Handling remaining PROTOTYPE markers in features/tuples branch

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

@@ -21,7 +21,7 @@ private BoundExpression BindDeconstructionAssignment(AssignmentExpressionSyntax
             var left = (TupleExpressionSyntax)node.Left;
             ArrayBuilder<DeconstructionVariable> checkedVariables = BindDeconstructionAssignmentVariables(left.Arguments, left, diagnostics);
 
-            var result = BindDeconstructionAssignment(node, node.Right, checkedVariables, diagnostics);
+            var result = BindDeconstructionAssignment(node, node.Right, checkedVariables, diagnostics, isDeclaration: false);
             FreeDeconstructionVariables(checkedVariables);
 
             return result;
@@ -47,7 +47,7 @@ private static void FreeDeconstructionVariables(ArrayBuilder<DeconstructionVaria
         /// Deconstruct steps for tuples have no invocation to Deconstruct, but steps for non-tuples do.
         /// The caller is responsible for releasing all the ArrayBuilders in checkedVariables.
         /// </summary>
-        private BoundDeconstructionAssignmentOperator BindDeconstructionAssignment(CSharpSyntaxNode node, ExpressionSyntax right, ArrayBuilder<DeconstructionVariable> checkedVariables, DiagnosticBag diagnostics, BoundDeconstructValuePlaceholder rhsPlaceholder = null)
+        private BoundDeconstructionAssignmentOperator BindDeconstructionAssignment(CSharpSyntaxNode node, ExpressionSyntax right, ArrayBuilder<DeconstructionVariable> checkedVariables, DiagnosticBag diagnostics, bool isDeclaration, BoundDeconstructValuePlaceholder rhsPlaceholder = null)
         {
             TypeSymbol voidType = GetSpecialType(SpecialType.System_Void, diagnostics, node);
 
@@ -56,7 +56,7 @@ private BoundDeconstructionAssignmentOperator BindDeconstructionAssignment(CShar
 
             if ((object)boundRHS.Type == null)
             {
-                if (boundRHS.Kind == BoundKind.TupleLiteral)
+                if (boundRHS.Kind == BoundKind.TupleLiteral && !isDeclaration)
                 {
                     // tuple literal without type such as `(null, null)`, let's fix it up by peeking at the LHS
                     TypeSymbol lhsAsTuple = MakeTupleTypeFromDeconstructionLHS(checkedVariables, diagnostics, Compilation);
@@ -496,7 +496,7 @@ internal BoundDeconstructionAssignmentOperator BindDeconstructionDeclaration(CSh
         {
             ArrayBuilder<DeconstructionVariable> locals = BindDeconstructionDeclarationLocals(declaration, declaration.Type, diagnostics);
 
-            var result = BindDeconstructionAssignment(node, right, locals, diagnostics, rightPlaceholder);
+            var result = BindDeconstructionAssignment(node, right, locals, diagnostics, isDeclaration: true, rhsPlaceholder: rightPlaceholder);
             FreeDeconstructionVariables(locals);
 
             return result;

src/Compilers/CSharp/Portable/CSharpCodeAnalysis.csproj

@@ -761,7 +761,10 @@
     <Compile Include="Syntax\DeclarationStatementSyntax.cs" />
     <Compile Include="Syntax\DelegateDeclarationSyntax.cs" />
     <Compile Include="Syntax\DirectiveTriviaSyntax.cs" />
+    <Compile Include="Syntax\EventFieldDeclarationSyntax.cs" />
     <Compile Include="Syntax\ExpressionStatementSyntax.cs" />
+    <Compile Include="Syntax\FieldDeclarationSyntax.cs" />
+    <Compile Include="Syntax\FixedStatementSyntax.cs" />
     <Compile Include="Syntax\ForEachStatementSyntax.cs" />
     <Compile Include="Syntax\GenericNameSyntax.cs" />
     <Compile Include="Syntax\InternalSyntax\BinaryExpressionSyntax.cs" />

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_DeconstructionAssignmentOperator.cs

