private bool TryVarianceAdjustmentToGetAccessibleType(CSemanticChecker semanticChecker, AggregateDeclaration context, AggregateType typeSrc, out CType typeDst)
{
Debug.Assert(typeSrc != null);
Debug.Assert(typeSrc.IsInterfaceType || typeSrc.IsDelegateType);
typeDst = null;
AggregateSymbol aggSym = typeSrc.OwningAggregate;
AggregateType aggOpenType = aggSym.getThisType();
if (!semanticChecker.CheckTypeAccess(aggOpenType, context))
{
// if the aggregate symbol itself is not accessible, then forget it, there is no
// variance that will help us arrive at an accessible type.
return(false);
}
TypeArray typeArgs = typeSrc.TypeArgsThis;
TypeArray typeParams = aggOpenType.TypeArgsThis;
CType[] newTypeArgsTemp = new CType[typeArgs.Count];
for (int i = 0; i < newTypeArgsTemp.Length; i++)
{
CType typeArg = typeArgs[i];
if (semanticChecker.CheckTypeAccess(typeArg, context))
{
// we have an accessible argument, this position is not a problem.
newTypeArgsTemp[i] = typeArg;
continue;
}
if (!typeArg.IsReferenceType || !((TypeParameterType)typeParams[i]).Covariant)
{
// This guy is inaccessible, and we are not going to be able to vary him, so we need to fail.
return(false);
}
newTypeArgsTemp[i] = GetBestAccessibleType(semanticChecker, context, typeArg);
// now we either have a value type (which must be accessible due to the above
// check, OR we have an inaccessible type (which must be a ref type). In either
// case, the recursion worked out and we are OK to vary this argument.
}
TypeArray newTypeArgs = semanticChecker.getBSymmgr().AllocParams(typeArgs.Count, newTypeArgsTemp);
CType intermediateType = GetAggregate(aggSym, typeSrc.OuterType, newTypeArgs);
// All type arguments were varied successfully, which means now we must be accessible. But we could
// have violated constraints. Let's check that out.
if (!TypeBind.CheckConstraints(semanticChecker, errHandling: null, intermediateType, CheckConstraintsFlags.NoErrors))
{
return(false);
}
typeDst = intermediateType;
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, context));
return(true);
}
private bool TryArrayVarianceAdjustmentToGetAccessibleType(CSemanticChecker semanticChecker, BindingContext bindingContext, ArrayType typeSrc, out CType typeDst)
{
Debug.Assert(typeSrc != null);
typeDst = null;
// We are here because we have an array type with an inaccessible element type. If possible,
// we should create a new array type that has an accessible element type for which a
// conversion exists.
CType elementType = typeSrc.GetElementType();
if (!elementType.IsRefType())
{
// Covariant array conversions exist for reference types only.
return(false);
}
CType intermediateType;
if (GetBestAccessibleType(semanticChecker, bindingContext, elementType, out intermediateType))
{
typeDst = this.GetArray(intermediateType, typeSrc.rank, typeSrc.IsSZArray);
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup));
return(true);
}
return(false);
}
private bool TryArrayVarianceAdjustmentToGetAccessibleType(CSemanticChecker semanticChecker, AggregateDeclaration context, ArrayType typeSrc, out CType typeDst)
{
Debug.Assert(typeSrc != null);
// We are here because we have an array type with an inaccessible element type. If possible,
// we should create a new array type that has an accessible element type for which a
// conversion exists.
CType elementType = typeSrc.ElementType;
// Covariant array conversions exist for reference types only.
if (elementType.IsReferenceType)
{
CType destElement = GetBestAccessibleType(semanticChecker, context, elementType);
typeDst = GetArray(destElement, typeSrc.Rank, typeSrc.IsSZArray);
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, context));
return(true);
}
typeDst = null;
return(false);
}
private bool SearchSingleType(AggregateType typeCur, out bool pfHideByName)
{
bool fFoundSome = false;
pfHideByName = false;
// Make sure this type is accessible. It may not be due to private inheritance
// or friend assemblies.
bool fInaccess = !CSemanticChecker.CheckTypeAccess(typeCur, _symWhere);
if (fInaccess && (_csym != 0 || _swtInaccess != null))
{
return(false);
}
// Loop through symbols.
