Add local functions to BoundBlock

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

@@ -157,6 +157,14 @@ internal virtual ImmutableArray<LocalSymbol> GetDeclaredLocalsForScope(CSharpSyn
             return this.Next.GetDeclaredLocalsForScope(node);
         }
 
+        /// <summary>
+        /// Get local functions declared immediately in scope represented by the node.
+        /// </summary>
+        internal virtual ImmutableArray<LocalFunctionSymbol> GetDeclaredLocalFunctionsForScope(CSharpSyntaxNode node)
+        {
+            return this.Next.GetDeclaredLocalFunctionsForScope(node);
+        }
+
         /// <summary>
         /// The member containing the binding context.  Note that for the purposes of the compiler,
         /// a lambda expression is considered a "member" of its enclosing method, field, or lambda.

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

@@ -2132,7 +2132,11 @@ internal static BoundBlock BindBlock(BlockSyntax node, DiagnosticBag diagnostics
                 }
             }
 
-            return new BoundBlock(node, blockBinder.GetDeclaredLocalsForScope(node), boundStatements.ToImmutableAndFree());
+            return new BoundBlock(
+                node,
+                blockBinder.GetDeclaredLocalsForScope(node),
+                blockBinder.GetDeclaredLocalFunctionsForScope(node),
+                boundStatements.ToImmutableAndFree());
         }
 
         internal BoundExpression GenerateConversionForAssignment(TypeSymbol targetType, BoundExpression expression, DiagnosticBag diagnostics, bool isDefaultParameter = false)
@@ -3271,7 +3275,7 @@ internal BoundBlock CreateBlockFromExpression(CSharpSyntaxNode node, ImmutableAr
             }
 
             // Need to attach the tree for when we generate sequence points.
-            return new BoundBlock(node, locals, ImmutableArray.Create(statement)) { WasCompilerGenerated = node.Kind() != SyntaxKind.ArrowExpressionClause };
+            return new BoundBlock(node, locals, ImmutableArray<LocalFunctionSymbol>.Empty, ImmutableArray.Create(statement)) { WasCompilerGenerated = node.Kind() != SyntaxKind.ArrowExpressionClause };
         }
 
         /// <summary>

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

@@ -56,5 +56,22 @@ internal override ImmutableArray<LocalSymbol> GetDeclaredLocalsForScope(CSharpSy
 
             throw ExceptionUtilities.Unreachable;
         }
+
+        internal override ImmutableArray<LocalFunctionSymbol> GetDeclaredLocalFunctionsForScope(CSharpSyntaxNode node)
+        {
+            if (node.Kind() == SyntaxKind.Block)
+            {
+                if (((BlockSyntax)node).Statements == _statements)
+                {
+                    return this.LocalFunctions;
+                }
+            }
+            else if (_statements.Count == 1 && _statements.First() == node)
+            {
+                return this.LocalFunctions;
+            }
+
+            throw ExceptionUtilities.Unreachable;
+        }
     }
 }

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

@@ -154,6 +154,11 @@ internal override ImmutableArray<LocalSymbol> GetDeclaredLocalsForScope(CSharpSy
             throw ExceptionUtilities.Unreachable;
         }
 
+        internal override ImmutableArray<LocalFunctionSymbol> GetDeclaredLocalFunctionsForScope(CSharpSyntaxNode node)
+        {
+            throw ExceptionUtilities.Unreachable;
+        }
+
         internal override BoundSwitchStatement BindSwitchExpressionAndSections(SwitchStatementSyntax node, Binder originalBinder, DiagnosticBag diagnostics)
         {
             // There's supposed to be a SwitchBinder (or other overrider of this method) in the chain.

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

@@ -46,5 +46,15 @@ internal override ImmutableArray<LocalSymbol> GetDeclaredLocalsForScope(CSharpSy
 
             throw ExceptionUtilities.Unreachable;
         }
+
+        internal override ImmutableArray<LocalFunctionSymbol> GetDeclaredLocalFunctionsForScope(CSharpSyntaxNode node)
+        {
+            if (node == _syntax)
+            {
+                return ImmutableArray<LocalFunctionSymbol>.Empty;
+            }
+
+            throw ExceptionUtilities.Unreachable;
+        }
     }
 }

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

@@ -46,5 +46,15 @@ internal override ImmutableArray<LocalSymbol> GetDeclaredLocalsForScope(CSharpSy
 
             throw ExceptionUtilities.Unreachable;
         }
+
+        internal override ImmutableArray<LocalFunctionSymbol> GetDeclaredLocalFunctionsForScope(CSharpSyntaxNode node)
+        {
+            if (node == _syntax)
+            {
+                return ImmutableArray<LocalFunctionSymbol>.Empty;
+            }
+
+            throw ExceptionUtilities.Unreachable;
+        }
     }
 }

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

@@ -444,5 +444,10 @@ internal override ImmutableArray<LocalSymbol> GetDeclaredLocalsForScope(CSharpSy
         {
             throw ExceptionUtilities.Unreachable;
         }
+
+        internal override ImmutableArray<LocalFunctionSymbol> GetDeclaredLocalFunctionsForScope(CSharpSyntaxNode node)
+        {
+            throw ExceptionUtilities.Unreachable;
+        }
     }
 }

src/Compilers/CSharp/Portable/BoundTree/BoundNodes.xml

@@ -549,6 +549,7 @@
   -->
   <Node Name="BoundBlock" Base="BoundStatementList">
     <Field Name="Locals" Type="ImmutableArray&lt;LocalSymbol&gt;"/>
+    <Field Name="LocalFunctions" Type="ImmutableArray&lt;LocalFunctionSymbol&gt;"/>
   </Node>
 
   <!--

src/Compilers/CSharp/Portable/BoundTree/Constructors.cs

@@ -525,21 +525,19 @@ internal partial class BoundBlock
     {
         public static BoundBlock SynthesizedNoLocals(CSharpSyntaxNode syntax, BoundStatement statement)
         {
-            return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty,
+            return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray<LocalFunctionSymbol>.Empty,
                 ImmutableArray.Create(statement))
             { WasCompilerGenerated = true };
         }
 
         public static BoundBlock SynthesizedNoLocals(CSharpSyntaxNode syntax, ImmutableArray<BoundStatement> statements)
         {
-            Debug.Assert(statements.Length > 0);
-            return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, statements) { WasCompilerGenerated = true };
+            return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray<LocalFunctionSymbol>.Empty, statements) { WasCompilerGenerated = true };
         }
 
         public static BoundBlock SynthesizedNoLocals(CSharpSyntaxNode syntax, params BoundStatement[] statements)
         {
-            Debug.Assert(statements.Length > 0);
-            return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, statements.AsImmutableOrNull()) { WasCompilerGenerated = true };
+            return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray<LocalFunctionSymbol>.Empty, statements.AsImmutableOrNull()) { WasCompilerGenerated = true };
         }
     }
 

src/Compilers/CSharp/Portable/Compiler/AnonymousTypeMethodBodySynthesizer.cs

@@ -145,7 +145,7 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
                 BoundStatement retStatement = F.Return(retExpression);
 
