C# SDK compatibility

The bounded contract is morphir-dotnet-sdk-v1, schema 1, profile dotnet-sdk-v1: 67 operations, 207 required observations and eight separately reported representation exclusions. It does not claim the entire Morphir SDK. The checked-in fixtures retain independent upstream source evidence. Runtime test expectations are read from those fixtures, not computed by this runtime.

The excluded observations concern Int range or negative Int powers, supplementary Char, and exact Decimal96 representation/nontermination limits. The precise IDs and reasons remain in tests/Fixtures/MorphirSDK/cases.json. Strings support well-formed UTF-16 including supplementary scalars. Char accepts one non-surrogate BMP scalar. Dates, parsing, transcendental operations and unlisted collection functions are outside this inventory.

The runtime targets net10.0 and works with trimming and NativeAOT without reflection or dynamic code discovery. Runtime targeting is separate from the compiler SDK and numeric language version used by a consumer. Root global.json is not changed for isolated compiler verification. Ordinary package consumption must restore only Morphir.SDK.CSharp, without a project reference or repository source files. This is separate from the deferred Roslyn generator adapter.

The same ordinary consumer source was restored from an isolated local feed, compiled and executed under both exact toolchains below. Each fresh package cache contained only Morphir.SDK.CSharp; neither consumer referenced repository projects or source files.

Both target net10.0 and execute with runtime 10.0.14. SDK selection is disabled from rolling forward in each isolated global.json. The RC toolchain uses its matching 10.0.13 reference packs for net10.0 compilation; these tooling inputs are separate from package dependencies. The RC ZIP was checked against Microsoft’s release metadata. No root global.json, user setting or machine setting changed.

The same public consumer was also published and executed as self-contained trimmed and NativeAOT applications on Windows arm64, RID win-arm64, using SDK 10.0.403 and runtime 10.0.14. Both passed the ordinary consumer’s assertions and produced the same output. Trim and AOT warnings were treated as errors. The NativeAOT executable is an ARM64 native PE without a CLR header or managed Consumer.dll/coreclr.dll payload. This verifies that representative runtime consumer on that OS/RID, not every deployment target or every generic closure.

Reproduce with the checked-in PowerShell harness and installed exact toolchains:

& tests/Morphir.SDK.CSharp.Tests/verify-package-consumers.ps1 `
  -EvidenceDirectory C:/Temp/owned-fresh-sdk-proof `
  -StableDotnet C:/path/to/stable/dotnet.exe `
  -RcDotnet C:/path/to/isolated-rc/dotnet.exe

The RC directory needs its matching net10.0 targeting packs. NativeAOT needs Microsoft’s native prerequisites. The harness uses fresh local feeds/caches and process-local environment values, runs commands serially with bounded parallelism, and preserves logs on failure. SDK/compiler versions and numeric language versions are separate settings. This proof does not require native C# unions or implement the deferred source generator.