Adjust scope of locals declared within Lock Statements according to the latest design.

Related to #12597.

src/Compilers/CSharp/Portable/Binder/Binder_Statements.cs

@@ -250,7 +250,7 @@ private BoundStatement BindLockStatement(LockStatementSyntax node, DiagnosticBag
         {
             var lockBinder = this.GetBinder(node);
             Debug.Assert(lockBinder != null);
-            return lockBinder.WrapWithVariablesIfAny(node, lockBinder.BindLockStatementParts(diagnostics, lockBinder));
+            return lockBinder.BindLockStatementParts(diagnostics, lockBinder);
         }
 
         internal virtual BoundStatement BindLockStatementParts(DiagnosticBag diagnostics, Binder originalBinder)
@@ -278,6 +278,7 @@ internal BoundStatement BindPossibleEmbeddedStatement(StatementSyntax node, Diag
                 case SyntaxKind.ExpressionStatement:
                 case SyntaxKind.WhileStatement:
                 case SyntaxKind.DoStatement:
+                case SyntaxKind.LockStatement:
                     Binder binder = this.GetBinder(node);
                     Debug.Assert(binder != null);
                     return binder.WrapWithVariablesIfAny(node, binder.BindStatement(node, diagnostics)); 

src/Compilers/CSharp/Portable/Binder/LocalBinderFactory.cs

@@ -454,8 +454,7 @@ public override void VisitFixedStatement(FixedStatementSyntax node)
 
         public override void VisitLockStatement(LockStatementSyntax node)
         {
-            var patternBinder = new ExpressionVariableBinder(node, _enclosing);
-            var lockBinder = new LockBinder(patternBinder, node);
+            var lockBinder = new LockBinder(_enclosing, node);
             AddToMap(node, lockBinder);
 
             Visit(node.Expression, lockBinder);
@@ -717,8 +716,6 @@ private void VisitPossibleEmbeddedStatement(StatementSyntax statement, Binder en
         {
             if (statement != null)
             {
-                BlockBinder blockBinder;
-
                 switch (statement.Kind())
                 {
                     case SyntaxKind.LocalDeclarationStatement:
@@ -729,18 +726,13 @@ private void VisitPossibleEmbeddedStatement(StatementSyntax statement, Binder en
                         // inside a block.
 
                     case SyntaxKind.ExpressionStatement:
-                        Debug.Assert((object)_containingMemberOrLambda == enclosing.ContainingMemberOrLambda);
-                        blockBinder = new BlockBinder(enclosing, new SyntaxList<StatementSyntax>(statement));
-                        AddToMap(statement, blockBinder);
-                        Visit(statement, blockBinder);
-                        return;
-
                     case SyntaxKind.WhileStatement:
                     case SyntaxKind.DoStatement:
+                    case SyntaxKind.LockStatement:
                         Debug.Assert((object)_containingMemberOrLambda == enclosing.ContainingMemberOrLambda);
-                        blockBinder = new BlockBinder(enclosing, new SyntaxList<StatementSyntax>(statement));
+                        var blockBinder = new BlockBinder(enclosing, new SyntaxList<StatementSyntax>(statement));
+                        AddToMap(statement, blockBinder);
                         Visit(statement, blockBinder);
-                        Debug.Assert(_map.ContainsKey(statement));
                         return;
 
                     default:

src/Compilers/CSharp/Portable/Binder/LocalScopeBinder.cs

@@ -197,6 +197,7 @@ protected ImmutableArray<LocalSymbol> BuildLocals(SyntaxList<StatementSyntax> st
 
                     case SyntaxKind.WhileStatement:
                     case SyntaxKind.DoStatement:
+                    case SyntaxKind.LockStatement:
                         ExpressionVariableFinder.FindExpressionVariables(this, locals, innerStatement, enclosingBinder.GetBinder(innerStatement));
                         break;
 

src/Compilers/CSharp/Test/Semantic/Semantics/OutVarTests.cs

@@ -2794,6 +2794,15 @@ static bool TakeOutParam(int y, out int x)
             var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe, parseOptions: TestOptions.Regular);
             CompileAndVerify(compilation, expectedOutput: @"2
 2");
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = GetOutVarDeclarations(tree, "x1").ToArray();
+            var x1Ref = GetReferences(tree, "x1").ToArray();
+            Assert.Equal(1, x1Decl.Length);
+            Assert.Equal(2, x1Ref.Length);
+            VerifyModelForOutVar(model, x1Decl[0], x1Ref);
         }
 