                 // Create a bound block 
-                F.CloseMethod(F.Block(ImmutableArray.Create<LocalSymbol>(boundLocal.LocalSymbol), assignment, retStatement));
+                F.CloseMethod(F.Block(ImmutableArray.Create<LocalSymbol>(boundLocal.LocalSymbol), ImmutableArray<LocalFunctionSymbol>.Empty, assignment, retStatement));
             }
 
             internal override bool HasSpecialName

src/Compilers/CSharp/Portable/Compiler/MethodBodySynthesizer.Lowered.cs

@@ -81,6 +81,7 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
 
                 var body = F.Block(
                         ImmutableArray.Create<LocalSymbol>(hashCode, i),
+                        ImmutableArray<LocalFunctionSymbol>.Empty,
                         F.If(
                             F.Binary(BinaryOperatorKind.ObjectNotEqual, F.SpecialType(SpecialType.System_Boolean),
                                 F.Parameter(text),

src/Compilers/CSharp/Portable/Compiler/MethodBodySynthesizer.cs

@@ -200,7 +200,7 @@ internal static BoundBlock ConstructAutoPropertyAccessorBody(SourceMethodSymbol
 
             statement = new BoundSequencePoint(accessor.SyntaxNode, statement) { WasCompilerGenerated = true };
 
-            return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray.Create<BoundStatement>(statement)) { WasCompilerGenerated = true };
+            return BoundBlock.SynthesizedNoLocals(syntax, statement);
         }
 
         /// <summary>
@@ -358,10 +358,7 @@ internal static BoundBlock ConstructFieldLikeEventAccessorBody_Regular(SourceEve
                                                                       memberDescriptor.Name),
                                                                       syntax.Location));
 
-                return new BoundBlock(syntax,
-                    locals: ImmutableArray<LocalSymbol>.Empty,
-                    statements: ImmutableArray.Create<BoundStatement>(@return))
-                { WasCompilerGenerated = true };
+                return BoundBlock.SynthesizedNoLocals(syntax, @return);
             }
 
             Binder.ReportUseSiteDiagnostics(updateMethod, diagnostics, syntax);
@@ -404,12 +401,10 @@ internal static BoundBlock ConstructFieldLikeEventAccessorBody_Regular(SourceEve
                     { WasCompilerGenerated = true })
                 { WasCompilerGenerated = true };
 
-                return new BoundBlock(syntax,
-                    locals: ImmutableArray<LocalSymbol>.Empty,
+                return BoundBlock.SynthesizedNoLocals(syntax,
                     statements: ImmutableArray.Create<BoundStatement>(
                         eventUpdate,
-                        @return))
-                { WasCompilerGenerated = true };
+                        @return));
             }
 
             compareExchangeMethod = compareExchangeMethod.Construct(ImmutableArray.Create<TypeSymbol>(delegateType));
@@ -505,6 +500,7 @@ internal static BoundBlock ConstructFieldLikeEventAccessorBody_Regular(SourceEve
 
             return new BoundBlock(syntax,
                 locals: tmps.AsImmutable(),
+                localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                 statements: ImmutableArray.Create<BoundStatement>(
                     tmp0Init,
                     loopStart,
@@ -548,6 +544,7 @@ internal static BoundBlock ConstructDestructorBody(MethodSymbol method, BoundBlo
                 return new BoundBlock(
                     syntax,
                     ImmutableArray<LocalSymbol>.Empty,
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     ImmutableArray.Create<BoundStatement>(
                         new BoundTryStatement(
                             syntax,
@@ -556,6 +553,7 @@ internal static BoundBlock ConstructDestructorBody(MethodSymbol method, BoundBlo
                             new BoundBlock(
                                 syntax,
                                 ImmutableArray<LocalSymbol>.Empty,
+                                ImmutableArray<LocalFunctionSymbol>.Empty,
                                 ImmutableArray.Create<BoundStatement>(
                                     baseFinalizeCall)
                             )

src/Compilers/CSharp/Portable/Compiler/MethodCompiler.cs

@@ -847,7 +847,7 @@ public override object VisitField(FieldSymbol symbol, TypeCompilationState argum
 
                 if (methodSymbol.IsScriptConstructor)
                 {
-                    body = new BoundBlock(methodSymbol.GetNonNullSyntaxNode(), ImmutableArray<LocalSymbol>.Empty, ImmutableArray<BoundStatement>.Empty) { WasCompilerGenerated = true };
+                    body = BoundBlock.SynthesizedNoLocals(methodSymbol.GetNonNullSyntaxNode(), ImmutableArray<BoundStatement>.Empty);
                     includeInitializersInBody = false;
                     importChain = null;
                 }
@@ -858,7 +858,7 @@ public override object VisitField(FieldSymbol symbol, TypeCompilationState argum
                     BoundTypeOrInstanceInitializers initializerStatements = InitializerRewriter.Rewrite(processedInitializers.BoundInitializers, methodSymbol, submissionResultType);
 
                     // the lowered script initializers should not be treated as initializers anymore but as a method body:
-                    body = new BoundBlock(initializerStatements.Syntax, ImmutableArray<LocalSymbol>.Empty, initializerStatements.Statements) { WasCompilerGenerated = true };
+                    body = BoundBlock.SynthesizedNoLocals(initializerStatements.Syntax, initializerStatements.Statements);
                     includeInitializersInBody = false;
 
                     importChain = null;
@@ -883,7 +883,7 @@ public override object VisitField(FieldSymbol symbol, TypeCompilationState argum
                         if (body != null && methodSymbol.ContainingType.IsStructType() && !methodSymbol.IsImplicitConstructor)
                         {
                             // In order to get correct diagnostics, we need to analyze initializers and the body together.
-                            body = body.Update(body.Locals, body.Statements.Insert(0, analyzedInitializers));
+                            body = body.Update(body.Locals, body.LocalFunctions, body.Statements.Insert(0, analyzedInitializers));
                             includeInitializersInBody = false;
                             analyzedInitializers = null;
                         }
@@ -1592,7 +1592,7 @@ private static BoundBlock BindMethodBody(MethodSymbol method, TypeCompilationSta
                 statements = ImmutableArray.Create(constructorInitializer, body);
             }
 
-            return new BoundBlock(method.GetNonNullSyntaxNode(), ImmutableArray<LocalSymbol>.Empty, statements) { WasCompilerGenerated = true };
+            return BoundBlock.SynthesizedNoLocals(method.GetNonNullSyntaxNode(), statements);
         }
 
         /// <summary>

src/Compilers/CSharp/Portable/FlowAnalysis/DataFlowPass.cs

@@ -26,6 +26,12 @@ internal partial class DataFlowPass : AbstractFlowPass<DataFlowPass.LocalState>
         /// </summary>
         private readonly PooledHashSet<LocalSymbol> _usedVariables = PooledHashSet<LocalSymbol>.GetInstance();
 
