src/Workspaces/SharedUtilitiesAndExtensions/Workspace/CSharp/LanguageServices/CSharpSemanticFactsService.cs - main - githubmirror/roslyn

src/Workspaces/SharedUtilitiesAndExtensions/Workspace/CSharp/LanguageServices/CSharpSemanticFactsService.cs
133 строки7 KB
Cyrus Najmabadi
initial move
08 дек 2025, 13:42
08 дек 2025, 13:421d11d0c
// 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.Linq;
using System.Threading;
using Microsoft.CodeAnalysis.CSharp.Extensions;
using Microsoft.CodeAnalysis.CSharp.Extensions.ContextQuery;
using Microsoft.CodeAnalysis.CSharp.LanguageService;
using Microsoft.CodeAnalysis.CSharp.Syntax;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.CodeAnalysis.Operations;
using Microsoft.CodeAnalysis.Shared.Extensions;

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.
        // Similarly, a nested primary constructor parameter list can shadow outer parameters in outer types.
        var languageVersion = semanticModel.Compilation.LanguageVersion().MapSpecifiedToEffectiveVersion();
        var isLanguageVersionGreaterOrEqualToCSharp8 = languageVersion >= LanguageVersion.CSharp8;
        if (isLanguageVersionGreaterOrEqualToCSharp8 &&
            SyntaxFacts.IsParameterList(container))
        {
            if (container.Parent is LocalFunctionStatementSyntax or TypeDeclarationSyntax)
                visibleSymbols = visibleSymbols.WhereAsArray(s => s is not ILocalSymbol and not IParameterSymbol);
        }

        // 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.GetAllDeclaredSymbols(container, cancellationToken, descendInto: ShouldDescendInto);

        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)
            => 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);

#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);
    }
}