer method on it, when executing the script I get a panic with nil pointer dereference error message, however nilaway fails to detect this.

[sonalmahajan15]

@zsaurabhsabharwal , thanks for reporting! We'll look into adding support for this in NilAway. Contributions are welcome, of course. :)

[yuxincs]

FWIW, for this particular case (and possibly other similar cases from stdlib), we can probably model it in NilAway (basically treating the return value as nilable without analyzing the body). The reason is that it uses functions from runtime (i.e., unsafe here) that NilAway simply cannot analyze, even if told to do so.