Selfhost Compiler Crashed with Segmentation Fault printing a LinkedList

[horenso]

WHF :) On the most recent main branch (commit 9c52bee6) I tried to compile the following progam:

struct LinkedList {
    value: i64
    next: LinkedList?
}

function main() {
    mut node1 = LinkedList(value: 1, next: None)
}

and the compiler (not the resulting program) crashed with a Segmentation Fault.|

Steps I took:

cargo install --path .
jakt ./selfhost/main.jakt && mv ./build/main ./jakt_selfhost
./jakt_selfhost test.jakt # test.jakt is the program shown above

The Rust-based compiler doesn't crash and produces some Cpp which clang then rejects with
error: invalid application of 'sizeof' to an incomplete type 'Jakt::LinkedList'

[robryanx]

It is basically this line: if struct_.record_type is Class and not top_level { in codegen.jakt
As the record type is Struct it ends up with infinite recursion.
If the code is changed from struct to class it works, I am not sure if there should be an error about recursion in structs or that the codegen should be changed to handle it.

[horenso]

Ah interesting, since Struct is a value type it makes sense that it cannot contain itself as a value. I think the typechecker should handle that case.

[maddanio]

Basically the same as with recursive enums which have to be boxed (aka class)

[7w17chy]

So the compiler should reject code in which a value type references itself directly, as in:

struct S {
    field: S
}

and indirectly through other value types such as tuples, arrays or other structs (e. g. Optional):

struct S {
    field: S?
}

whilst allowing non-value types such as pointers to reference it safely?

[maddanio]

only if it is a struct, it should work for classes.

[maddanio]

i.e. this should be ok:

class S {
    field: S
}