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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.
#nullable disable
using System;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using System.Threading;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Roslyn.Utilities;
using Microsoft.CodeAnalysis.PooledObjects;
using System.Runtime.CompilerServices;
namespace Microsoft.CodeAnalysis.CSharp.Symbols
{
/// <summary>
/// Represents a local variable in a method body.
/// </summary>
internal class SourceLocalSymbol : LocalSymbol
{
private readonly Binder _scopeBinder;
/// <summary>
/// Might not be a method symbol.
/// </summary>
private readonly Symbol _containingSymbol;
private readonly SyntaxToken _identifierToken;
private readonly TypeSyntax _typeSyntax;
private readonly RefKind _refKind;
private readonly LocalDeclarationKind _declarationKind;
private readonly ScopedKind _scope;
#nullable enable
private TypeWithAnnotations.Boxed? _type;
// Please don't use thread local storage widely. This should be one of only a few uses.
[ThreadStatic] private static PooledHashSet<LocalTypeInferenceInProgressKey>? s_LocalTypeInferenceInProgress;
private ConcurrentSet<SyntaxNode>? _forbiddenReferences;
private readonly struct LocalTypeInferenceInProgressKey : IEquatable<LocalTypeInferenceInProgressKey>
{
public readonly SourceLocalSymbol Local;
public readonly SyntaxNode Reference;
public LocalTypeInferenceInProgressKey(SourceLocalSymbol local, SyntaxNode reference)
{
Local = local;
Reference = reference;
}
public bool Equals(LocalTypeInferenceInProgressKey other)
{
return Local == (object)other.Local && Reference == other.Reference;
}
public override bool Equals(object? obj)
{
return obj is LocalTypeInferenceInProgressKey && Equals((LocalTypeInferenceInProgressKey)obj);
}
public override int GetHashCode()
{
return Hash.Combine(RuntimeHelpers.GetHashCode(Local), Reference.GetHashCode());
}
}
#nullable disable
private SourceLocalSymbol(
Symbol containingSymbol,
Binder scopeBinder,
bool allowRefKind,
bool allowScoped,
TypeSyntax typeSyntax,
SyntaxToken identifierToken,
LocalDeclarationKind declarationKind)
{
Debug.Assert(identifierToken.Kind() != SyntaxKind.None);
Debug.Assert(declarationKind != LocalDeclarationKind.None);
Debug.Assert(scopeBinder != null);
Debug.Assert(containingSymbol.DeclaringCompilation == scopeBinder.Compilation);
this._scopeBinder = scopeBinder;
this._containingSymbol = containingSymbol;
this._identifierToken = identifierToken;
this._typeSyntax = typeSyntax;
bool isScoped;
typeSyntax = typeSyntax.SkipScoped(out isScoped);
isScoped = isScoped && allowScoped;
// Diagnostics for ref-locals is reported by caller in BindDeclarationStatementParts.
if (allowRefKind)
typeSyntax.SkipRefInLocalOrReturn(diagnostics: null, out _refKind);
_scope = _refKind != RefKind.None
? isScoped ? ScopedKind.ScopedRef : ScopedKind.None
: isScoped ? ScopedKind.ScopedValue : ScopedKind.None;
this._declarationKind = declarationKind;
}
/// <summary>
/// Binder that owns the scope for the local, the one that returns it in its <see cref="Binder.Locals"/> array.
/// </summary>
internal Binder ScopeBinder
{
get { return _scopeBinder; }
}
internal override SyntaxNode ScopeDesignatorOpt
{
get { return _scopeBinder.ScopeDesignator; }
}
internal sealed override ScopedKind Scope => _scope;
/// <summary>
/// Binder that should be used to bind type syntax for the local.
/// </summary>
internal Binder TypeSyntaxBinder
{
get { return _scopeBinder; } // Scope binder should be good enough for this.
