Epic: 2.5.0 #219

Goal

2.5.0 takes the parts of Metalama 2027.0 that help TypeKit: AspectTesting on xunit.v3, the aspect-author analyzers, type facets, and union and closed-class awareness in the code model beyond #223 (release notes, read 2026-10-30 at 2027.0.4-preview). The roadmap's Metalama 2027.0 item holds the plan.

The move to Metalama 2027.0 itself (#173), the woven-union checks (#272) and what the generators do with a union or a closed class (#223) went to 2.4.0 on 2026-10-31 (decision 129): Metalama 2026.1 fails a web project where SDK 11 is the only SDK (#275), and 2.4.0 must build there.

In scope and out of scope

In:

• the work Metalama 2027.0 enables beyond building, attached here;
• additions and gaps from the roadmap;
• fixes for defects in 2.5.0's own new work.

Out:

• Metalama interceptors in a shipped package. They need a registered Metalama license (Community or higher; the interceptors docs, 2027.0), and the transitive fabric would put that requirement on every consumer project. That conflicts with the license-free build Move the Generators package to Metalama 2027.0 in 2.4.0 (decisions 120 and 129) #173 requires in 2.4.0.
• A union introduced by the generators. It exists on net11.0 only, against rule 3 of decision 120 (generated members are the same on every target), so it would need a new record first.
• Anything breaking, which waits for 3.0.0.
• A fix for a bug that shipped in 2.4.0, which is a 2.4.x patch.

Done when

Every sub-issue is closed, the suite passes, oracles seeds shows every seed caught, v2.5.0 is tagged on the merge of release/2.5.0 into main, and the packages are on nuget.org. The release PR into main closes this epic.