         [Fact]
@@ -7231,7 +7240,7 @@ void Test4()
         var x4 = 11;
         Dummy(x4);
 
-        lock (Dummy(TakeOutParam(true, out var x4) && x4))
+        lock (Dummy(TakeOutParam(true, out var x4) && x4 > 0))
             Dummy(x4);
     }
 
@@ -7326,18 +7335,18 @@ static bool TakeOutParam(int y, out int x)
                 // (87,13): error CS1023: Embedded statement cannot be a declaration or labeled statement
                 //             var y12 = 12;
                 Diagnostic(ErrorCode.ERR_BadEmbeddedStmt, "var y12 = 12;").WithLocation(87, 13),
-                // (29,48): error CS0136: A local or parameter named 'x4' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
-                //         lock (Dummy(TakeOutParam(true, out var x4) && x4))
-                Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x4").WithArguments("x4").WithLocation(29, 48),
+                // (29,48): error CS0128: A local variable named 'x4' is already defined in this scope
+                //         lock (Dummy(TakeOutParam(true, out var x4) && x4 > 0))
+                Diagnostic(ErrorCode.ERR_LocalDuplicate, "x4").WithArguments("x4").WithLocation(29, 48),
                 // (35,21): error CS0841: Cannot use local variable 'x6' before it is declared
                 //         lock (Dummy(x6 && TakeOutParam(true, out var x6)))
                 Diagnostic(ErrorCode.ERR_VariableUsedBeforeDeclaration, "x6").WithArguments("x6").WithLocation(35, 21),
                 // (43,17): error CS0136: A local or parameter named 'x7' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
                 //             var x7 = 12;
                 Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x7").WithArguments("x7").WithLocation(43, 17),
-                // (53,34): error CS0103: The name 'x8' does not exist in the current context
-                //         System.Console.WriteLine(x8);
-                Diagnostic(ErrorCode.ERR_NameNotInContext, "x8").WithArguments("x8").WithLocation(53, 34),
+                // (60,19): error CS0841: Cannot use local variable 'x9' before it is declared
+                //             Dummy(x9);
+                Diagnostic(ErrorCode.ERR_VariableUsedBeforeDeclaration, "x9").WithArguments("x9").WithLocation(60, 19),
                 // (61,52): error CS0136: A local or parameter named 'x9' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
                 //             lock (Dummy(TakeOutParam(true, out var x9) && x9)) // 2
                 Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x9").WithArguments("x9").WithLocation(61, 52),
@@ -7369,7 +7378,9 @@ static bool TakeOutParam(int y, out int x)
             var x4Ref = GetReferences(tree, "x4").ToArray();
             Assert.Equal(3, x4Ref.Length);
             VerifyNotAnOutLocal(model, x4Ref[0]);
-            VerifyModelForOutVar(model, x4Decl, x4Ref[1], x4Ref[2]);
+            VerifyNotAnOutLocal(model, x4Ref[1]);
+            VerifyNotAnOutLocal(model, x4Ref[2]);
+            VerifyModelForOutVarDuplicateInSameScope(model, x4Decl);
 
             var x6Decl = GetOutVarDeclarations(tree, "x6").Single();
             var x6Ref = GetReferences(tree, "x6").ToArray();
@@ -7385,15 +7396,14 @@ static bool TakeOutParam(int y, out int x)
             var x8Decl = GetOutVarDeclarations(tree, "x8").Single();
             var x8Ref = GetReferences(tree, "x8").ToArray();
             Assert.Equal(3, x8Ref.Length);
-            VerifyModelForOutVar(model, x8Decl, x8Ref[0], x8Ref[1]);
-            VerifyNotInScope(model, x8Ref[2]);
+            VerifyModelForOutVar(model, x8Decl, x8Ref);
 
             var x9Decl = GetOutVarDeclarations(tree, "x9").ToArray();
             var x9Ref = GetReferences(tree, "x9").ToArray();
             Assert.Equal(2, x9Decl.Length);
             Assert.Equal(4, x9Ref.Length);
-            VerifyModelForOutVar(model, x9Decl[0], x9Ref[0], x9Ref[1]);
-            VerifyModelForOutVar(model, x9Decl[1], x9Ref[2], x9Ref[3]);
+            VerifyModelForOutVar(model, x9Decl[0], x9Ref[0]);
+            VerifyModelForOutVar(model, x9Decl[1], x9Ref[1], x9Ref[2], x9Ref[3]);
 
             var y10Ref = GetReferences(tree, "y10").ToArray();
             Assert.Equal(2, y10Ref.Length);
@@ -7411,6 +7421,52 @@ static bool TakeOutParam(int y, out int x)
             VerifyModelForOutVarDuplicateInSameScope(model, x14Decl[1]);
         }
 