}
// When the variable's type has not yet been inferred,
// don't let the debugger force inference.
internal override string GetDebuggerDisplay()
{
return _type != null
? base.GetDebuggerDisplay()
: $"{this.Kind} <var> ${this.Name}";
}
public static SourceLocalSymbol MakeForeachLocal(
MethodSymbol containingMethod,
ForEachLoopBinder binder,
TypeSyntax typeSyntax,
SyntaxToken identifierToken,
ExpressionSyntax collection)
{
return new ForEachLocalSymbol(containingMethod, binder, typeSyntax, identifierToken, collection, LocalDeclarationKind.ForEachIterationVariable);
}
/// <summary>
/// Make a local variable symbol for an element of a deconstruction,
/// which can be inferred (if necessary) by binding the enclosing statement.
/// </summary>
/// <param name="containingSymbol"></param>
/// <param name="scopeBinder">
/// Binder that owns the scope for the local, the one that returns it in its <see cref="Binder.Locals"/> array.
/// </param>
/// <param name="nodeBinder">
/// Enclosing binder for the location where the local is declared.
/// It should be used to bind something at that location.
/// </param>
/// <param name="closestTypeSyntax"></param>
/// <param name="identifierToken"></param>
/// <param name="kind"></param>
/// <param name="deconstruction"></param>
/// <returns></returns>
public static SourceLocalSymbol MakeDeconstructionLocal(
Symbol containingSymbol,
Binder scopeBinder,
Binder nodeBinder,
TypeSyntax closestTypeSyntax,
SyntaxToken identifierToken,
LocalDeclarationKind kind,
SyntaxNode deconstruction)
{
Debug.Assert(closestTypeSyntax != null);
Debug.Assert(nodeBinder != null);
return closestTypeSyntax.SkipScoped(out _).SkipRef().IsVar
? new DeconstructionLocalSymbol(containingSymbol, scopeBinder, nodeBinder, closestTypeSyntax, identifierToken, kind, deconstruction)
: new SourceLocalSymbol(containingSymbol, scopeBinder, allowRefKind: false, allowScoped: true, closestTypeSyntax, identifierToken, kind);
}
#nullable enable
/// <summary>
/// Make a local variable symbol whose type can be inferred (if necessary) by binding and enclosing construct.
/// </summary>
internal static LocalSymbol MakeLocalSymbolWithEnclosingContext(
Symbol containingSymbol,
Binder scopeBinder,
Binder nodeBinder,
TypeSyntax typeSyntax,
SyntaxToken identifierToken,
LocalDeclarationKind kind,
SyntaxNode nodeToBind)
{
Debug.Assert(
nodeToBind.Kind() == SyntaxKind.CasePatternSwitchLabel ||
nodeToBind.Kind() == SyntaxKind.ThisConstructorInitializer ||
nodeToBind.Kind() == SyntaxKind.BaseConstructorInitializer ||
nodeToBind.Kind() == SyntaxKind.PrimaryConstructorBaseType || // initializer for a record constructor
nodeToBind.Kind() == SyntaxKind.SwitchExpressionArm ||
nodeToBind.Kind() == SyntaxKind.ArgumentList && (nodeToBind.Parent is ConstructorInitializerSyntax || nodeToBind.Parent is PrimaryConstructorBaseTypeSyntax) ||
nodeToBind.Kind() == SyntaxKind.GotoCaseStatement || // for error recovery
nodeToBind.Kind() == SyntaxKind.VariableDeclarator &&
new[] { SyntaxKind.LocalDeclarationStatement, SyntaxKind.ForStatement, SyntaxKind.UsingStatement, SyntaxKind.FixedStatement }.
Contains(nodeToBind.Ancestors().OfType<StatementSyntax>().First().Kind()) ||
nodeToBind is ExpressionSyntax);
Debug.Assert(!(nodeToBind.Kind() == SyntaxKind.SwitchExpressionArm) || nodeBinder is SwitchExpressionArmBinder);
return typeSyntax?.SkipScoped(out _).SkipRef().IsVar != false && kind != LocalDeclarationKind.DeclarationExpressionVariable
? new LocalSymbolWithEnclosingContext(containingSymbol, scopeBinder, nodeBinder, typeSyntax, identifierToken, kind, nodeToBind)
: new SourceLocalSymbol(containingSymbol, scopeBinder, allowRefKind: false, allowScoped: true, typeSyntax, identifierToken, kind);
}
#nullable disable
/// <summary>
/// Make a local variable symbol which can be inferred (if necessary) by binding its initializing expression.
