You're seeing just the function validate_schemaless_type_fields, go back to Domo.Changeset module for more information.
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validate_schemaless_type_fields(changeset, struct, fields, opts \\ [])

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Validates that only given fields of the changeset conforms to appropriate types defined within the schema's t() type.

Function calls validate_required/2 with given fields having no nil types in t(). Then it validates that each given field's value conforms to its type defined in t() by calling validate_change/3.

Options given as opts are bypassed to validate_required/2. F.e. it can be the :trim boolean option specifying if spaces should be trimmed before validation.


{%{}, %{name: :string, email: :string, age: :integer}}
|> cast(%{name: "Hello world", email: "some@address"}, [:name, :email])
|> validate_schemaless_type_fields(User, [:name, :email])

In the example above :name and :email values are validated to conform to appropriate types in t().