+        /// <summary>
+        /// Variables that were used anywhere, in the sense required to suppress warnings about
+        /// unused variables.
+        /// </summary>
+        private readonly PooledHashSet<LocalFunctionSymbol> _usedLocalFunctions = PooledHashSet<LocalFunctionSymbol>.GetInstance();
+
         /// <summary>
         /// Variables that were initialized or written anywhere.
         /// </summary>
@@ -102,6 +108,7 @@ internal partial class DataFlowPass : AbstractFlowPass<DataFlowPass.LocalState>
         protected override void Free()
         {
             _usedVariables.Free();
+            _usedLocalFunctions.Free();
             _writtenVariables.Free();
             _capturedVariables.Free();
             _unsafeAddressTakenVariables.Free();
@@ -394,6 +401,11 @@ protected virtual void NoteRead(Symbol variable, ParameterSymbol rangeVariableUn
             {
                 _usedVariables.Add(local);
             }
+            var localFunction = variable as LocalFunctionSymbol;
+            if ((object)localFunction != null)
+            {
+                _usedLocalFunctions.Add(localFunction);
+            }
 
             if ((object)variable != null)
             {
@@ -1281,6 +1293,7 @@ public override BoundNode VisitBlock(BoundBlock node)
             DeclareVariables(node.Locals);
             var result = base.VisitBlock(node);
             ReportUnusedVariables(node.Locals);
+            ReportUnusedVariables(node.LocalFunctions);
             return result;
         }
 
@@ -1455,6 +1468,25 @@ private void ReportIfUnused(LocalSymbol symbol, bool assigned)
             }
         }
 
+        private void ReportUnusedVariables(ImmutableArray<LocalFunctionSymbol> locals)
+        {
+            foreach (var symbol in locals)
+            {
+                ReportIfUnused(symbol, assigned: true);
+            }
+        }
+
+        private void ReportIfUnused(LocalFunctionSymbol symbol, bool assigned)
+        {
+            if (!_usedLocalFunctions.Contains(symbol))
+            {
+                if (!string.IsNullOrEmpty(symbol.Name)) // avoid diagnostics for parser-inserted names
+                {
+                    Diagnostics.Add(assigned && _writtenVariables.Contains(symbol) ? ErrorCode.WRN_UnreferencedVarAssg : ErrorCode.WRN_UnreferencedVar, symbol.Locations[0], symbol.Name);
+                }
+            }
+        }
+
         public override BoundNode VisitLocal(BoundLocal node)
         {
             // Note: the caller should avoid allowing this to be called for the left-hand-side of
@@ -1494,7 +1526,7 @@ public override BoundNode VisitCall(BoundCall node)
         {
             if (node.Method.MethodKind == MethodKind.LocalFunction)
             {
-                CheckAssigned(node.Method, node.Syntax);
+                CheckAssigned(node.Method.OriginalDefinition, node.Syntax);
             }
             return base.VisitCall(node);
         }
@@ -1503,7 +1535,7 @@ public override BoundNode VisitConversion(BoundConversion node)
         {
             if (node.ConversionKind == ConversionKind.MethodGroup && node.SymbolOpt?.MethodKind == MethodKind.LocalFunction)
             {
-                CheckAssigned(node.SymbolOpt, node.Syntax);
+                CheckAssigned(node.SymbolOpt.OriginalDefinition, node.Syntax);
             }
             return base.VisitConversion(node);
         }
@@ -1512,11 +1544,23 @@ public override BoundNode VisitDelegateCreationExpression(BoundDelegateCreationE
         {
             if (node.MethodOpt?.MethodKind == MethodKind.LocalFunction)
             {
-                CheckAssigned(node.MethodOpt, node.Syntax);
+                CheckAssigned(node.MethodOpt.OriginalDefinition, node.Syntax);
             }
             return base.VisitDelegateCreationExpression(node);
         }
 
+        public override BoundNode VisitMethodGroup(BoundMethodGroup node)
+        {
+            foreach (var method in node.Methods)
+            {
+                if (method.MethodKind == MethodKind.LocalFunction)
+                {
+                    CheckAssigned(method, node.Syntax);
+                }
+            }
+            return base.VisitMethodGroup(node);
+        }
+
         public override BoundNode VisitLambda(BoundLambda node)
         {
             return VisitLambdaOrLocalFunction(node);

src/Compilers/CSharp/Portable/FlowAnalysis/FlowAnalysisPass.cs

@@ -88,10 +88,10 @@ internal static BoundBlock AppendImplicitReturn(BoundStatement node, MethodSymbo
             {
                 case BoundKind.Block:
                     var block = (BoundBlock)node;
-                    return block.Update(block.Locals, block.Statements.Add(ret));
+                    return block.Update(block.Locals, block.LocalFunctions, block.Statements.Add(ret));
 
                 default:
-                    return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray.Create(ret, node));
+                    return new BoundBlock(syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray<LocalFunctionSymbol>.Empty, ImmutableArray.Create(ret, node));
             }
         }
 

src/Compilers/CSharp/Portable/Lowering/AsyncRewriter/AsyncExceptionHandlerRewriter.cs

@@ -226,6 +226,7 @@ public override BoundNode VisitTryStatement(BoundTryStatement node)
 
             var completeTry = _F.Block(
                 locals.ToImmutableAndFree(),
+                ImmutableArray<LocalFunctionSymbol>.Empty,
                 statements.ToImmutableAndFree());
 
             return completeTry;
@@ -402,6 +403,7 @@ private BoundStatement UnpendException(LocalSymbol pendingExceptionLocal)
 
             return _F.Block(
                     ImmutableArray.Create<LocalSymbol>(obj),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     objInit,
                     _F.If(
                         _F.ObjectNotEqual(
@@ -430,6 +432,7 @@ private BoundStatement Rethrow(LocalSymbol obj)
                 // better rethrow 
                 rethrow = _F.Block(
                     ImmutableArray.Create(ex),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     assignment,
                     _F.If(_F.ObjectEqual(_F.Local(ex), _F.Null(ex.Type)), rethrow),
                     // ExceptionDispatchInfo.Capture(pendingExceptionLocal).Throw();
@@ -484,6 +487,7 @@ private BoundStatement RewriteFinalizedRegion(BoundTryStatement node)
                         currentAwaitCatchFrame.pendingCaughtException,
                         currentAwaitCatchFrame.pendingCatch).
                         AddRange(currentAwaitCatchFrame.GetHoistedLocals()),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     _F.HiddenSequencePoint(),
                     _F.Assignment(
                         _F.Local(currentAwaitCatchFrame.pendingCatch),
@@ -616,6 +620,7 @@ public override BoundNode VisitCatchBlock(BoundCatchBlock node)
 
             var handler = _F.Block(
                     handlerLocals,
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     handlerStatements.ToImmutableAndFree()
                 );
 

src/Compilers/CSharp/Portable/Lowering/AsyncRewriter/AsyncMethodToStateMachineRewriter.cs

