public static bool TryGetElementTypesIfTupleOrCompatible(this TypeSymbol type, out ImmutableArray <TypeSymbol> elementTypes)
{
if (type.IsTupleType)
{
elementTypes = ((TupleTypeSymbol)type).TupleElementTypes;
return(true);
}
// The following codepath should be very uncommon since it would be rare
// to see a tuple underlying type not represented as a tuple.
// It still might happen since tuple underlying types are creatable via public APIs
// and it is also possible that they would be passed in.
// PERF: if allocations here become nuisance, consider caching the results
// in the type symbols that can actually be tuple compatible
int cardinality;
if (!type.IsTupleCompatible(out cardinality))
{
// source not a tuple or compatible
elementTypes = default(ImmutableArray <TypeSymbol>);
return(false);
}
var elementTypesBuilder = ArrayBuilder <TypeSymbol> .GetInstance(cardinality);
TupleTypeSymbol.AddElementTypes((NamedTypeSymbol)type, elementTypesBuilder);
Debug.Assert(elementTypesBuilder.Count == cardinality);
elementTypes = elementTypesBuilder.ToImmutableAndFree();
return(true);
}
protected override bool HasImplicitTupleConversion(BoundExpression source, TypeSymbol destination, ref HashSet <DiagnosticInfo> useSiteDiagnostics)
{
if (source.Kind != BoundKind.TupleLiteral)
{
// source must be a tuple literal with no conversions
return(false);
}
var tupleExpression = (BoundTupleLiteral)source;
var arguments = tupleExpression.Arguments;
// check if the type is actually compatible type for a tuple of given cardinality
if (!destination.IsTupleOrCompatibleWithTupleOfCardinality(arguments.Length))
{
return(false);
}
var targetElementTypes = ArrayBuilder <TypeSymbol> .GetInstance(arguments.Length);
TupleTypeSymbol.AddElementTypes((NamedTypeSymbol)destination, targetElementTypes);
Debug.Assert(arguments.Length == targetElementTypes.Count);
try
{
// check arguments against flattened list of target element types
for (int i = 0; i < arguments.Length; i++)
{
var argument = arguments[i];
var result = ClassifyImplicitConversionFromExpression(argument, targetElementTypes[i], ref useSiteDiagnostics);
if (!result.Exists)
{
return(false);
}
}
return(true);
}
finally
{
targetElementTypes.Free();
}
}
public static ImmutableArray <TypeSymbol> GetElementTypesOfTupleOrCompatible(this TypeSymbol type)
{
if (type.IsTupleType)
{
return(((TupleTypeSymbol)type).TupleElementTypes);
}
// The following codepath should be very uncommon since it would be rare
// to see a tuple underlying type not represented as a tuple.
// It still might happen since tuple underlying types are creatable via public APIs
// and it is also possible that they would be passed in.
Debug.Assert(type.IsTupleCompatible());
// PERF: if allocations here become nuisance, consider caching the results
// in the type symbols that can actually be tuple compatible
var elementTypesBuilder = ArrayBuilder <TypeSymbol> .GetInstance();
TupleTypeSymbol.AddElementTypes((NamedTypeSymbol)type, elementTypesBuilder);
return(elementTypesBuilder.ToImmutableAndFree());
}