Remove the addInterval method from interval trees.

src/EditorFeatures/Test/Collections/IntervalTreeTests.cs

@@ -33,14 +33,6 @@ public int GetLength(Tuple<int, int, T> value)
         private static IEnumerable<SimpleIntervalTree<Tuple<int, int, string>>> CreateTrees(IEnumerable<Tuple<int, int, string>> values)
         {
             yield return SimpleIntervalTree.Create(new TupleIntrospector<string>(), values);
-
-            var tree1 = SimpleIntervalTree.Create(new TupleIntrospector<string>());
-            foreach (var v in values)
-            {
-                tree1 = tree1.AddInterval(v);
-            }
-
-            yield return tree1;
         }
 
         [Fact]

src/Workspaces/CSharp/Portable/Extensions/DirectiveSyntaxExtensions.DirectiveInfo.cs

@@ -17,7 +17,7 @@ private class DirectiveInfo
             public IDictionary<DirectiveTriviaSyntax, DirectiveTriviaSyntax> DirectiveMap { get; }
 
             // Maps a #If/#elif/#else/#endIf directive to its list of matching #If/#elif/#else/#endIf directives
-            public IDictionary<DirectiveTriviaSyntax, IEnumerable<DirectiveTriviaSyntax>> ConditionalMap { get; }
+            public IDictionary<DirectiveTriviaSyntax, IReadOnlyList<DirectiveTriviaSyntax>> ConditionalMap { get; }
 
             // A set of inactive regions spans.  The items in the tuple are the start and end line
             // *both inclusive* of the inactive region. Actual PP lines are not contined within.
@@ -28,7 +28,7 @@ private class DirectiveInfo
 
             public DirectiveInfo(
                 IDictionary<DirectiveTriviaSyntax, DirectiveTriviaSyntax> directiveMap,
-                IDictionary<DirectiveTriviaSyntax, IEnumerable<DirectiveTriviaSyntax>> conditionalMap,
+                IDictionary<DirectiveTriviaSyntax, IReadOnlyList<DirectiveTriviaSyntax>> conditionalMap,
                 ISet<Tuple<int, int>> inactiveRegionLines)
             {
                 this.DirectiveMap = directiveMap;

src/Workspaces/CSharp/Portable/Extensions/DirectiveSyntaxExtensions.DirectiveWalker.cs

@@ -16,7 +16,7 @@ internal partial class DirectiveSyntaxExtensions
         private class DirectiveWalker : CSharpSyntaxWalker
         {
             private readonly IDictionary<DirectiveTriviaSyntax, DirectiveTriviaSyntax> _directiveMap;
-            private readonly IDictionary<DirectiveTriviaSyntax, IEnumerable<DirectiveTriviaSyntax>> _conditionalMap;
+            private readonly IDictionary<DirectiveTriviaSyntax, IReadOnlyList<DirectiveTriviaSyntax>> _conditionalMap;
             private readonly CancellationToken _cancellationToken;
 
             private readonly Stack<DirectiveTriviaSyntax> _regionStack = new Stack<DirectiveTriviaSyntax>();
@@ -24,7 +24,7 @@ private class DirectiveWalker : CSharpSyntaxWalker
 
             public DirectiveWalker(
                 IDictionary<DirectiveTriviaSyntax, DirectiveTriviaSyntax> directiveMap,
-                IDictionary<DirectiveTriviaSyntax, IEnumerable<DirectiveTriviaSyntax>> conditionalMap,
+                IDictionary<DirectiveTriviaSyntax, IReadOnlyList<DirectiveTriviaSyntax>> conditionalMap,
                 CancellationToken cancellationToken) :
                 base(SyntaxWalkerDepth.Token)
             {
@@ -105,8 +105,16 @@ private void HandleEndIfDirective(DirectiveTriviaSyntax directive)
                     return;
                 }
 
+                FinishIf(directive);
+            }
+
+            private void FinishIf(DirectiveTriviaSyntax directiveOpt)
+            {
                 var condDirectives = new List<DirectiveTriviaSyntax>();
-                condDirectives.Add(directive);
+                if (directiveOpt != null)
+                {
+                    condDirectives.Add(directiveOpt);
+                }
 
                 while (!_ifStack.IsEmpty())
                 {
@@ -132,8 +140,11 @@ private void HandleEndIfDirective(DirectiveTriviaSyntax directive)
                     ifDirective.Kind() == SyntaxKind.ElifDirectiveTrivia ||
                     ifDirective.Kind() == SyntaxKind.ElseDirectiveTrivia);
 
