protected override Conversion GetExplicitTupleLiteralConversion(BoundTupleLiteral source, TypeSymbol destination, ref HashSet <DiagnosticInfo> useSiteDiagnostics, bool forCast)
{
var arguments = source.Arguments;
// check if the type is actually compatible type for a tuple of given cardinality
if (!destination.IsTupleOrCompatibleWithTupleOfCardinality(arguments.Length))
{
return(Conversion.NoConversion);
}
ImmutableArray <TypeSymbol> targetElementTypes = destination.GetElementTypesOfTupleOrCompatible();
Debug.Assert(arguments.Length == targetElementTypes.Length);
// check arguments against flattened list of target element types
var argumentConversions = ArrayBuilder <Conversion> .GetInstance(arguments.Length);
for (int i = 0; i < arguments.Length; i++)
{
var result = ClassifyConversionFromExpression(arguments[i], targetElementTypes[i], ref useSiteDiagnostics, forCast);
if (!result.Exists)
{
argumentConversions.Free();
return(Conversion.NoConversion);
}
argumentConversions.Add(result);
}
return(new Conversion(ConversionKind.ExplicitTupleLiteral, argumentConversions.ToImmutableAndFree()));
}
protected override Conversion GetImplicitTupleLiteralConversion(BoundTupleLiteral source, TypeSymbol destination, ref HashSet<DiagnosticInfo> useSiteDiagnostics)
{
var arguments = source.Arguments;
// check if the type is actually compatible type for a tuple of given cardinality
if (!destination.IsTupleOrCompatibleWithTupleOfCardinality(arguments.Length))
{
return Conversion.NoConversion;
}
ImmutableArray<TypeSymbol> targetElementTypes = destination.GetElementTypesOfTupleOrCompatible();
Debug.Assert(arguments.Length == targetElementTypes.Length);
// check arguments against flattened list of target element types
var argumentConversions = ArrayBuilder<Conversion>.GetInstance(arguments.Length);
for (int i = 0; i < arguments.Length; i++)
{
var argument = arguments[i];
var result = ClassifyImplicitConversionFromExpression(argument, targetElementTypes[i], ref useSiteDiagnostics);
if (!result.Exists)
{
argumentConversions.Free();
return Conversion.NoConversion;
}
argumentConversions.Add(result);
}
return new Conversion(ConversionKind.ImplicitTupleLiteral, argumentConversions.ToImmutableAndFree());
}
public override BoundNode VisitTupleLiteral(BoundTupleLiteral node)
{
if (_inExpressionLambda)
{
Error(ErrorCode.ERR_ExpressionTreeContainsTupleLiteral, node);
}
return(base.VisitTupleLiteral(node));
}
private void CheckForDeconstructionAssignmentToSelf(BoundTupleLiteral 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.Kind == BoundKind.TupleLiteral)
{
CheckForDeconstructionAssignmentToSelf((BoundTupleLiteral)leftArgument, rightArgument);
}
else if (IsSameLocalOrField(leftArgument, rightArgument))
{
Error(ErrorCode.WRN_AssignmentToSelf, leftArgument);
}
}
}
private BoundDeconstructionConstructionStep MakeDeconstructionConstructionStep(CSharpSyntaxNode node, DiagnosticBag diagnostics,
ImmutableArray <BoundDeconstructValuePlaceholder> constructionInputs)
{
var tuple = TupleTypeSymbol.Create(locationOpt: null,
elementTypes: constructionInputs.SelectAsArray(e => e.Type),
elementLocations: default(ImmutableArray <Location>),
elementNames: default(ImmutableArray <string>),
compilation: Compilation,
diagnostics: diagnostics,
syntax: node);
var outputPlaceholder = new BoundDeconstructValuePlaceholder(node, tuple)
{
WasCompilerGenerated = true
};
BoundExpression construction = new BoundTupleLiteral(node, default(ImmutableArray <string>), constructionInputs.CastArray <BoundExpression>(), tuple);
return(new BoundDeconstructionConstructionStep(node, construction, outputPlaceholder));
}
/// <summary>
/// For cases where the RHS of a deconstruction-declaration is a tuple literal, we merge type information from both the LHS and RHS.