Symbol symCur;
for (symCur = SymbolLoader.LookupAggMember(_name, typeCur.OwningAggregate, symbmask_t.MASK_Member);
symCur != null;
symCur = symCur.LookupNext(symbmask_t.MASK_Member))
{
Debug.Assert(!(symCur is AggregateSymbol));
// Check for arity.
// For non-zero arity, only methods of the correct arity are considered.
// For zero arity, don't filter out any methods since we do type argument
// inferencing.
// All others are only considered when arity is zero.
if (_arity > 0 && (!(symCur is MethodSymbol curMeth) || curMeth.typeVars.Count != _arity))
{
if (!_swtBadArity)
{
_swtBadArity.Set(symCur, typeCur);
}
continue;
}
// Check for user callability.
if (symCur.IsOverride() && !symCur.IsHideByName())
{
continue;
}
MethodOrPropertySymbol methProp = symCur as MethodOrPropertySymbol;
MethodSymbol meth = symCur as MethodSymbol;
if (methProp != null && (_flags & MemLookFlags.UserCallable) != 0 && !methProp.isUserCallable())
{
// If its an indexed property method symbol, let it through.
// This is too liberal, but maintained for compatibility.
if (meth == null ||
!meth.isPropertyAccessor() ||
(!symCur.name.Text.StartsWith("set_", StringComparison.Ordinal) || meth.Params.Count <= 1) &&
(!symCur.name.Text.StartsWith("get_", StringComparison.Ordinal) || meth.Params.Count <= 0))
{
if (!_swtInaccess)
{
_swtInaccess.Set(symCur, typeCur);
}
continue;
}
}
if (fInaccess || !CSemanticChecker.CheckAccess(symCur, typeCur, _symWhere, _typeQual))
{
// Not accessible so get the next sym.
if (!_swtInaccess)
{
_swtInaccess.Set(symCur, typeCur);
}
if (fInaccess)
{
return(false);
}
continue;
}
PropertySymbol prop = symCur as PropertySymbol;
// Make sure that whether we're seeing a ctor, operator, or indexer is consistent with the flags.
if (((_flags & MemLookFlags.Ctor) == 0) != (meth == null || !meth.IsConstructor()) ||
((_flags & MemLookFlags.Operator) == 0) != (meth == null || !meth.isOperator) ||
((_flags & MemLookFlags.Indexer) == 0) != !(prop is IndexerSymbol))
{
if (!_swtBad)
{
_swtBad.Set(symCur, typeCur);
}
continue;
}
// We can't call CheckBogus on methods or indexers because if the method has the wrong
// number of parameters people don't think they should have to /r the assemblies containing
// the parameter types and they complain about the resulting CS0012 errors.
if (!(symCur is MethodSymbol) && (_flags & MemLookFlags.Indexer) == 0 && CSemanticChecker.CheckBogus(symCur))
{
// A bogus member - we can't use these, so only record them for error reporting.
if (!_swtBogus)
{
_swtBogus.Set(symCur, typeCur);
}
continue;
}
// if we are in a calling context then we should only find a property if it is delegate valued
if ((_flags & MemLookFlags.MustBeInvocable) != 0)
{
if ((symCur is FieldSymbol field && !IsDelegateType(field.GetType(), typeCur) && !IsDynamicMember(symCur)) ||
(prop != null && !IsDelegateType(prop.RetType, typeCur) && !IsDynamicMember(symCur)))
{
if (!_swtBad)
{
_swtBad.Set(symCur, typeCur);
}
continue;
}
}
if (methProp != null)
{
MethPropWithType mwpInsert = new MethPropWithType(methProp, typeCur);
_methPropWithTypeList.Add(mwpInsert);
}
// We have a visible symbol.
fFoundSome = true;
if (_swtFirst)
{
if (!typeCur.IsInterfaceType)
{
// Non-interface case.
Debug.Assert(_fMulti || typeCur == _prgtype[0]);
if (!_fMulti)
{
if (_swtFirst.Sym is FieldSymbol && symCur is EventSymbol
// The isEvent bit is only set on symbols which come from source...
// This is not a problem for the compiler because the field is only
// accessible in the scope in which it is declared,
// but in the EE we ignore accessibility...
