> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sifr.sh/llms.txt
> Use this file to discover all available pages before exploring further.

# SIFR-META-0003: Package const-specialization issue declaration is malformed.

> Package const-specialization issue declaration is malformed.

`SIFR-META-0003` belongs to the **Package metaprogramming** diagnostic family. It means: package const-specialization issue declaration is malformed.

## Why It Happens

Deterministic package specialization either reported a bounded issue or declared issue data that does not match its compiler-checked template. Fix the static schema input or the package issue declaration named by the diagnostic.

<Info>
  Use `sifr --explain SIFR-META-0003` locally to see the renderer's exact message template and any machine-applicable suggestions for the compiler version you are running.
</Info>

## Erroneous Code

```python theme={null}
@const_specialize
def describe[T]() -> ConstSpecializationOutcome[str]:
    return fatal("shape.unknown", {"undeclared_argument": "value"})
```

## How To Fix It

Declare the package reason code and its exact bounded argument template, then emit only those argument names. Compiler- and LSP-reserved names such as `rule` cannot be package template arguments.

## Fixed Code

```python theme={null}
@const_specialize
def describe[T]() -> ConstSpecializationOutcome[str]:
    return fatal("shape.unsupported", {"kind": "unknown"})
```

## Details

| Field                  | Value                                              |
| ---------------------- | -------------------------------------------------- |
| Code                   | `SIFR-META-0003`                                   |
| Family                 | `META`                                             |
| Severity               | Error                                              |
| Stability              | stable                                             |
| Owner                  | `sifr_frontend::const_specialization`              |
| Representative fixture | `crates/sifr_frontend/src/const_specialization.rs` |

See the [Error Codes index](/diagnostics/error-codes) for the complete catalog.