protected void EmitConditionalAccess(EmitContext ec)
{
var a_expr = arguments [0].Expr;
var des = a_expr as DynamicExpressionStatement;
if (des != null)
{
des.EmitConditionalAccess(ec);
}
if (HasConditionalAccess())
{
var NullOperatorLabel = ec.DefineLabel();
if (ExpressionAnalyzer.IsInexpensiveLoad(a_expr))
{
a_expr.Emit(ec);
}
else
{
var lt = new LocalTemporary(a_expr.Type);
lt.EmitAssign(ec, a_expr, true, false);
Arguments [0].Expr = lt;
}
ec.Emit(OpCodes.Brtrue_S, NullOperatorLabel);
if (!ec.ConditionalAccess.Statement)
{
if (ec.ConditionalAccess.Type.IsNullableType)
{
Nullable.LiftedNull.Create(ec.ConditionalAccess.Type, Location.Null).Emit(ec);
}
else
{
ec.EmitNull();
}
}
ec.Emit(OpCodes.Br, ec.ConditionalAccess.EndLabel);
ec.MarkLabel(NullOperatorLabel);
return;
}
if (a_expr.HasConditionalAccess())
{
var lt = new LocalTemporary(a_expr.Type);
lt.EmitAssign(ec, a_expr, false, false);
Arguments [0].Expr = lt;
}
}
protected override Expression DoResolve(ResolveContext rc)
{
var src = source.Resolve(rc);
if (src == null)
{
return(null);
}
if (InternalType.HasNoType(src.Type))
{
rc.Report.Error(8131, source.Location, "Deconstruct assignment requires an expression with a type on the right-hand-side");
return(null);
}
var src_type = src.Type;
if (src_type.IsTupleType)
{
if (src_type.Arity != targetExprs.Count)
{
rc.Report.Error(8132, loc, "Cannot deconstruct a tuple of `{0}' elements into `{1}' variables",
src_type.Arity.ToString(), targetExprs.Count.ToString());
return(null);
}
var tupleLiteral = src as TupleLiteral;
if (tupleLiteral == null && !ExpressionAnalyzer.IsInexpensiveLoad(src))
{
var expr_variable = LocalVariable.CreateCompilerGenerated(source.Type, rc.CurrentBlock, loc);
source = new CompilerAssign(expr_variable.CreateReferenceExpression(rc, loc), source, loc);
instance = expr_variable.CreateReferenceExpression(rc, loc);
}
for (int i = 0; i < targetExprs.Count; ++i)
{
var tle = src_type.TypeArguments [i];
var lv = variablesToInfer? [i];
if (lv != null)
{
if (InternalType.HasNoType(tle))
{
rc.Report.Error(8130, Location, "Cannot infer the type of implicitly-typed deconstruction variable `{0}'", lv.Name);
lv.Type = InternalType.ErrorType;
continue;
}
lv.Type = tle;
lv.PrepareAssignmentAnalysis((BlockContext)rc);
}
var element_src = tupleLiteral == null ? new MemberAccess(instance, NamedTupleSpec.GetElementPropertyName(i)) : tupleLiteral.Elements [i].Expr;
targetExprs [i] = new SimpleAssign(targetExprs [i], element_src).Resolve(rc);
}
eclass = ExprClass.Value;
// TODO: The type is same only if there is no target element conversion
// var res = (/*byte*/ b, /*short*/ s) = (2, 4);
type = src.Type;
return(this);
}
if (src_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
{
rc.Report.Error(8133, loc, "Cannot deconstruct dynamic objects");
return(null);
}
/*
* var args = new Arguments (targetExprs.Count);
* foreach (var t in targetExprs) {
* args.Add (new Argument (t, Argument.AType.Out));
* }
*
* var invocation = new Invocation (new MemberAccess (src, "Deconstruct"), args);
* var res = invocation.Resolve (rc);
*/
throw new NotImplementedException("Custom deconstruct");
}
public void Emit(EmitContext ec, bool conditionalAccess)
{
Label NullOperatorLabel;
Nullable.Unwrap unwrap;
if (conditionalAccess && Expression.IsNeverNull(instance))
{
conditionalAccess = false;
}
if (conditionalAccess)
{
NullOperatorLabel = ec.DefineLabel();
unwrap = instance as Nullable.Unwrap;
}
else
{
NullOperatorLabel = new Label();
unwrap = null;
}
IMemoryLocation instance_address = null;
bool conditional_access_dup = false;
if (unwrap != null)
{
unwrap.Store(ec);
unwrap.EmitCheck(ec);
ec.Emit(OpCodes.Brtrue_S, NullOperatorLabel);
}
else
{
if (conditionalAccess && addressRequired)
{
//
// Don't allocate temp variable when instance load is cheap and load and load-address
// operate on same memory
//
instance_address = instance as VariableReference;
if (instance_address == null)
{
instance_address = instance as LocalTemporary;
}
if (instance_address == null)
{
EmitLoad(ec, false);
ec.Emit(OpCodes.Dup);
ec.EmitLoadFromPtr(instance.Type);
conditional_access_dup = true;
}
else
{
instance.Emit(ec);
}
}
else
{
EmitLoad(ec, !conditionalAccess);
if (conditionalAccess)
{
conditional_access_dup = !ExpressionAnalyzer.IsInexpensiveLoad(instance);
if (conditional_access_dup)
{
ec.Emit(OpCodes.Dup);
}
}
}
if (conditionalAccess)
{
