[Bug]: OpenAPI 3 emitter incorrectly generate duplicate name error

[allenjzhang]

Describe the bug

Simple model definition generates:

@typespec/openapi/duplicate-type-name
Duplicate type name: 'Foo'. Check @friendlyName decorators and overlap with types in TypeSpec or service namespace.

Reproduction

Playground link

Checklist

• Follow our Code of Conduct
• Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion.
• The provided reproduction is a minimal reproducible example of the bug.

[bterlson]

A slightly more minimal repro

import "@typespec/http";

using TypeSpec.Http;

@service({
  title: "Test Service",
})
namespace DemoService;
model Foo is TrackedResource {
  @path name: string;
}
model Resource {}
model TrackedResource extends Resource {}

Does not repro when without an extends chain 3 deep or more.

[timotheeguerin]

the problems comes from the fact that we use Visibility.all to render the unreachable models but when figuring out if the properties are the same we use Visibility.read so Foo gets emitted with both.

[timotheeguerin]

though it is weird because it is only doing that with derived models