Report spill local await boundary errors at their declaration

dotnet · Apr 8, 2024 · b4cc4b5 · b4cc4b5
1 parent 1804c58
commit b4cc4b5
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Showing 5 changed files with 32 additions and 36 deletions.
diff --git a/src/Compilers/CSharp/Portable/Lowering/StateMachineRewriter/IteratorAndAsyncCaptureWalker.cs b/src/Compilers/CSharp/Portable/Lowering/StateMachineRewriter/IteratorAndAsyncCaptureWalker.cs
@@ -79,15 +79,18 @@ public static OrderedSet<Symbol> Analyze(CSharpCompilation compilation, MethodSy
 
                     if (variable is LocalSymbol local)
                     {
-                        if (local.SynthesizedKind is SynthesizedLocalKind.Spill)
-                        {
-                            reportLocalAcrossAwaitError(diagnostics, local, local.GetFirstLocation());
-                        }
-                        else
+                        foreach (var syntax in kvp.Value)
                         {
-                            foreach (var syntax in kvp.Value)
+                            if (local.TypeWithAnnotations.IsRestrictedType())
                             {
-                                reportLocalAcrossAwaitError(diagnostics, local, syntax.Location);
+                                // CS4007: Instance of type '{0}' cannot be preserved across 'await' or 'yield' boundary.
+                                diagnostics.Add(ErrorCode.ERR_ByRefTypeAndAwait, syntax.Location, local.TypeWithAnnotations);
+                            }
+                            else
+                            {
+                                Debug.Assert(local.RefKind != RefKind.None);
+                                // CS9217: A 'ref' local cannot be preserved across 'await' or 'yield' boundary.
+                                diagnostics.Add(ErrorCode.ERR_RefLocalAcrossAwait, syntax.Location);
                             }
                         }
                     }
@@ -128,21 +131,6 @@ public static OrderedSet<Symbol> Analyze(CSharpCompilation compilation, MethodSy
             walker.Free();
 
             return variablesToHoist;
-
-            static void reportLocalAcrossAwaitError(DiagnosticBag diagnostics, LocalSymbol local, Location location)
-            {
-                if (local.TypeWithAnnotations.IsRestrictedType())
-                {
-                    // CS4007: Instance of type '{0}' cannot be preserved across 'await' or 'yield' boundary.
-                    diagnostics.Add(ErrorCode.ERR_ByRefTypeAndAwait, location, local.TypeWithAnnotations);
-                }
-                else
-                {
-                    Debug.Assert(local.RefKind != RefKind.None);
-                    // CS9217: A 'ref' local cannot be preserved across 'await' or 'yield' boundary.
-                    diagnostics.Add(ErrorCode.ERR_RefLocalAcrossAwait, location);
-                }
-            }
         }
 
         private static bool HoistInDebugBuild(Symbol symbol)

diff --git a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenAsyncSpillTests.cs b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenAsyncSpillTests.cs
@@ -3789,9 +3789,11 @@ static async Task Main()
                 var comp = CreateCompilationWithMscorlibAndSpan(source, options: options);
                 comp.VerifyDiagnostics();
                 comp.VerifyEmitDiagnostics(
-                    // (9,66): error CS4007: Instance of type 'System.Span<int>' cannot be preserved across 'await' or 'yield' boundary.
-                    //         await Async1(F1(), G(F2(), stackalloc int[] { 1, 2, 3 }, await F3()));
-                    Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "await F3()").WithArguments("System.Span<int>").WithLocation(9, 66)
+                    // (8,5): error CS4007: Instance of type 'System.Span<int>' cannot be preserved across 'await' or 'yield' boundary.
+                    //     {
+                    Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, @"{
+        await Async1(F1(), G(F2(), stackalloc int[] { 1, 2, 3 }, await F3()));
+    }").WithArguments("System.Span<int>").WithLocation(8, 5)
                     );
             }
         }