@@ -130,6 +130,7 @@ internal void GenerateMoveNext(BoundStatement body, MethodSymbol moveNextMethod)
             bodyBuilder.Add(
                 F.Try(
                     F.Block(ImmutableArray<LocalSymbol>.Empty,
+                        ImmutableArray<LocalFunctionSymbol>.Empty,
                         // switch (state) ...
                         F.HiddenSequencePoint(),
                         Dispatch(),
@@ -201,6 +202,7 @@ internal void GenerateMoveNext(BoundStatement body, MethodSymbol moveNextMethod)
                     body.Syntax, 
                     F.Block(
                         locals.ToImmutableAndFree(), 
+                        ImmutableArray<LocalFunctionSymbol>.Empty,
                         newStatements));
 
             if (rootScopeHoistedLocals.Length > 0)
@@ -301,6 +303,7 @@ private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpressi
                 LocalSymbol resultTemp = F.SynthesizedLocal(type);
                 return F.Block(
                     ImmutableArray.Create(awaiterTemp, resultTemp),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                         awaitIfIncomplete,
                         F.Assignment(F.Local(resultTemp), getResultCall),
                         F.ExpressionStatement(nullAwaiter),
@@ -312,6 +315,7 @@ private BoundBlock VisitAwaitExpression(BoundAwaitExpression node, BoundExpressi
                 // $awaiterTemp = null;
                 return F.Block(
                     ImmutableArray.Create(awaiterTemp),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                         awaitIfIncomplete,
                         F.ExpressionStatement(getResultCall),
                         F.ExpressionStatement(nullAwaiter));
@@ -474,6 +478,7 @@ private BoundStatement GenerateAwaitOnCompletedDynamic(LocalSymbol awaiterTemp)
 
                     thenClause: F.Block(
                         ImmutableArray.Create(notifyCompletionTemp),
+                        ImmutableArray<LocalFunctionSymbol>.Empty,
                         F.Assignment(
                             F.Local(notifyCompletionTemp),
                                 // Use reference conversion rather than dynamic conversion:
@@ -505,6 +510,7 @@ private BoundStatement GenerateAwaitOnCompletedDynamic(LocalSymbol awaiterTemp)
 
             return F.Block(
                 SingletonOrPair(criticalNotifyCompletedTemp, thisTemp),
+                ImmutableArray<LocalFunctionSymbol>.Empty,
                 blockBuilder.ToImmutableAndFree());
         }
 

src/Compilers/CSharp/Portable/Lowering/AsyncRewriter/AsyncRewriter.cs

@@ -193,6 +193,7 @@ protected override BoundStatement GenerateStateMachineCreation(LocalSymbol state
 
                 return F.Block(
                     ImmutableArray.Create(builderVariable),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     bodyBuilder.ToImmutableAndFree());
             }
             catch (SyntheticBoundNodeFactory.MissingPredefinedMember ex)

src/Compilers/CSharp/Portable/Lowering/AsyncRewriter/AwaitExpressionSpiller.cs

@@ -302,7 +302,7 @@ private BoundStatement UpdateStatement(BoundSpillSequenceBuilder builder, BoundS
             }
 
             var substituterOpt = (substituteTemps && _tempSubstitution.Count > 0) ? new LocalSubstituter(_tempSubstitution) : null;
-            var result = _F.Block(builder.GetLocals(), builder.GetStatements(substituterOpt));
+            var result = _F.Block(builder.GetLocals(), ImmutableArray<LocalFunctionSymbol>.Empty, builder.GetStatements(substituterOpt));
 
             builder.Free();
             return result;

src/Compilers/CSharp/Portable/Lowering/IteratorRewriter/IteratorMethodToStateMachineRewriter.cs

@@ -95,7 +95,7 @@ internal void GenerateMoveNextAndDispose(BoundStatement body, SynthesizedImpleme
             // state_0:
             // state = -1;
             // [[rewritten body]]
-            newBody = F.Block(ImmutableArray.Create(cachedState),
+            newBody = F.Block(ImmutableArray.Create(cachedState), ImmutableArray<LocalFunctionSymbol>.Empty,
                     F.Block(
                         F.HiddenSequencePoint(),
                         F.Assignment(F.Local(cachedState), F.Field(F.This(), stateField))
@@ -153,6 +153,7 @@ internal void GenerateMoveNextAndDispose(BoundStatement body, SynthesizedImpleme
 
                 var disposeBody = F.Block(
                                     ImmutableArray.Create<LocalSymbol>(stateLocal),
+                                    ImmutableArray<LocalFunctionSymbol>.Empty,
                                     F.Assignment(F.Local(stateLocal), F.Field(F.This(), stateField)),
                                     EmitFinallyFrame(rootFrame, state),
                                     F.Return());
@@ -179,6 +180,7 @@ private BoundStatement HandleReturn(BoundStatement newBody)
                 //   return methodValue;
                 newBody = F.Block(
                         ImmutableArray.Create<LocalSymbol>(_methodValue),
+                        ImmutableArray<LocalFunctionSymbol>.Empty,
                         newBody,
                         F.Assignment(this.F.Local(_methodValue), this.F.Literal(true)),
                         F.Label(_exitLabel),

src/Compilers/CSharp/Portable/Lowering/IteratorRewriter/IteratorRewriter.cs

@@ -267,7 +267,7 @@ private void GenerateEnumerableImplementation(ref BoundExpression managedThreadI
             }
 
             bodyBuilder.Add(F.Return(F.Local(resultVariable)));
-            F.CloseMethod(F.Block(ImmutableArray.Create(resultVariable), bodyBuilder.ToImmutableAndFree()));
+            F.CloseMethod(F.Block(ImmutableArray.Create(resultVariable), ImmutableArray<LocalFunctionSymbol>.Empty, bodyBuilder.ToImmutableAndFree()));
 
             // Generate IEnumerable.GetEnumerator
             var getEnumerator = OpenMethodImplementation(IEnumerable_GetEnumerator);

src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.cs

@@ -248,7 +248,7 @@ private BoundStatement AddStatementsIfNeeded(BoundStatement body)
             if (_addedLocals != null)
             {
                 _addedStatements.Add(body);
-                body = new BoundBlock(body.Syntax, _addedLocals.ToImmutableAndFree(), _addedStatements.ToImmutableAndFree()) { WasCompilerGenerated = true };
+                body = new BoundBlock(body.Syntax, _addedLocals.ToImmutableAndFree(), ImmutableArray<LocalFunctionSymbol>.Empty, _addedStatements.ToImmutableAndFree()) { WasCompilerGenerated = true };
                 _addedLocals = null;
                 _addedStatements = null;
             }
@@ -839,7 +839,7 @@ private BoundBlock RewriteBlock(BoundBlock node, ArrayBuilder<BoundExpression> p
             }
 
             // TODO: we may not need to update if there was nothing to rewrite.
-            return node.Update(newLocals.ToImmutableAndFree(), newStatements.ToImmutableAndFree());
+            return node.Update(newLocals.ToImmutableAndFree(), node.LocalFunctions, newStatements.ToImmutableAndFree());
         }
 
         public override BoundNode VisitCatchBlock(BoundCatchBlock node)
@@ -965,7 +965,7 @@ public override BoundNode VisitStatementList(BoundStatementList node)
                         newStatements.Add((BoundStatement)this.Visit(s));
                     }
 
-                    return new BoundBlock(node.Syntax, newLocals.ToImmutableAndFree(), newStatements.ToImmutableAndFree(), node.HasErrors);
+                    return new BoundBlock(node.Syntax, newLocals.ToImmutableAndFree(), ImmutableArray<LocalFunctionSymbol>.Empty, newStatements.ToImmutableAndFree(), node.HasErrors);
                 });
             }
             else
@@ -986,7 +986,7 @@ public override BoundNode VisitSwitchStatement(BoundSwitchStatement node)
                     InsertAndFreePrologue(newStatements, prologue);
                     newStatements.Add((BoundStatement)base.VisitSwitchStatement(node));
 