@@ -73,7 +73,6 @@ private ImmutableArray<BoundExpression> LeftHandSideSideEffects(ImmutableArray<B
 
             foreach (var variable in variables)
             {
-                // PROTOTYPE(tuples) should the dynamic flag always be false?
                 lhsReceivers.Add(TransformCompoundAssignmentLHS(variable, stores, temps, isDynamicAssignment: false));
             }
 

src/Compilers/CSharp/Portable/Parser/LanguageParser.cs

@@ -8558,7 +8558,6 @@ private VariableDeclarationSyntax ParseDeconstructionTypeIdPart()
         /// <summary>
         /// Check ahead for a deconstruction declaration. This requires at least one good-looking variable and the presence of an equals sign.
         /// Doesn't move the cursor.
-        /// PROTOTYPE(tuples) Can this be done without allocations?
         /// </summary>
         private bool IsPossibleDeconstructionDeclaration()
         {

src/Compilers/CSharp/Portable/Syntax/EventFieldDeclarationSyntax.cs

@@ -0,0 +1,11 @@
+
+namespace Microsoft.CodeAnalysis.CSharp.Syntax
+{
+    public sealed partial class EventFieldDeclarationSyntax : BaseFieldDeclarationSyntax
+    {
+        public EventFieldDeclarationSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
+        {
+            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
+        }
+    }
+}

src/Compilers/CSharp/Portable/Syntax/FieldDeclarationSyntax.cs

@@ -0,0 +1,11 @@
+
+namespace Microsoft.CodeAnalysis.CSharp.Syntax
+{
+    public sealed partial class FieldDeclarationSyntax : BaseFieldDeclarationSyntax
+    {
+        public FieldDeclarationSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
+        {
+            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
+        }
+    }
+}

src/Compilers/CSharp/Portable/Syntax/FixedStatementSyntax.cs

@@ -0,0 +1,11 @@
+
+namespace Microsoft.CodeAnalysis.CSharp.Syntax
+{
+    public sealed partial class FixedStatementSyntax : StatementSyntax
+    {
+        public FixedStatementSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
+        {
+            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
+        }
+    }
+}

src/Compilers/CSharp/Portable/Syntax/LocalDeclarationStatementSyntax.cs

@@ -1,8 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using Microsoft.CodeAnalysis.CSharp.Symbols;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Text;
 
 namespace Microsoft.CodeAnalysis.CSharp.Syntax
 {
@@ -12,6 +10,11 @@ public LocalDeclarationStatementSyntax Update(SyntaxTokenList modifiers, Variabl
         {
             return Update(modifiers, this.RefKeyword, declaration, semicolonToken);
         }
+
+        public LocalDeclarationStatementSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
+        {
+            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
+        }
     }
 }
 

src/Compilers/CSharp/Portable/Syntax/SyntaxFactory.cs

@@ -2650,39 +2650,3 @@ internal partial class ContextAwareSyntax
 #endif
     }
 }
-
-// PROTOTYPE(tuples) Move this to a better place
-namespace Microsoft.CodeAnalysis.CSharp.Syntax
-{
-    public sealed partial class EventFieldDeclarationSyntax : BaseFieldDeclarationSyntax
-    {
-        public EventFieldDeclarationSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
-        {
-            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
-        }
-    }
-
-    public sealed partial class FieldDeclarationSyntax : BaseFieldDeclarationSyntax
-    {
-        public FieldDeclarationSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
-        {
-            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
-        }
-    }
-
-    public sealed partial class FixedStatementSyntax : StatementSyntax
-    {
-        public FixedStatementSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
-        {
-            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
-        }
-    }
-
-    public sealed partial class LocalDeclarationStatementSyntax : StatementSyntax
-    {
-        public LocalDeclarationStatementSyntax AddDeclarationVariables(params VariableDeclaratorSyntax[] items)
-        {
-            return this.WithDeclaration(this.Declaration.WithVariables(this.Declaration.Variables.AddRange(items)));
-        }
-    }
-}

