Report MA0153 when the type of a logged property or field is classified

[meziantou]

What

MA0153 checked the declaring type for logged properties and fields, but the value type for parameters. An attribute inheriting from DataClassificationAttribute placed on the type of a logged property or field was therefore never reported:

[Taxonomy] class Credentials { }

void A(Credentials p) => logger.LogInformation("{P}", p);   // reported
logger.LogInformation("{Prop}", new Dummy().Prop);          // Dummy.Prop is Credentials -> not reported

Since a property or field is the most common way classified data is exposed, the rule gave a false sense of coverage for exactly the data it is meant to protect.

How

The parameter, property and field branches were three near-duplicates that had drifted apart. They now share one ValidateSymbol local function that checks, in order:

1. the attribute on the symbol itself,
2. the attribute on the symbol's type,
3. the attribute on the declaring type (members only — null for parameters, whose declaring type is the enclosing method's type and says nothing about the value).

Unifying the branches also closed a second hole of the same shape: the MA0153.report_types_with_data_classification_attributes opt-in — reporting a value whose type contains classified members — was implemented only for parameters, so a property or field of such a type was silently missed even with the option on. It now applies to all three.

Reviewer notes

• The opt-in option is off by default, so the behavior change it unlocks does not affect anyone who has not enabled it.
• The new detection on the value type does report more code by default. That is the intent of the fix: the attribute means the value is classified, wherever the value comes from.
• Existing behavior is unchanged for parameters, and the ContainingType check for members is preserved (a new test guards it).

Tests

5 cases added to DoNotLogClassifiedDataAnalyzerTests: attribute on a property's type, on a field's type, on a property's declaring type (regression guard), and the property/type-with-classified-members case with the option both enabled and disabled.

21/21 MA0153 tests pass on all five Roslyn versions (4.8, 4.14, 5.0, 5.6, 5.9); the full solution builds with 0 warnings. dotnet run --project src/DocumentationGenerator exits 0 with no further changes after the docs/Rules/MA0153.md update, which documents the three attribute locations and adds a sample.