// Based on SymbolLoader::ResolveBounds.
public static TypeParameterBounds ResolveBounds(
this TypeParameterSymbol typeParameter,
AssemblySymbol corLibrary,
ConsList <TypeParameterSymbol> inProgress,
ImmutableArray <TypeSymbol> constraintTypes,
bool inherited,
CSharpCompilation currentCompilation,
ArrayBuilder <TypeParameterDiagnosticInfo> diagnosticsBuilder,
ref ArrayBuilder <TypeParameterDiagnosticInfo> useSiteDiagnosticsBuilder)
{
Debug.Assert(currentCompilation == null || typeParameter.IsFromCompilation(currentCompilation));
ImmutableArray <NamedTypeSymbol> interfaces;
NamedTypeSymbol effectiveBaseClass = corLibrary.GetSpecialType(typeParameter.HasValueTypeConstraint ? SpecialType.System_ValueType : SpecialType.System_Object);
TypeSymbol deducedBaseType = effectiveBaseClass;
DynamicTypeEraser dynamicEraser = null;
if (constraintTypes.Length == 0)
{
interfaces = ImmutableArray <NamedTypeSymbol> .Empty;
}
else
{
var constraintTypesBuilder = ArrayBuilder <TypeSymbol> .GetInstance();
var interfacesBuilder = ArrayBuilder <NamedTypeSymbol> .GetInstance();
var conversions = new TypeConversions(corLibrary);
HashSet <DiagnosticInfo> useSiteDiagnostics = null;
// Resolve base types, determine the effective base class and
// interfaces, and filter out any constraint types that cause cycles.
foreach (var constraintType in constraintTypes)
{
NamedTypeSymbol constraintEffectiveBase;
TypeSymbol constraintDeducedBase;
switch (constraintType.TypeKind)
{
case TypeKind.Dynamic:
Debug.Assert(inherited || currentCompilation == null);
continue;
case TypeKind.TypeParameter:
{
var containingSymbol = typeParameter.ContainingSymbol;
var constraintTypeParameter = (TypeParameterSymbol)constraintType;
ConsList <TypeParameterSymbol> constraintsInProgress;
if (constraintTypeParameter.ContainingSymbol == containingSymbol)
{
// The constraint type parameter is from the same containing type or method.
if (inProgress.ContainsReference(constraintTypeParameter))
{
// "Circular constraint dependency involving '{0}' and '{1}'"
diagnosticsBuilder.Add(new TypeParameterDiagnosticInfo(constraintTypeParameter, new CSDiagnosticInfo(ErrorCode.ERR_CircularConstraint, constraintTypeParameter, typeParameter)));
continue;
}
constraintsInProgress = inProgress;
}
else
{
// The constraint type parameter is from a different containing symbol so no cycle.
constraintsInProgress = ConsList <TypeParameterSymbol> .Empty;
}
// Use the calculated bounds from the constraint type parameter.
constraintEffectiveBase = constraintTypeParameter.GetEffectiveBaseClass(constraintsInProgress);
constraintDeducedBase = constraintTypeParameter.GetDeducedBaseType(constraintsInProgress);
AddInterfaces(interfacesBuilder, constraintTypeParameter.GetInterfaces(constraintsInProgress));
if (constraintTypeParameter.HasValueTypeConstraint && !inherited && currentCompilation != null && constraintTypeParameter.IsFromCompilation(currentCompilation))
{
// "Type parameter '{1}' has the 'struct' constraint so '{1}' cannot be used as a constraint for '{0}'"
diagnosticsBuilder.Add(new TypeParameterDiagnosticInfo(typeParameter, new CSDiagnosticInfo(ErrorCode.ERR_ConWithValCon, typeParameter, constraintTypeParameter)));
continue;
}
}
break;
case TypeKind.Interface:
case TypeKind.Class:
case TypeKind.Delegate:
NamedTypeSymbol erasedConstraintType;
if (inherited || currentCompilation == null)
{
// only inherited constraints may contain dynamic
if (dynamicEraser == null)
{
dynamicEraser = new DynamicTypeEraser(corLibrary.GetSpecialType(SpecialType.System_Object));
}
