// 13.2.2 Explicit enumeration conversions
//
// The explicit enumeration conversions are:
//
// * From sbyte, byte, short, ushort, int, uint, long, ulong, char, float, double, or
// decimal to any enum-type.
//
// * From any enum-type to sbyte, byte, short, ushort, int, uint, long, ulong, char,
// float, double, or decimal.
//
// * From any enum-type to any other enum-type.
//
// * An explicit enumeration conversion between two types is processed by treating any
// participating enum-type as the underlying type of that enum-type, and then performing
// an implicit or explicit numeric conversion between the resulting types.
private AggCastResult bindExplicitConversionFromEnumToAggregate(AggregateType aggTypeDest)
{
Debug.Assert(_typeSrc != null);
Debug.Assert(aggTypeDest != null);
if (!_typeSrc.isEnumType())
{
return(AggCastResult.Failure);
}
AggregateSymbol aggDest = aggTypeDest.getAggregate();
if (aggDest.isPredefAgg(PredefinedType.PT_DECIMAL))
{
return(bindExplicitConversionFromEnumToDecimal(aggTypeDest));
}
if (!aggDest.getThisType().isNumericType() &&
!aggDest.IsEnum() &&
!(aggDest.IsPredefined() && aggDest.GetPredefType() == PredefinedType.PT_CHAR))
{
return(AggCastResult.Failure);
}
if (_exprSrc.GetConst() != null)
{
ConstCastResult result = _binder.bindConstantCast(_exprSrc, _exprTypeDest, _needsExprDest, out _exprDest, true);
if (result == ConstCastResult.Success)
{
return(AggCastResult.Success);
}
else if (result == ConstCastResult.CheckFailure)
{
return(AggCastResult.Abort);
}
}
if (_needsExprDest)
{
_binder.bindSimpleCast(_exprSrc, _exprTypeDest, out _exprDest);
}
return(AggCastResult.Success);
}
private bool bindImplicitConversionBetweenSimpleTypes(AggregateType aggTypeSrc)
{
AggregateSymbol aggSrc = aggTypeSrc.getAggregate();
Debug.Assert(aggSrc.getThisType().isSimpleType());
Debug.Assert(typeDest.isSimpleType());
Debug.Assert(aggSrc.IsPredefined() && typeDest.isPredefined());
PredefinedType ptSrc = aggSrc.GetPredefType();
PredefinedType ptDest = typeDest.getPredefType();
ConvKind convertKind;
bool fConstShrinkCast = false;
Debug.Assert((int)ptSrc < NUM_SIMPLE_TYPES && (int)ptDest < NUM_SIMPLE_TYPES);
// 13.1.7 Implicit constant expression conversions
//
// An implicit constant expression conversion permits the following conversions:
// * A constant-expression (14.16) of type int can be converted to type sbyte, byte, short,
// ushort, uint, or ulong, provided the value of the constant-expression is within the range
// of the destination type.
// * A constant-expression of type long can be converted to type ulong, provided the value of
// the constant-expression is not negative.
// Note: Don't use GetConst here since the conversion only applies to bona-fide compile time constants.
if (exprSrc != null && exprSrc.isCONSTANT_OK() &&
((ptSrc == PredefinedType.PT_INT && ptDest != PredefinedType.PT_BOOL && ptDest != PredefinedType.PT_CHAR) ||
(ptSrc == PredefinedType.PT_LONG && ptDest == PredefinedType.PT_ULONG)) &&
isConstantInRange(exprSrc.asCONSTANT(), typeDest))
{
// Special case (CLR 6.1.6): if integral constant is in range, the conversion is a legal implicit conversion.
convertKind = ConvKind.Implicit;
fConstShrinkCast = needsExprDest && (GetConvKind(ptSrc, ptDest) != ConvKind.Implicit);
}
else if (ptSrc == ptDest)
{
// Special case: precision limiting casts to float or double
Debug.Assert(ptSrc == PredefinedType.PT_FLOAT || ptSrc == PredefinedType.PT_DOUBLE);
Debug.Assert(0 != (flags & CONVERTTYPE.ISEXPLICIT));
convertKind = ConvKind.Implicit;
}
else
{
convertKind = GetConvKind(ptSrc, ptDest);
Debug.Assert(convertKind != ConvKind.Identity);
// identity conversion should have been handled at first.
}
if (convertKind != ConvKind.Implicit)
{
return(false);
}
// An implicit conversion exists. Do the conversion.
if (exprSrc.GetConst() != null)
{
// Fold the constant cast if possible.
ConstCastResult result = binder.bindConstantCast(exprSrc, exprTypeDest, needsExprDest, out exprDest, false);
if (result == ConstCastResult.Success)
{
return(true); // else, don't fold and use a regular cast, below.
}
// REVIEW: I don't think this can ever be hit. If exprSrc is a constant then
// it's either a floating point number (which always succeeds), it's a numeric implicit
// conversion (which always succeeds), or it's a constant numeric conversion (which
// has already been checked by isConstantInRange, so should always succeed)
}
if (isUserDefinedConversion(ptSrc, ptDest))
{
if (!needsExprDest)
{
return(true);
}
// According the language, this is a standard conversion, but it is implemented
// through a user-defined conversion. Because it's a standard conversion, we don't
// test the NOUDC flag here.
return(binder.bindUserDefinedConversion(exprSrc, aggTypeSrc, typeDest, needsExprDest, out exprDest, true));
}
if (needsExprDest)
{
binder.bindSimpleCast(exprSrc, exprTypeDest, out exprDest);
}
return(true);
}
