private AggCastResult bindExplicitConversionFromDecimalToEnum(AggregateType aggTypeDest)
{
Debug.Assert(_typeSrc != null);
Debug.Assert(_typeSrc.IsPredefType(PredefinedType.PT_DECIMAL));
Debug.Assert(aggTypeDest.IsEnumType);
// There is an explicit conversion from decimal to all integral types.
if (_exprSrc.GetConst() != null)
{
// Fold the constant cast if possible.
ConstCastResult result = _binder.bindConstantCast(_exprSrc, _typeDest, _needsExprDest, out _exprDest, true);
if (result == ConstCastResult.Success)
{
return(AggCastResult.Success); // else, don't fold and use a regular cast, below.
}
if (result == ConstCastResult.CheckFailure && 0 == (_flags & CONVERTTYPE.CHECKOVERFLOW))
{
return(AggCastResult.Abort);
}
}
// All casts from decimal to integer types are bound as user-defined conversions.
bool bIsConversionOK = true;
if (_needsExprDest)
{
// 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 CONVERTTYPE.NOUDC flag here.
CType underlyingType = aggTypeDest.UnderlyingEnumType;
bIsConversionOK = _binder.bindUserDefinedConversion(_exprSrc, _typeSrc, underlyingType, _needsExprDest, out _exprDest, false);
if (bIsConversionOK)
{
// upcast to the Enum type
_binder.bindSimpleCast(_exprDest, _typeDest, out _exprDest);
}
}
return(bIsConversionOK ? AggCastResult.Success : AggCastResult.Failure);
}
private static CType TypeFromOperands(Expr first, Expr second)
{
CType type = first.Type;
if (type.IsPredefType(PredefinedType.PT_STRING))
{
return(type);
}
Debug.Assert(second.Type.IsPredefType(PredefinedType.PT_STRING));
return(second.Type);
}
private bool bindImplicitConversionFromNull()
{
// null type can be implicitly converted to any reference type or pointer type or type
// variable with reference-type constraint.
FUNDTYPE ftDest = _typeDest.FundamentalType;
if (ftDest != FUNDTYPE.FT_REF && ftDest != FUNDTYPE.FT_PTR &&
// null is convertible to System.Nullable<T>.
!_typeDest.IsPredefType(PredefinedType.PT_G_OPTIONAL))
{
return false;
}
if (_needsExprDest)
{
// If the conversion argument is a constant null then return a ZEROINIT.
// Otherwise, bind this as a cast to the destination type. In a later
// rewrite pass we will rewrite the cast as SEQ(side effects, ZEROINIT).
_exprDest = _exprSrc is ExprConstant
? ExprFactory.CreateZeroInit(_typeDest)
: ExprFactory.CreateCast(_typeDest, _exprSrc);
}
return true;
}
public bool HasBaseConversion(CType pSource, CType pDest)
{
// By a "base conversion" we mean:
//
// * an identity conversion
// * an implicit reference conversion
// * an implicit boxing conversion
// * an implicit type parameter conversion
//
// In other words, these are conversions that can be made to a base
// class, base interface or co/contravariant type without any change in
// representation other than boxing. A conversion from, say, int to double,
// is NOT a "base conversion", because representation is changed. A conversion
// from, say, lambda to expression tree is not a "base conversion" because
// do not have a type.
//
// The existence of a base conversion depends solely upon the source and
// destination types, not the source expression.
//
// This notion is not found in the spec but it is useful in the implementation.
if (pSource is AggregateType && pDest.IsPredefType(PredefinedType.PT_OBJECT))
{
// If we are going from any aggregate type (class, struct, interface, enum or delegate)
// to object, we immediately return true. This may seem like a mere optimization --
// after all, if we have an aggregate then we have some kind of implicit conversion
// to object.
//
// However, it is not a mere optimization; this introduces a control flow change
// in error reporting scenarios for unresolved type forwarders. If a type forwarder
// cannot be resolved then the resulting type symbol will be an aggregate, but
// we will not be able to classify it into class, struct, etc.
