private NamedTypeSymbol MakeAcyclicBaseType(BindingDiagnosticBag diagnostics)
{
var typeKind = this.TypeKind;
var compilation = this.DeclaringCompilation;
NamedTypeSymbol declaredBase;
if (typeKind == TypeKind.Enum)
{
Debug.Assert(
(object)GetDeclaredBaseType(basesBeingResolved: null) == null,
"Computation skipped for enums"
);
declaredBase = compilation.GetSpecialType(SpecialType.System_Enum);
}
else
{
declaredBase = GetDeclaredBaseType(basesBeingResolved: null);
}
if ((object)declaredBase == null)
{
switch (typeKind)
{
case TypeKind.Class:
if (this.SpecialType == SpecialType.System_Object)
{
return(null);
}
declaredBase = compilation.GetSpecialType(SpecialType.System_Object);
break;
case TypeKind.Struct:
declaredBase = compilation.GetSpecialType(SpecialType.System_ValueType);
break;
case TypeKind.Interface:
return(null);
case TypeKind.Delegate:
declaredBase = compilation.GetSpecialType(
SpecialType.System_MulticastDelegate
);
break;
default:
throw ExceptionUtilities.UnexpectedValue(typeKind);
}
}
if (BaseTypeAnalysis.TypeDependsOn(declaredBase, this))
{
return(new ExtendedErrorTypeSymbol(
declaredBase,
LookupResultKind.NotReferencable,
diagnostics.Add(ErrorCode.ERR_CircularBase, Locations[0], declaredBase, this)
));
}
this.SetKnownToHaveNoDeclaredBaseCycles();
var useSiteInfo = new CompoundUseSiteInfo <AssemblySymbol>(
diagnostics,
ContainingAssembly
);
NamedTypeSymbol current = declaredBase;
do
{
if (current.DeclaringCompilation == this.DeclaringCompilation)
{
break;
}
current.AddUseSiteInfo(ref useSiteInfo);
current = current.BaseTypeNoUseSiteDiagnostics;
} while ((object)current != null);
diagnostics.Add(
useSiteInfo.Diagnostics.IsNullOrEmpty()
? Location.None
: (FindBaseRefSyntax(declaredBase) ?? Locations[0]),
useSiteInfo
);
return(declaredBase);
}