&& _swtFirst.Field().isEvent
)
{
// m_swtFirst is just the field behind the event symCur so ignore symCur.
continue;
}
else if (_swtFirst.Sym is FieldSymbol && symCur is EventSymbol)
{
// symCur is the matching event.
continue;
}
goto LAmbig;
}
if (_swtFirst.Sym.getKind() != symCur.getKind())
{
if (typeCur == _prgtype[0])
{
goto LAmbig;
}
// This one is hidden by the first one. This one also hides any more in base types.
pfHideByName = true;
continue;
}
}
// Interface case.
// m_fMulti : n n n y y y y y
// same-kind : * * * y n n n n
// fDiffHidden: * * * * y n n n
// meth : * * * * * y n * can n happen? just in case, we better handle it....
// hack : n * y * * y * n
// meth-2 : * n y * * * * *
// res : A A S R H H A A
else if (!_fMulti)
{
// Give method groups priority.
if (!(symCur is MethodSymbol))
{
goto LAmbig;
}
// Erase previous results so we'll record this method as the first.
_prgtype = new List <AggregateType>();
_csym = 0;
_swtFirst.Clear();
_swtAmbig.Clear();
}
else if (_swtFirst.Sym.getKind() != symCur.getKind())
{
if (!typeCur.DiffHidden)
{
// Give method groups priority.
if (!(_swtFirst.Sym is MethodSymbol))
{
goto LAmbig;
}
}
// This one is hidden by another. This one also hides any more in base types.
pfHideByName = true;
continue;
}
}
RecordType(typeCur, symCur);
if (methProp != null && methProp.isHideByName)
{
pfHideByName = true;
}
// We've found a symbol in this type but need to make sure there aren't any conflicting
// syms here, so keep searching the type.
}
Debug.Assert(!fInaccess || !fFoundSome);
return(fFoundSome);
LAmbig:
// Ambiguous!
if (!_swtAmbig)
{
_swtAmbig.Set(symCur, typeCur);
}
pfHideByName = true;
return(true);
}
/*
* 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);
}
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// RUNTIME BINDER ONLY CHANGE
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
internal bool GetBestAccessibleType(CSemanticChecker semanticChecker, BindingContext bindingContext, CType typeSrc, out CType typeDst)
{
// This method implements the "best accessible type" algorithm for determining the type
// of untyped arguments in the runtime binder. It is also used in method type inference
// to fix type arguments to types that are accessible.
// The new type is returned in an out parameter. The result will be true (and the out param
// non-null) only when the algorithm could find a suitable accessible type.
Debug.Assert(semanticChecker != null);
Debug.Assert(bindingContext != null);
Debug.Assert(typeSrc != null);
typeDst = null;
if (semanticChecker.CheckTypeAccess(typeSrc, bindingContext.ContextForMemberLookup))
{
// If we already have an accessible type, then use it. This is the terminal point of the recursion.
typeDst = typeSrc;
return(true);
}
// These guys have no accessibility concerns.
Debug.Assert(!(typeSrc is VoidType) && !(typeSrc is ErrorType) && !(typeSrc is TypeParameterType));
if (typeSrc is ParameterModifierType || typeSrc is PointerType)
{
// We cannot vary these.
return(false);
}
CType intermediateType;
if (typeSrc is AggregateType aggSrc && (aggSrc.isInterfaceType() || aggSrc.isDelegateType()) && TryVarianceAdjustmentToGetAccessibleType(semanticChecker, bindingContext, aggSrc, out intermediateType))
{
// If we have an interface or delegate type, then it can potentially be varied by its type arguments
// to produce an accessible type, and if that's the case, then return that.
// Example: IEnumerable<PrivateConcreteFoo> --> IEnumerable<PublicAbstractFoo>
typeDst = intermediateType;
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup));
return(true);
}
if (typeSrc is ArrayType arrSrc && TryArrayVarianceAdjustmentToGetAccessibleType(semanticChecker, bindingContext, arrSrc, out intermediateType))
{
// Similarly to the interface and delegate case, arrays are covariant in their element type and
// so we can potentially produce an array type that is accessible.
// Example: PrivateConcreteFoo[] --> PublicAbstractFoo[]
typeDst = intermediateType;
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup));
return(true);
}
if (typeSrc is NullableType)
{
// We have an inaccessible nullable type, which means that the best we can do is System.ValueType.
typeDst = GetPredefAgg(PredefinedType.PT_VALUE).getThisType();
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup));
return(true);
}
if (typeSrc is ArrayType)
{
// We have an inaccessible array type for which we could not earlier find a better array type
// with a covariant conversion, so the best we can do is System.Array.
typeDst = GetPredefAgg(PredefinedType.PT_ARRAY).getThisType();
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup));
return(true);
}
Debug.Assert(typeSrc is AggregateType);
if (typeSrc is AggregateType aggType)
{
// We have an AggregateType, so recurse on its base class.
