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Binder_Conversions.cs
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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using Microsoft.CodeAnalysis.Collections;
using Microsoft.CodeAnalysis.CSharp.Symbols;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.PooledObjects;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.CSharp
{
internal partial class Binder
{
internal BoundExpression CreateConversion(
BoundExpression source,
TypeSymbol destination,
BindingDiagnosticBag diagnostics)
{
CompoundUseSiteInfo<AssemblySymbol> useSiteInfo = GetNewCompoundUseSiteInfo(diagnostics);
var conversion = Conversions.ClassifyConversionFromExpression(source, destination, isChecked: CheckOverflowAtRuntime, ref useSiteInfo);
diagnostics.Add(source.Syntax, useSiteInfo);
return CreateConversion(source.Syntax, source, conversion, isCast: false, conversionGroupOpt: null, destination: destination, diagnostics: diagnostics);
}
internal BoundExpression CreateConversion(
BoundExpression source,
Conversion conversion,
TypeSymbol destination,
BindingDiagnosticBag diagnostics)
{
return CreateConversion(source.Syntax, source, conversion, isCast: false, conversionGroupOpt: null, destination: destination, diagnostics: diagnostics);
}
internal BoundExpression CreateConversion(
SyntaxNode syntax,
BoundExpression source,
Conversion conversion,
bool isCast,
ConversionGroup? conversionGroupOpt,
TypeSymbol destination,
BindingDiagnosticBag diagnostics)
{
return CreateConversion(syntax, source, conversion, isCast: isCast, conversionGroupOpt, source.WasCompilerGenerated, destination, diagnostics);
}
protected BoundExpression CreateConversion(
SyntaxNode syntax,
BoundExpression source,
Conversion conversion,
bool isCast,
ConversionGroup? conversionGroupOpt,
bool wasCompilerGenerated,
TypeSymbol destination,
BindingDiagnosticBag diagnostics,
bool hasErrors = false)
{
var result = createConversion(syntax, source, conversion, isCast, conversionGroupOpt, wasCompilerGenerated, destination, diagnostics, hasErrors);
Debug.Assert(result is BoundConversion || (conversion.IsIdentity && ((object)result == source) || source.NeedsToBeConverted()) || hasErrors);
#if DEBUG
if (source is BoundValuePlaceholder placeholder1)
{
Debug.Assert(filterConversion(conversion));
Debug.Assert(BoundNode.GetConversion(result, placeholder1) == conversion);
}
else if (source.Type is not null && filterConversion(conversion))
{
var placeholder2 = new BoundValuePlaceholder(source.Syntax, source.Type);
var result2 = createConversion(syntax, placeholder2, conversion, isCast, conversionGroupOpt, wasCompilerGenerated, destination, BindingDiagnosticBag.Discarded, hasErrors);
Debug.Assert(BoundNode.GetConversion(result2, placeholder2) == conversion);
}
static bool filterConversion(Conversion conversion)
{
return !conversion.IsInterpolatedString &&
!conversion.IsInterpolatedStringHandler &&
!conversion.IsSwitchExpression &&
!conversion.IsCollectionExpression &&
!(conversion.IsTupleLiteralConversion || (conversion.IsNullable && conversion.UnderlyingConversions[0].IsTupleLiteralConversion)) &&
(!conversion.IsUserDefined || filterConversion(conversion.UserDefinedFromConversion));
}
#endif
return result;
BoundExpression createConversion(
SyntaxNode syntax,
BoundExpression source,
Conversion conversion,
bool isCast,
ConversionGroup? conversionGroupOpt,
bool wasCompilerGenerated,
TypeSymbol destination,
BindingDiagnosticBag diagnostics,
bool hasErrors = false)
{
RoslynDebug.Assert(source != null);
RoslynDebug.Assert((object)destination != null);
RoslynDebug.Assert(!isCast || conversionGroupOpt != null || wasCompilerGenerated);
if (conversion.IsIdentity)
{
if (source is BoundTupleLiteral sourceTuple)
{
NamedTypeSymbol.ReportTupleNamesMismatchesIfAny(destination, sourceTuple, diagnostics);
}
// identity tuple and switch conversions result in a converted expression
// to indicate that such conversions are no longer applicable.
source = BindToNaturalType(source, diagnostics);
RoslynDebug.Assert(source.Type is object);
// We need to preserve any conversion that changes the type (even identity conversions, like object->dynamic),
// or that was explicitly written in code (so that GetSemanticInfo can find the syntax in the bound tree).
if (!isCast && source.Type.Equals(destination, TypeCompareKind.IgnoreNullableModifiersForReferenceTypes))
{
return source;
}
}
if (conversion.IsMethodGroup)
{
return CreateMethodGroupConversion(syntax, source, conversion, isCast: isCast, conversionGroupOpt, destination, diagnostics);
}
// Obsolete diagnostics for method group are reported as part of creating the method group conversion.
