Matching no types to the right from isa throws an error

[izmalk]

Description

When matching types, there can be a situation where no types are matched by the schema.
Using a concept variable that matches no types as a type in an isa produces an error.

Environment

1. TypeDB distribution: Core
2. TypeDB version: 2.26.6
3. Environment: macOS
4. Client and version: Studio 2.26.0
5. Other details:

Reproducible Steps

1. Set up

Any schema with no @key annotations.
The @key here is not of utmost importance, just a convenient way of matching no types.

2. Execute

match
$f isa! $type;
$type owns $a @key;
get;

3. Unexpected result

[QRY16] Invalid Query Pattern: Could not infer compatible types for the match pattern:
'{{ $type owns $a@@key; 
$f isa! $type; }}'.

Expected result

Empty collection (iterator/stream).

Additional information

Relevant logs from TypeDB or Driver:

14:32:11.725 [typedb-service::0] ERROR com.vaticle.typedb.core.server.TransactionService -- [QRY16] Invalid Query Pattern: Could not infer compatible types for the match pattern:
'{{ $type owns $a@@key;
$f isa! $type; }}'.

I'm not sure why @ is duplicated in the server logs.

[flyingsilverfin]

Makes sense.
I've fixed the wrong toString for now!