/// </summary>
/// <param name="containingSymbol"></param>
/// <param name="scopeBinder">
/// Binder that owns the scope for the local, the one that returns it in its <see cref="Binder.Locals"/> array.
/// </param>
/// <param name="allowRefKind"></param>
/// <param name="allowScoped"></param>
/// <param name="typeSyntax"></param>
/// <param name="identifierToken"></param>
/// <param name="declarationKind"></param>
/// <param name="initializer"></param>
/// <param name="initializerBinderOpt">
/// Binder that should be used to bind initializer, if different from the <paramref name="scopeBinder"/>.
/// </param>
/// <returns></returns>
public static SourceLocalSymbol MakeLocal(
Symbol containingSymbol,
Binder scopeBinder,
bool allowRefKind,
bool allowScoped,
TypeSyntax typeSyntax,
SyntaxToken identifierToken,
LocalDeclarationKind declarationKind,
EqualsValueClauseSyntax initializer,
Binder initializerBinderOpt = null)
{
Debug.Assert(declarationKind != LocalDeclarationKind.ForEachIterationVariable);
return (initializer != null)
? new LocalWithInitializer(containingSymbol, scopeBinder, typeSyntax, identifierToken, initializer, initializerBinderOpt ?? scopeBinder, declarationKind, allowScoped)
: new SourceLocalSymbol(containingSymbol, scopeBinder, allowRefKind: allowRefKind, allowScoped: allowScoped, typeSyntax, identifierToken, declarationKind);
}
internal override bool IsImportedFromMetadata
{
get { return false; }
}
internal override LocalDeclarationKind DeclarationKind
{
get { return _declarationKind; }
}
internal override SynthesizedLocalKind SynthesizedKind
{
get { return SynthesizedLocalKind.UserDefined; }
}
internal override LocalSymbol WithSynthesizedLocalKindAndSyntax(
SynthesizedLocalKind kind, SyntaxNode syntax
#if DEBUG
,
[CallerLineNumber] int createdAtLineNumber = 0,
[CallerFilePath] string createdAtFilePath = null
#endif
)
{
throw ExceptionUtilities.Unreachable();
}
internal override bool IsPinned
{
get
{
// even when dealing with "fixed" locals it is the underlying managed reference that gets pinned
// the pointer variable itself is not pinned.
return false;
}
}
internal sealed override bool IsKnownToReferToTempIfReferenceType
{
get { return false; }
}
public override Symbol ContainingSymbol
{
get { return _containingSymbol; }
}
/// <summary>
/// Gets the name of the local variable.
/// </summary>
public override string Name
{
get
{
return _identifierToken.ValueText;
}
}
// Get the identifier token that defined this local symbol. This is useful for robustly
// checking if a local symbol actually matches a particular definition, even in the presence
// of duplicates.
internal override SyntaxToken IdentifierToken
{
get
{
return _identifierToken;
}
}
#if DEBUG
// We use this to detect infinite recursion in type inference.
private int concurrentTypeResolutions = 0;
#endif
public override TypeWithAnnotations TypeWithAnnotations
{
get
{
return GetTypeWithAnnotations(CSharpSyntaxTree.Dummy.GetRoot(), BindingDiagnosticBag.Discarded);
}
}
/// <summary>
/// The diagnostic code to be reported when an inferred variable is used
/// in its forbidden zone.
/// </summary>
protected virtual ErrorCode ForbiddenDiagnostic => ErrorCode.ERR_VariableUsedBeforeDeclaration;
public bool IsVar
{
get
{
if (_typeSyntax == null)
{
// in "e is {} x" there is no syntax corresponding to the type.