-                    return new BoundBlock(node.Syntax, newLocals.ToImmutableAndFree(), newStatements.ToImmutableAndFree(), node.HasErrors);
+                    return new BoundBlock(node.Syntax, newLocals.ToImmutableAndFree(), ImmutableArray<LocalFunctionSymbol>.Empty, newStatements.ToImmutableAndFree(), node.HasErrors);
                 });
             }
             else

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

@@ -14,7 +14,7 @@ public override BoundNode VisitBlock(BoundBlock node)
         {
             if (node.WasCompilerGenerated || !this.GenerateDebugInfo || node.Syntax.Kind() == SyntaxKind.ArrowExpressionClause)
             {
-                return node.Update(node.Locals, VisitList(node.Statements));
+                return node.Update(node.Locals, node.LocalFunctions, VisitList(node.Statements));
             }
 
             BlockSyntax syntax = node.Syntax as BlockSyntax;
@@ -39,13 +39,13 @@ public override BoundNode VisitBlock(BoundBlock node)
                 builder.Add(new BoundSequencePointWithSpan(syntax, null, cBspan));
             }
 
-            return new BoundBlock(syntax, node.Locals, builder.ToImmutableAndFree(), node.HasErrors);
+            return new BoundBlock(syntax, node.Locals, node.LocalFunctions, builder.ToImmutableAndFree(), node.HasErrors);
         }
 
         public override BoundNode VisitNoOpStatement(BoundNoOpStatement node)
         {
             return (node.WasCompilerGenerated || !this.GenerateDebugInfo)
-                ? new BoundBlock(node.Syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray<BoundStatement>.Empty)
+                ? new BoundBlock(node.Syntax, ImmutableArray<LocalSymbol>.Empty, ImmutableArray<LocalFunctionSymbol>.Empty, ImmutableArray<BoundStatement>.Empty)
                 : AddSequencePoint(node);
         }
     }

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

@@ -55,6 +55,7 @@ public override BoundNode VisitFixedStatement(BoundFixedStatement node)
             {
                 return _factory.Block(
                     localBuilder.ToImmutableAndFree(),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     new BoundTryStatement(
                         _factory.Syntax,
                         _factory.Block(statementBuilder.ToImmutableAndFree()),
@@ -64,7 +65,7 @@ public override BoundNode VisitFixedStatement(BoundFixedStatement node)
             else
             {
                 statementBuilder.AddRange(cleanup);
-                return _factory.Block(localBuilder.ToImmutableAndFree(), statementBuilder.ToImmutableAndFree());
+                return _factory.Block(localBuilder.ToImmutableAndFree(), ImmutableArray<LocalFunctionSymbol>.Empty, statementBuilder.ToImmutableAndFree());
             }
         }
 

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

@@ -208,6 +208,7 @@ private BoundStatement RewriteEnumeratorForEachStatement(BoundForEachStatement n
 
                     finallyBlockOpt = new BoundBlock(forEachSyntax,
                         locals: ImmutableArray<LocalSymbol>.Empty,
+                        localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                         statements: ImmutableArray.Create<BoundStatement>(disposeStmt));
                 }
                 else
@@ -259,6 +260,7 @@ private BoundStatement RewriteEnumeratorForEachStatement(BoundForEachStatement n
                     // if (d != null) d.Dispose();
                     finallyBlockOpt = new BoundBlock(forEachSyntax,
                         locals: ImmutableArray.Create<LocalSymbol>(disposableVar),
+                        localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                         statements: ImmutableArray.Create<BoundStatement>(disposableVarDecl, ifStmt));
                 }
 
@@ -274,6 +276,7 @@ private BoundStatement RewriteEnumeratorForEachStatement(BoundForEachStatement n
                 BoundStatement tryFinally = new BoundTryStatement(forEachSyntax,
                     tryBlock: new BoundBlock(forEachSyntax,
                         locals: ImmutableArray<LocalSymbol>.Empty,
+                        localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                         statements: ImmutableArray.Create<BoundStatement>(whileLoop)),
                     catchBlocks: ImmutableArray<BoundCatchBlock>.Empty,
                     finallyBlockOpt: finallyBlockOpt);
@@ -284,6 +287,7 @@ private BoundStatement RewriteEnumeratorForEachStatement(BoundForEachStatement n
                 result = new BoundBlock(
                     syntax: forEachSyntax,
                     locals: ImmutableArray.Create(enumeratorVar),
+                    localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                     statements: ImmutableArray.Create<BoundStatement>(enumeratorVarDecl, tryFinally));
             }
             else
@@ -296,6 +300,7 @@ private BoundStatement RewriteEnumeratorForEachStatement(BoundForEachStatement n
                 result = new BoundBlock(
                     syntax: forEachSyntax,
                     locals: ImmutableArray.Create(enumeratorVar),
+                    localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                     statements: ImmutableArray.Create<BoundStatement>(enumeratorVarDecl, whileLoop));
             }
 
@@ -502,6 +507,7 @@ private BoundStatement RewriteStringForEachStatement(BoundForEachStatement node)
             return new BoundBlock(
                 forEachSyntax,
                 locals: ImmutableArray.Create(iterationVariable),
+                localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                 statements: ImmutableArray.Create(iteratorVariableInitialization, rewrittenBody));
         }
 
@@ -808,6 +814,7 @@ private BoundStatement RewriteMultiDimensionalArrayForEachStatement(BoundForEach
             BoundStatement result = new BoundBlock(
                 forEachSyntax,
                 ImmutableArray.Create(arrayVar).Concat(upperVar.AsImmutableOrNull()),
+                ImmutableArray<LocalFunctionSymbol>.Empty,
                 ImmutableArray.Create(arrayVarDecl).Concat(upperVarDecl.AsImmutableOrNull()).Add(forLoop));
 
             AddForEachKeywordSequencePoint(forEachSyntax, ref result);

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

@@ -150,7 +150,7 @@ public override BoundNode VisitForStatement(BoundForStatement node)
             statementBuilder.Add(new BoundLabelStatement(syntax, breakLabel));
 
             var statements = statementBuilder.ToImmutableAndFree();
-            return new BoundBlock(syntax, outerLocals, statements, hasErrors);
+            return new BoundBlock(syntax, outerLocals, ImmutableArray<LocalFunctionSymbol>.Empty, statements, hasErrors);
         }
     }
 }

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

@@ -120,6 +120,7 @@ public override BoundNode VisitLockStatement(BoundLockStatement node)
                 return new BoundBlock(
                     lockSyntax,
                     ImmutableArray.Create(boundLockTemp.LocalSymbol, boundLockTakenTemp.LocalSymbol),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     ImmutableArray.Create(
                         MakeInitialLockSequencePoint(boundLockTempInit, lockSyntax),
                         boundLockTakenTempInit,
@@ -170,6 +171,7 @@ public override BoundNode VisitLockStatement(BoundLockStatement node)
                 return new BoundBlock(
                     lockSyntax,
                     ImmutableArray.Create(boundLockTemp.LocalSymbol),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     ImmutableArray.Create(
                         MakeInitialLockSequencePoint(boundLockTempInit, lockSyntax),
                         enterCall,

