feat(generator): intercept calls whose types generated code cannot name

[glennawatson]

Summary

The generator now intercepts calls whose types it could not name before, and fails the build at any call it still cannot generate.

• Calls whose selector result is an anonymous type or a private nested type are intercepted. The result type becomes a generic parameter.
• Calls on private or protected types and members are intercepted from inside the caller's partial class, which hosts the generated code in a private nested class.
• Calls made through the caller's type parameters, such as a generic view base or a receiver typed T, are intercepted with code that is generic over them.
• A call that cannot be intercepted, on the Roslyn 4.8 build or with interceptors off, is now a build error at the call instead of a warning followed by a throw at run time.
• Anonymous result types, file-local types and BindCommand with a stored parameter expression no longer produce broken generated code.

Why

A call naming a type the generated code could not reach was skipped with a warning, and the call then threw InvalidOperationException at run time. An anonymous result type was not skipped at all, and the generator wrote the anonymous type's display name into the generated source, which then failed to compile.

Breaking changes

RXUIBIND001, 003, 006, 009, 012, 013, 015, 016 and 021 are now errors. Every call they report already threw at run time, so only code that was already broken stops compiling. To fix such a call, make the types or members it uses reachable (internal, or inside a partial class), or call the matching *Unsafe method. RXUIBIND021 stays a warning when the member is declared only by another source generator. This ships as a minor release.

How this was verified

New generator, analyzer and runtime tests cover each intercepted shape with real values for every generated API, the error path on the Roslyn 4.8 build and with interceptors off, and the shapes that still cannot be intercepted. The AOT example could not be linked locally without clang.

Notes for the reviewer

Start with Helpers/CallSiteHosting.cs and InvocationPipeline.cs, which decide whether a call is intercepted with a generic result, hosted in the caller's partial class, or reported. CodeGeneration/HostedCallSiteEmitter.cs and HostedSourceReader.cs emit the hosted code. The per-API emitters are unchanged. The analyzer changes skip any call the generator intercepts, and the AnalyzerReleases files record the severity changes. The test and snapshot files are mechanical.

Checklist

• I have read the Contribute guide
• The PR title follows Conventional Commits
• Tests cover this change, or the summary says why they do not
• New or changed public API has XML documentation

[codecov]

Codecov Report

❌ Patch coverage is 99.84917% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 99.28%. Comparing base (cbb8e3c) to head (ab95a7b).

Files with missing lines	Patch %	Lines
...g.SourceGenerators/Helpers/InteractionExtractor.cs	93.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #167      +/-   ##
==========================================
+ Coverage   99.23%   99.28%   +0.04%     
==========================================
  Files         396      403       +7     
  Lines       14469    15028     +559     
  Branches     2065     2227     +162     
==========================================
+ Hits        14359    14920     +561     
+ Misses        110      108       -2     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
99.8% Coverage on New Code
0.1% Duplication on New Code

See analysis details on SonarQube Cloud