VB: Bug fixes for Async methods.

***NO_CI***
 (changeset 1365691)

Src/Compilers/VisualBasic/Portable/Compilation/MethodCompiler.vb

@@ -857,27 +857,29 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End If
 
             For Each methodWithBody In compilationState.SynthesizedMethods
-                Dim method = methodWithBody.Method
-                Dim diagnosticsThisMethod As DiagnosticBag = DiagnosticBag.GetInstance()
+                If Not methodWithBody.Body.HasErrors Then
+                    Dim method = methodWithBody.Method
+                    Dim diagnosticsThisMethod As DiagnosticBag = DiagnosticBag.GetInstance()
+
+                    Dim emittedBody = GenerateMethodBody(_moduleBeingBuiltOpt,
+                                                         method,
+                                                         methodWithBody.Body,
+                                                         stateMachineTypeOpt:=Nothing,
+                                                         variableSlotAllocatorOpt:=Nothing,
+                                                         debugDocumentProvider:=_debugDocumentProvider,
+                                                         diagnostics:=diagnosticsThisMethod,
+                                                         namespaceScopes:=GetNamespaceScopes(methodWithBody.Method))
 
-                Dim emittedBody = GenerateMethodBody(_moduleBeingBuiltOpt,
-                                                     method,
-                                                     methodWithBody.Body,
-                                                     stateMachineTypeOpt:=Nothing,
-                                                     variableSlotAllocatorOpt:=Nothing,
-                                                     debugDocumentProvider:=_debugDocumentProvider,
-                                                     diagnostics:=diagnosticsThisMethod,
-                                                     namespaceScopes:=GetNamespaceScopes(methodWithBody.Method))
+                    _diagnostics.AddRange(diagnosticsThisMethod)
+                    diagnosticsThisMethod.Free()
 
-                _diagnostics.AddRange(diagnosticsThisMethod)
-                diagnosticsThisMethod.Free()
+                    ' error while generating IL
+                    If emittedBody Is Nothing Then
+                        Exit For
+                    End If
 
-                ' error while generating IL
-                If emittedBody Is Nothing Then
-                    Exit For
+                    _moduleBeingBuiltOpt.SetMethodBody(method, emittedBody)
                 End If
-
-                _moduleBeingBuiltOpt.SetMethodBody(method, emittedBody)
             Next
         End Sub
 

Src/Compilers/VisualBasic/Portable/Lowering/AsyncRewriter/AsyncRewriter.AsyncMethodToClassRewriter.Spilling.vb

@@ -233,7 +233,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Function
 
             Private Function SpillValue(expr As BoundExpression, isReceiver As Boolean, <[In], Out> ByRef builder As SpillBuilder) As BoundExpression
-                If Unspillable(expr) OrElse expr.Kind = BoundKind.FieldAccess AndAlso Unspillable(DirectCast(expr, BoundFieldAccess).ReceiverOpt) Then
+                If Unspillable(expr) Then
                     Return expr
 
                 ElseIf isReceiver OrElse expr.IsLValue Then

Src/Compilers/VisualBasic/Portable/Lowering/SyntheticBoundNodeFactory.vb

@@ -978,7 +978,10 @@ nextm:
         End Function
 
         Public Function [Catch](local As LocalSymbol, block As BoundBlock) As BoundCatchBlock
-            Return New BoundCatchBlock(Syntax, local, Me.Local(local, False), Nothing, Nothing, block)
+            Dim m1 = WellKnownMember(Of MethodSymbol)(Microsoft.CodeAnalysis.WellKnownMember.Microsoft_VisualBasic_CompilerServices_ProjectData__SetProjectError)
+            Dim m2 = WellKnownMember(Of MethodSymbol)(Microsoft.CodeAnalysis.WellKnownMember.Microsoft_VisualBasic_CompilerServices_ProjectData__ClearProjectError)
+            Return New BoundCatchBlock(Syntax, local, Me.Local(local, False), Nothing, Nothing, block,
+                                       hasErrors:=m1 Is Nothing OrElse m2 Is Nothing)
         End Function
 
         Public Function SequencePoint(syntax As VisualBasicSyntaxNode, statement As BoundStatement) As BoundStatement

Src/Compilers/VisualBasic/Test/Semantic/Semantics/AsyncAwait.vb

@@ -5479,5 +5479,109 @@ End Class
 
             CompileAndVerify(compilation, expectedOutput:="")
         End Sub
+
+        <Fact(), WorkItem(1066694, "DevDiv")>
+        Public Sub Bug1066694()
+            Dim source =
+<compilation>
+    <file name="a.vb">
+        <![CDATA[
+Imports System
+Imports System.Threading.Tasks
+
+Module Module1
+    Sub Main()
+        System.Console.WriteLine("Non-Async")
+        System.Console.WriteLine()
+        TestLocal()
+        System.Console.WriteLine()
+        System.Console.WriteLine("Async")
+        System.Console.WriteLine()
+        Task.WaitAll(TestLocalAsync())
+    End Sub
+    Sub TestLocal()
+        Dim l = New TestClass("Unchanged")
+        l.M1(l, Mutate(l))
+        System.Console.WriteLine(l.State)
+    End Sub
+
+    Async Function DummyAsync(x As Object) As Task(Of Object)
+        Return x
+    End Function
+    Async Function TestLocalAsync() As Task
+        Dim l = New TestClass("Unchanged")
+        l.M1(l, Await DummyAsync(Mutate(l)))
+        System.Console.WriteLine(l.State)
+    End Function
+    Function Mutate(ByRef x As TestClass) As Object
+        x = New TestClass("Changed")
+        Return x
+    End Function
+End Module
+Class TestClass
+    Private ReadOnly fld1 As String
+    Sub New(val As String)
+        fld1 = val
+    End Sub
+    Function State() As String
+        Return fld1
+    End Function
+    Sub M1(arg1 As TestClass, arg2 As Object)
+        System.Console.WriteLine(Me.State)
+        System.Console.WriteLine(arg1.State)
+    End Sub
+End Class
+]]>
+    </file>
+</compilation>
+
+            Dim compilation = CreateCompilationWithReferences(source, {MscorlibRef_v4_0_30316_17626, MsvbRef_v4_0_30319_17929}, TestOptions.ReleaseExe)
+
+            CompileAndVerify(compilation, expectedOutput:=
+            <![CDATA[
+Non-Async
+
+Unchanged
+Unchanged
+Changed
+
+Async
+
+Unchanged
+Unchanged
+Changed
+]]>)
+        End Sub
+
+        <Fact(), WorkItem(1068084, "DevDiv")>
+        Public Sub Bug1068084()
+            Dim source =
+<compilation>
+    <file name="a.vb">
+        <![CDATA[
+Imports System.Threading.Tasks
+ 
+Class Test
+    Async Sub F()
+        Await Task.Delay(0)
+    End Sub
+End Class
+]]>
+    </file>
+</compilation>
+
+            Dim compilation = CreateCompilationWithReferences(source, {MscorlibRef_v4_0_30316_17626}, TestOptions.ReleaseDll)
+
+            AssertTheseEmitDiagnostics(compilation,
+<expected>
+BC35000: Requested operation is not available because the runtime library function 'Microsoft.VisualBasic.CompilerServices.ProjectData.ClearProjectError' is not defined.
+    Async Sub F()
+    ~~~~~~~~~~~~~~
+BC35000: Requested operation is not available because the runtime library function 'Microsoft.VisualBasic.CompilerServices.ProjectData.SetProjectError' is not defined.
+    Async Sub F()
+    ~~~~~~~~~~~~~~
+</expected>)
+        End Sub
+
     End Class
 End Namespace