Base:
method
IsFinalSpanSemanticallyValidSpan
Microsoft.CodeAnalysis.ExtractMethod.AbstractExtractMethodService<TStatementSyntax, TExecutableStatementSyntax, TExpressionSyntax>.SelectionResult.IsFinalSpanSemanticallyValidSpan(System.Collections.Immutable.ImmutableArray<TExecutableStatementSyntax>, System.Threading.CancellationToken)