+        [Fact]
+        public void Scope_Lock_02()
+        {
+            var source =
+@"
+public class X
+{
+    public static void Main()
+    {
+    }
+
+    object Dummy(params object[] x) {return null;}
+
+    void Test1()
+    {
+        if (true)
+            lock (Dummy(TakeOutParam(true, out var x1)))
+            {
+            }
+
+        x1++;
+    }
+
+    static object TakeOutParam(bool y, out bool x) 
+    {
+        x = y;
+        return true;
+    }
+}
+";
+            var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe, parseOptions: TestOptions.Regular);
+            compilation.VerifyDiagnostics(
+                // (17,9): error CS0103: The name 'x1' does not exist in the current context
+                //         x1++;
+                Diagnostic(ErrorCode.ERR_NameNotInContext, "x1").WithArguments("x1").WithLocation(17, 9)
+                );
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = GetOutVarDeclarations(tree, "x1").Single();
+            var x1Ref = GetReferences(tree, "x1").Single();
+            VerifyModelForOutVar(model, x1Decl);
+            VerifyNotInScope(model, x1Ref);
+        }
+
         [Fact]
         public void Lock_01()
         {
@@ -7424,6 +7480,8 @@ public static void Main()
         {
             System.Console.WriteLine(x1);
         }
+
+        System.Console.WriteLine(x1);
     }
 
     static object Dummy(object y, object z) 
@@ -7442,7 +7500,68 @@ static bool TakeOutParam<T>(T y, out T x)
             var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe, parseOptions: TestOptions.Regular);
             CompileAndVerify(compilation, expectedOutput:
 @"lock
+lock
 lock");
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = GetOutVarDeclarations(tree, "x1").ToArray();
+            var x1Ref = GetReferences(tree, "x1").ToArray();
+            Assert.Equal(1, x1Decl.Length);
+            Assert.Equal(3, x1Ref.Length);
+            VerifyModelForOutVar(model, x1Decl[0], x1Ref);
+        }
+
+        [Fact]
+        public void Lock_02()
+        {
+            var source =
+@"
+public class X
+{
+    public static void Main()
+    {
+        bool f = true;
+
+        if (f)        
+            lock (Dummy(f, TakeOutParam((f ? 1 : 2), out var x1), x1))
+                {}
+
+        if (f)        
+        {
+            lock (Dummy(f, TakeOutParam((f ? 3 : 4), out var x1), x1))
+                {}
+        }
+    }
+
+    static object Dummy(bool x, object y, object z) 
+    {
+        System.Console.WriteLine(z);
+        return x;
+    }
+
+    static bool TakeOutParam<T>(T y, out T x) 
+    {
+        x = y;
+        return true;
+    }
+}
+";
+            var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe, parseOptions: TestOptions.Regular);
+            CompileAndVerify(compilation, expectedOutput:
+@"1
+3");
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = GetOutVarDeclarations(tree, "x1").ToArray();
+            var x1Ref = GetReferences(tree, "x1").ToArray();
+            Assert.Equal(2, x1Decl.Length);
+            Assert.Equal(2, x1Ref.Length);
+            VerifyModelForOutVar(model, x1Decl[0], x1Ref[0]);
+            VerifyModelForOutVar(model, x1Decl[1], x1Ref[1]);
         }
 
         [Fact]
@@ -9926,6 +10045,48 @@ static bool TakeOutParam<T>(T y, out T x)
             Assert.Equal("System.Int32", model.GetTypeInfo(yRef).Type.ToTestDisplayString());
         }
 