reportUseSiteDiagnostics(syntax, conversion, source, destination, diagnostics);
if (conversion.IsAnonymousFunction && source.Kind == BoundKind.UnboundLambda)
{
return CreateAnonymousFunctionConversion(syntax, source, conversion, isCast: isCast, conversionGroupOpt, destination, diagnostics);
}
if (conversion.Kind == ConversionKind.FunctionType)
{
return CreateFunctionTypeConversion(syntax, source, conversion, isCast: isCast, conversionGroupOpt, destination, diagnostics);
}
if (conversion.IsStackAlloc)
{
return CreateStackAllocConversion(syntax, source, conversion, isCast, conversionGroupOpt, destination, diagnostics);
}
if (conversion.IsTupleLiteralConversion ||
(conversion.IsNullable && conversion.UnderlyingConversions[0].IsTupleLiteralConversion))
{
return CreateTupleLiteralConversion(syntax, (BoundTupleLiteral)source, conversion, isCast: isCast, conversionGroupOpt, destination, diagnostics);
}
if (conversion.Kind == ConversionKind.SwitchExpression)
{
var convertedSwitch = ConvertSwitchExpression((BoundUnconvertedSwitchExpression)source, destination, conversionIfTargetTyped: conversion, diagnostics);
return new BoundConversion(
syntax,
convertedSwitch,
conversion,
CheckOverflowAtRuntime,
explicitCastInCode: isCast && !wasCompilerGenerated,
conversionGroupOpt,
convertedSwitch.ConstantValueOpt,
destination,
hasErrors);
}
if (conversion.Kind == ConversionKind.ConditionalExpression)
{
var convertedConditional = ConvertConditionalExpression((BoundUnconvertedConditionalOperator)source, destination, conversionIfTargetTyped: conversion, diagnostics);
return new BoundConversion(
syntax,
convertedConditional,
conversion,
CheckOverflowAtRuntime,
explicitCastInCode: isCast && !wasCompilerGenerated,
conversionGroupOpt,
convertedConditional.ConstantValueOpt,
destination,
hasErrors);
}
if (conversion.Kind == ConversionKind.InterpolatedString)
{
Debug.Assert(destination.SpecialType != SpecialType.System_String);
var unconvertedSource = (BoundUnconvertedInterpolatedString)source;
source = BindUnconvertedInterpolatedExpressionToFormattableStringFactory(unconvertedSource, destination, diagnostics);
}
if (conversion.Kind == ConversionKind.InterpolatedStringHandler)
{
return new BoundConversion(
syntax,
BindUnconvertedInterpolatedExpressionToHandlerType(source, (NamedTypeSymbol)destination, diagnostics),
conversion,
@checked: CheckOverflowAtRuntime,
explicitCastInCode: isCast && !wasCompilerGenerated,
conversionGroupOpt,
constantValueOpt: null,
destination);
}
if (source.Kind == BoundKind.UnconvertedSwitchExpression)
{
TypeSymbol? type = source.Type;
if (type is null)
{
Debug.Assert(!conversion.Exists);
type = CreateErrorType();
hasErrors = true;
}
source = ConvertSwitchExpression((BoundUnconvertedSwitchExpression)source, type, conversionIfTargetTyped: null, diagnostics, hasErrors);
if (destination.Equals(type, TypeCompareKind.ConsiderEverything) && wasCompilerGenerated)
{
return source;
}
}
if (conversion.IsObjectCreation)
{
return ConvertObjectCreationExpression(syntax, (BoundUnconvertedObjectCreationExpression)source, conversion, isCast, destination, conversionGroupOpt, wasCompilerGenerated, diagnostics);
}
if (source.Kind == BoundKind.UnconvertedCollectionExpression)
{
Debug.Assert(conversion.IsCollectionExpression
|| (conversion.IsNullable && conversion.UnderlyingConversions[0].IsCollectionExpression)
|| !conversion.Exists);
var collectionExpression = ConvertCollectionExpression(
(BoundUnconvertedCollectionExpression)source,
destination,
conversion,
diagnostics);
return new BoundConversion(
syntax,
collectionExpression,
conversion,
@checked: CheckOverflowAtRuntime,
explicitCastInCode: isCast && !wasCompilerGenerated,
conversionGroupOpt,
constantValueOpt: null,
type: destination);
}
if (source.Kind == BoundKind.UnconvertedConditionalOperator)
{
Debug.Assert(source.Type is null);
Debug.Assert(!conversion.Exists);
hasErrors = true;
source = ConvertConditionalExpression((BoundUnconvertedConditionalOperator)source, CreateErrorType(), conversionIfTargetTyped: null, diagnostics, hasErrors);
}
if (conversion.IsUserDefined)
{
// User-defined conversions are likely to be represented as multiple
// BoundConversion instances so a ConversionGroup is necessary.
return CreateUserDefinedConversion(syntax, source, conversion, isCast: isCast, conversionGroupOpt ?? new ConversionGroup(conversion), destination, diagnostics, hasErrors);
}
ConstantValue? constantValue = this.FoldConstantConversion(syntax, source, conversion, destination, diagnostics);
if (conversion.Kind == ConversionKind.DefaultLiteral)
{
source = new BoundDefaultExpression(source.Syntax, targetType: null, constantValue, type: destination)
.WithSuppression(source.IsSuppressed);
}
if (!hasErrors && conversion.Exists)
{
ensureAllUnderlyingConversionsChecked(syntax, source, conversion, wasCompilerGenerated, destination, diagnostics);
if (conversion.Kind is ConversionKind.ImplicitReference or ConversionKind.ExplicitReference &&
source.Type is { } sourceType &&
sourceType.IsWellKnownTypeLock())
{
diagnostics.Add(ErrorCode.WRN_ConvertingLock, source.Syntax);
}
}
return new BoundConversion(
syntax,
BindToNaturalType(source, diagnostics),
conversion,
@checked: CheckOverflowAtRuntime,
explicitCastInCode: isCast && !wasCompilerGenerated,
conversionGroupOpt,
constantValueOpt: constantValue,
type: destination,
hasErrors: hasErrors)
{ WasCompilerGenerated = wasCompilerGenerated };
void reportUseSiteDiagnostics(SyntaxNode syntax, Conversion conversion, BoundExpression source, TypeSymbol destination, BindingDiagnosticBag diagnostics)
{
// Obsolete diagnostics for method group are reported as part of creating the method group conversion.