return true;
}
TypeSyntax typeSyntax = _typeSyntax.SkipScoped(out _).SkipRef();
if (typeSyntax.IsVar)
{
bool isVar;
TypeWithAnnotations declType = this.TypeSyntaxBinder.BindTypeOrVarKeyword(typeSyntax, BindingDiagnosticBag.Discarded, out isVar);
return isVar;
}
return false;
}
}
#nullable enable
public override TypeWithAnnotations GetTypeWithAnnotations(SyntaxNode reference, BindingDiagnosticBag diagnostics)
{
if (_forbiddenReferences?.Contains(reference) == true)
{
diagnostics.Add(ForbiddenDiagnostic, reference.Location, reference);
return TypeWithAnnotations.Create(this.DeclaringCompilation.ImplicitlyTypedVariableUsedInForbiddenZoneType);
}
if (_type == null)
{
#if DEBUG
concurrentTypeResolutions++;
Debug.Assert(concurrentTypeResolutions < 50);
#endif
Binder typeBinder = this.TypeSyntaxBinder;
bool isVar;
TypeWithAnnotations declType;
if (_typeSyntax == null) // In recursive patterns the type may be omitted.
{
isVar = true;
declType = default;
}
else
{
//
// Note that we drop the diagnostics on the floor! That is because this code is invoked mainly in
// IDE scenarios where we are attempting to use the types of a variable before we have processed
// the code which causes the variable's type to be inferred. In batch compilation, on the
// other hand, local variables have their type inferred, if necessary, in the course of binding
// the statements of a method from top to bottom, and an inferred type is given to a variable
// before the variable's type is used by the compiler.
//
declType = typeBinder.BindTypeOrVarKeyword(_typeSyntax.SkipScoped(out _).SkipRef(), BindingDiagnosticBag.Discarded, out isVar);
}
if (isVar)
{
bool free = false;
var localTypeInferenceInProgress = s_LocalTypeInferenceInProgress;
if (localTypeInferenceInProgress is null)
{
free = true;
localTypeInferenceInProgress = (s_LocalTypeInferenceInProgress = PooledHashSet<LocalTypeInferenceInProgressKey>.GetInstance());
}
var key = new LocalTypeInferenceInProgressKey(this, reference);
if (!localTypeInferenceInProgress.Add(key))
{
Debug.Assert(!free);
Debug.Assert(reference != CSharpSyntaxTree.Dummy.GetRoot());
if (_forbiddenReferences is null)
{
Interlocked.CompareExchange(ref _forbiddenReferences, new ConcurrentSet<SyntaxNode>(), null);
}
bool added = _forbiddenReferences.Add(reference);
Debug.Assert(added); // This assert can fail if there is a race between multiple threads. We can remove it if it becomes a problem, confirming the case.
diagnostics.Add(ForbiddenDiagnostic, reference.Location, reference);
return TypeWithAnnotations.Create(this.DeclaringCompilation.ImplicitlyTypedVariableUsedInForbiddenZoneType);
}
TypeWithAnnotations inferredType;
try
{
inferredType = InferTypeOfVarVariable();
}
finally
{
Debug.Assert(localTypeInferenceInProgress == s_LocalTypeInferenceInProgress);
bool removed = localTypeInferenceInProgress.Remove(key);
Debug.Assert(removed);
Debug.Assert(free == (localTypeInferenceInProgress.Count == 0));
if (free)
{
s_LocalTypeInferenceInProgress = null;
localTypeInferenceInProgress.Free();
}
}
if (_forbiddenReferences?.Contains(reference) == true)
{
diagnostics.Add(ForbiddenDiagnostic, reference.Location, reference);
return TypeWithAnnotations.Create(this.DeclaringCompilation.ImplicitlyTypedVariableUsedInForbiddenZoneType);
}
// If we got a valid result that was not void then use the inferred type
// else create an error type.
if (inferredType.HasType &&
!inferredType.IsVoidType())
{
declType = inferredType;
}
else
{
declType = TypeWithAnnotations.Create(DeclaringCompilation.ImplicitlyTypedVariableInferenceFailedType);
}
}
Debug.Assert(declType.HasType);
SetTypeWithAnnotations(declType);
return _type?.Value ?? declType;
}
return _type.Value;
}
#nullable disable
protected virtual TypeWithAnnotations InferTypeOfVarVariable()
{
// TODO: this method must be overridden for pattern variables to bind the
// expression or statement that is the nearest enclosing to the pattern variable's
// declaration. That will cause the type of the pattern variable to be set as a side-effect.
return _type?.Value ?? default;
}
internal void SetTypeWithAnnotations(TypeWithAnnotations newType)
{
Debug.Assert(newType.Type is object);
TypeWithAnnotations? originalType = _type?.Value;
// In the event that we race to set the type of a local, we should
// always deduce the same type, or deduce that the type is an error.
