# LDC-E5404 — Revision edge points at no declared edition

## What it means

A revision edge links two declared editions: the `previous` one its
operations start from and the `next` one they must produce. Both names must
resolve to editions declared in the same package. When either side names
something undeclared, there is nothing to apply the operations to, so the
compiler reports the broken link before looking at any operation.

## Example

```law
language "law.core" version "0.2";
package demo.diagnostics version "0.1.0";
namespace "urn:law:demo:diagnostics";

source ORDER { kind ministerial_order; }
edition ED_2025 of ORDER { language ru; officiality official; }
edition ED_2026 of ORDER { language ru; officiality official; }
fragment F_OLD in ED_2025 { kind article; locator "article/5";
  text ru official """старая редакция"""; }
fragment F_NEW in ED_2026 { kind article; locator "article/5";
  text ru official """новая редакция"""; }
revision LAW_1 {
  previous ED_1999;
  next ED_2026;
  relation amends;
  op replace { locator "article/5"; language ru; text """новая редакция"""; }
}
```

## Fix

```law
language "law.core" version "0.2";
package demo.diagnostics version "0.1.0";
namespace "urn:law:demo:diagnostics";

source ORDER { kind ministerial_order; }
edition ED_2025 of ORDER { language ru; officiality official; }
edition ED_2026 of ORDER { language ru; officiality official; }
fragment F_OLD in ED_2025 { kind article; locator "article/5";
  text ru official """старая редакция"""; }
fragment F_NEW in ED_2026 { kind article; locator "article/5";
  text ru official """новая редакция"""; }
revision LAW_1 {
  previous ED_2025;
  next ED_2026;
  relation amends;
  op replace { locator "article/5"; language ru; text """новая редакция"""; }
}
```

## Engine message

The engine reports this in its own wording:

```text
example.law:12:10: error LDC-E5404: edge "LAW_1": previous does not resolve to a declared edition — there is nothing to apply operations to (§32.2)
```

## Related

- [Sources](/constructs/sources/) — how editions of a source work are declared.
- [Time](/constructs/time/) — how editions and effective moments order amendments.