Debug.Assert(!conversion.IsMethodGroup);
ReportDiagnosticsIfObsolete(diagnostics, conversion, syntax, hasBaseReceiver: false);
if (conversion.Method is not null)
{
ReportUseSite(conversion.Method, diagnostics, syntax.Location);
}
checkConstraintLanguageVersionAndRuntimeSupportForConversion(syntax, conversion, source, destination, diagnostics);
}
}
void ensureAllUnderlyingConversionsChecked(SyntaxNode syntax, BoundExpression source, Conversion conversion, bool wasCompilerGenerated, TypeSymbol destination, BindingDiagnosticBag diagnostics)
{
if (conversion.IsNullable)
{
Debug.Assert(conversion.UnderlyingConversions.Length == 1);
if (destination.IsNullableType())
{
switch (source.Type?.IsNullableType())
{
case true:
_ = CreateConversion(
syntax,
new BoundValuePlaceholder(source.Syntax, source.Type.GetNullableUnderlyingType()),
conversion.UnderlyingConversions[0],
isCast: false,
conversionGroupOpt: null,
wasCompilerGenerated,
destination.GetNullableUnderlyingType(),
diagnostics);
break;
case false:
_ = CreateConversion(
syntax,
source,
conversion.UnderlyingConversions[0],
isCast: false,
conversionGroupOpt: null,
wasCompilerGenerated,
destination.GetNullableUnderlyingType(),
diagnostics);
break;
}
conversion.UnderlyingConversions[0].AssertUnderlyingConversionsChecked();
conversion.MarkUnderlyingConversionsChecked();
}
else if (source.Type?.IsNullableType() == true)
{
_ = CreateConversion(
syntax,
new BoundValuePlaceholder(source.Syntax, source.Type.GetNullableUnderlyingType()),
conversion.UnderlyingConversions[0],
isCast: false,
conversionGroupOpt: null,
wasCompilerGenerated,
destination,
diagnostics);
conversion.UnderlyingConversions[0].AssertUnderlyingConversionsChecked();
conversion.MarkUnderlyingConversionsChecked();
}
}
else if (conversion.IsTupleConversion)
{
ImmutableArray<TypeWithAnnotations> sourceTypes;
ImmutableArray<TypeWithAnnotations> destTypes;
if (source.Type?.TryGetElementTypesWithAnnotationsIfTupleType(out sourceTypes) == true &&
destination.TryGetElementTypesWithAnnotationsIfTupleType(out destTypes) &&
sourceTypes.Length == destTypes.Length)
{
var elementConversions = conversion.UnderlyingConversions;
Debug.Assert(elementConversions.Length == sourceTypes.Length);
for (int i = 0; i < sourceTypes.Length; i++)
{
_ = CreateConversion(
syntax,
new BoundValuePlaceholder(source.Syntax, sourceTypes[i].Type),
elementConversions[i],
isCast: false,
conversionGroupOpt: null,
wasCompilerGenerated,
destTypes[i].Type,
diagnostics);
elementConversions[i].AssertUnderlyingConversionsChecked();
}
conversion.MarkUnderlyingConversionsChecked();
}
}
else if (conversion.IsDynamic)
{
Debug.Assert(conversion.UnderlyingConversions.IsDefault);
conversion.MarkUnderlyingConversionsChecked();
}
conversion.AssertUnderlyingConversionsCheckedRecursive();
}
void checkConstraintLanguageVersionAndRuntimeSupportForConversion(SyntaxNode syntax, Conversion conversion, BoundExpression source, TypeSymbol destination, BindingDiagnosticBag diagnostics)
{
Debug.Assert(syntax.SyntaxTree is object);
if (conversion.IsUserDefined)
{
if (conversion.Method is MethodSymbol method && method.IsStatic)
{
if (method.IsAbstract || method.IsVirtual)
{
Debug.Assert(conversion.ConstrainedToTypeOpt is TypeParameterSymbol);
if (Compilation.SourceModule != method.ContainingModule)
{
CheckFeatureAvailability(syntax, MessageID.IDS_FeatureStaticAbstractMembersInInterfaces, diagnostics);
if (!Compilation.Assembly.RuntimeSupportsStaticAbstractMembersInInterfaces)
{
Error(diagnostics, ErrorCode.ERR_RuntimeDoesNotSupportStaticAbstractMembersInInterfaces, syntax);
}
}
}
if (SyntaxFacts.IsCheckedOperator(method.Name) &&
Compilation.SourceModule != method.ContainingModule)
{
CheckFeatureAvailability(syntax, MessageID.IDS_FeatureCheckedUserDefinedOperators, diagnostics);
}
}
}
else if (conversion.IsInlineArray)
{
