From 715ba29b09de4dd99d7ad357913d9e0e152d0da0 Mon Sep 17 00:00:00 2001
From: Andrew Arnott <andarno@microsoft.com>
Date: Sat, 22 Sep 2018 17:57:54 -0700
Subject: [PATCH] Add VSTHRD002 check for ValueTask sync blocking methods

---
 doc/analyzers/VSTHRD002.md                    |  2 +-
 .../VSTHRD002UseJtfRunAnalyzerTests.cs        | 62 ++++++++++++++++++-
 .../CommonInterest.cs                         |  2 +
 3 files changed, 63 insertions(+), 3 deletions(-)

diff --git a/doc/analyzers/VSTHRD002.md b/doc/analyzers/VSTHRD002.md
index 40659f61..676a919b 100644
--- a/doc/analyzers/VSTHRD002.md
+++ b/doc/analyzers/VSTHRD002.md
@@ -1,6 +1,6 @@
 # VSTHRD002 Avoid problematic synchronous waits
 
-Synchronously waiting on `Task` objects or awaiters is dangerous and may cause dead locks.
+Synchronously waiting on `Task`, `ValueTask`, or awaiters is dangerous and may cause dead locks.
 
 ## Examples of patterns that are flagged by this analyzer
 
diff --git a/src/Microsoft.VisualStudio.Threading.Analyzers.Tests/VSTHRD002UseJtfRunAnalyzerTests.cs b/src/Microsoft.VisualStudio.Threading.Analyzers.Tests/VSTHRD002UseJtfRunAnalyzerTests.cs
index 373646cb..ecd54294 100644
--- a/src/Microsoft.VisualStudio.Threading.Analyzers.Tests/VSTHRD002UseJtfRunAnalyzerTests.cs
+++ b/src/Microsoft.VisualStudio.Threading.Analyzers.Tests/VSTHRD002UseJtfRunAnalyzerTests.cs
@@ -61,7 +61,7 @@ class Test {
         }
 
         [Fact]
-        public async Task TaskResultShouldReportWarning()
+        public async Task Task_Result_ShouldReportWarning()
         {
             var test = @"
 using System;
@@ -89,6 +89,35 @@ class Test {
             await Verify.VerifyCodeFixAsync(test, expected, withFix);
         }
 
+        [Fact]
+        public async Task ValueTask_Result_ShouldReportWarning()
+        {
+            var test = @"
+using System;
+using System.Threading.Tasks;
+
+class Test {
+    void F() {
+        ValueTask<int> task = default;
+        var result = task.Result;
+    }
+}
+";
+            var withFix = @"
+using System;
+using System.Threading.Tasks;
+
+class Test {
+    async Task FAsync() {
+        ValueTask<int> task = default;
+        var result = await task;
+    }
+}
+";
+            var expected = Verify.Diagnostic().WithSpan(8, 27, 8, 33);
+            await Verify.VerifyCodeFixAsync(test, expected, withFix);
+        }
+
         [Fact]
         public async Task TaskResultShouldReportWarning_WithinAnonymousDelegate()
         {
@@ -142,7 +171,7 @@ class Test {
         }
 
         [Fact]
-        public async Task AwaiterGetResultShouldReportWarning()
+        public async Task Task_GetAwaiter_GetResult_ShouldReportWarning()
         {
             var test = @"
 using System;
@@ -170,6 +199,35 @@ class Test {
             await Verify.VerifyCodeFixAsync(test, expected, withFix);
         }
 
+        [Fact]
+        public async Task ValueTask_GetAwaiter_GetResult_ShouldReportWarning()
+        {
+            var test = @"
+using System;
+using System.Threading.Tasks;
+
+class Test {
+    void F() {
+        ValueTask task = default;
+        task.GetAwaiter().GetResult();
+    }
+}
+";
+            var withFix = @"
+using System;
+using System.Threading.Tasks;
+
+class Test {
+    async Task FAsync() {
+        ValueTask task = default;
+        await task;
+    }
+}
+";
+            var expected = Verify.Diagnostic().WithSpan(8, 27, 8, 36);
+            await Verify.VerifyCodeFixAsync(test, expected, withFix);
+        }
+
         [Fact]
         public async Task TaskResult_FixUpdatesCallers()
         {
diff --git a/src/Microsoft.VisualStudio.Threading.Analyzers/CommonInterest.cs b/src/Microsoft.VisualStudio.Threading.Analyzers/CommonInterest.cs
index 5d56cf8d..99f255fc 100644
--- a/src/Microsoft.VisualStudio.Threading.Analyzers/CommonInterest.cs
+++ b/src/Microsoft.VisualStudio.Threading.Analyzers/CommonInterest.cs
@@ -32,6 +32,7 @@ namespace Microsoft.VisualStudio.Threading.Analyzers
         {
             new SyncBlockingMethod(new QualifiedMember(new QualifiedType(Namespaces.SystemThreadingTasks, nameof(Task)), nameof(Task.Wait)), null),
             new SyncBlockingMethod(new QualifiedMember(new QualifiedType(Namespaces.SystemRuntimeCompilerServices, nameof(TaskAwaiter)), nameof(TaskAwaiter.GetResult)), null),
+            new SyncBlockingMethod(new QualifiedMember(new QualifiedType(Namespaces.SystemRuntimeCompilerServices, nameof(ValueTaskAwaiter)), nameof(ValueTaskAwaiter.GetResult)), null),
         };
 
         internal static readonly IEnumerable<SyncBlockingMethod> SyncBlockingMethods = JTFSyncBlockers.Concat(ProblematicSyncBlockingMethods).Concat(new[]
@@ -55,6 +56,7 @@ namespace Microsoft.VisualStudio.Threading.Analyzers
         internal static readonly IReadOnlyList<SyncBlockingMethod> SyncBlockingProperties = new[]
         {
             new SyncBlockingMethod(new QualifiedMember(new QualifiedType(Namespaces.SystemThreadingTasks, nameof(Task)), nameof(Task<int>.Result)), null),
+            new SyncBlockingMethod(new QualifiedMember(new QualifiedType(Namespaces.SystemThreadingTasks, nameof(ValueTask)), nameof(ValueTask<int>.Result)), null),
         };
 
         internal static readonly IEnumerable<QualifiedMember> ThreadAffinityTestingMethods = new[]