-                _directiveMap.Add(directive, ifDirective);
-                _directiveMap.Add(ifDirective, directive);
+                if (directiveOpt != null)
+                {
+                    _directiveMap.Add(directiveOpt, ifDirective);
+                    _directiveMap.Add(ifDirective, directiveOpt);
+                }
             }
 
             private void HandleEndRegionDirective(DirectiveTriviaSyntax directive)
@@ -148,6 +159,16 @@ private void HandleEndRegionDirective(DirectiveTriviaSyntax directive)
                 _directiveMap.Add(directive, previousDirective);
                 _directiveMap.Add(previousDirective, directive);
             }
+
+            internal void Finish() {
+                while (_regionStack.Count > 0) {
+                    _directiveMap.Add(_regionStack.Pop(), null);
+                }
+
+                while (_ifStack.Count > 0) {
+                    FinishIf(directiveOpt: null);
+                }
+            }
         }
     }
 }

src/Workspaces/CSharp/Portable/Extensions/DirectiveSyntaxExtensions.cs

@@ -40,11 +40,12 @@ private static DirectiveInfo GetDirectiveInfo(SyntaxNode node, CancellationToken
             {
                 var directiveMap = new Dictionary<DirectiveTriviaSyntax, DirectiveTriviaSyntax>(
                     DirectiveSyntaxEqualityComparer.Instance);
-                var conditionalMap = new Dictionary<DirectiveTriviaSyntax, IEnumerable<DirectiveTriviaSyntax>>(
+                var conditionalMap = new Dictionary<DirectiveTriviaSyntax, IReadOnlyList<DirectiveTriviaSyntax>>(
                     DirectiveSyntaxEqualityComparer.Instance);
 
                 var walker = new DirectiveWalker(directiveMap, conditionalMap, cancellationToken);
                 walker.Visit(r);
+                walker.Finish();
 
                 return new DirectiveInfo(directiveMap, conditionalMap, inactiveRegionLines: null);
             });
@@ -67,7 +68,7 @@ internal static DirectiveTriviaSyntax GetMatchingDirective(this DirectiveTriviaS
             return result;
         }
 
-        internal static IEnumerable<DirectiveTriviaSyntax> GetMatchingConditionalDirectives(this DirectiveTriviaSyntax directive, CancellationToken cancellationToken)
+        internal static IReadOnlyList<DirectiveTriviaSyntax> GetMatchingConditionalDirectives(this DirectiveTriviaSyntax directive, CancellationToken cancellationToken)
         {
             if (directive == null)
             {
@@ -76,7 +77,7 @@ internal static IEnumerable<DirectiveTriviaSyntax> GetMatchingConditionalDirecti
 
             var directiveConditionalMap = GetDirectiveInfo(directive, cancellationToken).ConditionalMap;
 
-            IEnumerable<DirectiveTriviaSyntax> result;
+            IReadOnlyList<DirectiveTriviaSyntax> result;
             directiveConditionalMap.TryGetValue(directive, out result);
 
             return result;

src/Workspaces/CSharp/Portable/Extensions/SyntaxNodeExtensions.cs

@@ -420,17 +420,13 @@ public static bool IsAnyLambdaOrAnonymousMethod(this SyntaxNode node)
             this SyntaxNode syntaxNode,
             CancellationToken cancellationToken)
         {
-            // Check if this node contains a start or end pp construct whose matching construct is
+            // Check if this node contains a start, middle or end pp construct whose matching construct is
             // not contained within this node.  If so, this node must be pinned and cannot move.
-            //
-            // Also, keep track of those spans so that if we see #else/#elif we can tell if they
-            // belong to a pp span that is entirely within the node.
-            var ifEndIfSpans = SimpleIntervalTree.Create(TextSpanIntervalIntrospector.Instance);
 
             var span = syntaxNode.Span;
             foreach (var token in syntaxNode.DescendantTokens())
             {
-                if (ContainsInterleavedDirective(span, token, ref ifEndIfSpans, cancellationToken))
+                if (ContainsInterleavedDirective(span, token, cancellationToken))
                 {
                     return true;
                 }
@@ -442,25 +438,23 @@ public static bool IsAnyLambdaOrAnonymousMethod(this SyntaxNode node)
         private static bool ContainsInterleavedDirective(
             TextSpan textSpan,
             SyntaxToken token,
-            ref SimpleIntervalTree<TextSpan> ifEndIfSpans,
             CancellationToken cancellationToken)
         {
             return
-                ContainsInterleavedDirective(textSpan, token.LeadingTrivia, ref ifEndIfSpans, cancellationToken) ||
-                ContainsInterleavedDirective(textSpan, token.TrailingTrivia, ref ifEndIfSpans, cancellationToken);
+                ContainsInterleavedDirective(textSpan, token.LeadingTrivia, cancellationToken) ||
+                ContainsInterleavedDirective(textSpan, token.TrailingTrivia, cancellationToken);
         }
 
