Add public API implementation for getting await info from await using and await foreach #80409
Description
Background and Motivation
Followup to #79818; in using the API in the SDK analyzers, we've realized that we also need async info for using declarations (both statement and local decl),
as well as await foreach. This adds APIs for accessing this information.
Proposed API
namespace Microsoft.CodeAnalysis.CSharp
{
public static class CSharpExtensions
{
+ public static AwaitExpressionInfo GetAwaitExpressionInfo(this SemanticModel? semanticModel, LocalDeclarationStatementSyntax awaitExpression);
+ public static AwaitExpressionInfo GetAwaitExpressionInfo(this SemanticModel? semanticModel, UsingStatementSyntax awaitExpression);
}
public class CSharpSemanticModel
{
+ public AwaitExpressionInfo GetAwaitExpressionInfo(LocalDeclarationStatementSyntax awaitExpression);
+ public AwaitExpressionInfo GetAwaitExpressionInfo(UsingStatementSyntax awaitExpression);
}
public struct ForEachStatementInfo
{
+ /// <summary>
+ /// Gets the awaitable info for the <see cref="MoveNextMethod"/> in an asynchronous foreach. <see langword="default"/> if this is a synchronous foreach.
+ /// </summary>
+ public AwaitExpressionInfo MoveNextAwaitableInfo { get; }
+ /// <summary>
+ /// Gets the awaitable info for the <see cref="DisposeMethod"/> in an asynchronous foreach. <see langword="default"/> if this is a synchronous foreach.
+ /// </summary>
+ public AwaitExpressionInfo DisposeAwaitableInfo { get; }
}
}Usage Examples
Await Using Declaration
// Analyze await using declaration
var tree = compilation.SyntaxTrees.First();
var model = compilation.GetSemanticModel(tree);
var awaitUsingDeclaration = tree.GetRoot()
.DescendantNodes()
.OfType<LocalDeclarationStatementSyntax>()
.First(n => n.AwaitKeyword.IsKind(SyntaxKind.AwaitKeyword));
var awaitInfo = model.GetAwaitExpressionInfo(awaitUsingDeclaration);
Console.WriteLine($"GetAwaiter: {awaitInfo.GetAwaiterMethod}");
Console.WriteLine($"IsCompleted: {awaitInfo.IsCompletedProperty}");
Console.WriteLine($"GetResult: {awaitInfo.GetResultMethod}");Await Using Statement
// Analyze await using statement
var awaitUsingStatement = tree.GetRoot()
.DescendantNodes()
.OfType<UsingStatementSyntax>()
.First(n => n.AwaitKeyword.IsKind(SyntaxKind.AwaitKeyword));
var awaitInfo = model.GetAwaitExpressionInfo(awaitUsingStatement);
// Access awaitable information for the dispose operationAwait Foreach
// Analyze await foreach statement
var awaitForeachStatement = tree.GetRoot()
.DescendantNodes()
.OfType<ForEachStatementSyntax>()
.First(n => n.AwaitKeyword.IsKind(SyntaxKind.AwaitKeyword));
var foreachInfo = model.GetForEachStatementInfo(awaitForeachStatement);
// Access awaitable info for MoveNextAsync()
var moveNextAwaitInfo = foreachInfo.MoveNextAwaitableInfo;
Console.WriteLine($"MoveNext GetAwaiter: {moveNextAwaitInfo.GetAwaiterMethod}");
// Access awaitable info for DisposeAsync()
var disposeAwaitInfo = foreachInfo.DisposeAwaitableInfo;
Console.WriteLine($"Dispose GetAwaiter: {disposeAwaitInfo.GetAwaiterMethod}");