/// <summary>
/// Creates a generated expression for a default argument value.
/// </summary>
public static Expression?CreateGenerated(Context cx, IParameterSymbol parameter, IExpressionParentEntity parent,
int childIndex, Extraction.Entities.Location location)
{
if (!parameter.HasExplicitDefaultValue)
{
return(null);
}
var defaultValue = parameter.ExplicitDefaultValue;
if (parameter.Type is INamedTypeSymbol nt && nt.EnumUnderlyingType is not null)
{
// = (MyEnum)1, = MyEnum.Value1, = default(MyEnum), = new MyEnum()
// we're generating a (MyEnum)value cast expression:
defaultValue ??= 0;
Action <Expression, int> createChild = (parent, index) => Literal.CreateGenerated(cx, parent, index, nt.EnumUnderlyingType, defaultValue, location);
return(Cast.CreateGenerated(cx, parent, childIndex, parameter.Type, defaultValue, createChild, location));
}
if (defaultValue is null)
{
// = null, = default, = default(T), = new MyStruct()
// we're generating a default expression:
return(Default.CreateGenerated(cx, parent, childIndex, location, parameter.Type.IsReferenceType ? ValueAsString(null) : null));
}
// const literal:
return(Literal.CreateGenerated(cx, parent, childIndex, parameter.Type, defaultValue, location));
}
/// <summary>
/// Creates a generated expression for a default argument value.
/// </summary>
public static Expression?CreateGenerated(Context cx, IParameterSymbol parameter, IExpressionParentEntity parent,
int childIndex, Extraction.Entities.Location location)
{
if (!parameter.HasExplicitDefaultValue ||
parameter.Type is IErrorTypeSymbol)
{
return(null);
}
var defaultValue = parameter.ExplicitDefaultValue;
var type = parameter.Type;
if (type.IsBoundNullable() && type is INamedTypeSymbol named)
{
type = named.TypeArguments[0];
}
if (type is INamedTypeSymbol nt && nt.EnumUnderlyingType is not null)
{
// = (MyEnum)1, = MyEnum.Value1, = default(MyEnum), = new MyEnum()
// we're generating a (MyEnum)value cast expression:
defaultValue ??= 0;
Action <Expression, int> createChild = (parent, index) => Literal.CreateGenerated(cx, parent, index, nt.EnumUnderlyingType, defaultValue, location);
return(Cast.CreateGenerated(cx, parent, childIndex, parameter.Type, defaultValue, createChild, location));
}
if (defaultValue is null)
{
// = null, = default, = default(T), = new MyStruct()
// we're generating a default expression:
return(Default.CreateGenerated(cx, parent, childIndex, location, parameter.Type.IsReferenceType ? ValueAsString(null) : null));
}
if (parameter.Type.SpecialType is SpecialType.System_Object)
{
// this can happen in VB.NET
cx.ExtractionError($"Extracting default argument value 'object {parameter.Name} = default' instead of 'object {parameter.Name} = {defaultValue}'. The latter is not supported in C#.",
null, null, severity: Util.Logging.Severity.Warning);
// we're generating a default expression:
return(Default.CreateGenerated(cx, parent, childIndex, location, ValueAsString(null)));
}
// const literal:
return(Literal.CreateGenerated(cx, parent, childIndex, type, defaultValue, location));
}
/// <summary>
/// Creates a generated expression from a typed constant.
/// </summary>
public static Expression?CreateGenerated(Context cx, TypedConstant constant, IExpressionParentEntity parent,
int childIndex, Extraction.Entities.Location location)
{
if (constant.IsNull ||
constant.Type is null)
{
return(Literal.CreateGeneratedNullLiteral(cx, parent, childIndex, location));
}
switch (constant.Kind)
{
case TypedConstantKind.Primitive:
return(Literal.CreateGenerated(cx, parent, childIndex, constant.Type, constant.Value, location));
case TypedConstantKind.Enum:
// Enum value is generated in the following format: (Enum)value
Action <Expression, int> createChild = (parent, index) => Literal.CreateGenerated(cx, parent, index, ((INamedTypeSymbol)constant.Type).EnumUnderlyingType !, constant.Value, location);
var cast = Cast.CreateGenerated(cx, parent, childIndex, constant.Type !, constant.Value, createChild, location);
return(cast);
case TypedConstantKind.Type:
var type = ((ITypeSymbol)constant.Value !).OriginalDefinition;
return(TypeOf.CreateGenerated(cx, parent, childIndex, type, location));
case TypedConstantKind.Array:
// Single dimensional arrays are in the following format:
// * new Type[N] { item1, item2, ..., itemN }
// * new Type[0]
//
// itemI is generated recursively.
return(NormalArrayCreation.CreateGenerated(cx, parent, childIndex, constant.Type, constant.Values, location));
case TypedConstantKind.Error:
default:
cx.ExtractionError("Couldn't extract constant in attribute", constant.ToString(), location);
return(null);
}
}