/// For cases where the RHS of a deconstruction-assignment is a tuple literal, the type information from the LHS determines the merged type, since all variables have a type.
/// Returns null if a merged tuple type could not be fabricated.
/// </summary>
private static TypeSymbol MakeMergedTupleType(ArrayBuilder <DeconstructionVariable> lhsVariables, BoundTupleLiteral rhsLiteral, CSharpSyntaxNode syntax, CSharpCompilation compilation, DiagnosticBag diagnostics)
{
int leftLength = lhsVariables.Count;
int rightLength = rhsLiteral.Arguments.Length;
var typesBuilder = ArrayBuilder <TypeSymbol> .GetInstance(leftLength);
for (int i = 0; i < rightLength; i++)
{
BoundExpression element = rhsLiteral.Arguments[i];
TypeSymbol mergedType = element.Type;
if (i < leftLength)
{
var variable = lhsVariables[i];
if (variable.HasNestedVariables)
{
if (element.Kind == BoundKind.TupleLiteral)
{
// (variables) on the left and (elements) on the right
mergedType = MakeMergedTupleType(variable.NestedVariables, (BoundTupleLiteral)element, syntax, compilation, diagnostics);
}
else if ((object)mergedType == null)
{
// (variables) on the left and null on the right
Error(diagnostics, ErrorCode.ERR_DeconstructRequiresExpression, element.Syntax);
}
}
else
{
if ((object)variable.Single.Type != null)
{
// typed-variable on the left
mergedType = variable.Single.Type;
}
else if ((object)mergedType == null)
{
// typeless-variable on the left and typeless-element on the right
Error(diagnostics, ErrorCode.ERR_DeconstructCouldNotInferMergedType, syntax, variable.Syntax, element.Syntax);
}
}
}
else
{
if ((object)mergedType == null)
{
// a typeless element on the right, matching no variable on the left
Error(diagnostics, ErrorCode.ERR_DeconstructRequiresExpression, element.Syntax);
}
}
typesBuilder.Add(mergedType);
}
if (typesBuilder.Any(t => t == null))
{
typesBuilder.Free();
return(null);
}
return(TupleTypeSymbol.Create(locationOpt: null, elementTypes: typesBuilder.ToImmutableAndFree(), elementLocations: default(ImmutableArray <Location>), elementNames: default(ImmutableArray <string>), compilation: compilation, diagnostics: diagnostics));
}
public override BoundNode VisitTupleLiteral(BoundTupleLiteral node)
{
return(VisitTupleExpression(node));
}
protected override Conversion GetExplicitTupleLiteralConversion(BoundTupleLiteral source, TypeSymbol destination, ref HashSet<DiagnosticInfo> useSiteDiagnostics, bool forCast)
{
// Tuple conversions require a Binder, recursively
throw ExceptionUtilities.Unreachable;
}
protected override Conversion GetExplicitTupleLiteralConversion(BoundTupleLiteral source, TypeSymbol destination, ref HashSet <DiagnosticInfo> useSiteDiagnostics, bool forCast)
{
// Tuple conversions require a Binder, recursively
throw ExceptionUtilities.Unreachable;
}
public override BoundNode VisitTupleLiteral(BoundTupleLiteral node)
{
return VisitTupleExpression(node);
}
private void MakeExplicitParameterTypeInferences(Binder binder, BoundTupleLiteral argument, TypeSymbol target, bool isExactInference, ref HashSet<DiagnosticInfo> useSiteDiagnostics)
{
// if tuple has a type we will try to match the type as a single input
// Example:
// if "(a: 1, b: 2)" is passed as T arg
// then T becomes (int a, int b)
var source = argument.Type;
if (IsReallyAType(source))
{
if (isExactInference)
{
// SPEC: * If V is one of the unfixed Xi then U is added to the set of
// SPEC: exact bounds for Xi.