Debug.Assert((object)originalType?.DefaultType == null ||
originalType.Value.DefaultType.IsErrorType() && newType.Type.IsErrorType() ||
originalType.Value.TypeSymbolEquals(newType, TypeCompareKind.ConsiderEverything));
if (_type is null &&
(newType.Type != (object)DeclaringCompilation.ImplicitlyTypedVariableInferenceFailedType ||
(s_LocalTypeInferenceInProgress?.Any(static (key, @this) => key.Local == (object)@this, this) != true)))
{
Interlocked.CompareExchange(ref _type, new TypeWithAnnotations.Boxed(newType), null);
}
}
public override Location TryGetFirstLocation()
=> _identifierToken.GetLocation();
/// <summary>
/// Gets the locations where the local symbol was originally defined in source.
/// There should not be local symbols from metadata, and there should be only one local variable declared.
/// TODO: check if there are multiple same name local variables - error symbol or local symbol?
/// </summary>
public override ImmutableArray<Location> Locations
=> ImmutableArray.Create(GetFirstLocation());
internal sealed override SyntaxNode GetDeclaratorSyntax()
{
return _identifierToken.Parent;
}
internal override bool HasSourceLocation => true;
public override ImmutableArray<SyntaxReference> DeclaringSyntaxReferences
{
get
{
SyntaxNode node = _identifierToken.Parent;
#if DEBUG
switch (_declarationKind)
{
case LocalDeclarationKind.RegularVariable:
Debug.Assert(node is VariableDeclaratorSyntax);
break;
case LocalDeclarationKind.Constant:
case LocalDeclarationKind.FixedVariable:
case LocalDeclarationKind.UsingVariable:
Debug.Assert(node is VariableDeclaratorSyntax);
break;
case LocalDeclarationKind.ForEachIterationVariable:
Debug.Assert(node is ForEachStatementSyntax || node is SingleVariableDesignationSyntax);
break;
case LocalDeclarationKind.CatchVariable:
Debug.Assert(node is CatchDeclarationSyntax);
break;
case LocalDeclarationKind.OutVariable:
case LocalDeclarationKind.DeclarationExpressionVariable:
case LocalDeclarationKind.DeconstructionVariable:
case LocalDeclarationKind.PatternVariable:
Debug.Assert(node is SingleVariableDesignationSyntax);
break;
default:
throw ExceptionUtilities.UnexpectedValue(_declarationKind);
}
#endif
return ImmutableArray.Create(node.GetReference());
}
}
internal override bool IsCompilerGenerated
{
get { return false; }
}
internal override ConstantValue GetConstantValue(SyntaxNode node, LocalSymbol inProgress, BindingDiagnosticBag diagnostics)
{
return null;
}
internal override ReadOnlyBindingDiagnostic<AssemblySymbol> GetConstantValueDiagnostics(BoundExpression boundInitValue)
{
return ReadOnlyBindingDiagnostic<AssemblySymbol>.Empty;
}
public override RefKind RefKind
{
get { return _refKind; }
}
public sealed override bool Equals(Symbol obj, TypeCompareKind compareKind)
{
if (obj == (object)this)
{
return true;
}
// If we're comparing against a symbol that was wrapped and updated for nullable,
// delegate to its handling of equality, rather than our own.
if (obj is UpdatedContainingSymbolAndNullableAnnotationLocal updated)
{
return updated.Equals(this, compareKind);
}
return obj is SourceLocalSymbol symbol
&& symbol._identifierToken.Equals(_identifierToken)
&& symbol._containingSymbol.Equals(_containingSymbol, compareKind);
}
public sealed override int GetHashCode()
{
return Hash.Combine(_identifierToken.GetHashCode(), _containingSymbol.GetHashCode());
}
/// <summary>
/// Symbol for a local whose type can be inferred by binding its initializer.
