/// <summary>
/// Converts the expression for creating a tuple instance into an expression creating a ValueTuple (if short) or nested ValueTuples (if longer).
///
/// For instance, for a long tuple we'll generate:
/// creationExpression(ctor=largestCtor, args=firstArgs+(nested creationExpression for remainder, with smaller ctor and next few args))
/// </summary>
private BoundNode RewriteTupleCreationExpression(BoundTupleExpression node, ImmutableArray<BoundExpression> rewrittenArguments)
{
NamedTypeSymbol underlyingTupleType = node.Type.TupleUnderlyingType;
ArrayBuilder<NamedTypeSymbol> underlyingTupleTypeChain = ArrayBuilder<NamedTypeSymbol>.GetInstance();
TupleTypeSymbol.GetUnderlyingTypeChain(underlyingTupleType, underlyingTupleTypeChain);
try
{
// make a creation expression for the smallest type
NamedTypeSymbol smallestType = underlyingTupleTypeChain.Pop();
ImmutableArray<BoundExpression> smallestCtorArguments = ImmutableArray.Create(rewrittenArguments,
underlyingTupleTypeChain.Count * (TupleTypeSymbol.RestPosition - 1),
smallestType.Arity);
var smallestCtor = (MethodSymbol)TupleTypeSymbol.GetWellKnownMemberInType(smallestType.OriginalDefinition,
TupleTypeSymbol.GetTupleCtor(smallestType.Arity),
_diagnostics,
node.Syntax);
if ((object)smallestCtor == null)
{
return node;
}
MethodSymbol smallestConstructor = smallestCtor.AsMember(smallestType);
BoundObjectCreationExpression currentCreation = new BoundObjectCreationExpression(node.Syntax, smallestConstructor, smallestCtorArguments);
if (underlyingTupleTypeChain.Count > 0)
{
NamedTypeSymbol tuple8Type = underlyingTupleTypeChain.Peek();
var tuple8Ctor = (MethodSymbol)TupleTypeSymbol.GetWellKnownMemberInType(tuple8Type.OriginalDefinition,
TupleTypeSymbol.GetTupleCtor(TupleTypeSymbol.RestPosition),
_diagnostics,
node.Syntax);
if ((object)tuple8Ctor == null)
{
return node;
}
// make successively larger creation expressions containing the previous one
do
{
ImmutableArray<BoundExpression> ctorArguments = ImmutableArray.Create(rewrittenArguments,
(underlyingTupleTypeChain.Count - 1) * (TupleTypeSymbol.RestPosition - 1),
TupleTypeSymbol.RestPosition - 1)
.Add(currentCreation);
MethodSymbol constructor = tuple8Ctor.AsMember(underlyingTupleTypeChain.Pop());
currentCreation = new BoundObjectCreationExpression(node.Syntax, constructor, ctorArguments);
}
while (underlyingTupleTypeChain.Count > 0);
}
return currentCreation;
}
finally
{
underlyingTupleTypeChain.Free();
}
}
/// <summary>
/// Converts the expression for creating a tuple instance into an expression creating a ValueTuple (if short) or nested ValueTuples (if longer).
///
/// For instance, for a long tuple we'll generate:
/// creationExpression(ctor=largestCtor, args=firstArgs+(nested creationExpression for remainder, with smaller ctor and next few args))
/// </summary>
private BoundNode RewriteTupleCreationExpression(BoundTupleExpression node, ImmutableArray <BoundExpression> rewrittenArguments)
{
NamedTypeSymbol underlyingTupleType = node.Type.TupleUnderlyingType;
ArrayBuilder <NamedTypeSymbol> underlyingTupleTypeChain = ArrayBuilder <NamedTypeSymbol> .GetInstance();
TupleTypeSymbol.GetUnderlyingTypeChain(underlyingTupleType, underlyingTupleTypeChain);
try
{
// make a creation expression for the smallest type
NamedTypeSymbol smallestType = underlyingTupleTypeChain.Pop();
ImmutableArray <BoundExpression> smallestCtorArguments = ImmutableArray.Create(rewrittenArguments,
underlyingTupleTypeChain.Count * (TupleTypeSymbol.RestPosition - 1),
smallestType.Arity);
var smallestCtor = (MethodSymbol)TupleTypeSymbol.GetWellKnownMemberInType(smallestType.OriginalDefinition,
TupleTypeSymbol.GetTupleCtor(smallestType.Arity),
_diagnostics,
node.Syntax);
if ((object)smallestCtor == null)
{
return(node);
}
MethodSymbol smallestConstructor = smallestCtor.AsMember(smallestType);