+        [Fact]
+        public void Scope_SwitchLabelGuard_05()
+        {
+            var source =
+@"
+public class X
+{
+    public static void Main()
+    {
+        Test(1);
+    }
+
+    static void Test(int val)
+    {
+        switch (val)
+        {
+            case 1 when TakeOutParam(123, out var x1):
+                lock ((object)TakeOutParam(x1, out var y1)) {}
+                System.Console.WriteLine(y1);
+                break;
+        }
+    }
+
+    static bool TakeOutParam<T>(T y, out T x) 
+    {
+        x = y;
+        return true;
+    }
+}
+";
+            var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe, parseOptions: TestOptions.Regular);
+
+            CompileAndVerify(compilation, expectedOutput: @"123").VerifyDiagnostics();
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var yRef = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "y1").Single();
+
+            Assert.Equal("System.Int32", model.GetTypeInfo(yRef).Type.ToTestDisplayString());
+        }
+
         [Fact]
         public void Scope_SwitchLabelPattern_01()
         {

src/Compilers/CSharp/Test/Semantic/Semantics/PatternMatchingTests.cs

@@ -7511,6 +7511,15 @@ static bool Dummy(bool x, object y, object z)
             var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe);
             CompileAndVerify(compilation, expectedOutput:@"2
 2");
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = tree.GetRoot().DescendantNodes().OfType<DeclarationPatternSyntax>().Where(p => p.Identifier.ValueText == "x1").ToArray();
+            var x1Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x1").ToArray();
+            Assert.Equal(1, x1Decl.Length);
+            Assert.Equal(2, x1Ref.Length);
+            VerifyModelForDeclarationPattern(model, x1Decl[0], x1Ref);
         }
 
         [Fact]
@@ -9476,18 +9485,18 @@ void Test14()
     // (87,13): error CS1023: Embedded statement cannot be a declaration or labeled statement
     //             var y12 = 12;
     Diagnostic(ErrorCode.ERR_BadEmbeddedStmt, "var y12 = 12;").WithLocation(87, 13),
-    // (29,33): error CS0136: A local or parameter named 'x4' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
+    // (29,33): error CS0128: A local variable named 'x4' is already defined in this scope
     //         lock (Dummy(true is var x4 && x4))
-    Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x4").WithArguments("x4").WithLocation(29, 33),
+    Diagnostic(ErrorCode.ERR_LocalDuplicate, "x4").WithArguments("x4").WithLocation(29, 33),
     // (35,21): error CS0841: Cannot use local variable 'x6' before it is declared
     //         lock (Dummy(x6 && true is var x6))
     Diagnostic(ErrorCode.ERR_VariableUsedBeforeDeclaration, "x6").WithArguments("x6").WithLocation(35, 21),
     // (43,17): error CS0136: A local or parameter named 'x7' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
     //             var x7 = 12;
     Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x7").WithArguments("x7").WithLocation(43, 17),
-    // (53,34): error CS0103: The name 'x8' does not exist in the current context
-    //         System.Console.WriteLine(x8);
-    Diagnostic(ErrorCode.ERR_NameNotInContext, "x8").WithArguments("x8").WithLocation(53, 34),
+    // (60,19): error CS0841: Cannot use local variable 'x9' before it is declared
+    //             Dummy(x9);
+    Diagnostic(ErrorCode.ERR_VariableUsedBeforeDeclaration, "x9").WithArguments("x9").WithLocation(60, 19),
     // (61,37): error CS0136: A local or parameter named 'x9' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
     //             lock (Dummy(true is var x9 && x9)) // 2
     Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x9").WithArguments("x9").WithLocation(61, 37),
@@ -9519,7 +9528,9 @@ void Test14()
             var x4Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x4").ToArray();
             Assert.Equal(3, x4Ref.Length);
             VerifyNotAPatternLocal(model, x4Ref[0]);
-            VerifyModelForDeclarationPattern(model, x4Decl, x4Ref[1], x4Ref[2]);
+            VerifyNotAPatternLocal(model, x4Ref[1]);
+            VerifyNotAPatternLocal(model, x4Ref[2]);
+            VerifyModelForDeclarationPatternDuplicateInSameScope(model, x4Decl);
 
             var x6Decl = tree.GetRoot().DescendantNodes().OfType<DeclarationPatternSyntax>().Where(p => p.Identifier.ValueText == "x6").Single();
             var x6Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x6").ToArray();
@@ -9535,15 +9546,14 @@ void Test14()
             var x8Decl = tree.GetRoot().DescendantNodes().OfType<DeclarationPatternSyntax>().Where(p => p.Identifier.ValueText == "x8").Single();
             var x8Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x8").ToArray();
             Assert.Equal(3, x8Ref.Length);
-            VerifyModelForDeclarationPattern(model, x8Decl, x8Ref[0], x8Ref[1]);
-            VerifyNotInScope(model, x8Ref[2]);
+            VerifyModelForDeclarationPattern(model, x8Decl, x8Ref);
 
