private BoundExpression RewriteTupleConversion(
CSharpSyntaxNode syntax,
BoundExpression rewrittenOperand,
ConversionKind conversionKind,
bool @checked,
bool explicitCastInCode,
NamedTypeSymbol rewrittenType)
{
var destElementTypes = rewrittenType.GetElementTypesOfTupleOrCompatible();
var numElements = destElementTypes.Length;
ImmutableArray<FieldSymbol> srcElementFields;
TypeSymbol srcType = rewrittenOperand.Type;
if (srcType.IsTupleType)
{
srcElementFields = ((TupleTypeSymbol)srcType).TupleElementFields;
}
else
{
// The following codepath should be very uncommon (if reachable at all)
// we should generally not see tuple compatible types in bound trees and
// see actual tuple types instead.
Debug.Assert(srcType.IsTupleCompatible());
// PERF: if allocations here become nuisance, consider caching the TupleTypeSymbol
// in the type symbols that can actually be tuple compatible
srcElementFields = TupleTypeSymbol.Create((NamedTypeSymbol)srcType).TupleElementFields;
}
var fieldAccessorsBuilder = ArrayBuilder<BoundExpression>.GetInstance(numElements);
BoundAssignmentOperator assignmentToTemp;
var savedTuple = _factory.StoreToTemp(rewrittenOperand, out assignmentToTemp);
for (int i = 0; i < numElements; i++)
{
var field = srcElementFields[i];
DiagnosticInfo useSiteInfo = field.GetUseSiteDiagnostic();
if ((object)useSiteInfo != null && useSiteInfo.Severity == DiagnosticSeverity.Error)
{
Symbol.ReportUseSiteDiagnostic(useSiteInfo, _diagnostics, syntax.Location);
}
var fieldAccess = MakeTupleFieldAccess(syntax, field, savedTuple, null, LookupResultKind.Empty);
var convertedFieldAccess = MakeConversion(fieldAccess, destElementTypes[i], @checked);
fieldAccessorsBuilder.Add(convertedFieldAccess);
}
var result = MakeTupleCreationExpression(syntax, rewrittenType, fieldAccessorsBuilder.ToImmutableAndFree());
return _factory.Sequence(savedTuple.LocalSymbol, assignmentToTemp, result);
}