if (ExactTypeParameterInference(source, target))
{
return;
}
}
else
{
// SPEC: A lower-bound inference from a type U to a type V is made as follows:
// SPEC: * If V is one of the unfixed Xi then U is added to the set of
// SPEC: lower bounds for Xi.
if (LowerBoundTypeParameterInference(source, target))
{
return;
}
}
}
// try match up element-wise to the destination tuple (or underlying type)
// Example:
// if "(a: 1, b: "qq")" is passed as (T, U) arg
// then T becomes int and U becomes string
if (target.Kind != SymbolKind.NamedType)
{
// tuples can only match to tuples or tuple underlying types.
return;
}
var destination = (NamedTypeSymbol)target;
var sourceArguments = argument.Arguments;
// check if the type is actually compatible type for a tuple of given cardinality
if (!destination.IsTupleOrCompatibleWithTupleOfCardinality(sourceArguments.Length))
{
// target is not a tuple of appropriate shape
return;
}
var destTypes = destination.GetElementTypesOfTupleOrCompatible();
Debug.Assert(sourceArguments.Length == destTypes.Length);
// NOTE: we are losing tuple element names when recursing into argument expressions.
// that is ok, because we are inferring type parameters used in the matching elements,
// This is not the situation where entire tuple literal is used to infer a single type param
for (int i = 0; i < sourceArguments.Length; i++)
{
var sourceArgument = sourceArguments[i];
var destType = destTypes[i];
MakeExplicitParameterTypeInferences(binder, sourceArgument, destType, isExactInference, ref useSiteDiagnostics);
}
}
private BoundExpression CreateTupleLiteralConversion(CSharpSyntaxNode syntax, BoundTupleLiteral sourceTuple, Conversion conversion, bool isCast, TypeSymbol destination, DiagnosticBag diagnostics)
{
// We have a successful tuple conversion; rather than producing a separate conversion node
// which is a conversion on top of a tuple literal, tuple conversion is an element-wise conversion of arguments.
Debug.Assert(conversion.Kind == ConversionKind.ImplicitTupleLiteral || conversion.Kind == ConversionKind.ImplicitNullable);
Debug.Assert((conversion.Kind == ConversionKind.ImplicitNullable) == destination.IsNullableType());
TypeSymbol destinationWithoutNullable = conversion.Kind == ConversionKind.ImplicitNullable ?
destinationWithoutNullable = destination.GetNullableUnderlyingType() :
destination;
NamedTypeSymbol targetType = (NamedTypeSymbol)destinationWithoutNullable;
if (targetType.IsTupleType)
{
var destTupleType = (TupleTypeSymbol)targetType;
// do not lose the original element names in the literal if different from names in the target
// Come back to this, what about locations? (https://github.com/dotnet/roslyn/issues/11013)
targetType = destTupleType.WithElementNames(sourceTuple.ArgumentNamesOpt);
}
var arguments = sourceTuple.Arguments;
var convertedArguments = ArrayBuilder<BoundExpression>.GetInstance(arguments.Length);
ImmutableArray<TypeSymbol> targetElementTypes = targetType.GetElementTypesOfTupleOrCompatible();
Debug.Assert(targetElementTypes.Length == arguments.Length, "converting a tuple literal to incompatible type?");
for (int i = 0; i < arguments.Length; i++)
{
var argument = arguments[i];
var destType = targetElementTypes[i];
HashSet<DiagnosticInfo> useSiteDiagnostics = null;
Conversion elementConversion;
if (isCast)
{
elementConversion = this.Conversions.ClassifyConversionForCast(argument, destType, ref useSiteDiagnostics);
}
else
{
elementConversion = this.Conversions.ClassifyConversionFromExpression(argument, destType, ref useSiteDiagnostics);
}
diagnostics.Add(syntax, useSiteDiagnostics);
convertedArguments.Add(CreateConversion(argument.Syntax, argument, elementConversion, isCast, destType, diagnostics));
}
BoundExpression result = new BoundConvertedTupleLiteral(
sourceTuple.Syntax,
sourceTuple.Type,
convertedArguments.ToImmutableAndFree(),
targetType);
// We need to preserve any conversion that changes the type (even identity conversions),
// or that was explicitly written in code (so that GetSemanticInfo can find the syntax in the bound tree).
