# `Statifier.Compiler.Error`
[🔗](https://github.com/riddler/statifier-ex/blob/v2.0.0/lib/statifier/compiler/error.ex#L1)

The compiler's own error shape: `{reason, message, location}`,
character-identical in style to `Statifier.Lowering.Error`
(`lib/statifier/lowering/error.ex:21-36`).

This union is deliberately small. `Statifier.Validator` owns every
non-expression failure mode exclusively (checks 1-11 at
`lib/statifier/validator.ex:47-59`): every id `Statifier.Compiler` looks
up is guaranteed present by the time it gets there, so an unresolved
reference reaching the compiler is a validator bug, left to raise rather
than converted into a value of this type. The one failure mode that *is*
the compiler's own - a `cond`/`expr`/`<content>` source that fails to
compile - is `:expression_compile_error`, built by
`Statifier.Compiler.Expressions.compile/3` on its failure path.

# `reason`

```elixir
@type reason() ::
  {:expression_compile_error, Statifier.Compiler.Expressions.owner_ref(),
   source :: String.t(), Predicator.Errors.ParseError.t()}
```

Closed reason union. `:expression_compile_error` names the owning node
(`Statifier.Compiler.Expressions.owner_ref/0` - a transition, a content
node, or a final state's donedata), the raw expression `source`, and
predicator's own `%Predicator.Errors.ParseError{}` verbatim, in
predicator's own `{line, column}` coordinate space - the translation into
document columns happens at reporting time, not here.

# `t`

```elixir
@type t() :: %Statifier.Compiler.Error{
  location: Statifier.Parser.Location.t(),
  message: binary(),
  reason: reason()
}
```

# `expression_compile_error`

```elixir
@spec expression_compile_error(
  owner :: Statifier.Compiler.Expressions.owner_ref(),
  source :: String.t(),
  parse_error :: Predicator.Errors.ParseError.t(),
  location :: Statifier.Parser.Location.t()
) :: t()
```

A `cond`/`expr`/`<content>` source that failed to compile. `location` is
the caller's choice - the attribute *value* span
(`attribute_locations[:cond]` / `[:expr]`) when the author wrote the
attribute, the owning node's own `location` when
`Statifier.Lowering.Attributes.put_location/4` produced no entry
(`lib/statifier/lowering/attributes.ex:76-98`) - never derived here, since
this module has no access to the node the caller is compiling from.

The message names the source, predicator's message, and predicator's own
position, so a human can find the character in the file from the message
alone even before consulting `location`.

---

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