diff --git a/src/Compilers/CSharp/Test/Emit2/Semantics/InlineArrayTests.cs b/src/Compilers/CSharp/Test/Emit2/Semantics/InlineArrayTests.cs
@@ -4691,9 +4691,12 @@ static async Task<T> FromResult<T>(T r)
 ";
             var comp = CreateCompilation(src + Buffer10Definition, targetFramework: TargetFramework.Net80, options: TestOptions.ReleaseExe);
             comp.VerifyEmitDiagnostics(
-                // (24,22): error CS4007: Instance of type 'System.ReadOnlySpan<Buffer10<int>>' cannot be preserved across 'await' or 'yield' boundary.
-                //            [Get01()][await FromResult(Get02(x))];
-                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "await FromResult(Get02(x))").WithArguments("System.ReadOnlySpan<Buffer10<int>>").WithLocation(24, 22)
+                // (20,12): error CS4007: Instance of type 'System.ReadOnlySpan<Buffer10<int>>' cannot be preserved across 'await' or 'yield' boundary.
+                //         => MemoryMarshal.CreateReadOnlySpan(
+                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, @"MemoryMarshal.CreateReadOnlySpan(
+                ref Unsafe.As<Buffer10<Buffer10<int>>, Buffer10<int>>(
+                        ref Unsafe.AsRef(in GetC(x).F)),
+                10)").WithArguments("System.ReadOnlySpan<Buffer10<int>>").WithLocation(20, 12)
                 );
         }
 
@@ -4743,9 +4746,12 @@ static async Task<T> FromResult<T>(T r)
 ";
             var comp = CreateCompilation(src + Buffer10Definition, targetFramework: TargetFramework.Net80, options: TestOptions.ReleaseExe);
             comp.VerifyEmitDiagnostics(
-                // (24,13): error CS4007: Instance of type 'System.ReadOnlySpan<int>' cannot be preserved across 'await' or 'yield' boundary.
-                //            [await FromResult(Get02(x))];
-                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "await FromResult(Get02(x))").WithArguments("System.ReadOnlySpan<int>").WithLocation(24, 13)
+                // (20,12): error CS4007: Instance of type 'System.ReadOnlySpan<int>' cannot be preserved across 'await' or 'yield' boundary.
+                //         => MemoryMarshal.CreateReadOnlySpan(
+                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, @"MemoryMarshal.CreateReadOnlySpan(
+                ref Unsafe.As<Buffer10<int>, int>(
+                        ref Unsafe.AsRef(in GetC(x).F[Get01()])),
+                10)").WithArguments("System.ReadOnlySpan<int>").WithLocation(20, 12)
                 );
         }
 

diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/AwaitExpressionTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/AwaitExpressionTests.cs
@@ -243,7 +243,7 @@ static async Task Goo()
             comp.VerifyEmitDiagnostics(
                 // (8,27): error CS4007: Instance of type 'System.TypedReference' cannot be preserved across 'await' or 'yield' boundary.
                 //         Console.WriteLine(new TypedReference().Equals(await Task.FromResult(0)));
-                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "await Task.FromResult(0)").WithArguments("System.TypedReference").WithLocation(8, 55));
+                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "new TypedReference()").WithArguments("System.TypedReference").WithLocation(8, 27));
         }
 
         [Fact]

diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/SpanStackSafetyTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/SpanStackSafetyTests.cs
@@ -1418,9 +1418,9 @@ public static async Task<int> I1()
 
             var expectedDiagnostics = new[]
             {
-                // (17,39): error CS4007: Instance of type 'System.Span<int>' cannot be preserved across 'await' or 'yield' boundary.
+                // (17,19): error CS4007: Instance of type 'System.Span<int>' cannot be preserved across 'await' or 'yield' boundary.
                 //         TakesSpan(default(Span<int>), await I1());
-                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "await I1()").WithArguments("System.Span<int>").WithLocation(17, 39)
+                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "default(Span<int>)").WithArguments("System.Span<int>").WithLocation(17, 19)
             };
 
             comp.VerifyEmitDiagnostics(expectedDiagnostics);
@@ -1468,9 +1468,9 @@ public static async Task<int> I1()
 
             var expectedDiagnostics = new[]
             {
-                // (14,45): error CS4007: Instance of type 'System.Span<int>' cannot be preserved across 'await' or 'yield' boundary.
+                // (14,22): error CS4007: Instance of type 'System.Span<int>' cannot be preserved across 'await' or 'yield' boundary.
                 //         TakesSpan(s: default(Span<int>), i: await I1());
-                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "await I1()").WithArguments("System.Span<int>").WithLocation(14, 45)
+                Diagnostic(ErrorCode.ERR_ByRefTypeAndAwait, "default(Span<int>)").WithArguments("System.Span<int>").WithLocation(14, 22)
             };
 
             comp.VerifyEmitDiagnostics(expectedDiagnostics);