if (!Compilation.Assembly.RuntimeSupportsInlineArrayTypes)
{
Error(diagnostics, ErrorCode.ERR_RuntimeDoesNotSupportInlineArrayTypes, syntax);
}
CheckFeatureAvailability(syntax, MessageID.IDS_FeatureInlineArrays, diagnostics);
Debug.Assert(source.Type is { });
FieldSymbol? elementField = source.Type.TryGetInlineArrayElementField();
Debug.Assert(elementField is { });
diagnostics.ReportUseSite(elementField, syntax);
if (destination.OriginalDefinition.Equals(Compilation.GetWellKnownType(WellKnownType.System_ReadOnlySpan_T), TypeCompareKind.AllIgnoreOptions))
{
if (CheckValueKind(syntax, source, BindValueKind.RefersToLocation, checkingReceiver: false, BindingDiagnosticBag.Discarded))
{
_ = GetWellKnownTypeMember(WellKnownMember.System_Runtime_InteropServices_MemoryMarshal__CreateReadOnlySpan, diagnostics, syntax: syntax); // This also takes care of an 'int' type
_ = GetWellKnownTypeMember(WellKnownMember.System_Runtime_CompilerServices_Unsafe__AsRef_T, diagnostics, syntax: syntax);
_ = GetWellKnownTypeMember(WellKnownMember.System_Runtime_CompilerServices_Unsafe__As_T, diagnostics, syntax: syntax);
}
else
{
Error(diagnostics, ErrorCode.ERR_InlineArrayConversionToReadOnlySpanNotSupported, syntax, destination);
}
}
else
{
Debug.Assert(destination.OriginalDefinition.Equals(Compilation.GetWellKnownType(WellKnownType.System_Span_T), TypeCompareKind.AllIgnoreOptions));
if (CheckValueKind(syntax, source, BindValueKind.RefersToLocation | BindValueKind.Assignable, checkingReceiver: false, BindingDiagnosticBag.Discarded))
{
_ = GetWellKnownTypeMember(WellKnownMember.System_Runtime_InteropServices_MemoryMarshal__CreateSpan, diagnostics, syntax: syntax); // This also takes care of an 'int' type
_ = GetWellKnownTypeMember(WellKnownMember.System_Runtime_CompilerServices_Unsafe__As_T, diagnostics, syntax: syntax);
}
else
{
Error(diagnostics, ErrorCode.ERR_InlineArrayConversionToSpanNotSupported, syntax, destination);
}
}
CheckInlineArrayTypeIsSupported(syntax, source.Type, elementField.Type, diagnostics);
}
else if (conversion.IsSpan)
{
Debug.Assert(source.Type is not null);
Debug.Assert(destination.IsSpan() || destination.IsReadOnlySpan());
CheckFeatureAvailability(syntax, MessageID.IDS_FeatureFirstClassSpan, diagnostics);
// NOTE: We cannot use well-known members because per the spec
// the Span types involved in the Span conversions can be any that match the type name.
// Span<T>.op_Implicit(T[]) or ReadOnlySpan<T>.op_Implicit(T[])
if (source.Type is ArrayTypeSymbol)
{
reportUseSiteOrMissing(
TryFindImplicitOperatorFromArray(destination.OriginalDefinition),
destination.OriginalDefinition,
WellKnownMemberNames.ImplicitConversionName,
syntax,
diagnostics);
}
// ReadOnlySpan<T> Span<T>.op_Implicit(Span<T>)
if (source.Type.IsSpan())
{
Debug.Assert(destination.IsReadOnlySpan());
reportUseSiteOrMissing(
TryFindImplicitOperatorFromSpan(source.Type.OriginalDefinition, destination.OriginalDefinition),
source.Type.OriginalDefinition,
WellKnownMemberNames.ImplicitConversionName,
syntax,
diagnostics);
}
// ReadOnlySpan<T> ReadOnlySpan<T>.CastUp<TDerived>(ReadOnlySpan<TDerived>)
if (source.Type.IsSpan() || source.Type.IsReadOnlySpan())
{
Debug.Assert(destination.IsReadOnlySpan());
if (NeedsSpanCastUp(source.Type, destination))
{
// If converting Span<TDerived> -> ROS<TDerived> -> ROS<T>,
// the source of the CastUp is the return type of the op_Implicit (i.e., the ROS<TDerived>)
// which has the same original definition as the destination ROS<T>.
TypeSymbol sourceForCastUp = source.Type.IsSpan()
? destination.OriginalDefinition
: source.Type.OriginalDefinition;
MethodSymbol? castUpMethod = TryFindCastUpMethod(sourceForCastUp, destination.OriginalDefinition);
reportUseSiteOrMissing(
castUpMethod,
destination.OriginalDefinition,
WellKnownMemberNames.CastUpMethodName,
syntax,
diagnostics);
castUpMethod?