//
// We know that we will have an error in this case; we do not wish to compound
// that error by giving a spurious "you cannot convert this thing to object"
// error, which, after all, will go away when the type forwarding problem is
// fixed.
return(true);
}
return(HasIdentityOrImplicitReferenceConversion(pSource, pDest) || HasImplicitBoxingConversion(pSource, pDest));
}
private bool HasArrayConversionToInterface(ArrayType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
if (!pSource.IsSZArray || !pDest.IsInterfaceType)
{
return(false);
}
// * From a single-dimensional array type S[] to IList<T> or IReadOnlyList<T> and their base
// interfaces, provided that there is an implicit identity or reference
// conversion from S to T.
// We only have six interfaces to check. IList<T>, IReadOnlyList<T> and their bases:
// * The base interface of IList<T> is ICollection<T>.
// * The base interface of ICollection<T> is IEnumerable<T>.
// * The base interface of IEnumerable<T> is IEnumerable.
// * The base interface of IReadOnlyList<T> is IReadOnlyCollection<T>.
// * The base interface of IReadOnlyCollection<T> is IEnumerable<T>.
if (pDest.IsPredefType(PredefinedType.PT_IENUMERABLE))
{
return(true);
}
AggregateType atsDest = (AggregateType)pDest;
AggregateSymbol aggDest = atsDest.OwningAggregate;
if (!aggDest.isPredefAgg(PredefinedType.PT_G_ILIST) &&
!aggDest.isPredefAgg(PredefinedType.PT_G_ICOLLECTION) &&
!aggDest.isPredefAgg(PredefinedType.PT_G_IENUMERABLE) &&
!aggDest.isPredefAgg(PredefinedType.PT_G_IREADONLYCOLLECTION) &&
!aggDest.isPredefAgg(PredefinedType.PT_G_IREADONLYLIST))
{
return(false);
}
Debug.Assert(atsDest.TypeArgsAll.Count == 1);
return(HasIdentityOrImplicitReferenceConversion(pSource.ElementType, atsDest.TypeArgsAll[0]));
}
public static Expr CreateZeroInit(CType type)
{
Debug.Assert(type != null);
if (type.IsEnumType)
{
// For enum types, we create a constant that has the default value
// as an object pointer.
return(CreateConstant(type, ConstVal.Get(Activator.CreateInstance(type.AssociatedSystemType))));
}
Debug.Assert(type.FundamentalType > FUNDTYPE.FT_NONE);
Debug.Assert(type.FundamentalType < FUNDTYPE.FT_COUNT);
switch (type.FundamentalType)
{
case FUNDTYPE.FT_PTR:
{
// Just allocate a new node and fill it in.
return(CreateCast(0, type, CreateNull()));
}
case FUNDTYPE.FT_STRUCT:
if (type.IsPredefType(PredefinedType.PT_DECIMAL))
{
goto default;
}
goto case FUNDTYPE.FT_VAR;
case FUNDTYPE.FT_VAR:
return(new ExprZeroInit(type));
default:
return(CreateConstant(type, ConstVal.GetDefaultValue(type.ConstValKind)));
}
}
private static bool CheckSingleConstraint(Symbol symErr, TypeParameterType var, CType arg, TypeArray typeArgsCls, TypeArray typeArgsMeth, CheckConstraintsFlags flags)
{
Debug.Assert(!(arg is PointerType));
Debug.Assert(!arg.IsStaticClass);
bool fReportErrors = 0 == (flags & CheckConstraintsFlags.NoErrors);
if (var.HasRefConstraint && !arg.IsReferenceType)
{
if (fReportErrors)
{
throw ErrorHandling.Error(ErrorCode.ERR_RefConstraintNotSatisfied, symErr, new ErrArgNoRef(var), arg);
}
return(false);
}
TypeArray bnds = TypeManager.SubstTypeArray(var.Bounds, typeArgsCls, typeArgsMeth);
int itypeMin = 0;
if (var.HasValConstraint)
{
// If we have a type variable that is constrained to a value type, then we
// want to check if its a nullable type, so that we can report the
// constraint error below. In order to do this however, we need to check
// that either the type arg is not a value type, or it is a nullable type.
