Expression TryCompileCast(Source src, DataType targetType, Expression operand)
{
if (targetType.IsInvalid || operand.IsInvalid)
{
return(Expression.Invalid);
}
// Equal types == NOP
if (targetType.Equals(operand.ReturnType))
{
return(operand);
}
var cast = TryResolveCastOverload(src, NameResolver.GetTypeCasts(targetType, operand.ReturnType), ref operand);
if (cast != null)
{
return(new CallCast(src, cast, operand));
}
// Box
// Generic -> object
// Method -> delegate
// etc
var impl = TryCompileImplicitCast(src, targetType, operand);
if (impl != null)
{
return(impl);
}
// Down cast
if (targetType.IsReferenceType && operand.ReturnType.IsReferenceType ||
targetType.IsInterface || operand.ReturnType.IsInterface)
{
return(operand.ReturnType.IsInterface ||
operand.ReturnType.IsSubclassOf(targetType) ||
operand.ReturnType.IsImplementingInterface(targetType) ||
targetType.IsInterface ||
targetType.IsSubclassOf(operand.ReturnType) ||
targetType.IsImplementingInterface(operand.ReturnType)
? new CastOp(src, targetType, operand)
: Error(src, ErrorCode.E2028, targetType.Quote() + " and " + operand.ReturnType.Quote() + " are not compatible types"));
}
// Unbox
// Ref -> generic
if (targetType.IsValueType && operand.ReturnType.Equals(Essentials.Object) ||
targetType.IsGenericParameter && operand.ReturnType.IsReferenceType)
{
return(new CastOp(src, targetType, operand));
}
if (operand.ReturnType.IsEnum)
{
operand.ReturnType.AssignBaseType();
return(TryCompileCast(src, targetType, new CastOp(src, operand.ReturnType.Base ?? Essentials.Int, operand)));
}
if (targetType.IsEnum)
{
targetType.AssignBaseType();
var intValue = TryCompileCast(src, targetType.Base ?? Essentials.Int, operand);
if (intValue != null)
{
return(new CastOp(src, targetType, intValue));
}
}
return(null);
}
Expression TryCompileImplicitCast(Source src, DataType expectedType, Expression value, bool reportErrorIfNotFound)
{
if (ImplicitCastStack.Contains(expectedType))
{
ImplicitCastStack.Add(expectedType);
}
else
{
ImplicitCastStack.Add(expectedType);
if (Equals(expectedType, value.ReturnType))
{
return(value);
}
if (value.ReturnType is InvalidType || expectedType is InvalidType)
{
return(Expression.Invalid);
}
// (EnumType)0
if (expectedType is EnumType && value is Constant && value.ConstantValue is int && (int)value.ConstantValue == 0)
{
return(new Constant(value.Source, (EnumType)expectedType, (int)value.ConstantValue));
}
// Null type (must be done before delegate)
if (value.ReturnType.IsNull)
{
return(expectedType.IsReferenceType
? new Constant(src, expectedType, null) :
!reportErrorIfNotFound
? null
: Error(src, ErrorCode.E2043, "'<null>' has no implicit cast to " + expectedType.Quote() + " because that is not a reference type"));
}
// Delegate
if (expectedType is DelegateType && value is MethodGroup)
{
var dt = expectedType as DelegateType;
dt.AssignBaseType();
var mg = value as MethodGroup;
var candidates = mg.Candidates;
var compatibleMethods = new List <Method>();
foreach (var m in candidates)
{
if (!m.IsGenericDefinition &&
m.ReturnType.Equals(dt.ReturnType) &&
dt.CompareParameters(m))
{
compatibleMethods.Add(m);
}
}
if (compatibleMethods.Count == 0)
{
foreach (var c in candidates)
{
if (c.IsGenericDefinition)
{
var dummyArgs = new Expression[dt.Parameters.Length];
for (int i = 0; i < dummyArgs.Length; i++)
{
var p = dt.Parameters[i];
dummyArgs[i] = new Default(p.Source, p.Type);
switch (p.Modifier)
{
case ParameterModifier.Const:
dummyArgs[i] = new AddressOf(dummyArgs[i], AddressType.Const);
break;
case ParameterModifier.Ref:
dummyArgs[i] = new AddressOf(dummyArgs[i], AddressType.Ref);
break;
case ParameterModifier.Out:
dummyArgs[i] = new AddressOf(dummyArgs[i], AddressType.Out);
break;
}
}
candidates = CopyAndParameterizeGenericMethods(src, candidates, dummyArgs);
foreach (var m in candidates)
{
if (!m.IsGenericDefinition &&
m.ReturnType.Equals(dt.ReturnType) &&