if (instance.Type.Kind == MemberKind.TypeParameter)
{
ec.Emit(OpCodes.Box, instance.Type);
}
ec.Emit(OpCodes.Brtrue_S, NullOperatorLabel);
if (conditional_access_dup)
{
ec.Emit(OpCodes.Pop);
}
}
}
if (conditionalAccess)
{
if (!ec.ConditionalAccess.Statement)
{
var t = ec.ConditionalAccess.Type;
if (t.IsNullableType)
{
Nullable.LiftedNull.Create(t, Location.Null).Emit(ec);
}
else
{
ec.EmitNull();
if (t.IsGenericParameter)
{
ec.Emit(OpCodes.Unbox_Any, t);
}
}
}
ec.Emit(OpCodes.Br, ec.ConditionalAccess.EndLabel);
ec.MarkLabel(NullOperatorLabel);
if (instance_address != null)
{
instance_address.AddressOf(ec, AddressOp.Load);
}
else if (unwrap != null)
{
unwrap.Emit(ec);
if (addressRequired)
{
var tmp = ec.GetTemporaryLocal(unwrap.Type);
ec.Emit(OpCodes.Stloc, tmp);
ec.Emit(OpCodes.Ldloca, tmp);
ec.FreeTemporaryLocal(tmp, unwrap.Type);
}
}
else if (!conditional_access_dup)
{
instance.Emit(ec);
}
}
}
protected override Expression DoResolve(ResolveContext rc)
{
var src = source.Resolve(rc);
if (src == null)
{
return(null);
}
if (InternalType.HasNoType(src.Type))
{
rc.Report.Error(8131, source.Location, "Deconstruct assignment requires an expression with a type on the right-hand-side");
return(null);
}
var src_type = src.Type;
if (src_type.IsTupleType)
{
int target_count;
if (targetExprs == null)
{
target_count = variables.Count;
targetExprs = new List <Expression> (target_count);
}
else
{
target_count = targetExprs.Count;
}
if (src_type.Arity != target_count)
{
rc.Report.Error(8132, loc, "Cannot deconstruct a tuple of `{0}' elements into `{1}' variables",
src_type.Arity.ToString(CultureInfo.InvariantCulture), target_count.ToString(CultureInfo.InvariantCulture));
return(null);
}
var tupleLiteral = src as TupleLiteral;
if (tupleLiteral == null && !ExpressionAnalyzer.IsInexpensiveLoad(src))
{
var expr_variable = LocalVariable.CreateCompilerGenerated(source.Type, rc.CurrentBlock, loc);
source = new CompilerAssign(expr_variable.CreateReferenceExpression(rc, loc), source, loc);
instance = expr_variable.CreateReferenceExpression(rc, loc);
}
var element_srcs = new List <Expression> ();
var src_names = new List <string> ();
for (int i = 0; i < target_count; ++i)
{
var element_src = tupleLiteral == null ? new MemberAccess(instance, NamedTupleSpec.GetElementPropertyName(i)) : tupleLiteral.Elements [i].Expr;
element_srcs.Add(element_src);
if (element_src is VariableReference)
{
src_names.Add((element_src as VariableReference)?.Name);
}
}
for (int i = 0; i < target_count; ++i)
{
var tle = src_type.TypeArguments [i];
if (variables != null)
{
var variable = variables [i].Variable;
if (variable.Type == InternalType.Discard)
{
variables [i] = null;
targetExprs.Add(EmptyExpressionStatement.Instance);
continue;
}
var variable_type = variables [i].TypeExpression;
targetExprs.Add(new LocalVariableReference(variable, variable.Location));
if (variable_type is VarExpr)
{
if (InternalType.HasNoType(tle))
{
rc.Report.Error(8130, Location, "Cannot infer the type of implicitly-typed deconstruction variable `{0}'", variable.Name);
tle = InternalType.ErrorType;
}
variable.Type = tle;
}
else
{
variable.Type = variable_type.ResolveAsType(rc);
}
variable.PrepareAssignmentAnalysis((BlockContext)rc);
}
var element_target = (targetExprs [i] as SimpleName)?.LookupNameExpression(rc, MemberLookupRestrictions.None);
if (element_target != null && src_names.Contains((element_target as VariableReference)?.Name))
{
var tempType = element_target.Resolve(rc).Type;
var temp = new LocalTemporary(tempType);
tempExprs.Add(new SimpleAssign(temp, element_srcs [i]).Resolve(rc));
targetExprs [i] = new SimpleAssign(targetExprs [i], temp).Resolve(rc);
}
else
{
targetExprs [i] = new SimpleAssign(targetExprs [i], element_srcs [i]).Resolve(rc);
}
}
eclass = ExprClass.Value;
// TODO: The type is same only if there is no target element conversion
// var res = (/*byte*/ b, /*short*/ s) = (2, 4);
type = src.Type;
return(this);
}
if (src_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)
{
rc.Report.Error(8133, loc, "Cannot deconstruct dynamic objects");
return(null);
}
/*
* var args = new Arguments (targetExprs.Count);
* foreach (var t in targetExprs) {
* args.Add (new Argument (t, Argument.AType.Out));
* }
*
* var invocation = new Invocation (new MemberAccess (src, "Deconstruct"), args);
* var res = invocation.Resolve (rc);
*/
throw new NotImplementedException("Custom deconstruct");
}