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

@@ -172,7 +172,11 @@ public override BoundNode VisitSwitchStatement(BoundSwitchStatement node)
 
             statementBuilder.Add(rewrittenSwitchStatement);
 
-            return new BoundBlock(syntax, locals: (object)tempLocal == null ? ImmutableArray<LocalSymbol>.Empty : ImmutableArray.Create<LocalSymbol>(tempLocal), statements: statementBuilder.ToImmutableAndFree());
+            return new BoundBlock(
+                syntax,
+                locals: (object)tempLocal == null ? ImmutableArray<LocalSymbol>.Empty : ImmutableArray.Create<LocalSymbol>(tempLocal),
+                localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
+                statements: statementBuilder.ToImmutableAndFree());
         }
 
         private static LabelSymbol GetNullValueTargetSwitchLabel(ImmutableArray<BoundSwitchSection> sections, GeneratedLabelSymbol breakLabel)

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

@@ -56,6 +56,7 @@ public override BoundNode VisitUsingStatement(BoundUsingStatement node)
                 return new BoundBlock(
                     usingSyntax,
                     node.Locals,
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     ImmutableArray.Create<BoundStatement>(result));
             }
         }
@@ -141,6 +142,7 @@ private BoundBlock RewriteExpressionUsingStatement(BoundUsingStatement node, Bou
             return new BoundBlock(
                 syntax: usingSyntax,
                 locals: node.Locals.Add(boundTemp.LocalSymbol),
+                localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                 statements: ImmutableArray.Create<BoundStatement>(expressionStatement, tryFinally));
         }
 
@@ -190,6 +192,7 @@ private BoundBlock RewriteDeclarationUsingStatement(CSharpSyntaxNode usingSyntax
                 return new BoundBlock(
                     syntax: usingSyntax,
                     locals: ImmutableArray.Create<LocalSymbol>(boundTemp.LocalSymbol), //localSymbol will be declared by an enclosing block
+                    localFunctions: ImmutableArray<LocalFunctionSymbol>.Empty,
                     statements: ImmutableArray.Create<BoundStatement>(
                         rewrittenDeclaration,
                         new BoundExpressionStatement(declarationSyntax, tempAssignment),

src/Compilers/CSharp/Portable/Lowering/MethodToClassRewriter.cs

@@ -131,8 +131,9 @@ public override BoundNode VisitCatchBlock(BoundCatchBlock node)
         public override BoundNode VisitBlock(BoundBlock node)
         {
             var newLocals = RewriteLocals(node.Locals);
+            var newLocalFunctions = node.LocalFunctions;
             var newStatements = VisitList(node.Statements);
-            return node.Update(newLocals, newStatements);
+            return node.Update(newLocals, newLocalFunctions, newStatements);
         }
 
         public override BoundNode VisitSequence(BoundSequence node)

src/Compilers/CSharp/Portable/Lowering/StateMachineRewriter/StateMachineRewriter.cs

@@ -269,6 +269,7 @@ private BoundStatement GenerateKickoffMethodBody()
             bodyBuilder.Add(GenerateStateMachineCreation(stateMachineVariable, frameType));
             return F.Block(
                 ImmutableArray.Create(stateMachineVariable),
+                ImmutableArray<LocalFunctionSymbol>.Empty,
                 bodyBuilder.ToImmutableAndFree());
         }
 

src/Compilers/CSharp/Portable/Lowering/SyntheticBoundNodeFactory.cs

@@ -398,7 +398,7 @@ public BoundBlock Block()
 
         public BoundBlock Block(ImmutableArray<BoundStatement> statements)
         {
-            return Block(ImmutableArray<LocalSymbol>.Empty, statements);
+            return Block(ImmutableArray<LocalSymbol>.Empty, ImmutableArray<LocalFunctionSymbol>.Empty, statements);
         }
 
         public BoundBlock Block(params BoundStatement[] statements)
@@ -406,14 +406,14 @@ public BoundBlock Block(params BoundStatement[] statements)
             return Block(ImmutableArray.Create(statements));
         }
 
-        public BoundBlock Block(ImmutableArray<LocalSymbol> locals, params BoundStatement[] statements)
+        public BoundBlock Block(ImmutableArray<LocalSymbol> locals, ImmutableArray<LocalFunctionSymbol> localFunctions, params BoundStatement[] statements)
         {
-            return Block(locals, ImmutableArray.Create(statements));
+            return Block(locals, localFunctions, ImmutableArray.Create(statements));
         }
 
-        public BoundBlock Block(ImmutableArray<LocalSymbol> locals, ImmutableArray<BoundStatement> statements)
+        public BoundBlock Block(ImmutableArray<LocalSymbol> locals, ImmutableArray<LocalFunctionSymbol> localFunctions, ImmutableArray<BoundStatement> statements)
         {
-            return new BoundBlock(Syntax, locals, statements) { WasCompilerGenerated = true };
+            return new BoundBlock(Syntax, locals, localFunctions, statements) { WasCompilerGenerated = true };
         }
 
         public BoundReturnStatement Return(BoundExpression expression = null)

src/Compilers/CSharp/Portable/Symbols/Synthesized/SynthesizedEntryPointSymbol.cs

@@ -306,6 +306,7 @@ internal override BoundBlock CreateBody()
 
                 return new BoundBlock(syntax,
                     ImmutableArray.Create<LocalSymbol>(submissionLocal.LocalSymbol),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     ImmutableArray.Create<BoundStatement>(
                         // var script = new Script();
                         new BoundExpressionStatement(
@@ -440,6 +441,7 @@ internal override BoundBlock CreateBody()
 
                 return new BoundBlock(syntax,
                     ImmutableArray.Create<LocalSymbol>(submissionLocal.LocalSymbol),
+                    ImmutableArray<LocalFunctionSymbol>.Empty,
                     ImmutableArray.Create<BoundStatement>(submissionAssignment, returnStatement))
                 { WasCompilerGenerated = true };
             }

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

@@ -2766,7 +2766,10 @@ static void Main(string[] args)
     Diagnostic(ErrorCode.ERR_InvalidExprTerm, ")").WithArguments(")").WithLocation(6, 24),
     // (6,26): error CS1023: Embedded statement cannot be a declaration or labeled statement
     //         void f() { if () const int i = 0; }
-    Diagnostic(ErrorCode.ERR_BadEmbeddedStmt, "const int i = 0;").WithLocation(6, 26)
+    Diagnostic(ErrorCode.ERR_BadEmbeddedStmt, "const int i = 0;").WithLocation(6, 26),
+    // (6,14): warning CS0168: The variable 'f' is declared but never used
+    //         void f() { if () const int i = 0; }
+    Diagnostic(ErrorCode.WRN_UnreferencedVar, "f").WithArguments("f").WithLocation(6, 14)
                 );
         }
 