if (!isCast && targetType == destination)
{
return result;
}
// if we have a nullable cast combined with a name/dynamic cast
// name/dynamic cast must happen before converting to nullable
if (conversion.Kind == ConversionKind.ImplicitNullable &&
destinationWithoutNullable != targetType)
{
Debug.Assert(destinationWithoutNullable.Equals(targetType, ignoreDynamic: true));
result = new BoundConversion(
syntax,
result,
Conversion.Identity,
@checked: false,
explicitCastInCode: isCast,
constantValueOpt: ConstantValue.NotAvailable,
type: destinationWithoutNullable)
{ WasCompilerGenerated = sourceTuple.WasCompilerGenerated };
}
return new BoundConversion(
syntax,
result,
conversion,
@checked: false,
explicitCastInCode: isCast,
constantValueOpt: ConstantValue.NotAvailable,
type: destination)
{ WasCompilerGenerated = sourceTuple.WasCompilerGenerated };
}
private BoundExpression CreateTupleLiteralConversion(SyntaxNode syntax, BoundTupleLiteral sourceTuple, Conversion conversion, bool isCast, TypeSymbol destination, DiagnosticBag diagnostics)
{
// We have a successful tuple conversion; rather than producing a separate conversion node
// which is a conversion on top of a tuple literal, tuple conversion is an element-wise conversion of arguments.
Debug.Assert((conversion.Kind == ConversionKind.ImplicitNullable) == destination.IsNullableType());
var destinationWithoutNullable = destination;
var conversionWithoutNullable = conversion;
if (conversion.Kind == ConversionKind.ImplicitNullable)
{
destinationWithoutNullable = destination.GetNullableUnderlyingType();
conversionWithoutNullable = conversion.UnderlyingConversions[0];
}
Debug.Assert(conversionWithoutNullable.IsTupleLiteralConversion);
NamedTypeSymbol targetType = (NamedTypeSymbol)destinationWithoutNullable;
if (targetType.IsTupleType)
{
var destTupleType = (TupleTypeSymbol)targetType;
// do not lose the original element names in the literal if different from names in the target
TupleTypeSymbol.ReportNamesMismatchesIfAny(targetType, sourceTuple, diagnostics);
// Come back to this, what about locations? (https://github.com/dotnet/roslyn/issues/11013)
targetType = destTupleType.WithElementNames(sourceTuple.ArgumentNamesOpt);
}
var arguments = sourceTuple.Arguments;
var convertedArguments = ArrayBuilder<BoundExpression>.GetInstance(arguments.Length);
ImmutableArray<TypeSymbol> targetElementTypes = targetType.GetElementTypesOfTupleOrCompatible();
Debug.Assert(targetElementTypes.Length == arguments.Length, "converting a tuple literal to incompatible type?");
var underlyingConversions = conversionWithoutNullable.UnderlyingConversions;
for (int i = 0; i < arguments.Length; i++)
{
var argument = arguments[i];
var destType = targetElementTypes[i];
var elementConversion = underlyingConversions[i];
convertedArguments.Add(CreateConversion(argument.Syntax, argument, elementConversion, isCast, destType, diagnostics));
}
BoundExpression result = new BoundConvertedTupleLiteral(
sourceTuple.Syntax,
sourceTuple.Type,
convertedArguments.ToImmutableAndFree(),
targetType);
if (sourceTuple.Type != destination)
{
// literal cast is applied to the literal
result = new BoundConversion(
sourceTuple.Syntax,
result,
conversion,
@checked: false,
explicitCastInCode: isCast,
constantValueOpt: ConstantValue.NotAvailable,
type: destination);
}
// If we had a cast in the code, keep conversion in the tree.