.AsMember((NamedTypeSymbol)destination)
.Construct([((NamedTypeSymbol)source.Type).TypeArgumentsWithAnnotationsNoUseSiteDiagnostics[0]])
.CheckConstraints(new ConstraintsHelper.CheckConstraintsArgs(Compilation, Conversions, includeNullability: false, syntax.Location, diagnostics));
}
}
// ReadOnlySpan<char> MemoryExtensions.AsSpan(string)
if (source.Type.IsStringType())
{
reportUseSiteOrMissing(
TryFindAsSpanCharMethod(Compilation, destination),
WellKnownMemberNames.MemoryExtensionsTypeFullName,
WellKnownMemberNames.AsSpanMethodName,
syntax,
diagnostics);
}
}
}
static void reportUseSiteOrMissing(MethodSymbol? method, object containingType, string methodName, SyntaxNode syntax, BindingDiagnosticBag diagnostics)
{
if (method is not null)
{
diagnostics.ReportUseSite(method, syntax);
}
else
{
Error(diagnostics,
ErrorCode.ERR_MissingPredefinedMember,
syntax,
containingType,
methodName);
}
}
}
// {type}.op_Implicit(T[])
internal static MethodSymbol? TryFindImplicitOperatorFromArray(TypeSymbol type)
{
Debug.Assert(type.IsSpan() || type.IsReadOnlySpan());
Debug.Assert(type.IsDefinition);
return TryFindImplicitOperator(type, 0, static (_, method) =>
method.Parameters[0].Type is ArrayTypeSymbol { IsSZArray: true, ElementType: TypeParameterSymbol });
}
// ReadOnlySpan<T> Span<T>.op_Implicit(Span<T>)
internal static MethodSymbol? TryFindImplicitOperatorFromSpan(TypeSymbol spanType, TypeSymbol readonlySpanType)
{
Debug.Assert(spanType.IsSpan() && readonlySpanType.IsReadOnlySpan());
Debug.Assert(spanType.IsDefinition && readonlySpanType.IsDefinition);
return TryFindImplicitOperator(spanType, readonlySpanType,
static (readonlySpanType, method) => method.Parameters[0].Type.IsSpan() &&
readonlySpanType.Equals(method.ReturnType.OriginalDefinition, TypeCompareKind.ConsiderEverything));
}
private static MethodSymbol? TryFindImplicitOperator<TArg>(TypeSymbol type, TArg arg,
Func<TArg, MethodSymbol, bool> predicate)
{
return TryFindSingleMethod(type, WellKnownMemberNames.ImplicitConversionName, (predicate, arg),
static (arg, method) => method is
{
ParameterCount: 1,
Arity: 0,
IsStatic: true,
DeclaredAccessibility: Accessibility.Public,
} && arg.predicate(arg.arg, method));
}
internal static bool NeedsSpanCastUp(TypeSymbol source, TypeSymbol destination)
{
Debug.Assert(source.IsSpan() || source.IsReadOnlySpan());
Debug.Assert(destination.IsReadOnlySpan());
Debug.Assert(!source.IsDefinition && !destination.IsDefinition);
var sourceElementType = ((NamedTypeSymbol)source).TypeArgumentsWithAnnotationsNoUseSiteDiagnostics[0].Type;
var destinationElementType = ((NamedTypeSymbol)destination).TypeArgumentsWithAnnotationsNoUseSiteDiagnostics[0].Type;
var sameElementTypes = sourceElementType.Equals(destinationElementType, TypeCompareKind.AllIgnoreOptions);
Debug.Assert(!source.IsReadOnlySpan() || !sameElementTypes);
return !sameElementTypes;
}
// ReadOnlySpan<T> ReadOnlySpan<T>.CastUp<TDerived>(ReadOnlySpan<TDerived>) where TDerived : class
internal static MethodSymbol? TryFindCastUpMethod(TypeSymbol source, TypeSymbol destination)
{
Debug.Assert(source.IsReadOnlySpan() && destination.IsReadOnlySpan());
Debug.Assert(source.IsDefinition && destination.IsDefinition);
return TryFindSingleMethod(destination, WellKnownMemberNames.CastUpMethodName, (source, destination),
static (arg, method) => method is
{
ParameterCount: 1,
Arity: 1,
IsStatic: true,
DeclaredAccessibility: Accessibility.Public,
Parameters: [{ } parameter],
TypeArgumentsWithAnnotations: [{ } typeArgument],
} &&
// parameter type is the source ReadOnlySpan<>
arg.source.Equals(parameter.Type.OriginalDefinition, TypeCompareKind.ConsiderEverything) &&
// return type is the destination ReadOnlySpan<>
arg.destination.Equals(method.ReturnType.OriginalDefinition, TypeCompareKind.ConsiderEverything) &&
// TDerived : class
typeArgument.Type.IsReferenceType &&
// parameter type argument is TDerived
((NamedTypeSymbol)parameter.Type).TypeArgumentsWithAnnotationsNoUseSiteDiagnostics[0].Type.Equals(typeArgument.Type, TypeCompareKind.ConsiderEverything) &&
// return type argument is T
((NamedTypeSymbol)method.ReturnType).TypeArgumentsWithAnnotationsNoUseSiteDiagnostics[0].Type.Equals(((NamedTypeSymbol)arg.destination).TypeParameters[0], TypeCompareKind.ConsiderEverything));
}
// ReadOnlySpan<char> MemoryExtensions.AsSpan(string)
internal static MethodSymbol? TryFindAsSpanCharMethod(CSharpCompilation compilation, TypeSymbol readOnlySpanType)
{
Debug.Assert(readOnlySpanType.IsReadOnlySpan());
Debug.Assert(!readOnlySpanType.IsDefinition);
Debug.Assert(((NamedTypeSymbol)readOnlySpanType).TypeArgumentsWithAnnotationsNoUseSiteDiagnostics[0].SpecialType is SpecialType.System_Char);
MethodSymbol? result = null;
foreach (var memoryExtensionsType in compilation.GetTypesByMetadataName(WellKnownMemberNames.MemoryExtensionsTypeFullName))
{
if (memoryExtensionsType.DeclaredAccessibility == Accessibility.Public &&
TryFindSingleMethod(memoryExtensionsType.GetSymbol<NamedTypeSymbol>(), WellKnownMemberNames.AsSpanMethodName, 0,
static (_, method) => method is
{
ParameterCount: 1,
Arity: 0,
IsStatic: true,
DeclaredAccessibility: Accessibility.Public,
Parameters: [{ Type.SpecialType: SpecialType.System_String }]
}) is { } method &&
method.ReturnType.Equals(readOnlySpanType, TypeCompareKind.ConsiderEverything))
{
if (result is not null)
{
// Ambiguous member found.
