| name | cs0618-hunter |
| description | Detects and fixes CS0618 obsolete API warnings in .NET builds. The compiler is the authoritative source for what your project actually triggers — it catches transitive obsoletions, overload-resolution surprises, and project-local [Obsolete] attributes that static inspection cannot see. Pair with dotnet-inspect@0.7.8+ for the static / pre-build view. |
cs0618-hunter — compiler ground-truth for obsolete API usage
⚡ Prefer the MCP tool. The maf-autopilot MCP server exposes MafRunCs0618Hunt(projectPath) — it shells dotnet build, parses every CS0618 / CS0246 diagnostic, joins each one to its canonical fix in the obsolete-API registry, and returns a structured report. The procedural walkthrough below is preserved for when you need to run the steps manually (offline, debugging the tool itself, etc.).
Why the compiler stays authoritative
dotnet-inspect@0.7.8+ now surfaces [Obsolete] in member listings (PR #318 closes issue #316). That's an excellent pre-build static check, but three classes of obsoletion remain compiler-only:
- Transitive obsoletions — the API your code calls isn't obsolete, but it forwards to one that is.
- Overload-resolution surprises — a more-specific overload was added in a minor release and your literal types now bind to it.
- Project-local
[Obsolete] — types your team marked obsolete in this solution. Static inspection of NuGet packages can't see those.
For all three, dotnet build | Select-String "warning CS0618" is the only authoritative answer.
Manual fallback workflow
When MafRunCs0618Hunt is unavailable:
# Step 1: get the baseline
dotnet build 2>&1 | Select-String "warning CS0618"
# Step 2: for each warning, look up the canonical fix in the registry
# (the LLM should call MafRegistryLookup with the matching entry ID,
# or open .github/skills/maf-obsolete-api-registry/registry.yaml)
# Step 3: apply the fix; re-run the build; confirm the warning is gone
# Step 4: move on to the next warning. Never batch.
# Step 5: declare done only when:
dotnet build 2>&1 | Select-String "warning CS0618" | Measure-Object | Select-Object -ExpandProperty Count
# returns 0.
Quick reference
| Command | Purpose |
|---|
MafRunCs0618Hunt(projectPath) (MCP) | Full automated CS0618/CS0246 hunt |
MafApiSafety(apiName) (MCP) | Is a single API safe? (registry only) |
MafRegistryLookup(entryId) (MCP) | Full fix details for entry ID |
dotnet build 2>&1 | Select-String "CS0618" | Manual baseline scan |
