Description

When comparing two entities using ==, TypeDB Rust engine panics with “entered unreachable code”, crashing the server. The query should be rejected gracefully, not cause an internal panic.

Environment

1. TypeDB distribution: Core/Cloud
2. TypeDB version: 3.5.4
3. Environment: Mac/TypeDB Cloud
4. Client and version: TypeDB Server / Studio (matching server)
5. Other details: crash in Rust backend, in type_seeder.rs:1312

Reproducible Steps

1. Set up minimal schema:

define
  attribute name, value string;

  entity obj1,
    owns name;
  entity obj2,
    owns name;

2. Execute the following query:

match
  $o1 isa obj1;
  $o2 isa obj2;

  $o1 == $o2;

3. The TypeDB server crashes / panics internally.

Expected result

A controlled error, such as TypeQL Error: invalid comparison between concepts or similar, rejecting the query without bringing down the server.

Additional information

Relevant logs:

thread 'tokio-runtime-worker' panicked at compiler/annotation/type_seeder.rs:1312:22:
internal error: entered unreachable code: Expected attribute type
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace