Code Review

I found one issue that needs attention:

Snapshot Tests Required

This PR modifies the source generator output format by changing comma placement from end-of-line to beginning-of-line:

Before:

new Attribute1(),
new Attribute2(),
new Attribute3()

After:

new Attribute1()
,new Attribute2()
,new Attribute3()

While both formats are valid C#, this is a functional change to the generated code that requires snapshot test updates per CLAUDE.md Critical Rule #2:

"Snapshot Testing - Changes to source generator output or public APIs require running snapshot tests. Commit .verified.txt files."

Action needed:

cd TUnit.Core.SourceGenerator.Tests
dotnet test

# Review the changes in *.received.txt files, then accept them:
for f in *.received.txt; do mv "$f" "${f%.received.txt}.verified.txt"; done
git add *.verified.txt

Performance Analysis

The PR successfully achieves its performance goal with a ~0.6 MB reduction in allocations (101.25 MB → 100.62 MB), which aligns well with CLAUDE.md Critical Rule #4 (Performance First). The slight increase in execution time (~16 ms) is likely within margin of error given the non-ideal benchmark conditions noted in the PR description.

The refactoring eliminates the intermediate List<AttributeData> buffer, which is a good optimization for a hot path (source generation). The logic transformation is correct - the inverted conditional and first flag approach produce equivalent filtering behavior.

Is Claude hallucinating a bug here? The snapshot tests haven't failed and I don't think my changes would create that output.

Is Claude hallucinating a bug here? The snapshot tests haven't failed and I don't think my changes would create that output.

Yep 🤣