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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.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Threading;
using Microsoft.Cci;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.PooledObjects;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.CSharp.Symbols
{
internal sealed class LocalFunctionSymbol : LocalFunctionOrSourceMemberMethodSymbol
{
private readonly Binder _binder;
private readonly Symbol _containingSymbol;
private readonly DeclarationModifiers _declarationModifiers;
private readonly ImmutableArray<SourceMethodTypeParameterSymbol> _typeParameters;
private readonly RefKind _refKind;
private ImmutableArray<ParameterSymbol> _lazyParameters;
private bool _lazyIsVarArg;
// Initialized in two steps. Hold a copy if accessing during initialization.
private ImmutableArray<ImmutableArray<TypeWithAnnotations>> _lazyTypeParameterConstraintTypes;
private ImmutableArray<TypeParameterConstraintKind> _lazyTypeParameterConstraintKinds;
private TypeWithAnnotations.Boxed? _lazyReturnType;
// Lock for initializing lazy fields and registering their diagnostics
// Acquire this lock when initializing lazy objects to guarantee their declaration
// diagnostics get added to the store exactly once
private readonly DiagnosticBag _declarationDiagnostics;
private readonly HashSet<AssemblySymbol> _declarationDependencies;
public LocalFunctionSymbol(
Binder binder,
Symbol containingSymbol,
LocalFunctionStatementSyntax syntax)
: base(syntax.GetReference(), isIterator: SyntaxFacts.HasYieldOperations(syntax.Body))
{
Debug.Assert(containingSymbol.DeclaringCompilation == binder.Compilation);
_containingSymbol = containingSymbol;
_declarationDiagnostics = new DiagnosticBag();
_declarationDependencies = new HashSet<AssemblySymbol>();
_declarationModifiers =
DeclarationModifiers.Private |
syntax.Modifiers.ToDeclarationModifiers(isForTypeDeclaration: false, diagnostics: _declarationDiagnostics);
var diagnostics = BindingDiagnosticBag.GetInstance();
Debug.Assert(diagnostics.DiagnosticBag is { });
Debug.Assert(diagnostics.DependenciesBag is { });
this.CheckUnsafeModifier(_declarationModifiers, diagnostics);
ScopeBinder = binder;
binder = binder.SetOrClearUnsafeRegionIfNecessary(syntax.Modifiers);
_binder = binder;
if (syntax.TypeParameterList != null)
{
_typeParameters = MakeTypeParameters(diagnostics);
}
else
{
_typeParameters = ImmutableArray<SourceMethodTypeParameterSymbol>.Empty;
ReportErrorIfHasConstraints(syntax.ConstraintClauses, _declarationDiagnostics);
}
if (IsExtensionMethod)
{
_declarationDiagnostics.Add(ErrorCode.ERR_BadExtensionAgg, GetFirstLocation());
}
foreach (var param in syntax.ParameterList.Parameters)
{
ReportAttributesDisallowed(param.AttributeLists, diagnostics);
}
syntax.ReturnType.SkipRefInLocalOrReturn(diagnostics, out _refKind);
_declarationDiagnostics.AddRange(diagnostics.DiagnosticBag);
_declarationDependencies.AddAll(diagnostics.DependenciesBag);
diagnostics.Free();
}
/// <summary>
/// Binder that owns the scope for the local function symbol, namely the scope where the
/// local function is declared.