dt.CompareParameters(m))
{
compatibleMethods.Add(m);
}
}
break;
}
}
if (compatibleMethods.Count == 0)
{
foreach (var m in candidates)
{
if (!m.IsGenericDefinition &&
(m.ReturnType.Equals(dt.ReturnType) || m.ReturnType.IsReferenceType && m.ReturnType.IsSubclassOfOrEqual(dt.ReturnType)) &&
dt.CompareParametersEqualOrSubclassOf(m))
{
compatibleMethods.Add(m);
}
}
}
}
if (compatibleMethods.Count == 1)
{
var m = compatibleMethods[0];
if (m.IsStatic)
{
return(new NewDelegate(src, dt, null, m));
}
if (mg.Object != null && !mg.Object.ReturnType.IsReferenceType)
{
mg.Object = new CastOp(src, Essentials.Object, mg.Object.ActualValue);
}
return(new NewDelegate(src, dt, mg.Object, m));
}
return(!reportErrorIfNotFound
? null
: compatibleMethods.Count == 0
? Error(src, ErrorCode.E2045, "No methods matches the parameter list and return type of delegate type " + dt.Quote())
: ReportAmbiguousMatchError(src, compatibleMethods));
}
// Lambda
if (expectedType is DelegateType && value is UncompiledLambda)
{
expectedType.AssignBaseType();
return(TryCompileImplicitLambdaCast((UncompiledLambda)value, (DelegateType)expectedType));
}
// Constant
if (value is Constant && expectedType.IsIntrinsic)
{
var constant = value as Constant;
if (constant.Value is int)
{
int intValue = (int)constant.Value;
switch (expectedType.BuiltinType)
{
case BuiltinType.SByte:
if (intValue >= -0x80 && intValue <= 0x7f)
{
return(new Constant(constant.Source, expectedType, (sbyte)intValue));
}
break;
case BuiltinType.Byte:
if (intValue >= 0 && intValue <= 0xff)
{
return(new Constant(constant.Source, expectedType, (byte)intValue));
}
break;
case BuiltinType.Short:
if (intValue >= -0x8000 && intValue <= 0x7fff)
{
return(new Constant(constant.Source, expectedType, (short)intValue));
}
break;
case BuiltinType.UShort:
if (intValue >= 0 && intValue <= 0xffff)
{
return(new Constant(constant.Source, expectedType, (ushort)intValue));
}
break;
case BuiltinType.UInt:
if (intValue >= 0)
{
return(new Constant(constant.Source, expectedType, (uint)intValue));
}
break;
case BuiltinType.ULong:
if (intValue >= 0)
{
return(new Constant(constant.Source, expectedType, (ulong)intValue));
}
break;
}
}
if (constant.Value is long)
{
long longValue = (long)constant.Value;
switch (expectedType.BuiltinType)
{
case BuiltinType.ULong:
if (longValue >= 0)
{
return(new Constant(constant.Source, expectedType, (ulong)longValue));
}
break;
}
}
}
// Implict cast
bool ambiguous;
var cast = TryResolveCastOverload(src, NameResolver.GetTypeCasts(expectedType, value.ReturnType),
ref value, reportErrorIfNotFound, out ambiguous);
if (ambiguous)
{
goto ERROR;
}
if (cast != null && cast.IsImplicitCast)
{
return(new CallCast(src, cast, value));
}
// Up cast
if (expectedType == Essentials.Object ||
value.ReturnType.IsSubclassOf(expectedType) ||
expectedType.IsInterface && value.ReturnType.IsImplementingInterface(expectedType))
{
return(new CastOp(src, expectedType, value));
}
// Fixed Array
if (expectedType.IsFixedArray && value.ReturnType.IsFixedArray)
{
var t1 = expectedType as FixedArrayType;
var t2 = value.ReturnType as FixedArrayType;
if (t1.ElementType.Equals(t2.ElementType) && (
t1.OptionalSize == null || t2.OptionalSize == null ||
t1.OptionalSize is Constant && t2.OptionalSize is Constant && Equals(t1.OptionalSize.ConstantValue, t2.OptionalSize.ConstantValue)
))
{
return(value);
}
}
// T[] -> IEnumerable<T>
if (value.ReturnType.IsRefArray && expectedType.MasterDefinition == Essentials.IEnumerable_T)
{
ImplicitCastStack.RemoveLast();
var arrayEnumerable = TypeBuilder.Parameterize(src, Essentials.ArrayEnumerable_T, value.ReturnType.ElementType);
return(TryCompileImplicitCast(src, expectedType,
ILFactory.NewObject(src, arrayEnumerable, value), reportErrorIfNotFound));
}
}
ERROR:
return(!reportErrorIfNotFound
? null
: Error(src, ErrorCode.E2047, "No implicit cast from " + value.ReturnType.Quote() + " to " + expectedType.Quote()));
}