private EnumerationCount GetEnumerationCount(IOperation parameterOrLocalReferenceOperation, WellKnownSymbolsInfo wellKnownSymbolsInfo)
{
var(linqChainTailOperation, linqChainEnumerationCount) = SkipLinqChainAndConversionMethod(
parameterOrLocalReferenceOperation,
wellKnownSymbolsInfo);
if (IsOperationEnumeratedByInvocation(linqChainTailOperation, wellKnownSymbolsInfo) ||
IsGetEnumeratorOfForEachLoopInvoked(linqChainTailOperation))
{
return(InvocationSetHelpers.AddInvocationCount(linqChainEnumerationCount, EnumerationCount.One));
}
return(linqChainEnumerationCount);
}
static (IOperation linqChainTailOperation, EnumerationCount enumerationCount) VisitLinqChainAndCoversionMethod(
IOperation operation,
EnumerationCount enumerationCount,
WellKnownSymbolsInfo wellKnownSymbolsInfo)
{
if (IsValidImplicitConversion(operation.Parent, wellKnownSymbolsInfo))
{
// Go to the implicit conversion if needed
// e.g.
// void Bar (IOrderedEnumerable<T> c)
// {
// c.First();
// }
// here 'c' would be converted to IEnumerable<T>
return(VisitLinqChainAndCoversionMethod(operation.Parent, enumerationCount, wellKnownSymbolsInfo));
}
if (IsOperationIsArgumentOfLinqChainInvocation(operation.Parent, wellKnownSymbolsInfo, out var enumerateArgument))
{
// This operation is used as an argument of a deferred execution method.
// Check if the invocation of the deferred execution method is used in another deferred execution method.
return(VisitLinqChainAndCoversionMethod(
operation.Parent.Parent,
enumerateArgument
? InvocationSetHelpers.AddInvocationCount(enumerationCount, EnumerationCount.One)
: enumerationCount,
wellKnownSymbolsInfo));
}
if (IsInstanceOfLinqChainInvocation(operation, wellKnownSymbolsInfo, out var enumerateInstance))
{
// If the extension method could be used as reduced method, also check its invocation instance.
// Like in VB,
// 'i.Select(Function(a) a)', 'i' is the invocation instance of 'Select'
return(VisitLinqChainAndCoversionMethod(
operation.Parent,
enumerateInstance
? InvocationSetHelpers.AddInvocationCount(enumerationCount, EnumerationCount.One)
: enumerationCount,
wellKnownSymbolsInfo));
}
return(operation, enumerationCount);
}
