Is it possible to return SETOF <type-name> in a custom function?

When creating a function, it must return all the rows of a table:

> Return type: MUST be `SETOF `

Why can I not return `SETOF `, for example:

```sql
CREATE TYPE my_type AS (f1 text, f2 text);
```

There is a workaround where you can create a table with the required rows and return a `SETOF` that, but would types be neater?

The issue provides no repository file or test entry point. Start by tracing how custom PostgreSQL functions and declared return types are handled, then determine whether SETOF a user-defined composite type is supported; done would require an agreed behavior and corresponding implementation or documentation.

Written by the indexing model from the issue text.