/// </summary>
private sealed class LocalWithInitializer : SourceLocalSymbol
{
private readonly EqualsValueClauseSyntax _initializer;
private readonly Binder _initializerBinder;
/// <summary>
/// Store the constant value and the corresponding diagnostics together
/// to avoid having the former set by one thread and the latter set by
/// another.
/// </summary>
private EvaluatedConstant _constantTuple;
public LocalWithInitializer(
Symbol containingSymbol,
Binder scopeBinder,
TypeSyntax typeSyntax,
SyntaxToken identifierToken,
EqualsValueClauseSyntax initializer,
Binder initializerBinder,
LocalDeclarationKind declarationKind,
bool allowScoped) :
base(containingSymbol, scopeBinder, allowRefKind: true, allowScoped: allowScoped, typeSyntax, identifierToken, declarationKind)
{
Debug.Assert(declarationKind != LocalDeclarationKind.ForEachIterationVariable);
Debug.Assert(initializer != null);
_initializer = initializer;
_initializerBinder = initializerBinder;
if (this.IsConst)
{
_initializerBinder = _initializerBinder.GetBinder(initializer) ?? new LocalInProgressBinder(_initializer, initializerBinder); // for error scenarios
recordConstInBinderChain();
}
void recordConstInBinderChain()
{
for (var binder = _initializerBinder; binder != null; binder = binder.Next)
{
if (binder is LocalInProgressBinder localInProgressBinder && localInProgressBinder.InitializerSyntax == _initializer)
{
localInProgressBinder.SetLocalSymbol(this);
return;
}
}
throw ExceptionUtilities.Unreachable();
}
}
protected override TypeWithAnnotations InferTypeOfVarVariable()
{
BoundExpression initializerOpt = this._initializerBinder.BindInferredVariableInitializer(BindingDiagnosticBag.Discarded, RefKind, _initializer, _initializer);
return TypeWithAnnotations.Create(initializerOpt?.Type);
}
/// <summary>
/// Determine the constant value of this local and the corresponding diagnostics.
/// Set both to constantTuple in a single operation for thread safety.
/// </summary>
/// <param name="inProgress">Null for the initial call, non-null if we are in the process of evaluating a constant.</param>
/// <param name="boundInitValue">If we already have the bound node for the initial value, pass it in to avoid recomputing it.</param>
private void MakeConstantTuple(LocalSymbol inProgress, BoundExpression boundInitValue)
{
if (this.IsConst && _constantTuple == null)
{
var value = Microsoft.CodeAnalysis.ConstantValue.Bad;
var diagnostics = BindingDiagnosticBag.GetInstance();
Debug.Assert(inProgress != this);
var type = this.Type;
if (boundInitValue == null)
{
boundInitValue = this._initializerBinder.BindVariableOrAutoPropInitializerValue(_initializer, this.RefKind, type, diagnostics);
}
value = ConstantValueUtils.GetAndValidateConstantValue(boundInitValue, this, type, _initializer.Value, diagnostics);
Interlocked.CompareExchange(ref _constantTuple, new EvaluatedConstant(value, diagnostics.ToReadOnlyAndFree()), null);
}
}
internal override ConstantValue GetConstantValue(SyntaxNode node, LocalSymbol inProgress, BindingDiagnosticBag diagnostics = null)
{
if (this.IsConst && inProgress == this)
{
if (diagnostics != null)
{
diagnostics.Add(ErrorCode.ERR_CircConstValue, node.GetLocation(), this);
}
return Microsoft.CodeAnalysis.ConstantValue.Bad;
}
MakeConstantTuple(inProgress, boundInitValue: null);
return _constantTuple == null ? null : _constantTuple.Value;
}
internal override ReadOnlyBindingDiagnostic<AssemblySymbol> GetConstantValueDiagnostics(BoundExpression boundInitValue)
{
Debug.Assert(boundInitValue != null);
MakeConstantTuple(inProgress: null, boundInitValue: boundInitValue);
return _constantTuple == null ? ReadOnlyBindingDiagnostic<AssemblySymbol>.Empty : _constantTuple.Diagnostics;
}
}
/// <summary>
/// Symbol for a foreach iteration variable that can be inferred by binding the
/// collection element type of the foreach.
