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Merged
AlekseyTs merged 1 commit into from
Mar 17, 2020
Merged

Support await using/foreach statements in a Simple Program. #42485

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17 changes: 13 additions & 4 deletions src/Compilers/CSharp/Portable/Syntax/SyntaxFacts.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -492,8 +492,6 @@ internal static bool HasAnyBody(this BaseMethodDeclarationSyntax declaration)
return (declaration.Body ?? (SyntaxNode?)declaration.ExpressionBody) != null;
}

#nullable enable

internal static bool IsTopLevelStatement([NotNullWhen(true)] GlobalStatementSyntax? syntax)
{
return syntax?.Parent?.IsKind(SyntaxKind.CompilationUnit) == true;
Expand All @@ -507,8 +505,19 @@ internal static bool IsSimpleProgramTopLevelStatement(GlobalStatementSyntax? syn
internal static bool HasAwaitOperations(SyntaxNode node)
{
// Do not descend into functions
return node.DescendantNodesAndSelf(child => !IsNestedFunction(child)).
OfType<AwaitExpressionSyntax>().Any(); // PROTOTYPE(SimplePrograms): Recognize other async operations.
return node.DescendantNodesAndSelf(child => !IsNestedFunction(child)).Any(node =>
{
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@jcouv jcouv Mar 17, 2020

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nit: the indentation is really unfortunate for reviewing on github.

switch (node)
{
case AwaitExpressionSyntax _:
case LocalDeclarationStatementSyntax local when local.AwaitKeyword.IsKind(SyntaxKind.AwaitKeyword):
case CommonForEachStatementSyntax @foreach when @foreach.AwaitKeyword.IsKind(SyntaxKind.AwaitKeyword):
case UsingStatementSyntax @using when @using.AwaitKeyword.IsKind(SyntaxKind.AwaitKeyword):
return true;
default:
return false;
}
});
}

internal static bool IsNestedFunction(SyntaxNode child)
Expand Down
122 changes: 122 additions & 0 deletions src/Compilers/CSharp/Test/Semantic/Semantics/SimpleProgramsTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -747,6 +747,128 @@ public void Dispose()
CompileAndVerify(comp, expectedOutput: "12", verify: Verification.Skipped);
}

[Fact]
public void LocalDeclarationStatement_10()
{
string source = @"
await using var x = new C();
System.Console.Write(""body "");

class C : System.IAsyncDisposable, System.IDisposable
{
public System.Threading.Tasks.ValueTask DisposeAsync()
{
System.Console.Write(""DisposeAsync"");
return new System.Threading.Tasks.ValueTask(System.Threading.Tasks.Task.CompletedTask);
}
public void Dispose()
{
System.Console.Write(""IGNORED"");
}
}
";
var comp = CreateCompilationWithTasksExtensions(new[] { source, IAsyncDisposableDefinition }, options: TestOptions.DebugExe, parseOptions: DefaultParseOptions);
comp.VerifyDiagnostics();
CompileAndVerify(comp, expectedOutput: "body DisposeAsync");
}

[Fact]
public void UsingStatement_01()
{
string source = @"
await using (var x = new C())
{
System.Console.Write(""body "");
}

class C : System.IAsyncDisposable, System.IDisposable
{
public System.Threading.Tasks.ValueTask DisposeAsync()
{
System.Console.Write(""DisposeAsync"");
return new System.Threading.Tasks.ValueTask(System.Threading.Tasks.Task.CompletedTask);
}
public void Dispose()
{
System.Console.Write(""IGNORED"");
}
}
";
var comp = CreateCompilationWithTasksExtensions(new[] { source, IAsyncDisposableDefinition }, options: TestOptions.DebugExe, parseOptions: DefaultParseOptions);
comp.VerifyDiagnostics();
CompileAndVerify(comp, expectedOutput: "body DisposeAsync");
}

[Fact]
public void UsingStatement_02()
{
string source = @"
await using (new C())
{
System.Console.Write(""body "");
}

class C : System.IAsyncDisposable, System.IDisposable
{
public System.Threading.Tasks.ValueTask DisposeAsync()
{
System.Console.Write(""DisposeAsync"");
return new System.Threading.Tasks.ValueTask(System.Threading.Tasks.Task.CompletedTask);
}
public void Dispose()
{
System.Console.Write(""IGNORED"");
}
}
";
var comp = CreateCompilationWithTasksExtensions(new[] { source, IAsyncDisposableDefinition }, options: TestOptions.DebugExe, parseOptions: DefaultParseOptions);
comp.VerifyDiagnostics();
CompileAndVerify(comp, expectedOutput: "body DisposeAsync");
}

[Fact]
public void ForeachStatement_01()
{
string source = @"
using System.Threading.Tasks;

await foreach (var i in new C())
{
}

System.Console.Write(""Done"");

class C
{
public Enumerator GetAsyncEnumerator()
{
return new Enumerator();
}
public sealed class Enumerator
{
public async Task<bool> MoveNextAsync()
{
System.Console.Write(""MoveNextAsync "");
await Task.Yield();
return false;
}
public int Current
{
get => throw null;
}
public async Task DisposeAsync()
{
System.Console.Write(""DisposeAsync "");
await Task.Yield();
}
}
}
";
var comp = CreateCompilationWithTasksExtensions(new[] { source, s_IAsyncEnumerable }, options: TestOptions.DebugExe, parseOptions: DefaultParseOptions);
comp.VerifyDiagnostics();
CompileAndVerify(comp, expectedOutput: "MoveNextAsync DisposeAsync Done");
}

[Fact]
public void LocalUsedBeforeDeclaration_01()
{
Expand Down