// even though the literal is already converted to the target type.
if (isCast)
{
result = new BoundConversion(
syntax,
result,
Conversion.Identity,
@checked: false,
explicitCastInCode: isCast,
constantValueOpt: ConstantValue.NotAvailable,
type: destination);
}
return result;
}
private BoundDeconstructionConstructionStep MakeDeconstructionConstructionStep(CSharpSyntaxNode node, DiagnosticBag diagnostics,
ImmutableArray<BoundDeconstructValuePlaceholder> constructionInputs)
{
var tuple = TupleTypeSymbol.Create(locationOpt: null,
elementTypes: constructionInputs.SelectAsArray(e => e.Type),
elementLocations: default(ImmutableArray<Location>),
elementNames: default(ImmutableArray<string>),
compilation: Compilation,
diagnostics: diagnostics,
syntax: node);
var outputPlaceholder = new BoundDeconstructValuePlaceholder(node, tuple) { WasCompilerGenerated = true };
BoundExpression construction = new BoundTupleLiteral(node, default(ImmutableArray<string>), constructionInputs.CastArray<BoundExpression>(), tuple);
return new BoundDeconstructionConstructionStep(node, construction, outputPlaceholder);
}
private void MakeOutputTypeInferences(Binder binder, BoundTupleLiteral argument, TypeSymbol formalType, ref HashSet<DiagnosticInfo> useSiteDiagnostics)
{
if (formalType.Kind != SymbolKind.NamedType)
{
// tuples can only match to tuples or tuple underlying types.
return;
}
var destination = (NamedTypeSymbol)formalType;
Debug.Assert(argument.Type == null, "should not need to dig into elements if tuple has natural type");
var sourceArguments = argument.Arguments;
// check if the type is actually compatible type for a tuple of given cardinality
if (!destination.IsTupleOrCompatibleWithTupleOfCardinality(sourceArguments.Length))
{
return;
}
var destTypes = destination.GetElementTypesOfTupleOrCompatible();
Debug.Assert(sourceArguments.Length == destTypes.Length);
for (int i = 0; i < sourceArguments.Length; i++)
{
var sourceArgument = sourceArguments[i];
var destType = destTypes[i];
MakeOutputTypeInferences(binder, sourceArgument, destType, ref useSiteDiagnostics);
}
}
/// <summary>
/// For cases where the RHS of a deconstruction-declaration is a tuple literal, we merge type information from both the LHS and RHS.
/// For cases where the RHS of a deconstruction-assignment is a tuple literal, the type information from the LHS determines the merged type, since all variables have a type.
/// Returns null if a merged tuple type could not be fabricated.
/// </summary>
private static TypeSymbol MakeMergedTupleType(ArrayBuilder<DeconstructionVariable> lhsVariables, BoundTupleLiteral rhsLiteral, CSharpSyntaxNode syntax, CSharpCompilation compilation, DiagnosticBag diagnostics)
{
int leftLength = lhsVariables.Count;
int rightLength = rhsLiteral.Arguments.Length;
var typesBuilder = ArrayBuilder<TypeSymbol>.GetInstance(leftLength);
for (int i = 0; i < rightLength; i++)
{
BoundExpression element = rhsLiteral.Arguments[i];
TypeSymbol mergedType = element.Type;
if (i < leftLength)
{
var variable = lhsVariables[i];
if (variable.HasNestedVariables)
{
if (element.Kind == BoundKind.TupleLiteral)
{
// (variables) on the left and (elements) on the right
mergedType = MakeMergedTupleType(variable.NestedVariables, (BoundTupleLiteral)element, syntax, compilation, diagnostics);
}
else if ((object)mergedType == null)
{
// (variables) on the left and null on the right
Error(diagnostics, ErrorCode.ERR_DeconstructRequiresExpression, element.Syntax);
}
}
else
{
if ((object)variable.Single.Type != null)
{
// typed-variable on the left
mergedType = variable.Single.Type;
}
}
}
else
{
if ((object)mergedType == null)
{
// a typeless element on the right, matching no variable on the left
Error(diagnostics, ErrorCode.ERR_DeconstructRequiresExpression, element.Syntax);
}
}
typesBuilder.Add(mergedType);
}
if (typesBuilder.Any(t => t == null))
{
typesBuilder.Free();
return null;
}
return TupleTypeSymbol.Create(locationOpt: null, elementTypes: typesBuilder.ToImmutableAndFree(), elementLocations: default(ImmutableArray<Location>),
elementNames: default(ImmutableArray<string>), compilation: compilation, diagnostics: diagnostics);
}
public override BoundNode VisitTupleLiteral(BoundTupleLiteral node)
{
throw ExceptionUtilities.Unreachable;
}
/// <summary>
/// For cases where the RHS of a deconstruction-declaration is a tuple literal, we merge type information from both the LHS and RHS.