//
// To check whether or not its a nullable type, we need to get the resolved
// bound from the type argument and check against that.
if (!arg.IsNonNullableValueType)
{
if (fReportErrors)
{
throw ErrorHandling.Error(ErrorCode.ERR_ValConstraintNotSatisfied, symErr, new ErrArgNoRef(var), arg);
}
return(false);
}
// Since FValCon() is set it is redundant to check System.ValueType as well.
if (bnds.Count != 0 && bnds[0].IsPredefType(PredefinedType.PT_VALUE))
{
itypeMin = 1;
}
}
for (int j = itypeMin; j < bnds.Count; j++)
{
CType typeBnd = bnds[j];
if (!SatisfiesBound(arg, typeBnd))
{
if (fReportErrors)
{
// The bound isn't satisfied because of a constraint type. Explain to the user why not.
// There are 4 main cases, based on the type of the supplied type argument:
// - reference type, or type parameter known to be a reference type
// - nullable type, from which there is a boxing conversion to the constraint type(see below for details)
// - type variable
// - value type
// These cases are broken out because: a) The sets of conversions which can be used
// for constraint satisfaction is different based on the type argument supplied,
// and b) Nullable is one funky type, and user's can use all the help they can get
// when using it.
ErrorCode error;
if (arg.IsReferenceType)
{
// A reference type can only satisfy bounds to types
// to which they have an implicit reference conversion
error = ErrorCode.ERR_GenericConstraintNotSatisfiedRefType;
}
else if (arg is NullableType nubArg && SymbolLoader.HasBaseConversion(nubArg.UnderlyingType, typeBnd)) // This is inlining FBoxingConv
{
// nullable types do not satisfy bounds to every type that they are boxable to
// They only satisfy bounds of object and ValueType
if (typeBnd.IsPredefType(PredefinedType.PT_ENUM) || nubArg.UnderlyingType == typeBnd)
{
// Nullable types don't satisfy bounds of EnumType, or the underlying type of the enum
// even though the conversion from Nullable to these types is a boxing conversion
// This is a rare case, because these bounds can never be directly stated ...
// These bounds can only occur when one type paramter is constrained to a second type parameter
// and the second type parameter is instantiated with Enum or the underlying type of the first type
// parameter
error = ErrorCode.ERR_GenericConstraintNotSatisfiedNullableEnum;
}
else
{
// Nullable types don't satisfy the bounds of any interface type
// even when there is a boxing conversion from the Nullable type to
// the interface type. This will be a relatively common scenario
// so we cal it out separately from the previous case.
Debug.Assert(typeBnd.IsInterfaceType);
error = ErrorCode.ERR_GenericConstraintNotSatisfiedNullableInterface;
}
}
else
{
// Value types can only satisfy bounds through boxing conversions.
// Note that the exceptional case of Nullable types and boxing is handled above.
error = ErrorCode.ERR_GenericConstraintNotSatisfiedValType;
}
throw ErrorHandling.Error(error, new ErrArg(symErr), new ErrArg(typeBnd, ErrArgFlags.Unique), var, new ErrArg(arg, ErrArgFlags.Unique));
}
return(false);
}
}
/*
* BindImplicitConversion
*
* This is a complex routine with complex parameters. Generally, this should
* be called through one of the helper methods that insulates you
* from the complexity of the interface. This routine handles all the logic
* associated with implicit conversions.
*
* exprSrc - the expression being converted. Can be null if only type conversion
* info is being supplied.
* typeSrc - type of the source
* typeDest - type of the destination
* exprDest - returns an expression of the src converted to the dest. If null, we
* only care about whether the conversion can be attempted, not the
* expression tree.
* flags - flags possibly customizing the conversions allowed. E.g., can suppress
* user-defined conversions.
*
* returns true if the conversion can be made, false if not.
*/
public bool Bind()
{
// 13.1 Implicit conversions
//
// The following conversions are classified as implicit conversions:
//
// * Identity conversions
// * Implicit numeric conversions
// * Implicit enumeration conversions
// * Implicit reference conversions
// * Boxing conversions
// * Implicit type parameter conversions
// * Implicit constant expression conversions
// * User-defined implicit conversions
// * Implicit conversions from an anonymous method expression to a compatible delegate type
// * Implicit conversion from a method group to a compatible delegate type
// * Conversions from the null type (11.2.7) to any nullable type
// * Implicit nullable conversions
// * Lifted user-defined implicit conversions
//
// Implicit conversions can occur in a variety of situations, including function member invocations
// (14.4.3), cast expressions (14.6.6), and assignments (14.14).