return null;
}
result = method;
}
}
return result;
}
private static MethodSymbol? TryFindSingleMethod<TArg>(TypeSymbol type, string name, TArg arg, Func<TArg, MethodSymbol, bool> predicate)
{
var members = type.GetMembers(name);
MethodSymbol? result = null;
foreach (var member in members)
{
if (member is MethodSymbol method && predicate(arg, method))
{
if (result is not null)
{
// Ambiguous member found.
return null;
}
result = method;
}
}
return result;
}
private BoundExpression BindUnconvertedInterpolatedExpressionToFormattableStringFactory(BoundUnconvertedInterpolatedString unconvertedSource, TypeSymbol destination, BindingDiagnosticBag diagnostics)
{
Debug.Assert(destination.Equals(Compilation.GetWellKnownType(WellKnownType.System_IFormattable), TypeCompareKind.ConsiderEverything) ||
destination.Equals(Compilation.GetWellKnownType(WellKnownType.System_FormattableString), TypeCompareKind.ConsiderEverything));
ImmutableArray<BoundExpression> parts = BindInterpolatedStringPartsForFactory(unconvertedSource, diagnostics, out bool haveErrors);
var stringFactory = GetWellKnownType(WellKnownType.System_Runtime_CompilerServices_FormattableStringFactory, diagnostics, unconvertedSource.Syntax);
if (stringFactory.IsErrorType() || haveErrors)
{
return new BoundInterpolatedString(
unconvertedSource.Syntax,
interpolationData: null,
BindInterpolatedStringParts(unconvertedSource, diagnostics),
unconvertedSource.ConstantValueOpt,
unconvertedSource.Type,
unconvertedSource.HasErrors);
}
return BindUnconvertedInterpolatedExpressionToFactory(unconvertedSource, parts, stringFactory, factoryMethod: "Create", destination, diagnostics);
}
private static void CheckInlineArrayTypeIsSupported(SyntaxNode syntax, TypeSymbol inlineArrayType, TypeSymbol elementType, BindingDiagnosticBag diagnostics)
{
if (elementType.IsPointerOrFunctionPointer() || elementType.IsRestrictedType())
{
Error(diagnostics, ErrorCode.ERR_BadTypeArgument, syntax, elementType);
}
else if (inlineArrayType.IsRestrictedType())
{
Error(diagnostics, ErrorCode.ERR_BadTypeArgument, syntax, inlineArrayType);
}
}
private static BoundExpression ConvertObjectCreationExpression(
SyntaxNode syntax, BoundUnconvertedObjectCreationExpression node, Conversion conversion, bool isCast, TypeSymbol destination,
ConversionGroup? conversionGroupOpt, bool wasCompilerGenerated, BindingDiagnosticBag diagnostics)
{
var arguments = AnalyzedArguments.GetInstance(node.Arguments, node.ArgumentRefKindsOpt, node.ArgumentNamesOpt);
BoundExpression expr = bindObjectCreationExpression(node.Syntax, node.InitializerOpt, node.Binder, destination.StrippedType(), arguments, diagnostics);
arguments.Free();
Debug.Assert(expr is BoundObjectCreationExpressionBase { WasTargetTyped: true } or
BoundDelegateCreationExpression { WasTargetTyped: true } or
BoundBadExpression);
// Assert that the shape of the BoundBadExpression is sound and is not going to confuse NullableWalker for target-typed 'new'.