AggregateType baseType = aggType.GetBaseClass();
if (baseType == null)
{
// This happens with interfaces, for instance. But in that case, the
// conversion to object does exist, is an implicit reference conversion,
// and so we will use it.
baseType = GetPredefAgg(PredefinedType.PT_OBJECT).getThisType();
}
return(GetBestAccessibleType(semanticChecker, bindingContext, baseType, out typeDst));
}
return(false);
}
private bool TryVarianceAdjustmentToGetAccessibleType(CSemanticChecker semanticChecker, BindingContext bindingContext, AggregateType typeSrc, out CType typeDst)
{
Debug.Assert(typeSrc != null);
Debug.Assert(typeSrc.isInterfaceType() || typeSrc.isDelegateType());
typeDst = null;
AggregateSymbol aggSym = typeSrc.GetOwningAggregate();
AggregateType aggOpenType = aggSym.getThisType();
if (!semanticChecker.CheckTypeAccess(aggOpenType, bindingContext.ContextForMemberLookup))
{
// if the aggregate symbol itself is not accessible, then forget it, there is no
// variance that will help us arrive at an accessible type.
return(false);
}
TypeArray typeArgs = typeSrc.GetTypeArgsThis();
TypeArray typeParams = aggOpenType.GetTypeArgsThis();
CType[] newTypeArgsTemp = new CType[typeArgs.Count];
for (int i = 0; i < typeArgs.Count; i++)
{
if (semanticChecker.CheckTypeAccess(typeArgs[i], bindingContext.ContextForMemberLookup))
{
// we have an accessible argument, this position is not a problem.
newTypeArgsTemp[i] = typeArgs[i];
continue;
}
if (!typeArgs[i].IsRefType() || !((TypeParameterType)typeParams[i]).Covariant)
{
// This guy is inaccessible, and we are not going to be able to vary him, so we need to fail.
return(false);
}
CType intermediateTypeArg;
if (GetBestAccessibleType(semanticChecker, bindingContext, typeArgs[i], out intermediateTypeArg))
{
// now we either have a value type (which must be accessible due to the above
// check, OR we have an inaccessible type (which must be a ref type). In either
// case, the recursion worked out and we are OK to vary this argument.
newTypeArgsTemp[i] = intermediateTypeArg;
continue;
}
else
{
Debug.Assert(false, "GetBestAccessibleType unexpectedly failed on a type that was used as a type parameter");
return(false);
}
}
TypeArray newTypeArgs = semanticChecker.getBSymmgr().AllocParams(typeArgs.Count, newTypeArgsTemp);
CType intermediateType = this.GetAggregate(aggSym, typeSrc.outerType, newTypeArgs);
// All type arguments were varied successfully, which means now we must be accessible. But we could
// have violated constraints. Let's check that out.
if (!TypeBind.CheckConstraints(semanticChecker, null /*ErrorHandling*/, intermediateType, CheckConstraintsFlags.NoErrors))
{
return(false);
}
typeDst = intermediateType;
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup));
return(true);
}
private bool TryArrayVarianceAdjustmentToGetAccessibleType(CSemanticChecker semanticChecker, BindingContext bindingContext, ArrayType typeSrc, out CType typeDst)
{
Debug.Assert(typeSrc != null);
typeDst = null;
// We are here because we have an array type with an inaccessible element type. If possible,
// we should create a new array type that has an accessible element type for which a
// conversion exists.
CType elementType = typeSrc.GetElementType();
if (!elementType.IsRefType())
{
// Covariant array conversions exist for reference types only.
return false;
}
CType intermediateType;
if (GetBestAccessibleType(semanticChecker, bindingContext, elementType, out intermediateType))
{
typeDst = this.GetArray(intermediateType, typeSrc.rank);
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup()));
return true;
}
return false;
}
private bool TryVarianceAdjustmentToGetAccessibleType(CSemanticChecker semanticChecker, BindingContext bindingContext, AggregateType typeSrc, out CType typeDst)
{
Debug.Assert(typeSrc != null);
Debug.Assert(typeSrc.isInterfaceType() || typeSrc.isDelegateType());
typeDst = null;
AggregateSymbol aggSym = typeSrc.GetOwningAggregate();
AggregateType aggOpenType = aggSym.getThisType();
if (!semanticChecker.CheckTypeAccess(aggOpenType, bindingContext.ContextForMemberLookup()))
{
// if the aggregate symbol itself is not accessible, then forget it, there is no
// variance that will help us arrive at an accessible type.
