…8639)

The PoC's TestClassModelBuilder built its fully-qualified type names with SymbolDisplayMiscellaneousOptions.IncludeNullableReferenceTypeModifier, then fed the resulting FQN into both casts (where '?' is harmless and merely cosmetic, since the emitted setter already uses 'value!') and 'typeof(...)' expressions (where '?' on a reference type is invalid C# and produces CS8639).

Removing the flag fixes 'typeof(string?)' / 'typeof(MyRef?)' while preserving 'typeof(int?)' (nullable value types are rendered via UseSpecialTypes, which is unaffected).

Adds a focused regression test that runs the Roslyn compiler over the generated source and asserts both the textual shape ('typeof(global::Sample.TestContext)', 'typeof(string)', 'typeof(int?)') and the absence of any compile errors.

Discovered while building tests for microsoft#8574; depends on microsoft#9004 for the test infrastructure.

Part of microsoft#1837.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Today TestClassModelBuilder only enumerates members directly declared on the
`[TestClass]` type. As soon as a fixture extends a base class, MSTest members
(`[TestInitialize]`, `[TestCleanup]`, `[TestMethod]`, the `[TestContext]`
property, ...) declared on the base disappear from the generated registry.

This change makes the builder walk the inheritance chain (stopping at
`System.Object`):

* Methods and properties are folded from base types into the model.
* Iteration is derived-first; an override or `new`-shadowed member with the
  same signature/name wins over the base declaration. The signature key
  includes ref-kinds so genuine overloads survive.
* Attributes are collected across the `OverriddenMethod` / `OverriddenProperty`
  chain (deduped by attribute class FQN) so an `override` that does not
  re-apply `[TestMethod]` still sees the base attribute - matching the
  runtime `GetCustomAttributes(inherit: true)` semantics.
* Accessibility is broadened to include `Protected` / `ProtectedOrInternal` /
  `ProtectedAndInternal` so abstract bases can expose their hooks to the
  emitted code (which lives in the consumer's assembly).
* Constructors are NEVER inherited (only taken from the leaf type).

Adds 9 new tests covering: inherited methods, multi-level inheritance,
overridden virtual (attribute inheritance + de-dup), `new`-hidden methods,
overload preservation, inherited properties, no inherited constructors,
abstract-base fold-down, and not walking past `System.Object`.

Part of microsoft#1837. Depends on microsoft#9004 (test project), microsoft#9005 (typeof nullable).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Adds an AssemblyAttributes property to the emitted MSTestReflectionMetadata registry containing all attributes declared with [assembly: ...] in the same compilation. The attribute payload is built via the existing AttributeApplicationModel pipeline (reused from class/method attribute emission), so adapters can iterate without calling Assembly.GetCustomAttributes at runtime.

Part of microsoft#1837. Stacked on microsoft#9004, microsoft#9005, microsoft#9006.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Part of microsoft#1837.

Adds compile-time materialization of `[DataRow]` attribute applications on
`[TestMethod]` members. The generator now emits a `DataRows` property on
each `TestMethodReflectionInfo` containing a flat `IReadOnlyList<object?[]>`
mirroring the runtime shape of `DataRowAttribute.Data`, so a consumer can
iterate parameterised cases without re-reading the attributes via reflection.

Highlights:

- New `DataRowModel(EquatableArray<TypedConstantModel> Arguments)` capturing
  one row of arguments per attribute application.
- `BuildDataRows` detects `Microsoft.VisualStudio.TestTools.UnitTesting.DataRowAttribute`
  applications and flattens the variadic `params object?[] moreData` tail
  back into the row so the emitted array matches `DataRowAttribute.Data`
  rather than preserving a nested array.
- Inheritance-aware: reuses the inherited attribute walk introduced in microsoft#9006,
  so `[DataRow]` applied on a base method (when the override is virtual) is
  still picked up.
- Emitter always emits `DataRows` (empty array for non-data-driven tests)
  for shape parity with the other `TestMethodReflectionInfo` properties.

Deferred to a follow-up: `[DynamicData]` materialization. Resolving the
data source method/property/field at compile time is materially more complex
(handles `Method`/`Property`/`Field`/`AutoDetect` source kinds plus
`object[]` / `IEnumerable<object[]>` return shapes) and warrants its own
PR.

Tests:

- `Generator_EmitsEmptyDataRows_WhenMethodHasNoDataRow`
- `Generator_CapturesSingleDataRow_WithScalarArgs`
- `Generator_CapturesMultipleDataRows_InDeclarationOrder`
- `Generator_FlattensParamsArrayInDataRow`
- `Generator_HandlesNullValueInDataRow`

Total: 32/32 passing.

Depends on microsoft#9004, microsoft#9005, microsoft#9006, microsoft#9007.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Part of microsoft#1837.

Changes the emitted `TestMethodReflectionInfo.Invoke` delegate from
`Func<object?, object?[]?, object?>` to `Func<object?, object?[]?, Task>`
so the caller can `await` a single Task regardless of the underlying test
method's signature.

Per return shape:

- `void` / non-Task sync: `{ call; return Task.CompletedTask; }` — no
  allocation, no extra wrapping.
- `Task` / `Task<T>`: `{ Task? __t = call; return __t ?? Task.CompletedTask; }`
  — forward the Task; tolerate a misbehaving test returning `null` rather
  than NRE.
- `ValueTask` / `ValueTask<T>`:
  `{ var __vt = call; return __vt.IsCompletedSuccessfully ? Task.CompletedTask : __vt.AsTask(); }`
  — fast path for synchronous completion skips `AsTask()` allocation.
- Non-void non-Task sync (e.g. `int Test()`):
  `{ _ = call; return Task.CompletedTask; }` — value discarded, side
  effects retained.

Support type updated to declare `Invoke` as `Func<object?, object?[]?, Task>`
with default `static (_, _) => Task.CompletedTask`. Both the support-types
file and the registry file now import `System.Threading.Tasks`.

Also drops a duplicate blank line left over from PR-A4 (SA1507).

Tests:

- `Generator_SupportType_DeclaresInvokeAsTaskReturning`
- `Generator_InvokerForVoidMethod_ReturnsCompletedTask`
- `Generator_InvokerForTaskMethod_ForwardsTask`
- `Generator_InvokerForTaskOfTMethod_ForwardsTask`
- `Generator_InvokerForValueTaskMethod_UnwrapsViaAsTask`
- `Generator_InvokerForValueTaskOfTMethod_UnwrapsViaAsTask`
- `Generator_InvokerForNonVoidSyncMethod_DiscardsResultAndReturnsCompletedTask`
- `Generator_EmittedRegistry_ImportsSystemThreadingTasks`

Total: 40/40 passing (1 existing test updated for new shape).

Depends on microsoft#9004, microsoft#9005, microsoft#9006, microsoft#9007, microsoft#9011.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>