             var x9Decl = tree.GetRoot().DescendantNodes().OfType<DeclarationPatternSyntax>().Where(p => p.Identifier.ValueText == "x9").ToArray();
             var x9Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x9").ToArray();
             Assert.Equal(2, x9Decl.Length);
             Assert.Equal(4, x9Ref.Length);
-            VerifyModelForDeclarationPattern(model, x9Decl[0], x9Ref[0], x9Ref[1]);
-            VerifyModelForDeclarationPattern(model, x9Decl[1], x9Ref[2], x9Ref[3]);
+            VerifyModelForDeclarationPattern(model, x9Decl[0], x9Ref[0]);
+            VerifyModelForDeclarationPattern(model, x9Decl[1], x9Ref[1], x9Ref[2], x9Ref[3]);
 
             var y10Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "y10").ToArray();
             Assert.Equal(2, y10Ref.Length);
@@ -9561,6 +9571,46 @@ void Test14()
             VerifyModelForDeclarationPatternDuplicateInSameScope(model, x14Decl[1]);
         }
 
+        [Fact]
+        public void ScopeOfPatternVariables_Lock_02()
+        {
+            var source =
+@"
+public class X
+{
+    public static void Main()
+    {
+    }
+
+    object Dummy(params object[] x) {return null;}
+
+    void Test1()
+    {
+        if (true)
+            lock (Dummy(true is var x1))
+            {
+            }
+
+        x1++;
+    }
+}
+";
+            var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe);
+            compilation.VerifyDiagnostics(
+                // (17,9): error CS0103: The name 'x1' does not exist in the current context
+                //         x1++;
+                Diagnostic(ErrorCode.ERR_NameNotInContext, "x1").WithArguments("x1").WithLocation(17, 9)
+                );
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = tree.GetRoot().DescendantNodes().OfType<DeclarationPatternSyntax>().Where(p => p.Identifier.ValueText == "x1").Single();
+            var x1Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x1").Single();
+            VerifyModelForDeclarationPattern(model, x1Decl);
+            VerifyNotInScope(model, x1Ref);
+        }
+
         [Fact]
         public void Lock_01()
         {
@@ -9574,6 +9624,8 @@ public static void Main()
         {
             System.Console.WriteLine(x1);
         }
+
+        System.Console.WriteLine(x1);
     }
 
     static object Dummy(object y, object z) 
@@ -9586,7 +9638,62 @@ static object Dummy(object y, object z)
             var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe);
             CompileAndVerify(compilation, expectedOutput:
 @"lock
+lock
 lock");
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = tree.GetRoot().DescendantNodes().OfType<DeclarationPatternSyntax>().Where(p => p.Identifier.ValueText == "x1").ToArray();
+            var x1Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x1").ToArray();
+            Assert.Equal(1, x1Decl.Length);
+            Assert.Equal(3, x1Ref.Length);
+            VerifyModelForDeclarationPattern(model, x1Decl[0], x1Ref);
+        }
+
+        [Fact]
+        public void Lock_02()
+        {
+            var source =
+@"
+public class X
+{
+    public static void Main()
+    {
+        bool f = true;
+
+        if (f)
+            lock (Dummy(f, (f ? 1 : 2) is var x1, x1))
+                {}
+
+        if (f)
+        {
+            lock (Dummy(f, (f ? 3 : 4) is var x1, x1))
+                {}
+        }
+    }
+
+    static object Dummy(bool x, object y, object z) 
+    {
+        System.Console.WriteLine(z);
+        return x;
+    }
+}
+";
+            var compilation = CreateCompilationWithMscorlib45(source, options: TestOptions.DebugExe);
+            CompileAndVerify(compilation, expectedOutput:
+@"1
+3");
+
+            var tree = compilation.SyntaxTrees.Single();
+            var model = compilation.GetSemanticModel(tree);
+
+            var x1Decl = tree.GetRoot().DescendantNodes().OfType<DeclarationPatternSyntax>().Where(p => p.Identifier.ValueText == "x1").ToArray();
+            var x1Ref = tree.GetRoot().DescendantNodes().OfType<IdentifierNameSyntax>().Where(id => id.Identifier.ValueText == "x1").ToArray();
+            Assert.Equal(2, x1Decl.Length);
+            Assert.Equal(2, x1Ref.Length);
+            VerifyModelForDeclarationPattern(model, x1Decl[0], x1Ref[0]);
+            VerifyModelForDeclarationPattern(model, x1Decl[1], x1Ref[1]);
         }
 
         [Fact]