# `Schooner.Host.TypeError`
[🔗](https://github.com/ausimian/schooner/blob/1.2.0/lib/schooner/host/type_error.ex#L1)

Raised by `Schooner.Host` asserting accessors (`to_*!/2`) when a
Scheme value does not match the shape the host expected.

The exception carries `:op` (a host-supplied label naming the call
site, e.g. `"my-lib/info"`), `:expected` (a short description of the
shape that was demanded, e.g. `"string"`, `"proper list"`), and
`:got` (the actual value, rendered with `inspect/1` in the
message). Callers can match on `:op` and `:expected` without
depending on the message wording.

`:location` is the `Schooner.Location` of the script call that
reached the host function. It is only filled in when the script runs
with `debug: true`; see "Source locations" in `Schooner`. With
`debug: true`, `:scheme_backtrace` lists the procedure calls that
led to the error, most recent first (see `Schooner.Frame`); otherwise
it is `nil`.

# `t`

```elixir
@type t() :: %Schooner.Host.TypeError{
  __exception__: true,
  expected: binary(),
  got: term(),
  location: Schooner.Location.t() | nil,
  message: binary(),
  op: binary(),
  scheme_backtrace: [Schooner.Frame.t()] | nil
}
```

---

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