/// For cases where the RHS of a deconstruction-assignment is a tuple literal, the type information from the LHS determines the merged type, since all variables have a type.
/// Returns null if a merged tuple type could not be fabricated.
/// </summary>
private static TypeSymbol MakeMergedTupleType(ArrayBuilder <DeconstructionVariable> lhsVariables, BoundTupleLiteral rhsLiteral, CSharpSyntaxNode syntax, CSharpCompilation compilation, DiagnosticBag diagnostics)
{
int leftLength = lhsVariables.Count;
int rightLength = rhsLiteral.Arguments.Length;
var typesBuilder = ArrayBuilder <TypeSymbol> .GetInstance(leftLength);
var locationsBuilder = ArrayBuilder <Location> .GetInstance(leftLength);
for (int i = 0; i < rightLength; i++)
{
BoundExpression element = rhsLiteral.Arguments[i];
TypeSymbol mergedType = element.Type;
if (i < leftLength)
{
var variable = lhsVariables[i];
if (variable.HasNestedVariables)
{
if (element.Kind == BoundKind.TupleLiteral)
{
// (variables) on the left and (elements) on the right
mergedType = MakeMergedTupleType(variable.NestedVariables, (BoundTupleLiteral)element, syntax, compilation, diagnostics);
}
else if ((object)mergedType == null)
{
// (variables) on the left and null on the right
Error(diagnostics, ErrorCode.ERR_DeconstructRequiresExpression, element.Syntax);
}
}
else
{
if ((object)variable.Single.Type != null)
{
// typed-variable on the left
mergedType = variable.Single.Type;
}
}
}
else
{
if ((object)mergedType == null)
{
// a typeless element on the right, matching no variable on the left
Error(diagnostics, ErrorCode.ERR_DeconstructRequiresExpression, element.Syntax);
}
}
typesBuilder.Add(mergedType);
locationsBuilder.Add(element.Syntax.Location);
}
if (typesBuilder.Any(t => t == null))
{
typesBuilder.Free();
locationsBuilder.Free();
return(null);
}
// The tuple created here is not identical to the one created by
// DeconstructionVariablesAsTuple. It represents a smaller
// tree of types used for figuring out natural types in tuple literal.
return(TupleTypeSymbol.Create(
locationOpt: null,
elementTypes: typesBuilder.ToImmutableAndFree(),
elementLocations: locationsBuilder.ToImmutableAndFree(),
elementNames: default(ImmutableArray <string>),
compilation: compilation,
diagnostics: diagnostics,
shouldCheckConstraints: true,
errorPositions: default(ImmutableArray <bool>),
syntax: syntax));
}
public override BoundNode VisitTupleLiteral(BoundTupleLiteral node)
{
if (_inExpressionLambda)
{
Error(ErrorCode.ERR_ExpressionTreeContainsTupleLiteral, node);
}
return base.VisitTupleLiteral(node);
}