Migration Create -> InternalServerError: AssertionError: (due to invalid overloaded pointer)

[CarsonF]

• EdgeDB Version: 5.1+4ced01b
• EdgeDB CLI Version: 5.2.0-dev.1153+93311cf
• OS Version: mac

Steps to Reproduce:

1. migration create

edgedb error: InternalServerError: AssertionError: 
Server traceback:
  Traceback (most recent call last):
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler_pool/worker.py", line 178, in compile
      units, cstate = COMPILER.compile_request(
                      ^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler/compiler.py", line 857, in compile_request
      units, cstate = self.compile(
                      ^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler/compiler.py", line 937, in compile
      unit_group = compile(ctx=ctx, source=source)
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler/compiler.py", line 2585, in compile
      return _try_compile(ctx=ctx, source=source)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler/compiler.py", line 2663, in _try_compile
      comp, capabilities = _compile_dispatch_ql(
                           ^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler/compiler.py", line 2490, in _compile_dispatch_ql
      query = ddl.compile_dispatch_ql_migration(
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler/ddl.py", line 386, in compile_dispatch_ql_migration
      return _start_migration(ctx, ql, in_script)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/server/compiler/ddl.py", line 466, in _start_migration
      target_schema = s_ddl.apply_sdl(
                      ^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/ddl.py", line 595, in apply_sdl
      process(ddl_stmt)
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/ddl.py", line 537, in process
      cmd = cmd_from_ddl(
            ^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/ddl.py", line 467, in cmd_from_ddl
      res = sd.compile_ddl(schema, ddl, context=context)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/delta.py", line 4457, in compile_ddl
      cmd = cmdcls._cmd_tree_from_ast(schema, astnode, context)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/inheriting.py", line 1061, in _cmd_tree_from_ast
      cmd = super()._cmd_tree_from_ast(schema, astnode, context)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/delta.py", line 3583, in _cmd_tree_from_ast
      cmd = super()._cmd_tree_from_ast(schema, astnode, context)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/delta.py", line 1110, in _cmd_tree_from_ast
      subcmd = compile_ddl(schema, subastnode, context=context)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/delta.py", line 4457, in compile_ddl
      cmd = cmdcls._cmd_tree_from_ast(schema, astnode, context)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/unknown_pointers.py", line 94, in _cmd_tree_from_ast
      cmd._process_create_or_alter_ast(schema, fakenode, context)
    File "edgedb/portable/5.1/lib/python3.12/site-packages/edb/schema/pointers.py", line 1989, in _process_create_or_alter_ast
      assert astnode.target is not None
  AssertionError

Schema:
SeedCompany/cord-api-v3@8b7354c

[CarsonF]

Ok this is actually because I have overloaded owner which is a link that is no longer an inherited link. It was removed, and then this branch was rebased.

So just a nicer error message would help with this user error.