allow use of a byref parameter inside of nameof (#16596)

* allow use of a byref parameter inside of nameof

* remove random whitespace changes

* add handling for linq queries

* And -> AndAlso

* change name of linq query

* add linq assembly ref

src/Compilers/VisualBasic/Portable/Lowering/Diagnostics/DiagnosticsPass.vb

@@ -22,6 +22,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
         Private _containingSymbol As MethodSymbol
         Private _withExpressionPlaceholderMap As Dictionary(Of BoundValuePlaceholderBase, BoundWithStatement)
         Private _expressionsBeingVisited As Stack(Of BoundExpression)
+        Private _insideNameof As Boolean = False
 
         Private _inExpressionLambda As Boolean
 
@@ -66,7 +67,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
                 ' cannot access ByRef parameters in Lambdas
                 Dim parameterSymbolContainingSymbol As Symbol = parameterSymbol.ContainingSymbol
 
-                If _containingSymbol IsNot parameterSymbolContainingSymbol Then
+                If _containingSymbol IsNot parameterSymbolContainingSymbol AndAlso Not _insideNameof Then
                     ' Need to go up the chain of containers and see if the last lambda we see
                     ' is a QueryLambda, before we reach parameter's container. 
                     If Binder.IsTopMostEnclosingLambdaAQueryLambda(_containingSymbol, parameterSymbolContainingSymbol) Then
@@ -183,6 +184,13 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             Return Nothing
         End Function
 
+        Public Overrides Function VisitNameOfOperator(node As BoundNameOfOperator) As BoundNode
+            _insideNameof = True
+            Dim r = MyBase.VisitNameOfOperator(node)
+            _insideNameof = False
+            Return r
+        End Function
+
         Public Overrides Function Visit(node As BoundNode) As BoundNode
             Dim pop As Boolean = False
 

src/Compilers/VisualBasic/Test/Semantic/Semantics/NameOfTests.vb

@@ -3544,5 +3544,51 @@ TP
 ]]>).VerifyDiagnostics()
         End Sub
 
+        <Fact, WorkItem(10839, "https://github.com/dotnet/roslyn/issues/10839")>
+        Public Sub NameOfByRefInLambda()
+            Dim compilationDef =
+                <compilation>
+                    <file name="a.vb">
+Module Program
+    Sub DoSomething(ByRef x As Integer)
+        Dim f = Function()
+                    Return NameOf(x)
+                End Function
+        System.Console.WriteLine(f())
+    End Sub
+    Sub Main()
+        Dim x =  5
+        DoSomething(x)
+    End Sub
+End Module
+                </file>
+                </compilation>
+            Dim comp = CreateCompilationWithMscorlibAndVBRuntime(compilationDef, TestOptions.DebugExe)
+            CompileAndVerify(comp, expectedOutput:="x").VerifyDiagnostics()
+        End Sub
+
+        <Fact, WorkItem(10839, "https://github.com/dotnet/roslyn/issues/10839")>
+        Public Sub NameOfByRefInQuery()
+            Dim compilationDef =
+                <compilation>
+                    <file name="a.vb">
+Imports System.Linq
+
+Module Program
+    Sub DoSomething(ByRef x As Integer)
+        Dim f = from y in {1, 2, 3}
+                select nameof(x)
+        System.Console.WriteLine(f.Aggregate("", Function(a, b) a + b))
+    End Sub
+    Sub Main()
+        Dim x =  5
+        DoSomething(x)
+    End Sub
+End Module
+                </file>
+                </compilation>
+            Dim comp = CreateCompilationWithMscorlibAndVBRuntime(compilationDef, options:=TestOptions.DebugExe, additionalRefs:={LinqAssemblyRef})
+            CompileAndVerify(comp, expectedOutput:="xxx").VerifyDiagnostics()
+        End Sub
     End Class
 End Namespace