[meziantou]

A binlog showed MA0011 (UseIFormatProviderAnalyzer) as the slowest rule, about 2× MA0002.

What changed

AnalyzeInvocation used to compute these for every invocation before searching for an overload:

• the culture sensitivity of the invocation (HasArgumentOfType(IFormatProvider, inherits: true) reads AllInterfaces of every argument type, plus the interpolated string checks)
• the containing method (GetContainingMethod → SemanticModel.GetDeclaredSymbol)
• 3 configuration values

Most invocations have no overload to report, and the shared OverloadCandidateIndex rejects them cheaply. The overload is now searched first, in the same priority order (FindOverloadToReport). The exclusions and culture-sensitivity checks run only when an overload would be reported. Also:

• Configuration is read once. The second culture-sensitivity check (the one that doesn't unwrap Nullable<T>) is skipped when the options already don't unwrap, because the result would be the same.
• Diagnostics are unchanged: the overload search doesn't depend on culture sensitivity, and a report still requires both checks to pass.

Measurements

Local harness: CompilationWithAnalyzers, sequential analysis, analyzer execution time from telemetry. Corpus: meziantou.framework/src (6,747 files), warm runs.

Scenario	Before	After
MA0011 alone	~650 ms	~250–340 ms
MA0011 after MA0002 (shared index already built)	~300 ms	~72 ms

On a synthetic corpus where nearly every call reports (9,300 diagnostics), timing is unchanged and the diagnostics are identical to the previous build, properties included.

Note for reviewers

Part of the 2× gap in the binlog is attribution. OverloadCandidateIndex and Roslyn's lazy symbol data are shared per compilation, so they are billed to whichever analyzer touches them first:

• Run alone: MA0002 takes ~1.1–2 s and MA0011 ~650 ms.
• Run with MA0002 first: MA0011's time drops and MA0002's goes up.

The index's cache eviction is being looked at separately.

Tests

UseIFormatProviderAnalyzer tests: 120/120 pass on Roslyn 4.8, 4.14, 5.0, 5.6 and 5.9. DocumentationGenerator produces no changes.