# `Trogon.TypeProvider.UnregisteredMappingError`
[🔗](https://github.com/straw-hat-team/beam-monorepo/blob/trogon_typeprovider@v1.0.0/apps/trogon_typeprovider/lib/trogon/type_provider/unregistered_mapping_error.ex#L1)

Exception raised when attempting to access an unregistered type mapping in a TypeProvider.

This exception provides detailed information about the failed lookup,
including the mapping that was requested and the TypeProvider that was consulted.

# `t`

```elixir
@type t() :: %Trogon.TypeProvider.UnregisteredMappingError{
  __exception__: term(),
  mapping: term(),
  type_provider: module()
}
```

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*Consult [api-reference.md](api-reference.md) for complete listing*