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

@@ -168,6 +168,7 @@ void Params(params int x)
         {
             Console.WriteLine(x);
         }
+        Params(2);
     }
 }
 ";
@@ -190,6 +191,8 @@ void RefOut(ref int x = 2)
         {
             x++;
         }
+        int y = 2;
+        RefOut(ref y);
     }
 }
 ";
@@ -214,6 +217,7 @@ void NamedOptional(string x = 2)
         {
             Console.WriteLine(x);
         }
+        NamedOptional(""2"");
     }
 }
 ";
@@ -239,6 +243,7 @@ void CallerMemberName([CallerMemberName] int s = 2)
         {
             Console.WriteLine(s);
         }
+        CallerMemberName();
     }
 }
 ";
@@ -2184,11 +2189,13 @@ public void MainLocfuncIsntEntry()
             var source = @"
 void Main()
 {
-    Console.Write(""bad"");
+    Console.Write(4);
 }
 Console.Write(2);
+Console.Write(' ');
+Main();
 ";
-            VerifyOutputInMain(source, "2", "System");
+            VerifyOutputInMain(source, "2 4", "System");
         }
 
         [Fact]
@@ -2249,6 +2256,7 @@ void Local()
             {
                 Console.WriteLine(2);
             }
+            Local();
         }
         Local();
 
@@ -2261,12 +2269,13 @@ void Local2()
 }
 ";
             VerifyDiagnostics(source,
-    // (15,9): error CS0103: The name 'Local' does not exist in the current context
+    // (16,9): error CS0103: The name 'Local' does not exist in the current context
     //         Local();
-    Diagnostic(ErrorCode.ERR_NameNotInContext, "Local").WithArguments("Local").WithLocation(15, 9),
-    // (17,9): error CS0841: Cannot use local variable 'Local2' before it is declared
+    Diagnostic(ErrorCode.ERR_NameNotInContext, "Local").WithArguments("Local").WithLocation(16, 9),
+    // (18,9): error CS0841: Cannot use local variable 'Local2' before it is declared
     //         Local2();
-    Diagnostic(ErrorCode.ERR_VariableUsedBeforeDeclaration, "Local2").WithArguments("Local2").WithLocation(17, 9));
+    Diagnostic(ErrorCode.ERR_VariableUsedBeforeDeclaration, "Local2").WithArguments("Local2").WithLocation(18, 9)
+    );
         }
 
         [Fact]
@@ -2279,13 +2288,17 @@ static void Main(string[] args)
     {
         void Duplicate() { }
         void Duplicate() { }
+        Duplicate();
     }
 }
 ";
             VerifyDiagnostics(source,
     // (7,14): error CS0128: A local variable named 'Duplicate' is already defined in this scope
     //         void Duplicate() { }
-    Diagnostic(ErrorCode.ERR_LocalDuplicate, "Duplicate").WithArguments("Duplicate").WithLocation(7, 14)
+    Diagnostic(ErrorCode.ERR_LocalDuplicate, "Duplicate").WithArguments("Duplicate").WithLocation(7, 14),
+    // (7,14): warning CS0168: The variable 'Duplicate' is declared but never used
+    //         void Duplicate() { }
+    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Duplicate").WithArguments("Duplicate").WithLocation(7, 14)
     );
         }
 
@@ -2297,18 +2310,16 @@ class Program
 {
     static void Main(string[] args)
     {
-        int x;
+        int x = 2;
         void Param(int x) { }
+        Param(x);
     }
 }
 ";
             VerifyDiagnostics(source,
     // (7,24): error CS0136: A local or parameter named 'x' cannot be declared in this scope because that name is used in an enclosing local scope to define a local or parameter
     //         void Param(int x) { }
-    Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x").WithArguments("x").WithLocation(7, 24),
-    // (6,13): warning CS0168: The variable 'x' is declared but never used
-    //         int x;
-    Diagnostic(ErrorCode.WRN_UnreferencedVar, "x").WithArguments("x").WithLocation(6, 13)
+    Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "x").WithArguments("x").WithLocation(7, 24)
     );
         }
 
@@ -2322,6 +2333,7 @@ static void Main(string[] args)
     {
         int T;
         void Generic<T>() { }
+        Generic<int>();
     }
 }
 ";
@@ -2354,7 +2366,10 @@ static void Main(string[] args)
     Diagnostic(ErrorCode.ERR_LocalDuplicate, "Conflict").WithArguments("Conflict").WithLocation(7, 14),
     // (6,13): warning CS0168: The variable 'Conflict' is declared but never used
     //         int Conflict;
-    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Conflict").WithArguments("Conflict").WithLocation(6, 13)
+    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Conflict").WithArguments("Conflict").WithLocation(6, 13),
+    // (7,14): warning CS0168: The variable 'Conflict' is declared but never used
+    //         void Conflict() { }
+    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Conflict").WithArguments("Conflict").WithLocation(7, 14)
     );
         }
 
@@ -2378,7 +2393,10 @@ static void Main(string[] args)
     Diagnostic(ErrorCode.ERR_LocalIllegallyOverrides, "Conflict").WithArguments("Conflict").WithLocation(6, 14),
     // (7,13): warning CS0168: The variable 'Conflict' is declared but never used
     //         int Conflict;
-    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Conflict").WithArguments("Conflict").WithLocation(7, 13)
+    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Conflict").WithArguments("Conflict").WithLocation(7, 13),
+    // (6,14): warning CS0168: The variable 'Conflict' is declared but never used
+    //         void Conflict() { }
+    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Conflict").WithArguments("Conflict").WithLocation(6, 14)
     );
         }
 
@@ -2676,7 +2694,7 @@ static void Main(string[] args)
     );
         }
 
-        [Fact(Skip = "No usage detection at the moment")]
+        [Fact]
         public void BadNotUsed()
         {
             var source = @"
@@ -2693,7 +2711,11 @@ static void Main(string[] args)
         A();
     }
 }";
-            VerifyDiagnostics(source /*, ... diagnostics ... */);
+            VerifyDiagnostics(source,
+    // (6,14): warning CS0168: The variable 'Local' is declared but never used
+    //         void Local()
+    Diagnostic(ErrorCode.WRN_UnreferencedVar, "Local").WithArguments("Local").WithLocation(6, 14)
+    );
         }
 