// Can't convert to or from the error type.
if (_typeSrc == null || _typeDest == null || _typeDest is MethodGroupType)
{
return(false);
}
Debug.Assert(_typeSrc != null && _typeDest != null); // types must be supplied.
Debug.Assert(_exprSrc == null || _typeSrc == _exprSrc.Type); // type of source should be correct if source supplied
Debug.Assert(!_needsExprDest || _exprSrc != null); // need source expr to create dest expr
switch (_typeDest.TypeKind)
{
case TypeKind.TK_NullType:
// Can only convert to the null type if src is null.
if (!(_typeSrc is NullType))
{
return(false);
}
if (_needsExprDest)
{
_exprDest = _exprSrc;
}
return(true);
case TypeKind.TK_ArgumentListType:
return(_typeSrc == _typeDest);
case TypeKind.TK_VoidType:
return(false);
default:
break;
}
// 13.1.1 Identity conversion
//
// An identity conversion converts from any type to the same type. This conversion exists only
// such that an entity that already has a required type can be said to be convertible to that type.
if (_typeSrc == _typeDest &&
((_flags & CONVERTTYPE.ISEXPLICIT) == 0 || (!_typeSrc.IsPredefType(PredefinedType.PT_FLOAT) && !_typeSrc.IsPredefType(PredefinedType.PT_DOUBLE))))
{
if (_needsExprDest)
{
_exprDest = _exprSrc;
}
return(true);
}
if (_typeDest is NullableType nubDest)
{
return(BindNubConversion(nubDest));
}
if (_typeSrc is NullableType nubSrc)
{
return(bindImplicitConversionFromNullable(nubSrc));
}
if ((_flags & CONVERTTYPE.ISEXPLICIT) != 0)
{
_flags |= CONVERTTYPE.NOUDC;
}
// Get the fundamental types of destination.
FUNDTYPE ftDest = _typeDest.FundamentalType;
Debug.Assert(ftDest != FUNDTYPE.FT_NONE || _typeDest is ParameterModifierType);
switch (_typeSrc.TypeKind)
{
default:
Debug.Fail($"Bad type symbol kind: {_typeSrc.TypeKind}");
break;
case TypeKind.TK_VoidType:
case TypeKind.TK_ParameterModifierType:
case TypeKind.TK_ArgumentListType:
return(false);
case TypeKind.TK_NullType:
if (bindImplicitConversionFromNull())
{
return(true);
}
// If not, try user defined implicit conversions.
break;
case TypeKind.TK_ArrayType:
if (bindImplicitConversionFromArray())
{
return(true);
}
// If not, try user defined implicit conversions.
break;
case TypeKind.TK_PointerType:
if (bindImplicitConversionFromPointer())
{
return(true);
}
// If not, try user defined implicit conversions.
break;
case TypeKind.TK_AggregateType:
if (bindImplicitConversionFromAgg(_typeSrc as AggregateType))
{
return(true);
}
// If not, try user defined implicit conversions.
break;
}
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// RUNTIME BINDER ONLY CHANGE
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//
// Every incoming dynamic operand should be implicitly convertible
// to any type that it is an instance of.
object srcRuntimeObject = _exprSrc?.RuntimeObject;
if (srcRuntimeObject != null &&
_typeDest.AssociatedSystemType.IsInstanceOfType(srcRuntimeObject) &&
CSemanticChecker.CheckTypeAccess(_typeDest, _binder.Context.ContextForMemberLookup))
{
if (_needsExprDest)
{
_binder.bindSimpleCast(_exprSrc, _typeDest, out _exprDest, _exprSrc.Flags & EXPRFLAG.EXF_CANTBENULL);
}
return(true);
}
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// END RUNTIME BINDER ONLY CHANGE
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// 13.1.8 User-defined implicit conversions
//
// A user-defined implicit conversion consists of an optional standard implicit conversion,
// followed by execution of a user-defined implicit conversion operator, followed by another
// optional standard implicit conversion. The exact rules for evaluating user-defined
// conversions are described in 13.4.3.