BoundObjectCreationExpression currentCreation = new BoundObjectCreationExpression(node.Syntax, smallestConstructor, smallestCtorArguments);
if (underlyingTupleTypeChain.Count > 0)
{
NamedTypeSymbol tuple8Type = underlyingTupleTypeChain.Peek();
var tuple8Ctor = (MethodSymbol)TupleTypeSymbol.GetWellKnownMemberInType(tuple8Type.OriginalDefinition,
TupleTypeSymbol.GetTupleCtor(TupleTypeSymbol.RestPosition),
_diagnostics,
node.Syntax);
if ((object)tuple8Ctor == null)
{
return(node);
}
// make successively larger creation expressions containing the previous one
do
{
ImmutableArray <BoundExpression> ctorArguments = ImmutableArray.Create(rewrittenArguments,
(underlyingTupleTypeChain.Count - 1) * (TupleTypeSymbol.RestPosition - 1),
TupleTypeSymbol.RestPosition - 1)
.Add(currentCreation);
MethodSymbol constructor = tuple8Ctor.AsMember(underlyingTupleTypeChain.Pop());
currentCreation = new BoundObjectCreationExpression(node.Syntax, constructor, ctorArguments);
}while (underlyingTupleTypeChain.Count > 0);
}
return(currentCreation);
}
finally
{
underlyingTupleTypeChain.Free();
}
}
/// <summary>
/// The left represents a tree of L-values. The structure of right can be missing parts of the tree on the left.
/// The conversion holds nested conversions and deconstruction information, which matches the tree from the left,
/// and it provides the information to fill in the missing parts of the tree from the right and convert it to
/// the tree from the left.
///
/// A bound sequence is returned which has different phases of side-effects:
/// - the initialization phase includes side-effects from the left, followed by evaluations of the right
/// - the deconstruction phase includes all the invocations of Deconstruct methods and tuple element accesses below a Deconstruct call
/// - the conversion phase
/// - the assignment phase
/// </summary>
private BoundExpression?RewriteDeconstruction(BoundTupleExpression left, Conversion conversion, BoundExpression right, bool isUsed)
{
var lhsTemps = ArrayBuilder <LocalSymbol> .GetInstance();
var lhsEffects = ArrayBuilder <BoundExpression> .GetInstance();
ArrayBuilder <Binder.DeconstructionVariable> lhsTargets = GetAssignmentTargetsAndSideEffects(left, lhsTemps, lhsEffects);
Debug.Assert(left.Type is { });
private bool IsLikeTupleExpression(BoundExpression expr, out BoundTupleExpression tuple)
{
switch (expr)
{
case BoundTupleExpression t:
tuple = t;
return(true);
case BoundConversion {
Conversion: { Kind : ConversionKind.Identity }, Operand : var o
} :
private void CheckForDeconstructionAssignmentToSelf(
BoundTupleExpression leftTuple,
BoundExpression right
)
{
while (right.Kind == BoundKind.Conversion)
{
var conversion = (BoundConversion)right;
switch (conversion.ConversionKind)
{
case ConversionKind.Deconstruction:
case ConversionKind.ImplicitTupleLiteral:
case ConversionKind.Identity:
right = conversion.Operand;
break;
default:
return;
}
}
if (
right.Kind != BoundKind.ConvertedTupleLiteral &&
right.Kind != BoundKind.TupleLiteral
)
{
return;
}
var rightTuple = (BoundTupleExpression)right;
var leftArguments = leftTuple.Arguments;
int length = leftArguments.Length;
Debug.Assert(length == rightTuple.Arguments.Length);
for (int i = 0; i < length; i++)
{
var leftArgument = leftArguments[i];
var rightArgument = rightTuple.Arguments[i];
if (leftArgument is BoundTupleExpression tupleExpression)
{
CheckForDeconstructionAssignmentToSelf(tupleExpression, rightArgument);
}
else if (IsSameLocalOrField(leftArgument, rightArgument))
{
Error(ErrorCode.WRN_AssignmentToSelf, leftArgument);
}
}
}
/// <summary>
/// The left represents a tree of L-values. The structure of right can be missing parts of the tree on the left.
/// The conversion holds nested conversisons and deconstruction information, which matches the tree from the left,
/// and it provides the information to fill in the missing parts of the tree from the right and convert it to
/// the tree from the left.