/// </summary>
internal Binder ScopeBinder { get; }
internal override Binder OuterBinder => _binder;
internal override Binder WithTypeParametersBinder
=> _typeParameters.IsEmpty ? _binder : new WithMethodTypeParametersBinder(this, _binder);
internal LocalFunctionStatementSyntax Syntax => (LocalFunctionStatementSyntax)syntaxReferenceOpt.GetSyntax();
internal void GetDeclarationDiagnostics(BindingDiagnosticBag addTo)
{
// Force complete type parameters
foreach (var typeParam in _typeParameters)
{
typeParam.ForceComplete(null, filter: null, default(CancellationToken));
}
// force lazy init
ComputeParameters();
foreach (var p in _lazyParameters)
{
// Force complete parameters to retrieve all diagnostics
p.ForceComplete(null, filter: null, default(CancellationToken));
}
ComputeReturnType();
GetAttributes();
GetReturnTypeAttributes();
var compilation = DeclaringCompilation;
ParameterHelpers.EnsureRefKindAttributesExist(compilation, Parameters, addTo, modifyCompilation: false);
// Not emitting ParamCollectionAttribute/ParamArrayAttribute for local functions
ParameterHelpers.EnsureNativeIntegerAttributeExists(compilation, Parameters, addTo, modifyCompilation: false);
ParameterHelpers.EnsureScopedRefAttributeExists(compilation, Parameters, addTo, modifyCompilation: false);
ParameterHelpers.EnsureNullableAttributeExists(compilation, this, Parameters, addTo, modifyCompilation: false);
addTo.AddRange(_declarationDiagnostics);
addTo.AddDependencies((IReadOnlyCollection<AssemblySymbol>)_declarationDependencies);
AsyncMethodChecks(addTo);
var diagnostics = BindingDiagnosticBag.GetInstance(withDiagnostics: false, withDependencies: addTo.AccumulatesDependencies);
if (IsEntryPointCandidate && !IsGenericMethod &&
ContainingSymbol is SynthesizedSimpleProgramEntryPointSymbol &&
compilation.HasEntryPointSignature(this, diagnostics).IsCandidate)
{
addTo.Add(ErrorCode.WRN_MainIgnored, Syntax.Identifier.GetLocation(), this);
}
addTo.AddRangeAndFree(diagnostics);
}
internal override void AddDeclarationDiagnostics(BindingDiagnosticBag diagnostics)
{
if (diagnostics.DiagnosticBag is { } diagnosticBag)
{
_declarationDiagnostics.AddRange(diagnosticBag);
}
if (diagnostics.DependenciesBag is { } dependenciesBag)
{
_declarationDependencies.AddAll(dependenciesBag);
}
}
public override bool RequiresInstanceReceiver => false;
public override bool IsVararg
{
get
{
ComputeParameters();
return _lazyIsVarArg;
}
}
public override ImmutableArray<ParameterSymbol> Parameters
{
get
{
ComputeParameters();
return _lazyParameters;
}
}
private void ComputeParameters()
{
if (_lazyParameters != null)
{
return;
}
SyntaxToken arglistToken;
var diagnostics = BindingDiagnosticBag.GetInstance();
Debug.Assert(diagnostics.DiagnosticBag is { });
Debug.Assert(diagnostics.DependenciesBag is { });
var parameters = ParameterHelpers.MakeParameters(
WithTypeParametersBinder,
this,
this.Syntax.ParameterList,
arglistToken: out arglistToken,
allowRefOrOut: true,
allowThis: true,
addRefReadOnlyModifier: false,
diagnostics: diagnostics).Cast<SourceParameterSymbol, ParameterSymbol>();
// Note: we don't need to warn on annotations used in #nullable disable context for local functions, as this is handled in binding already
var isVararg = arglistToken.Kind() == SyntaxKind.ArgListKeyword;
if (isVararg)
{
diagnostics.Add(ErrorCode.ERR_IllegalVarArgs, arglistToken.GetLocation());
}
lock (_declarationDiagnostics)
{
if (_lazyParameters != null)
{
diagnostics.Free();
return;
}
_declarationDiagnostics.AddRange(diagnostics.DiagnosticBag);
_declarationDependencies.AddAll(diagnostics.DependenciesBag);
diagnostics.Free();
_lazyIsVarArg = isVararg;
_lazyParameters = parameters;
}
}
public override TypeWithAnnotations ReturnTypeWithAnnotations
{
get
{
ComputeReturnType();
return _lazyReturnType!.Value;
}
}
public override RefKind RefKind => _refKind;
internal void ComputeReturnType()
{
if (_lazyReturnType is object)
{
return;
}
var diagnostics = BindingDiagnosticBag.GetInstance();
Debug.Assert(diagnostics.DiagnosticBag is { });
Debug.Assert(diagnostics.DependenciesBag is { });
TypeSyntax returnTypeSyntax = Syntax.ReturnType;
Debug.Assert(returnTypeSyntax is not ScopedTypeSyntax);
TypeWithAnnotations returnType = WithTypeParametersBinder.BindType(returnTypeSyntax.SkipScoped(out _).SkipRef(), diagnostics);
var compilation = DeclaringCompilation;
// Skip some diagnostics when the local function is not associated with a compilation
// (specifically, local functions nested in expressions in the EE).