if (0 == (_flags & CONVERTTYPE.NOUDC))
{
return(_binder.bindUserDefinedConversion(_exprSrc, _typeSrc, _typeDest, _needsExprDest, out _exprDest, true));
}
// No conversion was found.
return(false);
}
private bool HasImplicitReferenceConversion(CType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
Debug.Assert(!(pSource is TypeParameterType));
// The implicit reference conversions are:
// * From any reference type to Object.
if (pSource.IsReferenceType && pDest.IsPredefType(PredefinedType.PT_OBJECT))
{
return(true);
}
if (pSource is AggregateType aggSource)
{
if (pDest is AggregateType aggDest)
{
switch (aggSource.OwningAggregate.AggKind())
{
case AggKindEnum.Class:
switch (aggDest.OwningAggregate.AggKind())
{
case AggKindEnum.Class:
// * From any class type S to any class type T provided S is derived from T.
return(IsBaseClass(aggSource, aggDest));
case AggKindEnum.Interface:
// ORIGINAL RULES:
// // * From any class type S to any interface type T provided S implements T.
// if (pSource.isClassType() && pDest.isInterfaceType() && IsBaseInterface(pSource, pDest))
// {
// return true;
// }
// // * from any interface type S to any interface type T, provided S is derived from T.
// if (pSource.isInterfaceType() && pDest.isInterfaceType() && IsBaseInterface(pSource, pDest))
// {
// return true;
// }
// VARIANCE EXTENSIONS:
// * From any class type S to any interface type T provided S implements an interface
// convertible to T.
// * From any interface type S to any interface type T provided S implements an interface
// convertible to T.
// * From any interface type S to any interface type T provided S is not T and S is
// an interface convertible to T.
return(HasAnyBaseInterfaceConversion(aggSource, aggDest));
}
break;
case AggKindEnum.Interface:
if (aggDest.IsInterfaceType)
{
return(HasAnyBaseInterfaceConversion(aggSource, aggDest) || HasInterfaceConversion(aggSource, aggDest));
}
break;
case AggKindEnum.Delegate:
// * From any delegate type to System.Delegate
//
// SPEC OMISSION:
//
// The spec should actually say
//
// * From any delegate type to System.Delegate
// * From any delegate type to System.MulticastDelegate
// * From any delegate type to any interface implemented by System.MulticastDelegate
if (aggDest.IsPredefType(PredefinedType.PT_MULTIDEL) ||
aggDest.IsPredefType(PredefinedType.PT_DELEGATE) || IsBaseInterface(
GetPredefindType(PredefinedType.PT_MULTIDEL), aggDest))
{
return(true);
}
// VARIANCE EXTENSION:
// * From any delegate type S to a delegate type T provided S is not T and
// S is a delegate convertible to T
return(pDest.IsDelegateType && HasDelegateConversion(aggSource, aggDest));
}
}
}
else if (pSource is ArrayType arrSource)
{
// * From an array type S with an element type SE to an array type T with element type TE
// provided that all of the following are true:
// * S and T differ only in element type. In other words, S and T have the same number of dimensions.
// * Both SE and TE are reference types.
// * An implicit reference conversion exists from SE to TE.
if (pDest is ArrayType arrDest)
{
return(HasCovariantArrayConversion(arrSource, arrDest));
}
if (pDest is AggregateType aggDest)
{
// * From any array type to System.Array or any interface implemented by System.Array.
if (aggDest.IsPredefType(PredefinedType.PT_ARRAY) ||
IsBaseInterface(GetPredefindType(PredefinedType.PT_ARRAY), aggDest))
{
return(true);
}
// * From a single-dimensional array type S[] to IList<T> and its base
// interfaces, provided that there is an implicit identity or reference
// conversion from S to T.
return(HasArrayConversionToInterface(arrSource, pDest));
}
}
else if (pSource is NullType)
{
// * From the null literal to any reference type
// NOTE: We extend the specification here. The C# 3.0 spec does not describe
// a "null type". Rather, it says that the null literal is typeless, and is
// convertible to any reference or nullable type. However, the C# 2.0 and 3.0
// implementations have a "null type" which some expressions other than the
// null literal may have. (For example, (null??null), which is also an
// extension to the specification.)
return(pDest.IsReferenceType || pDest is NullableType);
}
return(false);
}