////////////////////////////////////////////////////////////////////////////////
private static bool IsReallyAType(CType pType)
{
if (pType.IsNullType() || pType.IsBoundLambdaType() ||
pType.IsVoidType() ||
pType.IsMethodGroupType())
{
return false;
}
return true;
}
private bool HasImplicitReferenceConversion(CType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
// The implicit reference conversions are:
// * From any reference type to Object.
if (pSource.IsRefType() && pDest.isPredefType(PredefinedType.PT_OBJECT))
{
return(true);
}
// * From any class type S to any class type T provided S is derived from T.
if (pSource.isClassType() && pDest.isClassType() && IsBaseClass(pSource, pDest))
{
return(true);
}
// 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.
if (pSource.isClassType() && pDest.isInterfaceType() && HasAnyBaseInterfaceConversion(pSource, pDest))
{
return(true);
}
if (pSource.isInterfaceType() && pDest.isInterfaceType() && HasAnyBaseInterfaceConversion(pSource, pDest))
{
return(true);
}
if (pSource.isInterfaceType() && pDest.isInterfaceType() && pSource != pDest &&
HasInterfaceConversion(pSource.AsAggregateType(), pDest.AsAggregateType()))
{
return(true);
}
// * 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 (pSource.IsArrayType() && pDest.IsArrayType() &&
HasCovariantArrayConversion(pSource.AsArrayType(), pDest.AsArrayType()))
{
return(true);
}
// * From any array type to System.Array or any interface implemented by System.Array.
if (pSource.IsArrayType() && (pDest.isPredefType(PredefinedType.PT_ARRAY) ||
IsBaseInterface(GetReqPredefType(PredefinedType.PT_ARRAY, false), pDest)))
{
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.
if (pSource.IsArrayType() && HasArrayConversionToInterface(pSource.AsArrayType(), pDest))
{
return(true);
}
// * 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 (pSource.isDelegateType() &&
(pDest.isPredefType(PredefinedType.PT_MULTIDEL) ||
pDest.isPredefType(PredefinedType.PT_DELEGATE) ||
IsBaseInterface(GetReqPredefType(PredefinedType.PT_MULTIDEL, false), pDest)))
{
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
if (pSource.isDelegateType() && pDest.isDelegateType() &&
HasDelegateConversion(pSource.AsAggregateType(), pDest.AsAggregateType()))
{
return(true);
}
// * 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.)
if (pSource.IsNullType() && pDest.IsRefType())
{
return(true);
}
if (pSource.IsNullType() && pDest.IsNullableType())
{
return(true);
}
// * Implicit conversions involving type parameters that are known to be reference types.
if (pSource.IsTypeParameterType() &&
HasImplicitReferenceTypeParameterConversion(pSource.AsTypeParameterType(), pDest))
{
return(true);
}
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.IsNeverSameType())
{
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.GetTypeKind())
{
case TypeKind.TK_ErrorType:
Debug.Assert(typeDest.AsErrorType().HasTypeParent() || typeDest.AsErrorType().HasNSParent());
if (typeSrc != typeDest)
{
return(false);
}
if (needsExprDest)
{
exprDest = exprSrc;
}
return(true);
case TypeKind.TK_NullType:
// Can only convert to the null type if src is null.
if (!typeSrc.IsNullType())
{
return(false);
}
if (needsExprDest)
{
exprDest = exprSrc;
}
return(true);
case TypeKind.TK_MethodGroupType:
VSFAIL("Something is wrong with Type.IsNeverSameType()");
return(false);
case TypeKind.TK_NaturalIntegerType:
case TypeKind.TK_ArgumentListType:
return(typeSrc == typeDest);
case TypeKind.TK_VoidType:
return(false);
default:
break;
}
if (typeSrc.IsErrorType())
{
Debug.Assert(!typeDest.IsErrorType());
return(false);
}
// 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.IsNullableType())
{
return(BindNubConversion(typeDest.AsNullableType()));
}
if (typeSrc.IsNullableType())
{
return(bindImplicitConversionFromNullable(typeSrc.AsNullableType()));
}
if ((flags & CONVERTTYPE.ISEXPLICIT) != 0)
{
flags |= CONVERTTYPE.NOUDC;
}
// Get the fundamental types of destination.