///
/// A bound sequence is returned which has different phases of side-effects:
/// - the initialization phase includes side-effects from the left, followed by evaluations of the right
/// - the deconstruction phase includes all the invocations of Deconstruct methods and tuple element accesses below a Deconstruct call
/// - the conversion phase
/// - the assignment phase
/// </summary>
private BoundExpression RewriteDeconstruction(BoundTupleExpression left, Conversion conversion, BoundExpression right)
{
var temps = ArrayBuilder <LocalSymbol> .GetInstance();
var effects = DeconstructionSideEffects.GetInstance();
ArrayBuilder <Binder.DeconstructionVariable> lhsTargets = GetAssignmentTargetsAndSideEffects(left, temps, effects.init);
BoundExpression returnTuple = ApplyDeconstructionConversion(lhsTargets, right, conversion, temps, effects, inInit: true);
if (!returnTuple.HasErrors)
{
returnTuple = VisitExpression(returnTuple);
}
BoundExpression result = _factory.Sequence(temps.ToImmutableAndFree(), effects.ToImmutableAndFree(), returnTuple);
Binder.DeconstructionVariable.FreeDeconstructionVariables(lhsTargets);
return(result);
}
/// <summary>
/// The left represents a tree of L-values. The structure of right can be missing parts of the tree on the left.
/// The conversion holds nested conversions and deconstruction information, which matches the tree from the left,
/// and it provides the information to fill in the missing parts of the tree from the right and convert it to
/// the tree from the left.
///
/// A bound sequence is returned which has different phases of side-effects:
/// - the initialization phase includes side-effects from the left, followed by evaluations of the right
/// - the deconstruction phase includes all the invocations of Deconstruct methods and tuple element accesses below a Deconstruct call
/// - the conversion phase
/// - the assignment phase
/// </summary>
private BoundExpression RewriteDeconstruction(BoundTupleExpression left, Conversion conversion, BoundExpression right, bool isUsed)
{
var lhsTemps = ArrayBuilder <LocalSymbol> .GetInstance();
var lhsEffects = ArrayBuilder <BoundExpression> .GetInstance();
ArrayBuilder <Binder.DeconstructionVariable> lhsTargets = GetAssignmentTargetsAndSideEffects(left, lhsTemps, lhsEffects);
BoundExpression result = RewriteDeconstruction(lhsTargets, conversion, left.Type, right, isUsed);
Binder.DeconstructionVariable.FreeDeconstructionVariables(lhsTargets);
if (result is null)
{
lhsTemps.Free();
lhsEffects.Free();
return(null);
}
return(_factory.Sequence(lhsTemps.ToImmutableAndFree(), lhsEffects.ToImmutableAndFree(), result));
}
/// <summary>
/// The left represents a tree of L-values. The structure of right can be missing parts of the tree on the left.
/// The conversion holds nested conversions and deconstruction information, which matches the tree from the left,
/// and it provides the information to fill in the missing parts of the tree from the right and convert it to
/// the tree from the left.
///
/// A bound sequence is returned which has different phases of side-effects:
/// - the initialization phase includes side-effects from the left, followed by evaluations of the right
/// - the deconstruction phase includes all the invocations of Deconstruct methods and tuple element accesses below a Deconstruct call
/// - the conversion phase
/// - the assignment phase
/// </summary>
private BoundExpression RewriteDeconstruction(BoundTupleExpression left, Conversion conversion, BoundExpression right, bool isUsed)
{
var temps = ArrayBuilder <LocalSymbol> .GetInstance();
var effects = DeconstructionSideEffects.GetInstance();
ArrayBuilder <Binder.DeconstructionVariable> lhsTargets = GetAssignmentTargetsAndSideEffects(left, temps, effects.init);
BoundExpression returnValue = ApplyDeconstructionConversion(lhsTargets, right, conversion, temps, effects, isUsed, inInit: true);
effects.Consolidate();
BoundExpression result;
if (!isUsed)
{
// When a deconstruction is not used, the last effect is used as return value
Debug.Assert(returnValue is null);
var last = effects.PopLast();
if (last is null)
{
// Deconstructions with no effects lower to nothing. For example, `(_, _) = (1, 2);`
result = null;
temps.Free();
_ = effects.ToImmutableAndFree();
}
else
{
result = _factory.Sequence(temps.ToImmutableAndFree(), effects.ToImmutableAndFree(), last);
}
}
else
{
if (!returnValue.HasErrors)
{
returnValue = VisitExpression(returnValue);
}
result = _factory.Sequence(temps.ToImmutableAndFree(), effects.ToImmutableAndFree(), returnValue);
}
Binder.DeconstructionVariable.FreeDeconstructionVariables(lhsTargets);
return(result);
}
/// <summary>
/// Adds the side effects to stores and returns temporaries (as a flat list) to access them.