/// </summary>
private sealed class ForEachLocalSymbol : SourceLocalSymbol
{
private readonly ExpressionSyntax _collection;
public ForEachLocalSymbol(
Symbol containingSymbol,
ForEachLoopBinder scopeBinder,
TypeSyntax typeSyntax,
SyntaxToken identifierToken,
ExpressionSyntax collection,
LocalDeclarationKind declarationKind) :
base(containingSymbol, scopeBinder, allowRefKind: true, allowScoped: true, typeSyntax, identifierToken, declarationKind)
{
Debug.Assert(declarationKind == LocalDeclarationKind.ForEachIterationVariable);
_collection = collection;
}
/// <summary>
/// We initialize the base's ScopeBinder with a ForEachLoopBinder, so it is safe
/// to cast it to that type here.
/// </summary>
private ForEachLoopBinder ForEachLoopBinder => (ForEachLoopBinder)ScopeBinder;
protected override TypeWithAnnotations InferTypeOfVarVariable()
{
return ForEachLoopBinder.InferCollectionElementType(BindingDiagnosticBag.Discarded, _collection);
}
}
/// <summary>
/// Symbol for a deconstruction local that might require type inference.
/// For instance, local <c>x</c> in <c>var (x, y) = ...</c> or <c>(var x, int y) = ...</c>.
/// </summary>
private sealed class DeconstructionLocalSymbol : SourceLocalSymbol
{
private readonly SyntaxNode _deconstruction;
private readonly Binder _nodeBinder;
public DeconstructionLocalSymbol(
Symbol containingSymbol,
Binder scopeBinder,
Binder nodeBinder,
TypeSyntax typeSyntax,
SyntaxToken identifierToken,
LocalDeclarationKind declarationKind,
SyntaxNode deconstruction)
: base(containingSymbol, scopeBinder, allowRefKind: false, allowScoped: true, typeSyntax, identifierToken, declarationKind)
{
_deconstruction = deconstruction;
_nodeBinder = nodeBinder;
}
#nullable enable
protected override TypeWithAnnotations InferTypeOfVarVariable()
{
// Try binding enclosing deconstruction-declaration (the top-level VariableDeclaration), this should force the inference.
switch (_deconstruction.Kind())
{
case SyntaxKind.SimpleAssignmentExpression:
var assignment = (AssignmentExpressionSyntax)_deconstruction;
Debug.Assert(assignment.IsDeconstruction());
DeclarationExpressionSyntax? declaration = null;
ExpressionSyntax? expression = null;
_nodeBinder.BindDeconstruction(assignment, assignment.Left, assignment.Right, BindingDiagnosticBag.Discarded, ref declaration, ref expression);
break;
case SyntaxKind.ForEachVariableStatement:
Debug.Assert(this.ScopeBinder.GetBinder((ForEachVariableStatementSyntax)_deconstruction) == _nodeBinder);
_nodeBinder.BindForEachDeconstruction(BindingDiagnosticBag.Discarded, _nodeBinder);
break;
default:
return TypeWithAnnotations.Create(_nodeBinder.CreateErrorType());
}
return _type?.Value ?? default;
}
}
private sealed class LocalSymbolWithEnclosingContext : SourceLocalSymbol
{
private readonly Binder _nodeBinder;
private readonly SyntaxNode _nodeToBind;
public LocalSymbolWithEnclosingContext(
Symbol containingSymbol,
Binder scopeBinder,
Binder nodeBinder,
TypeSyntax? typeSyntax,
SyntaxToken identifierToken,
LocalDeclarationKind declarationKind,
SyntaxNode nodeToBind)
: base(containingSymbol, scopeBinder, allowRefKind: false, allowScoped: true, typeSyntax, identifierToken, declarationKind)
{
Debug.Assert(declarationKind is LocalDeclarationKind.OutVariable or LocalDeclarationKind.PatternVariable);
Debug.Assert(
nodeToBind.Kind() == SyntaxKind.CasePatternSwitchLabel ||
nodeToBind.Kind() == SyntaxKind.ThisConstructorInitializer ||
nodeToBind.Kind() == SyntaxKind.BaseConstructorInitializer ||
nodeToBind.Kind() == SyntaxKind.PrimaryConstructorBaseType || // initializer for a record constructor
nodeToBind.Kind() == SyntaxKind.ArgumentList && (nodeToBind.Parent is ConstructorInitializerSyntax || nodeToBind.Parent is PrimaryConstructorBaseTypeSyntax) ||
nodeToBind.Kind() == SyntaxKind.VariableDeclarator ||
nodeToBind.Kind() == SyntaxKind.SwitchExpressionArm ||
nodeToBind.Kind() == SyntaxKind.GotoCaseStatement ||
nodeToBind is ExpressionSyntax);
Debug.Assert(!(nodeToBind.Kind() == SyntaxKind.SwitchExpressionArm) || nodeBinder is SwitchExpressionArmBinder);
this._nodeBinder = nodeBinder;
this._nodeToBind = nodeToBind;
}
// This type is currently used for out variables and pattern variables.
