internal static Conversion Classify(TypeSymbol sourceType, TypeSymbol targetType, ParameterDirection direction)
{
if (sourceType.Equals(targetType))
return Identity;
// First, make sure we have a conversion from argument to parameter.
switch (direction)
{
case ParameterDirection.In:
if (!sourceType.HasImplicitConversionTo(targetType))
return sourceType.HasExplicitConversionTo(targetType) ? Explicit : None;
break;
case ParameterDirection.Out:
if (!targetType.HasImplicitConversionTo(sourceType))
return None;
break;
case ParameterDirection.Inout:
if (!sourceType.HasImplicitConversionTo(targetType) || !targetType.HasImplicitConversionTo(sourceType))
return None;
break;
default:
throw new ArgumentOutOfRangeException();
}
var conversionType = ConversionTypes.None;
var numericTargetType = targetType as IntrinsicNumericTypeSymbol;
var numericSourceType = sourceType as IntrinsicNumericTypeSymbol;
if (numericTargetType != null && numericSourceType != null)
{
conversionType |= ClassifyTypeConversion(numericSourceType, numericTargetType);
conversionType |= ClassifyDimensionConversion(numericSourceType, numericTargetType);
}
// TODO: Non-numeric implicit conversions.
return new Conversion(true, false, false, conversionType);
}
internal static bool HasExplicitConversionTo(this TypeSymbol left, TypeSymbol right)
{
if (left.Equals(right))
{
return(true);
}
if (left.IsIntrinsicNumericType() && right.Kind == SymbolKind.Struct)
{
return(true);
}
return(left.HasImplicitConversionTo(right));
}