/// </summary>
private ImmutableArray <BoundExpression> GetAssignmentTargetsAndSideEffects(BoundTupleExpression variables, ArrayBuilder <LocalSymbol> temps, ArrayBuilder <BoundExpression> stores)
{
var assignmentTargets = ArrayBuilder <BoundExpression> .GetInstance(variables.Arguments.Length);
variables.VisitAllElements(
(variable, args) =>
{
if (variable.Kind == BoundKind.DiscardExpression)
{
args.targets.Add(variable);
}
else
{
args.targets.Add(args.self.TransformCompoundAssignmentLHS(variable, args.stores, args.temps, isDynamicAssignment: variable.Type.IsDynamic()));
}
},
(temps: temps, stores: stores, targets: assignmentTargets, self: this)
);
return(assignmentTargets.ToImmutableAndFree());
}
/// <summary>
/// Converts the expression for creating a tuple instance into an expression creating a ValueTuple (if short) or nested ValueTuples (if longer).
///
/// For instance, for a long tuple we'll generate:
/// creationExpression(ctor=largestCtor, args=firstArgs+(nested creationExpression for remainder, with smaller ctor and next few args))
/// </summary>
private BoundExpression RewriteTupleCreationExpression(BoundTupleExpression node, ImmutableArray <BoundExpression> rewrittenArguments)
{
return(MakeTupleCreationExpression(node.Syntax, (NamedTypeSymbol)node.Type, rewrittenArguments));
}
private BoundNode VisitTupleExpression(BoundTupleExpression node)
{
ImmutableArray <BoundExpression> rewrittenArguments = VisitList(node.Arguments);
return(RewriteTupleCreationExpression(node, rewrittenArguments));
}
/// <summary>
/// Adds the side effects to effects and returns temporaries to access them.
/// The caller is responsible for releasing the nested ArrayBuilders.
/// The variables should be unlowered.
/// </summary>
private ArrayBuilder <Binder.DeconstructionVariable> GetAssignmentTargetsAndSideEffects(BoundTupleExpression variables, ArrayBuilder <LocalSymbol> temps, ArrayBuilder <BoundExpression> effects)
{
var assignmentTargets = ArrayBuilder <Binder.DeconstructionVariable> .GetInstance(variables.Arguments.Length);
foreach (var variable in variables.Arguments)
{
switch (variable.Kind)
{
case BoundKind.DiscardExpression:
assignmentTargets.Add(new Binder.DeconstructionVariable(variable, variable.Syntax));
break;
case BoundKind.TupleLiteral:
var tuple = (BoundTupleExpression)variable;
assignmentTargets.Add(new Binder.DeconstructionVariable(GetAssignmentTargetsAndSideEffects(tuple, temps, effects), tuple.Syntax));
break;
case BoundKind.ConvertedTupleLiteral:
throw ExceptionUtilities.UnexpectedValue(variable.Kind);
default:
var temp = this.TransformCompoundAssignmentLHS(variable, effects, temps, isDynamicAssignment: variable.Type.IsDynamic());
assignmentTargets.Add(new Binder.DeconstructionVariable(temp, variable.Syntax));
break;
}
}
return(assignmentTargets);
}
/// <summary>
/// Converts the expression for creating a tuple instance into an expression creating a ValueTuple (if short) or nested ValueTuples (if longer).
///
/// For instance, for a long tuple we'll generate:
/// creationExpression(ctor=largestCtor, args=firstArgs+(nested creationExpression for remainder, with smaller ctor and next few args))
/// </summary>
private BoundExpression RewriteTupleCreationExpression(BoundTupleExpression node, ImmutableArray <BoundExpression> rewrittenArguments)
{
Debug.Assert(node.Type is { });
private BoundNode VisitTupleExpression(BoundTupleExpression node)
{
ImmutableArray<BoundExpression> rewrittenArguments = VisitList(node.Arguments);
return RewriteTupleCreationExpression(node, rewrittenArguments);
}
/// <summary>
/// Converts the expression for creating a tuple instance into an expression creating a ValueTuple (if short) or nested ValueTuples (if longer).
///
/// For instance, for a long tuple we'll generate:
/// creationExpression(ctor=largestCtor, args=firstArgs+(nested creationExpression for remainder, with smaller ctor and next few args))
/// </summary>
private BoundExpression RewriteTupleCreationExpression(BoundTupleExpression node, ImmutableArray<BoundExpression> rewrittenArguments)
{
return MakeTupleCreationExpression(node.Syntax, (NamedTypeSymbol)node.Type, rewrittenArguments);
}