if (compilation is object)
{
Location? location = null;
if (_refKind == RefKind.RefReadOnly)
{
compilation.EnsureIsReadOnlyAttributeExists(diagnostics, location ??= returnTypeSyntax.Location, modifyCompilation: false);
}
if (compilation.ShouldEmitNativeIntegerAttributes(returnType.Type))
{
compilation.EnsureNativeIntegerAttributeExists(diagnostics, location ??= returnTypeSyntax.Location, modifyCompilation: false);
}
if (compilation.ShouldEmitNullableAttributes(this) &&
returnType.NeedsNullableAttribute())
{
compilation.EnsureNullableAttributeExists(diagnostics, location ??= returnTypeSyntax.Location, modifyCompilation: false);
// Note: we don't need to warn on annotations used in #nullable disable context for local functions, as this is handled in binding already
}
}
// span-like types are returnable in general
if (returnType.IsRestrictedType(ignoreSpanLikeTypes: true))
{
// The return type of a method, delegate, or function pointer cannot be '{0}'
diagnostics.Add(ErrorCode.ERR_MethodReturnCantBeRefAny, returnTypeSyntax.Location, returnType.Type);
}
Debug.Assert(_refKind == RefKind.None
|| !returnType.IsVoidType()
|| returnTypeSyntax.HasErrors);
lock (_declarationDiagnostics)
{
if (_lazyReturnType is object)
{
diagnostics.Free();
return;
}
_declarationDiagnostics.AddRange(diagnostics.DiagnosticBag);
_declarationDependencies.AddAll(diagnostics.DependenciesBag);
diagnostics.Free();
Interlocked.CompareExchange(ref _lazyReturnType, new TypeWithAnnotations.Boxed(returnType), null);
}
}
public override bool ReturnsVoid => ReturnType.IsVoidType();
public override int Arity => TypeParameters.Length;
public override ImmutableArray<TypeWithAnnotations> TypeArgumentsWithAnnotations => GetTypeParametersAsTypeArguments();
public override ImmutableArray<TypeParameterSymbol> TypeParameters
=> _typeParameters.Cast<SourceMethodTypeParameterSymbol, TypeParameterSymbol>();
public override bool IsExtensionMethod
{
get
{
// It is an error to be an extension method, but we need to compute it to report it
var firstParam = Syntax.ParameterList.Parameters.FirstOrDefault();
return firstParam != null &&
!firstParam.IsArgList &&
firstParam.Modifiers.Any(SyntaxKind.ThisKeyword);
}
}
public override MethodKind MethodKind => MethodKind.LocalFunction;
public sealed override Symbol ContainingSymbol => _containingSymbol;
public override string Name => Syntax.Identifier.ValueText ?? "";
public SyntaxToken NameToken => Syntax.Identifier;
public override ImmutableArray<MethodSymbol> ExplicitInterfaceImplementations => ImmutableArray<MethodSymbol>.Empty;
public override ImmutableArray<Location> Locations => ImmutableArray.Create(Syntax.Identifier.GetLocation());
public override Location TryGetFirstLocation() => Syntax.Identifier.GetLocation();
internal override bool GenerateDebugInfo => true;
public override ImmutableArray<CustomModifier> RefCustomModifiers => ImmutableArray<CustomModifier>.Empty;
internal override CallingConvention CallingConvention => CallingConvention.Default;
internal override OneOrMany<SyntaxList<AttributeListSyntax>> GetAttributeDeclarations()
{
return OneOrMany.Create(Syntax.AttributeLists);
}
protected override void NoteAttributesComplete(bool forReturnType) { }
public override Symbol? AssociatedSymbol => null;
public override Accessibility DeclaredAccessibility => ModifierUtils.EffectiveAccessibility(_declarationModifiers);
public override bool IsAsync => (_declarationModifiers & DeclarationModifiers.Async) != 0;
public override bool IsStatic => (_declarationModifiers & DeclarationModifiers.Static) != 0;
public override bool IsVirtual => (_declarationModifiers & DeclarationModifiers.Virtual) != 0;
public override bool IsOverride => (_declarationModifiers & DeclarationModifiers.Override) != 0;
public override bool IsAbstract => (_declarationModifiers & DeclarationModifiers.Abstract) != 0;
public override bool IsSealed => (_declarationModifiers & DeclarationModifiers.Sealed) != 0;
public override bool IsExtern => (_declarationModifiers & DeclarationModifiers.Extern) != 0;
public bool IsUnsafe => (_declarationModifiers & DeclarationModifiers.Unsafe) != 0;
internal bool IsExpressionBodied => Syntax is { Body: null, ExpressionBody: object _ };
internal override bool IsDeclaredReadOnly => false;
internal override bool IsInitOnly => false;
internal override bool IsMetadataNewSlot(bool ignoreInterfaceImplementationChanges = false) => false;
