Reject infinite size struct definition

[Y-Nak]

What is wrong?

Currently, the below codes are not appropriately rejected and lead to ICE when it is instantiated.

Self recursion

struct Foo:
    foo: Foo

contract MyContract:
    pub fn func(foo: Foo):
       pass

Mutual recursion

struct Foo:
    x: Bar
    
struct Bar:
    x: Foo

contract MyContract:
    pub fn func(foo: Foo):
       pass

How can it be fixed

Reject recursive struct definition in analyzer.
This could be done by checking recursions in analyzer::items::StructId::sink_diagnostics using analyzer::items::StructId::struct_depency_graph.

[Narasimha1997]

I can work on this.

[Narasimha1997]

@Y-Nak

salsa create panics when it sees a cycle in the dependency graph.

Here is the error message:

---- struct_recursive_cycles stdout ----
thread 'struct_recursive_cycles' panicked at 'Internal error, cycle detected:

DatabaseKeyIndex { group_index: 0, query_index: 57, key_index: 0 }
DatabaseKeyIndex { group_index: 0, query_index: 57, key_index: 1 }
', /home/narasimha/.cargo/registry/src/github.com-1ecc6299db9ec823/salsa-0.16.1/src/lib.rs:490:48
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Is there any way we can catch this Panic and handle it?

Check out the related issue here

[Y-Nak]

@Narasimha1997
Hi! Thanks for working on the issue!

One way to catch the cycle would be to use salsa::cycle. We use it here for example.

[Narasimha1997]

@Y-Nak thanks for reverting back.
Also if possible can you suggest me a suitable error message for this?