Debug.Assert(expr is not BoundBadExpression { ChildBoundNodes: var children } || !children.Any((child, node) => child.Syntax == node.Syntax, node));
if (wasCompilerGenerated)
{
expr.MakeCompilerGenerated();
}
expr = new BoundConversion(
syntax,
expr,
expr is BoundBadExpression ? Conversion.NoConversion : conversion,
node.Binder.CheckOverflowAtRuntime,
explicitCastInCode: isCast && !wasCompilerGenerated,
conversionGroupOpt,
expr.ConstantValueOpt,
destination)
{ WasCompilerGenerated = wasCompilerGenerated };
return expr;
static BoundExpression bindObjectCreationExpression(
SyntaxNode syntax, InitializerExpressionSyntax? initializerOpt, Binder binder,
TypeSymbol type, AnalyzedArguments arguments, BindingDiagnosticBag diagnostics)
{
switch (type.TypeKind)
{
case TypeKind.Enum:
case TypeKind.Struct:
case TypeKind.Class when !type.IsAnonymousType: // We don't want to enable object creation with unspeakable types
return binder.BindClassCreationExpression(syntax, type.Name, typeNode: syntax, (NamedTypeSymbol)type, arguments, diagnostics, initializerOpt, wasTargetTyped: true);
case TypeKind.TypeParameter:
return binder.BindTypeParameterCreationExpression(syntax, (TypeParameterSymbol)type, arguments, initializerOpt, typeSyntax: syntax, wasTargetTyped: true, diagnostics);
case TypeKind.Delegate:
return binder.BindDelegateCreationExpression(syntax, (NamedTypeSymbol)type, arguments, initializerOpt, wasTargetTyped: true, diagnostics);
case TypeKind.Interface:
return binder.BindInterfaceCreationExpression(syntax, (NamedTypeSymbol)type, diagnostics, typeNode: syntax, arguments, initializerOpt, wasTargetTyped: true);
case TypeKind.Array:
case TypeKind.Class:
case TypeKind.Dynamic:
Error(diagnostics, ErrorCode.ERR_ImplicitObjectCreationIllegalTargetType, syntax, type);
goto case TypeKind.Error;
case TypeKind.Pointer:
case TypeKind.FunctionPointer:
Error(diagnostics, ErrorCode.ERR_UnsafeTypeInObjectCreation, syntax, type);
goto case TypeKind.Error;
case TypeKind.Error:
return binder.MakeBadExpressionForObjectCreation(syntax, type, arguments, initializerOpt, typeSyntax: syntax, diagnostics);
case var v:
throw ExceptionUtilities.UnexpectedValue(v);
}
}
}
private BoundCollectionExpression ConvertCollectionExpression(
BoundUnconvertedCollectionExpression node,
TypeSymbol targetType,
Conversion conversion,
BindingDiagnosticBag diagnostics)
{
if (conversion.IsNullable)
{
targetType = targetType.GetNullableUnderlyingType();
conversion = conversion.UnderlyingConversions[0];
_ = GetSpecialTypeMember(SpecialMember.System_Nullable_T__ctor, diagnostics, syntax: node.Syntax);
}
var collectionTypeKind = conversion.GetCollectionExpressionTypeKind(out var elementType, out MethodSymbol? constructor, out bool isExpanded);
if (collectionTypeKind == CollectionExpressionTypeKind.None)
{
Debug.Assert(conversion.Kind is ConversionKind.NoConversion);
return BindCollectionExpressionForErrorRecovery(node, targetType, inConversion: false, diagnostics);
}
var syntax = node.Syntax;
if (LocalRewriter.IsAllocatingRefStructCollectionExpression(node, collectionTypeKind, elementType, Compilation))
{
diagnostics.Add(node.HasSpreadElements(out _, out _)
? ErrorCode.WRN_CollectionExpressionRefStructSpreadMayAllocate
: ErrorCode.WRN_CollectionExpressionRefStructMayAllocate,
syntax, targetType);
}
MethodSymbol? collectionBuilderMethod = null;
BoundValuePlaceholder? collectionBuilderInvocationPlaceholder = null;
BoundExpression? collectionBuilderInvocationConversion = null;
switch (collectionTypeKind)
{
case CollectionExpressionTypeKind.Span:
_ = GetWellKnownTypeMember(WellKnownMember.System_Span_T__ctor_Array, diagnostics, syntax: syntax);
break;
case CollectionExpressionTypeKind.ReadOnlySpan:
_ = GetWellKnownTypeMember(WellKnownMember.System_ReadOnlySpan_T__ctor_Array, diagnostics, syntax: syntax);
break;
case CollectionExpressionTypeKind.CollectionBuilder:
{
Debug.Assert(elementType is { });
var namedType = (NamedTypeSymbol)targetType;
collectionBuilderMethod = GetAndValidateCollectionBuilderMethod(syntax, namedType, diagnostics, out var updatedElementType);
if (collectionBuilderMethod is null)
{
return BindCollectionExpressionForErrorRecovery(node, targetType, inConversion: true, diagnostics);
}
elementType = updatedElementType;
collectionBuilderInvocationPlaceholder = new BoundValuePlaceholder(syntax, collectionBuilderMethod.ReturnType) { WasCompilerGenerated = true };
collectionBuilderInvocationConversion = CreateConversion(collectionBuilderInvocationPlaceholder, targetType, diagnostics);
}
break;
case CollectionExpressionTypeKind.ImplementsIEnumerable:
if (targetType.OriginalDefinition.Equals(Compilation.GetWellKnownType(WellKnownType.System_Collections_Immutable_ImmutableArray_T), TypeCompareKind.ConsiderEverything))
{
diagnostics.Add(ErrorCode.ERR_CollectionExpressionImmutableArray, syntax, targetType.OriginalDefinition);
return BindCollectionExpressionForErrorRecovery(node, targetType, inConversion: true, diagnostics);
}
break;
}
var elements = node.Elements;