return false;
}
TypeArray typeArgs = typeSrc.GetTypeArgsThis();
TypeArray typeParams = aggOpenType.GetTypeArgsThis();
CType[] newTypeArgsTemp = new CType[typeArgs.size];
for (int i = 0; i < typeArgs.size; i++)
{
if (semanticChecker.CheckTypeAccess(typeArgs.Item(i), bindingContext.ContextForMemberLookup()))
{
// we have an accessible argument, this position is not a problem.
newTypeArgsTemp[i] = typeArgs.Item(i);
continue;
}
if (!typeArgs.Item(i).IsRefType() || !typeParams.Item(i).AsTypeParameterType().Covariant)
{
// This guy is inaccessible, and we are not going to be able to vary him, so we need to fail.
return false;
}
CType intermediateTypeArg;
if (GetBestAccessibleType(semanticChecker, bindingContext, typeArgs.Item(i), out intermediateTypeArg))
{
// now we either have a value type (which must be accessible due to the above
// check, OR we have an inaccessible type (which must be a ref type). In either
// case, the recursion worked out and we are OK to vary this argument.
newTypeArgsTemp[i] = intermediateTypeArg;
continue;
}
else
{
Debug.Assert(false, "GetBestAccessibleType unexpectedly failed on a type that was used as a type parameter");
return false;
}
}
TypeArray newTypeArgs = semanticChecker.getBSymmgr().AllocParams(typeArgs.size, newTypeArgsTemp);
CType intermediateType = this.GetAggregate(aggSym, typeSrc.outerType, newTypeArgs);
// All type arguments were varied successfully, which means now we must be accessible. But we could
// have violated constraints. Let's check that out.
if (!TypeBind.CheckConstraints(semanticChecker, null/*ErrorHandling*/, intermediateType, CheckConstraintsFlags.NoErrors))
{
return false;
}
typeDst = intermediateType;
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup()));
return true;
}
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// RUNTIME BINDER ONLY CHANGE
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
internal bool GetBestAccessibleType(CSemanticChecker semanticChecker, BindingContext bindingContext, CType typeSrc, out CType typeDst)
{
// This method implements the "best accessible type" algorithm for determining the type
// of untyped arguments in the runtime binder. It is also used in method type inference
// to fix type arguments to types that are accessible.
// The new type is returned in an out parameter. The result will be true (and the out param
// non-null) only when the algorithm could find a suitable accessible type.
Debug.Assert(semanticChecker != null);
Debug.Assert(bindingContext != null);
Debug.Assert(typeSrc != null);
typeDst = null;
if (semanticChecker.CheckTypeAccess(typeSrc, bindingContext.ContextForMemberLookup()))
{
// If we already have an accessible type, then use it. This is the terminal point of the recursion.
typeDst = typeSrc;
return true;
}
// These guys have no accessibility concerns.
Debug.Assert(!typeSrc.IsVoidType() && !typeSrc.IsErrorType() && !typeSrc.IsTypeParameterType());
if (typeSrc.IsParameterModifierType() || typeSrc.IsPointerType())
{
// We cannot vary these.
return false;
}
CType intermediateType;
if ((typeSrc.isInterfaceType() || typeSrc.isDelegateType()) && TryVarianceAdjustmentToGetAccessibleType(semanticChecker, bindingContext, typeSrc.AsAggregateType(), out intermediateType))
{
// If we have an interface or delegate type, then it can potentially be varied by its type arguments
// to produce an accessible type, and if that's the case, then return that.
// Example: IEnumerable<PrivateConcreteFoo> --> IEnumerable<PublicAbstractFoo>
typeDst = intermediateType;
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup()));
return true;
}
if (typeSrc.IsArrayType() && TryArrayVarianceAdjustmentToGetAccessibleType(semanticChecker, bindingContext, typeSrc.AsArrayType(), out intermediateType))
{
// Similarly to the interface and delegate case, arrays are covariant in their element type and
// so we can potentially produce an array type that is accessible.