FUNDTYPE ftDest = typeDest.fundType();
Debug.Assert(ftDest != FUNDTYPE.FT_NONE || typeDest.IsParameterModifierType());
switch (typeSrc.GetTypeKind())
{
default:
VSFAIL("Bad type symbol kind");
break;
case TypeKind.TK_MethodGroupType:
if (exprSrc.isMEMGRP())
{
EXPRCALL outExpr;
bool retVal = binder.BindGrpConversion(exprSrc.asMEMGRP(), typeDest, needsExprDest, out outExpr, false);
exprDest = outExpr;
return(retVal);
}
return(false);
case TypeKind.TK_VoidType:
case TypeKind.TK_ErrorType:
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_TypeParameterType:
if (bindImplicitConversionFromTypeVar(typeSrc.AsTypeParameterType()))
{
return(true);
}
// If not, try user defined implicit conversions.
break;
case TypeKind.TK_AggregateType:
// TypeReference and ArgIterator can't be boxed (or converted to anything else)
if (typeSrc.isSpecialByRefType())
{
return(false);
}
if (bindImplicitConversionFromAgg(typeSrc.AsAggregateType()))
{
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.
if (exprSrc != null &&
exprSrc.RuntimeObject != null &&
typeDest.AssociatedSystemType.IsInstanceOfType(exprSrc.RuntimeObject) &&
binder.GetSemanticChecker().CheckTypeAccess(typeDest, binder.Context.ContextForMemberLookup()))
{
if (needsExprDest)
{
binder.bindSimpleCast(exprSrc, exprTypeDest, 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);
}
public bool HasImplicitReferenceConversion(CType pSource, CType pDest)
{
Debug.Assert(pSource != null);
Debug.Assert(pDest != null);
// The implicit reference conversions are:
// * From any reference type to Object.
if (pSource.IsRefType() && pDest.isPredefType(PredefinedType.PT_OBJECT))
{
return true;
}
// * From any class type S to any class type T provided S is derived from T.
if (pSource.isClassType() && pDest.isClassType() && IsBaseClass(pSource, pDest))
{
return true;
}
// 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.
if (pSource.isClassType() && pDest.isInterfaceType() && HasAnyBaseInterfaceConversion(pSource, pDest))
{
return true;
}
if (pSource.isInterfaceType() && pDest.isInterfaceType() && HasAnyBaseInterfaceConversion(pSource, pDest))
{
return true;
}
if (pSource.isInterfaceType() && pDest.isInterfaceType() && pSource != pDest &&
HasInterfaceConversion(pSource.AsAggregateType(), pDest.AsAggregateType()))
{
return true;
}
// * 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 (pSource.IsArrayType() && pDest.IsArrayType() &&
HasCovariantArrayConversion(pSource.AsArrayType(), pDest.AsArrayType()))
{
return true;
}
// * From any array type to System.Array or any interface implemented by System.Array.
if (pSource.IsArrayType() && (pDest.isPredefType(PredefinedType.PT_ARRAY) ||
IsBaseInterface(GetReqPredefType(PredefinedType.PT_ARRAY, false), pDest)))
{
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.
if (pSource.IsArrayType() && HasArrayConversionToInterface(pSource.AsArrayType(), pDest))
{
return true;
}
// * 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 (pSource.isDelegateType() &&
(pDest.isPredefType(PredefinedType.PT_MULTIDEL) ||
pDest.isPredefType(PredefinedType.PT_DELEGATE) ||
IsBaseInterface(GetReqPredefType(PredefinedType.PT_MULTIDEL, false), pDest)))
{
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
if (pSource.isDelegateType() && pDest.isDelegateType() &&
HasDelegateConversion(pSource.AsAggregateType(), pDest.AsAggregateType()))
{
return true;
}
// * 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.)
if (pSource.IsNullType() && pDest.IsRefType())
{
return true;
}
if (pSource.IsNullType() && pDest.IsNullableType())
{
return true;
}
// * Implicit conversions involving type parameters that are known to be reference types.
if (pSource.IsTypeParameterType() &&
HasImplicitReferenceTypeParameterConversion(pSource.AsTypeParameterType(), pDest))
{
return true;
}
return false;
}