var builder = ArrayBuilder<BoundNode>.GetInstance(elements.Length);
BoundExpression? collectionCreation = null;
BoundObjectOrCollectionValuePlaceholder? implicitReceiver = null;
if (collectionTypeKind is CollectionExpressionTypeKind.ImplementsIEnumerable)
{
if (targetType is NamedTypeSymbol namedType &&
HasParamsCollectionTypeInProgress(namedType, out NamedTypeSymbol? inProgress, out MethodSymbol? inProgressConstructor))
{
Debug.Assert(inProgressConstructor is not null);
diagnostics.Add(ErrorCode.ERR_ParamsCollectionInfiniteChainOfConstructorCalls, syntax, inProgress, inProgressConstructor.OriginalDefinition);
return BindCollectionExpressionForErrorRecovery(node, namedType, inConversion: true, diagnostics);
}
implicitReceiver = new BoundObjectOrCollectionValuePlaceholder(syntax, isNewInstance: true, targetType) { WasCompilerGenerated = true };
collectionCreation = BindCollectionExpressionConstructor(syntax, targetType, constructor, diagnostics);
Debug.Assert((collectionCreation is BoundNewT && !isExpanded && constructor is null) ||
(collectionCreation is BoundObjectCreationExpression creation && creation.Expanded == isExpanded && creation.Constructor == constructor));
if (collectionCreation.HasErrors)
{
return BindCollectionExpressionForErrorRecovery(node, targetType, inConversion: true, diagnostics);
}
if (!elements.IsDefaultOrEmpty && HasCollectionInitializerTypeInProgress(syntax, targetType))
{
diagnostics.Add(ErrorCode.ERR_CollectionInitializerInfiniteChainOfAddCalls, syntax, targetType);
return BindCollectionExpressionForErrorRecovery(node, targetType, inConversion: true, diagnostics);
}
var collectionInitializerAddMethodBinder = new CollectionInitializerAddMethodBinder(syntax, targetType, this);
foreach (var element in elements)
{
BoundNode convertedElement = element is BoundCollectionExpressionSpreadElement spreadElement ?
(BoundNode)BindCollectionExpressionSpreadElementAddMethod(
(SpreadElementSyntax)spreadElement.Syntax,
spreadElement,
collectionInitializerAddMethodBinder,
implicitReceiver,
diagnostics) :
BindCollectionInitializerElementAddMethod(
element.Syntax,
ImmutableArray.Create((BoundExpression)element),
hasEnumerableInitializerType: true,
collectionInitializerAddMethodBinder,
diagnostics,
implicitReceiver);
builder.Add(convertedElement);
}
}
else
{
if ((collectionTypeKind is CollectionExpressionTypeKind.ArrayInterface) ||
node.HasSpreadElements(out _, out _))
{
// Verify the existence of the List<T> members that may be used in lowering, even
// though not all will be used for any particular collection expression. Checking all
// gives a consistent behavior, regardless of collection expression elements.
_ = GetWellKnownTypeMember(WellKnownMember.System_Collections_Generic_List_T__ctor, diagnostics, syntax: syntax);
_ = GetWellKnownTypeMember(WellKnownMember.System_Collections_Generic_List_T__ctorInt32, diagnostics, syntax: syntax);
_ = GetWellKnownTypeMember(WellKnownMember.System_Collections_Generic_List_T__Add, diagnostics, syntax: syntax);
_ = GetWellKnownTypeMember(WellKnownMember.System_Collections_Generic_List_T__ToArray, diagnostics, syntax: syntax);
}
var elementConversions = conversion.UnderlyingConversions;
Debug.Assert(elementType is { });
Debug.Assert(elements.Length == elementConversions.Length);
Debug.Assert(elementConversions.All(c => c.Exists));
for (int i = 0; i < elements.Length; i++)
{
var element = elements[i];
var elementConversion = elementConversions[i];
var convertedElement = element is BoundCollectionExpressionSpreadElement spreadElement ?
bindSpreadElement(
spreadElement,
elementType,
elementConversion,
diagnostics) :
CreateConversion(
element.Syntax,
(BoundExpression)element,
elementConversion,
isCast: false,
conversionGroupOpt: null,
destination: elementType,
diagnostics);
builder.Add(convertedElement!);
}
conversion.MarkUnderlyingConversionsChecked();
}
return new BoundCollectionExpression(
syntax,
collectionTypeKind,
implicitReceiver,
collectionCreation,
collectionBuilderMethod,
collectionBuilderInvocationPlaceholder,
collectionBuilderInvocationConversion,
wasTargetTyped: true,
node,
builder.ToImmutableAndFree(),
targetType)
{ WasCompilerGenerated = node.IsParamsArrayOrCollection, IsParamsArrayOrCollection = node.IsParamsArrayOrCollection };
BoundNode bindSpreadElement(BoundCollectionExpressionSpreadElement element, TypeSymbol elementType, Conversion elementConversion, BindingDiagnosticBag diagnostics)
{
var enumeratorInfo = element.EnumeratorInfoOpt;
Debug.Assert(enumeratorInfo is { });
Debug.Assert(enumeratorInfo.ElementType is { }); // ElementType is set always, even for IEnumerable.
var expressionSyntax = element.Expression.Syntax;
var elementPlaceholder = new BoundValuePlaceholder(expressionSyntax, enumeratorInfo.ElementType) { WasCompilerGenerated = true };
elementPlaceholder = (BoundValuePlaceholder)elementPlaceholder.WithSuppression(element.Expression.IsSuppressed);
var convertElement = CreateConversion(
expressionSyntax,
elementPlaceholder,
elementConversion,
isCast: false,
conversionGroupOpt: null,