erasedConstraintType = (NamedTypeSymbol)dynamicEraser.EraseDynamic(constraintType);
}
else
{
Debug.Assert(!constraintType.ContainsDynamic());
Debug.Assert(constraintType.TypeKind != TypeKind.Delegate);
erasedConstraintType = (NamedTypeSymbol)constraintType;
}
if (constraintType.IsInterfaceType())
{
AddInterface(interfacesBuilder, erasedConstraintType);
constraintTypesBuilder.Add(constraintType);
continue;
}
else
{
constraintEffectiveBase = erasedConstraintType;
constraintDeducedBase = constraintType;
break;
}
case TypeKind.Struct:
Debug.Assert(inherited || currentCompilation == null);
constraintEffectiveBase = corLibrary.GetSpecialType(SpecialType.System_ValueType);
constraintDeducedBase = constraintType;
break;
case TypeKind.Enum:
Debug.Assert(inherited || currentCompilation == null);
constraintEffectiveBase = corLibrary.GetSpecialType(SpecialType.System_Enum);
constraintDeducedBase = constraintType;
break;
case TypeKind.Array:
Debug.Assert(inherited || currentCompilation == null);
constraintEffectiveBase = corLibrary.GetSpecialType(SpecialType.System_Array);
constraintDeducedBase = constraintType;
break;
case TypeKind.Error:
constraintEffectiveBase = (NamedTypeSymbol)constraintType;
constraintDeducedBase = constraintType;
break;
case TypeKind.Submission:
default:
throw ExceptionUtilities.UnexpectedValue(constraintType.TypeKind);
}
CheckEffectiveAndDeducedBaseTypes(conversions, constraintEffectiveBase, constraintDeducedBase);
constraintTypesBuilder.Add(constraintType);
// Determine the more encompassed of the current effective base
// class and the previously computed effective base class.
if (!deducedBaseType.IsErrorType() && !constraintDeducedBase.IsErrorType())
{
if (!IsEncompassedBy(conversions, deducedBaseType, constraintDeducedBase, ref useSiteDiagnostics))
{
if (!IsEncompassedBy(conversions, constraintDeducedBase, deducedBaseType, ref useSiteDiagnostics))
{
// "Type parameter '{0}' inherits conflicting constraints '{1}' and '{2}'"
diagnosticsBuilder.Add(new TypeParameterDiagnosticInfo(typeParameter, new CSDiagnosticInfo(ErrorCode.ERR_BaseConstraintConflict, typeParameter, constraintDeducedBase, deducedBaseType)));
}
else
{
deducedBaseType = constraintDeducedBase;
effectiveBaseClass = constraintEffectiveBase;
}
}
}
}
AppendUseSiteDiagnostics(useSiteDiagnostics, typeParameter, ref useSiteDiagnosticsBuilder);
CheckEffectiveAndDeducedBaseTypes(conversions, effectiveBaseClass, deducedBaseType);
constraintTypes = constraintTypesBuilder.ToImmutableAndFree();
interfaces = interfacesBuilder.ToImmutableAndFree();
}
Debug.Assert((effectiveBaseClass.SpecialType == SpecialType.System_Object) || (deducedBaseType.SpecialType != SpecialType.System_Object));
// Only create a TypeParameterBounds instance for this type
// parameter if the bounds are not the default values.
if ((constraintTypes.Length == 0) && (deducedBaseType.SpecialType == SpecialType.System_Object))
{
Debug.Assert(effectiveBaseClass.SpecialType == SpecialType.System_Object);
Debug.Assert(interfaces.Length == 0);
return(null);
}
var bounds = new TypeParameterBounds(constraintTypes, interfaces, effectiveBaseClass, deducedBaseType);
// Additional constraint checks for overrides.
if (inherited)
{
CheckOverrideConstraints(typeParameter, bounds, diagnosticsBuilder);
}
return(bounds);
}
internal static ArrayTypeSymbol CreateSZArray(
AssemblySymbol declaringAssembly,
TypeWithAnnotations elementType)
{
return(CreateSZArray(elementType, declaringAssembly.GetSpecialType(SpecialType.System_Array), GetSZArrayInterfaces(elementType, declaringAssembly)));
}