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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.Generic;
using System.Linq;
using System.Threading;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.Extensions.ContextQuery;
using Microsoft.CodeAnalysis.CSharp.LanguageService;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.CSharp.Utilities;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Operations;
using Microsoft.CodeAnalysis.Shared.Extensions;
using Roslyn.Utilities;
namespace Microsoft.CodeAnalysis.CSharp;
internal sealed partial class CSharpSemanticFactsService : AbstractSemanticFactsService, ISemanticFactsService
{
internal static readonly CSharpSemanticFactsService Instance = new();
public override ISyntaxFacts SyntaxFacts => CSharpSyntaxFacts.Instance;
public override IBlockFacts BlockFacts => CSharpBlockFacts.Instance;
protected override ISemanticFacts SemanticFacts => CSharpSemanticFacts.Instance;
private CSharpSemanticFactsService()
{
}
protected override SyntaxToken ToIdentifierToken(string identifier)
=> identifier.ToIdentifierToken();
protected override IEnumerable<ISymbol> GetCollidableSymbols(SemanticModel semanticModel, SyntaxNode location, SyntaxNode container, CancellationToken cancellationToken)
{
// Get all the symbols visible to the current location.
var visibleSymbols = semanticModel.LookupSymbols(location.SpanStart);
// Local function parameter is allowed to shadow variables since C# 8.
if (semanticModel.Compilation.LanguageVersion().MapSpecifiedToEffectiveVersion() >= LanguageVersion.CSharp8)
{
if (SyntaxFacts.IsParameterList(container) && SyntaxFacts.IsLocalFunctionStatement(container.Parent))
{
visibleSymbols = visibleSymbols.WhereAsArray(s => !s.MatchesKind(SymbolKind.Local, SymbolKind.Parameter));
}
}
// Some symbols in the enclosing block could cause conflicts even if they are not available at the location.
// E.g. symbols inside if statements / try catch statements.
var symbolsInBlock = semanticModel.GetExistingSymbols(container, cancellationToken,
descendInto: n => ShouldDescendInto(n));
return symbolsInBlock.Concat(visibleSymbols);
// Walk through the enclosing block symbols, but avoid exploring local functions
// a) Visible symbols from the local function would be returned by LookupSymbols
// (e.g. location is inside a local function, the local function method name).
// b) Symbols declared inside the local function do not cause collisions with symbols declared outside them, so avoid considering those symbols.
// Exclude lambdas as well when the language version is C# 8 or higher because symbols declared inside no longer collide with outer variables.
bool ShouldDescendInto(SyntaxNode node)
{
var isLanguageVersionGreaterOrEqualToCSharp8 = (semanticModel.Compilation as CSharpCompilation)?.LanguageVersion >= LanguageVersion.CSharp8;
return isLanguageVersionGreaterOrEqualToCSharp8 ? !SyntaxFacts.IsAnonymousOrLocalFunction(node) : !SyntaxFacts.IsLocalFunctionStatement(node);
}
}
public bool IsExpressionContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
{
return semanticModel.SyntaxTree.IsExpressionContext(
position,
semanticModel.SyntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken),
attributes: true, cancellationToken: cancellationToken, semanticModel: semanticModel);
}
public bool IsStatementContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
{
return semanticModel.SyntaxTree.IsStatementContext(
position, semanticModel.SyntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken), cancellationToken);
}
public bool IsTypeContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
=> semanticModel.SyntaxTree.IsTypeContext(position, cancellationToken, semanticModel);
public bool IsNamespaceContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
=> semanticModel.SyntaxTree.IsNamespaceContext(position, cancellationToken, semanticModel);
public bool IsNamespaceDeclarationNameContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
=> semanticModel.SyntaxTree.IsNamespaceDeclarationNameContext(position, cancellationToken);
public bool IsTypeDeclarationContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
{
return semanticModel.SyntaxTree.IsTypeDeclarationContext(
position, semanticModel.SyntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken), cancellationToken);
}
public bool IsMemberDeclarationContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
{
return semanticModel.SyntaxTree.IsMemberDeclarationContext(
position, semanticModel.SyntaxTree.FindTokenOnLeftOfPosition(position, cancellationToken));
}
public bool IsGlobalStatementContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
=> semanticModel.SyntaxTree.IsGlobalStatementContext(position, cancellationToken);
public bool IsLabelContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
=> semanticModel.SyntaxTree.IsLabelContext(position, cancellationToken);
public bool IsAttributeNameContext(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
=> semanticModel.SyntaxTree.IsAttributeNameContext(position, cancellationToken);
public CommonConversion ClassifyConversion(SemanticModel semanticModel, SyntaxNode expression, ITypeSymbol destination)
=> semanticModel.ClassifyConversion((ExpressionSyntax)expression, destination).ToCommonConversion();
#nullable enable
public IMethodSymbol? TryGetDisposeMethod(SemanticModel semanticModel, SyntaxNode node, CancellationToken cancellationToken)
{
var isAsync = false;
ExpressionSyntax? expression = null;
if (node is UsingStatementSyntax usingStatement)
{
isAsync = usingStatement.AwaitKeyword != default;
expression = usingStatement is { Declaration.Variables: [{ Initializer.Value: { } value }] } ? value : usingStatement.Expression;
}
else if (node is LocalDeclarationStatementSyntax { Declaration.Variables: [{ Initializer.Value: { } value }] } localDeclaration)
{
isAsync = localDeclaration.AwaitKeyword != default;
expression = value;
}
if (expression is null)
return null;
var type = semanticModel.GetTypeInfo(expression, cancellationToken).Type;
return FindDisposeMethod(semanticModel.Compilation, type, isAsync);
}
}
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