// Example: PrivateConcreteFoo[] --> PublicAbstractFoo[]
typeDst = intermediateType;
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup()));
return true;
}
if (typeSrc.IsNullableType())
{
// We have an inaccessible nullable type, which means that the best we can do is System.ValueType.
typeDst = this.GetOptPredefAgg(PredefinedType.PT_VALUE).getThisType();
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup()));
return true;
}
if (typeSrc.IsArrayType())
{
// We have an inaccessible array type for which we could not earlier find a better array type
// with a covariant conversion, so the best we can do is System.Array.
typeDst = this.GetReqPredefAgg(PredefinedType.PT_ARRAY).getThisType();
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, bindingContext.ContextForMemberLookup()));
return true;
}
Debug.Assert(typeSrc.IsAggregateType());
if (typeSrc.IsAggregateType())
{
// We have an AggregateType, so recurse on its base class.
AggregateType aggType = typeSrc.AsAggregateType();
AggregateType baseType = aggType.GetBaseClass();
if (baseType == null)
{
// This happens with interfaces, for instance. But in that case, the
// conversion to object does exist, is an implicit reference conversion,
// and so we will use it.
baseType = this.GetReqPredefAgg(PredefinedType.PT_OBJECT).getThisType();
}
return GetBestAccessibleType(semanticChecker, bindingContext, baseType, out typeDst);
}
return false;
}
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// RUNTIME BINDER ONLY CHANGE
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
internal CType GetBestAccessibleType(CSemanticChecker semanticChecker, AggregateDeclaration context, CType typeSrc)
{
// This method implements the "best accessible type" algorithm for determining the type
// of untyped arguments in the runtime binder. It is also used in method type inference
// to fix type arguments to types that are accessible.
// The new type is returned in an out parameter. The result will be true (and the out param
// non-null) only when the algorithm could find a suitable accessible type.
Debug.Assert(semanticChecker != null);
Debug.Assert(typeSrc != null);
Debug.Assert(!(typeSrc is ParameterModifierType));
Debug.Assert(!(typeSrc is PointerType));
if (semanticChecker.CheckTypeAccess(typeSrc, context))
{
// If we already have an accessible type, then use it.
return(typeSrc);
}
// These guys have no accessibility concerns.
Debug.Assert(!(typeSrc is VoidType) && !(typeSrc is TypeParameterType));
if (typeSrc is AggregateType aggSrc)
{
for (;;)
{
if ((aggSrc.IsInterfaceType || aggSrc.IsDelegateType) && TryVarianceAdjustmentToGetAccessibleType(semanticChecker, context, aggSrc, out CType typeDst))
{
// If we have an interface or delegate type, then it can potentially be varied by its type arguments
// to produce an accessible type, and if that's the case, then return that.
// Example: IEnumerable<PrivateConcreteFoo> --> IEnumerable<PublicAbstractFoo>
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, context));
return(typeDst);
}
// We have an AggregateType, so recurse on its base class.
AggregateType baseType = aggSrc.BaseClass;
if (baseType == null)
{
// This happens with interfaces, for instance. But in that case, the
// conversion to object does exist, is an implicit reference conversion,
// and is guaranteed to be accessible, so we will use it.
return(GetPredefAgg(PredefinedType.PT_OBJECT).getThisType());
}
if (semanticChecker.CheckTypeAccess(baseType, context))
{
return(baseType);
}
// baseType is always an AggregateType, so no need for logic of other types.
aggSrc = baseType;
}
}
if (typeSrc is ArrayType arrSrc)
{
if (TryArrayVarianceAdjustmentToGetAccessibleType(semanticChecker, context, arrSrc, out CType typeDst))
{
// Similarly to the interface and delegate case, arrays are covariant in their element type and
// so we can potentially produce an array type that is accessible.
// Example: PrivateConcreteFoo[] --> PublicAbstractFoo[]
Debug.Assert(semanticChecker.CheckTypeAccess(typeDst, context));
return(typeDst);
}
// We have an inaccessible array type for which we could not earlier find a better array type
// with a covariant conversion, so the best we can do is System.Array.
return(GetPredefAgg(PredefinedType.PT_ARRAY).getThisType());
}
Debug.Assert(typeSrc is NullableType);
// We have an inaccessible nullable type, which means that the best we can do is System.ValueType.
return(GetPredefAgg(PredefinedType.PT_VALUE).getThisType());
}