// Pattern variables do not have a forbidden zone, so we only need to produce
// the diagnostic for out variables here.
protected override ErrorCode ForbiddenDiagnostic => ErrorCode.ERR_ImplicitlyTypedVariableUsedInForbiddenZone;
protected override TypeWithAnnotations InferTypeOfVarVariable()
{
switch (_nodeToBind.Kind())
{
case SyntaxKind.ThisConstructorInitializer:
case SyntaxKind.BaseConstructorInitializer:
var initializer = (ConstructorInitializerSyntax)_nodeToBind;
_nodeBinder.BindConstructorInitializer(initializer, BindingDiagnosticBag.Discarded);
break;
case SyntaxKind.PrimaryConstructorBaseType:
_nodeBinder.BindConstructorInitializer((PrimaryConstructorBaseTypeSyntax)_nodeToBind, BindingDiagnosticBag.Discarded);
break;
case SyntaxKind.ArgumentList:
switch (_nodeToBind.Parent)
{
case ConstructorInitializerSyntax ctorInitializer:
_nodeBinder.BindConstructorInitializer(ctorInitializer, BindingDiagnosticBag.Discarded);
break;
case PrimaryConstructorBaseTypeSyntax ctorInitializer:
_nodeBinder.BindConstructorInitializer(ctorInitializer, BindingDiagnosticBag.Discarded);
break;
default:
throw ExceptionUtilities.UnexpectedValue(_nodeToBind.Parent);
}
break;
case SyntaxKind.CasePatternSwitchLabel:
_nodeBinder.BindPatternSwitchLabelForInference((CasePatternSwitchLabelSyntax)_nodeToBind, BindingDiagnosticBag.Discarded);
break;
case SyntaxKind.VariableDeclarator:
// This occurs, for example, in
// int x, y[out var Z, 1 is int I];
// for (int x, y[out var Z, 1 is int I]; ;) {}
_nodeBinder.BindDeclaratorArguments((VariableDeclaratorSyntax)_nodeToBind, BindingDiagnosticBag.Discarded);
break;
case SyntaxKind.SwitchExpressionArm:
var arm = (SwitchExpressionArmSyntax)_nodeToBind;
var armBinder = (SwitchExpressionArmBinder)_nodeBinder;
armBinder.BindSwitchExpressionArm(arm, BindingDiagnosticBag.Discarded);
break;
case SyntaxKind.GotoCaseStatement:
_nodeBinder.BindStatement((GotoStatementSyntax)_nodeToBind, BindingDiagnosticBag.Discarded);
break;
default:
_nodeBinder.BindExpression((ExpressionSyntax)_nodeToBind, BindingDiagnosticBag.Discarded);
break;
}
if (this._type == null)
{
Debug.Assert(this.DeclarationKind is LocalDeclarationKind.DeclarationExpressionVariable or LocalDeclarationKind.OutVariable);
SetTypeWithAnnotations(TypeWithAnnotations.Create(DeclaringCompilation.ImplicitlyTypedVariableInferenceFailedType));
}
return _type?.Value ?? default;
}
}
}
}
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