         [Fact]
@@ -2710,6 +2732,7 @@ void Local()
         {
             Console.WriteLine(x);
         }
+        Local();
     }
     static void Main()
     {
@@ -2736,6 +2759,7 @@ void Local()
         {
             Console.WriteLine(__arglist);
         }
+        Local();
     }
     static void B(__arglist)
     {
@@ -2743,6 +2767,7 @@ void Local()
         {
             Console.WriteLine(__arglist);
         }
+        Local();
     }
     static void C() // C and D produce different errors
     {
@@ -2750,6 +2775,7 @@ void Local(__arglist)
         {
             Console.WriteLine(__arglist);
         }
+        Local(__arglist());
     }
     static void D(__arglist)
     {
@@ -2757,6 +2783,7 @@ void Local(__arglist)
         {
             Console.WriteLine(__arglist);
         }
+        Local(__arglist());
     }
     static void Main()
     {
@@ -2767,15 +2794,15 @@ static void Main()
     // (10,31): error CS0190: The __arglist construct is valid only within a variable argument method
     //             Console.WriteLine(__arglist);
     Diagnostic(ErrorCode.ERR_ArgsInvalid, "__arglist").WithLocation(10, 31),
-    // (17,31): error CS4013: Instance of type 'RuntimeArgumentHandle' cannot be used inside an anonymous function, query expression, iterator block or async method
+    // (18,31): error CS4013: Instance of type 'RuntimeArgumentHandle' cannot be used inside an anonymous function, query expression, iterator block or async method
     //             Console.WriteLine(__arglist);
-    Diagnostic(ErrorCode.ERR_SpecialByRefInLambda, "__arglist").WithArguments("System.RuntimeArgumentHandle").WithLocation(17, 31),
-    // (24,31): error CS0190: The __arglist construct is valid only within a variable argument method
+    Diagnostic(ErrorCode.ERR_SpecialByRefInLambda, "__arglist").WithArguments("System.RuntimeArgumentHandle").WithLocation(18, 31),
+    // (26,31): error CS0190: The __arglist construct is valid only within a variable argument method
     //             Console.WriteLine(__arglist);
-    Diagnostic(ErrorCode.ERR_ArgsInvalid, "__arglist").WithLocation(24, 31),
-    // (31,31): error CS4013: Instance of type 'RuntimeArgumentHandle' cannot be used inside an anonymous function, query expression, iterator block or async method
+    Diagnostic(ErrorCode.ERR_ArgsInvalid, "__arglist").WithLocation(26, 31),
+    // (34,31): error CS4013: Instance of type 'RuntimeArgumentHandle' cannot be used inside an anonymous function, query expression, iterator block or async method
     //             Console.WriteLine(__arglist);
-    Diagnostic(ErrorCode.ERR_SpecialByRefInLambda, "__arglist").WithArguments("System.RuntimeArgumentHandle").WithLocation(31, 31)
+    Diagnostic(ErrorCode.ERR_SpecialByRefInLambda, "__arglist").WithArguments("System.RuntimeArgumentHandle").WithLocation(34, 31)
     );
         }
 
@@ -2794,6 +2821,7 @@ void Local()
         {
             Console.WriteLine(_a);
         }
+        Local();
     }
     static void Main()
     {
@@ -2821,6 +2849,8 @@ IEnumerable<int> RefEnumerable(ref int x)
         {
             yield return x;
         }
+        int y = 0;
+        RefEnumerable(ref y);
     }
 }
 ";
@@ -2835,6 +2865,7 @@ IEnumerable<int> RefEnumerable(ref int x)
         public void BadRefAsync()
         {
             var source = @"
+using System;
 using System.Threading.Tasks;
 
 class Program
@@ -2845,13 +2876,15 @@ async Task<int> RefAsync(ref int x)
         {
             return await Task.FromResult(x);
         }
+        int y = 2;
+        Console.Write(RefAsync(ref y).Result);
     }
 }
 ";
             VerifyDiagnostics(source,
-    // (8,42): error CS1988: Async methods cannot have ref or out parameters
+    // (9,42): error CS1988: Async methods cannot have ref or out parameters
     //         async Task<int> RefAsync(ref int x)
-    Diagnostic(ErrorCode.ERR_BadAsyncArgType, "x").WithLocation(8, 42)
+    Diagnostic(ErrorCode.ERR_BadAsyncArgType, "x").WithLocation(9, 42)
     );
         }
 
@@ -2900,6 +2933,10 @@ static void LocalStatic()
         volatile void LocalVolatile()
         {
         }
+        LocalConst();
+        LocalStatic();
+        LocalReadonly();
+        LocalVolatile();
     }
 }
 ";
@@ -3069,6 +3106,7 @@ var Local()
         {
             yield return 2;
         }
+        Local();
     }
 }
 ";
@@ -3091,6 +3129,7 @@ var Local()
         {
             yield break;
         }
+        Local();
     }
 }
 ";
@@ -3300,6 +3339,7 @@ static void Main(string[] args)
         void Local()
         {
         }
+        Local();
     }
 }
 ";

src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/Rewriters/CapturedVariableRewriter.cs

@@ -42,8 +42,9 @@ internal sealed class CapturedVariableRewriter : BoundTreeRewriter
         public override BoundNode VisitBlock(BoundBlock node)
         {
             var rewrittenLocals = node.Locals.WhereAsArray(local => local.IsCompilerGenerated || local.Name == null || this.GetVariable(local.Name) == null);
+            var rewrittenLocalFunctions = node.LocalFunctions;
             var rewrittenStatements = VisitList(node.Statements);
-            return node.Update(rewrittenLocals, rewrittenStatements);
+            return node.Update(rewrittenLocals, rewrittenLocalFunctions, rewrittenStatements);
         }
 
         public override BoundNode VisitLocal(BoundLocal node)

src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/Rewriters/LocalDeclarationRewriter.cs

@@ -38,7 +38,7 @@ internal static BoundNode Rewrite(CSharpCompilation compilation, EENamedTypeSymb
 
             if (hasChanged)
             {
-                node = new BoundBlock(node.Syntax, ImmutableArray<LocalSymbol>.Empty, builder.ToImmutable()) { WasCompilerGenerated = true };
+                node = BoundBlock.SynthesizedNoLocals(node.Syntax, builder.ToImmutable());
             }
 
             builder.Free();

src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/Symbols/EEConstructorSymbol.cs

@@ -18,6 +18,7 @@ internal EEConstructorSymbol(NamedTypeSymbol containingType)
         internal override void GenerateMethodBody(TypeCompilationState compilationState, DiagnosticBag diagnostics)
         {
             var noLocals = ImmutableArray<LocalSymbol>.Empty;
+            var noLocalFunctions = ImmutableArray<LocalFunctionSymbol>.Empty;
             var initializerInvocation = MethodCompiler.BindConstructorInitializer(this, diagnostics, compilationState.Compilation);
             var syntax = initializerInvocation.Syntax;
 
@@ -25,6 +26,7 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
                 new BoundBlock(
                     syntax,
                     noLocals,
+                    noLocalFunctions,
                     ImmutableArray.Create<BoundStatement>(
                         new BoundExpressionStatement(syntax, initializerInvocation),
                         new BoundReturnStatement(syntax, null))));

src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/Symbols/EEMethodSymbol.cs

@@ -482,7 +482,7 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
             }
             localsSet.Free();
 
-            body = new BoundBlock(syntax, localsBuilder.ToImmutableAndFree(), statementsBuilder.ToImmutableAndFree()) { WasCompilerGenerated = true };
+            body = new BoundBlock(syntax, localsBuilder.ToImmutableAndFree(), ImmutableArray<LocalFunctionSymbol>.Empty, statementsBuilder.ToImmutableAndFree()) { WasCompilerGenerated = true };
 
             Debug.Assert(!diagnostics.HasAnyErrors());
             Debug.Assert(!body.HasErrors);
@@ -600,7 +600,7 @@ internal override void GenerateMethodBody(TypeCompilationState compilationState,
                 localBuilder.Add(local);
             }
 
-            body = block.Update(localBuilder.ToImmutableAndFree(), block.Statements);
+            body = block.Update(localBuilder.ToImmutableAndFree(), block.LocalFunctions, block.Statements);
             TypeParameterChecker.Check(body, _allTypeParameters);
             compilationState.AddSynthesizedMethod(this, body);
         }