failed to use SkipValidation in nested models

[sydney-runkle]

Discussed in #7373

^{Originally posted by birdca September 8, 2023}
I was trying to use SkipValidation like this:

class ModelA(BaseModel):
    pass

class ModelB(BaseModel):
    a: ModelA
    pass

class ModelC(BaseModel):
    b: list[SkipValidation[ModelB]]
    pass

but i get

pydantic_core._pydantic_core.SchemaError: Invalid Schema:
function-after.schema.model.schema.model-fields.fields.b.schema.list.items_schema.any.serialization
  Input tag 'definition-ref' found using 'type' does not match any of the expected tags: 'none', 'int', 'bool', 'float', 'str', 'bytes', 'bytearray', 'list', 'tuple', 'set', 'frozenset', 'generator', 'dict', 'datetime', 'date', 'time', 'timedelta', 'url', 'multi-host-url', 'json', 'uuid', 'function-plain', 'function-wrap', 'format', 'to-string', 'model' [type=union_tag_invalid, input_value={'type': 'definition-ref'...ModelB:140286906022960'}, input_type=dict]
    For further information visit https://errors.pydantic.dev/2.3/v/union_tag_invalid

Wondering how to skip validation for b field?

[sydney-runkle]

fixed by #7381