src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenDeconstructTests.cs

@@ -1284,6 +1284,28 @@ static void Main()
                 );
         }
 
+        [Fact]
+        public void ErrorRight()
+        {
+            string source = @"
+class C
+{
+    static void Main()
+    {
+        int x;
+        (x, x) = undeclared;
+    }
+}
+";
+
+            var comp = CreateCompilationWithMscorlib(source, parseOptions: TestOptions.Regular.WithRefsFeature());
+            comp.VerifyDiagnostics(
+                // (7,18): error CS0103: The name 'undeclared' does not exist in the current context
+                //         (x, x) = undeclared;
+                Diagnostic(ErrorCode.ERR_NameNotInContext, "undeclared").WithArguments("undeclared").WithLocation(7, 18)
+                );
+        }
+
         [Fact]
         public void VoidRight()
         {
@@ -2484,7 +2506,8 @@ public void Deconstruct(out int a, out string b)
             comp.VerifyDiagnostics();
         }
 
-        [Fact(Skip = "PROTOTYPE(tuples)")]
+        [Fact(Skip = "https://github.com/dotnet/roslyn/issues/12400")]
+        [WorkItem(12400, "https://github.com/dotnet/roslyn/issues/12400")]
         public void AssignWithPostfixOperator()
         {
             string source = @"
@@ -2513,7 +2536,8 @@ public void Deconstruct(out int a, out string b)
     }
 }
 ";
-            // PROTOTYPE(tuples) we expect "2 hello" instead, which means the evaluation order is wrong
+            // https://github.com/dotnet/roslyn/issues/12400
+            // we expect "2 hello" instead, which means the evaluation order is wrong
             var comp = CompileAndVerify(source, expectedOutput: "1 hello");
             comp.VerifyDiagnostics();
         }
@@ -2936,7 +2960,7 @@ static void Main()
                 );
         }
 
-        [Fact(Skip = "PROTOTYPE(tuples)")]
+        [Fact]
         public void TypelessDeclaration()
         {
             string source = @"
@@ -2948,13 +2972,15 @@ static void Main()
     }
 }
 ";
-            // crash
             var comp = CreateCompilationWithMscorlib(source, references: new[] { ValueTupleRef, SystemRuntimeFacadeRef });
             comp.VerifyDiagnostics(
+                // (6,24): error CS8210: Deconstruct assignment requires an expression with a type on the right-hand-side.
+                //         var (x1, x2) = (1, null);
+                Diagnostic(ErrorCode.ERR_DeconstructRequiresExpression, "(1, null)").WithLocation(6, 24)
                 );
         }
 
-        [Fact(Skip = "PROTOTYPE(tuples)")]
+        [Fact]
         public void InferTypeOfTypelessDeclaration()
         {
             string source = @"
@@ -2967,9 +2993,12 @@ static void Main()
     }
 }
 ";
-            // crash
-            var comp = CompileAndVerify(source, expectedOutput: "1 2 ");
-            comp.VerifyDiagnostics();
+            var comp = CreateCompilationWithMscorlib(source, references: new[] { ValueTupleRef, SystemRuntimeFacadeRef });
+            comp.VerifyDiagnostics(
+                // (6,37): error CS8210: Deconstruct assignment requires an expression with a type on the right-hand-side.
+                //         (var (x1, x2), string x3) = ((1, 2), null);
+                Diagnostic(ErrorCode.ERR_DeconstructRequiresExpression, "((1, 2), null)").WithLocation(6, 37)
+                );
         }
 
         [Fact]

src/Compilers/CSharp/Test/Syntax/Parsing/DeconstructionTest.cs

@@ -5,6 +5,7 @@
 using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
 using Microsoft.CodeAnalysis.Test.Utilities;
 using Xunit;
+using Roslyn.Test.Utilities;
 
 namespace Microsoft.CodeAnalysis.CSharp.UnitTests.Parsing
 {
@@ -1728,7 +1729,8 @@ public void InvalidStatement()
             Assert.True(statement.HasErrors);
         }
 
-        [Fact(Skip = "PROTOTYPE(tuples)")]
+        [Fact(Skip = "https://github.com/dotnet/roslyn/issues/12402")]
+        [WorkItem(12402, "https://github.com/dotnet/roslyn/issues/12402")]
         public void ConfusedForWithDeconstruction()
         {
             var text = "for ((int x, var (y, z)) in foo) { }";