internal override bool IsMetadataVirtual(IsMetadataVirtualOption option = IsMetadataVirtualOption.None) => false;
internal override int CalculateLocalSyntaxOffset(int localPosition, SyntaxTree localTree)
{
throw ExceptionUtilities.Unreachable();
}
internal override bool TryGetThisParameter(out ParameterSymbol? thisParameter)
{
// Local function symbols have no "this" parameter
thisParameter = null;
return true;
}
private void ReportAttributesDisallowed(SyntaxList<AttributeListSyntax> attributes, BindingDiagnosticBag diagnostics)
{
var diagnosticInfo = MessageID.IDS_FeatureLocalFunctionAttributes.GetFeatureAvailabilityDiagnosticInfo((CSharpParseOptions)syntaxReferenceOpt.SyntaxTree.Options);
if (diagnosticInfo is object)
{
foreach (var attrList in attributes)
{
diagnostics.Add(diagnosticInfo, attrList.Location);
}
}
}
private ImmutableArray<SourceMethodTypeParameterSymbol> MakeTypeParameters(BindingDiagnosticBag diagnostics)
{
var result = ArrayBuilder<SourceMethodTypeParameterSymbol>.GetInstance();
var typeParameters = Syntax.TypeParameterList?.Parameters ?? default;
for (int ordinal = 0; ordinal < typeParameters.Count; ordinal++)
{
var parameter = typeParameters[ordinal];
if (parameter.VarianceKeyword.Kind() != SyntaxKind.None)
{
diagnostics.Add(ErrorCode.ERR_IllegalVarianceSyntax, parameter.VarianceKeyword.GetLocation());
}
ReportAttributesDisallowed(parameter.AttributeLists, diagnostics);
var identifier = parameter.Identifier;
var location = identifier.GetLocation();
var name = identifier.ValueText ?? "";
foreach (var @param in result)
{
if (name == @param.Name)
{
diagnostics.Add(ErrorCode.ERR_DuplicateTypeParameter, location, name);
break;
}
}
SourceMemberContainerTypeSymbol.ReportReservedTypeName(identifier.Text, this.DeclaringCompilation, diagnostics.DiagnosticBag, location);
var tpEnclosing = ContainingSymbol.FindEnclosingTypeParameter(name);
if ((object?)tpEnclosing != null)
{
ErrorCode typeError;
if (tpEnclosing.ContainingSymbol.Kind == SymbolKind.Method)
{
// Type parameter '{0}' has the same name as the type parameter from outer method '{1}'
typeError = ErrorCode.WRN_TypeParameterSameAsOuterMethodTypeParameter;
}
else
{
Debug.Assert(tpEnclosing.ContainingSymbol.Kind == SymbolKind.NamedType);
// Type parameter '{0}' has the same name as the type parameter from outer type '{1}'
typeError = ErrorCode.WRN_TypeParameterSameAsOuterTypeParameter;
}
diagnostics.Add(typeError, location, name, tpEnclosing.ContainingSymbol);
}
var typeParameter = new SourceMethodTypeParameterSymbol(
this,
name,
ordinal,
ImmutableArray.Create(location),
ImmutableArray.Create(parameter.GetReference()));
result.Add(typeParameter);
}
return result.ToImmutableAndFree();
}
public override ImmutableArray<ImmutableArray<TypeWithAnnotations>> GetTypeParameterConstraintTypes()
{
if (_lazyTypeParameterConstraintTypes.IsDefault)
{
GetTypeParameterConstraintKinds();
var syntax = Syntax;
var diagnostics = BindingDiagnosticBag.GetInstance();
Debug.Assert(diagnostics.DiagnosticBag is { });
Debug.Assert(diagnostics.DependenciesBag is { });
var constraints = this.MakeTypeParameterConstraintTypes(
WithTypeParametersBinder,
TypeParameters,
syntax.TypeParameterList,
syntax.ConstraintClauses,
diagnostics);
lock (_declarationDiagnostics)
{
if (_lazyTypeParameterConstraintTypes.IsDefault)
{
_declarationDiagnostics.AddRange(diagnostics.DiagnosticBag);
_declarationDependencies.AddAll(diagnostics.DependenciesBag);
_lazyTypeParameterConstraintTypes = constraints;
}
}
diagnostics.Free();
}
return _lazyTypeParameterConstraintTypes;
}
public override ImmutableArray<TypeParameterConstraintKind> GetTypeParameterConstraintKinds()
{
if (_lazyTypeParameterConstraintKinds.IsDefault)
{
var syntax = Syntax;
var constraints = this.MakeTypeParameterConstraintKinds(
WithTypeParametersBinder,
TypeParameters,
syntax.TypeParameterList,
syntax.ConstraintClauses);
ImmutableInterlocked.InterlockedInitialize(ref _lazyTypeParameterConstraintKinds, constraints);
}
return _lazyTypeParameterConstraintKinds;
}
internal override bool IsNullableAnalysisEnabled() => throw ExceptionUtilities.Unreachable();
public override int GetHashCode()
{
// this is what lambdas do (do not use hashes of other fields)
return Syntax.GetHashCode();
}
public sealed override bool Equals(Symbol symbol, TypeCompareKind compareKind)
{
if ((object)this == symbol) return true;
var localFunction = symbol as LocalFunctionSymbol;
return localFunction?.Syntax == Syntax;
}
}
}
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