         private static bool ContainsInterleavedDirective(
             TextSpan textSpan,
             SyntaxTriviaList list,
-            ref SimpleIntervalTree<TextSpan> ifEndIfSpans,
             CancellationToken cancellationToken)
         {
             foreach (var trivia in list)
             {
                 if (textSpan.Contains(trivia.Span))
                 {
-                    if (ContainsInterleavedDirective(textSpan, trivia, ref ifEndIfSpans, cancellationToken))
+                    if (ContainsInterleavedDirective(textSpan, trivia, cancellationToken))
                     {
                         return true;
                     }
@@ -473,18 +467,18 @@ public static bool IsAnyLambdaOrAnonymousMethod(this SyntaxNode node)
         private static bool ContainsInterleavedDirective(
             TextSpan textSpan,
             SyntaxTrivia trivia,
-            ref SimpleIntervalTree<TextSpan> ifEndIfSpans,
             CancellationToken cancellationToken)
         {
             if (trivia.HasStructure)
             {
-                var parentSpan = trivia.GetStructure().Span;
+                var structure = trivia.GetStructure();
+                var parentSpan = structure.Span;
                 if (trivia.GetStructure().IsKind(SyntaxKind.RegionDirectiveTrivia,
                                                  SyntaxKind.EndRegionDirectiveTrivia,
                                                  SyntaxKind.IfDirectiveTrivia,
                                                  SyntaxKind.EndIfDirectiveTrivia))
                 {
-                    var match = ((DirectiveTriviaSyntax)trivia.GetStructure()).GetMatchingDirective(cancellationToken);
+                    var match = ((DirectiveTriviaSyntax)structure).GetMatchingDirective(cancellationToken);
                     if (match != null)
                     {
                         var matchSpan = match.Span;
@@ -494,25 +488,20 @@ public static bool IsAnyLambdaOrAnonymousMethod(this SyntaxNode node)
                             // this node.
                             return true;
                         }
-
-                        if (trivia.GetStructure().IsKind(SyntaxKind.IfDirectiveTrivia, SyntaxKind.EndIfDirectiveTrivia))
-                        {
-                            var ppSpan = TextSpan.FromBounds(
-                                Math.Min(parentSpan.Start, matchSpan.Start),
-                                Math.Max(parentSpan.End, matchSpan.End));
-
-                            ifEndIfSpans = ifEndIfSpans.AddInterval(ppSpan);
-                        }
                     }
                 }
-                else if (
-                    trivia.GetStructure().IsKind(SyntaxKind.ElseDirectiveTrivia, SyntaxKind.ElifDirectiveTrivia))
+                else if (trivia.GetStructure().IsKind(SyntaxKind.ElseDirectiveTrivia, SyntaxKind.ElifDirectiveTrivia))
                 {
-                    if (!ifEndIfSpans.IntersectsWith(parentSpan.Start))
+                    var directives = ((DirectiveTriviaSyntax)structure).GetMatchingConditionalDirectives(cancellationToken);
+                    if (directives != null && directives.Count > 0)
                     {
-                        // This else/elif belongs to a pp span that isn't 
-                        // entirely within this node.
-                        return true;
+                        if (!textSpan.Contains(directives[0].SpanStart) ||
+                            !textSpan.Contains(directives[directives.Count - 1].SpanStart))
+                        {
+                            // This else/elif belongs to a pp span that isn't 
+                            // entirely within this node.
+                            return true;
+                        }
                     }
                 }
             }

src/Workspaces/Core/Portable/Shared/Collections/IntervalTree`1.cs

@@ -218,12 +218,6 @@ private IEnumerable<T> GetPreOrderIntervals(int start, int length, TestInterval
             }
         }
 
-        public IntervalTree<T> AddInterval(T value, IIntervalIntrospector<T> introspector)
-        {
-            var newNode = new Node(introspector, value);
-            return new IntervalTree<T>(Insert(root, newNode, introspector, inPlace: false));
-        }
-
         public bool IsEmpty()
         {
             return this.root == null;

src/Workspaces/Core/Portable/Shared/Collections/SimpleIntervalTree`1.cs

@@ -62,12 +62,6 @@ public bool IntersectsWith(int position)
             return GetIntersectingIntervals(position, 0).Any();
         }
 
-        public SimpleIntervalTree<T> AddInterval(T value)
-        {
-            var newNode = new Node(_introspector, value);
-            return new SimpleIntervalTree<T>(_introspector, Insert(root, newNode, _introspector, inPlace: false));
-        }
-
         protected int MaxEndValue(Node node)
         {
             return GetEnd(node.MaxEndNode.Value, _introspector);

src/Workspaces/VisualBasic/Portable/Extensions/DirectiveSyntaxExtensions.vb

@@ -26,12 +26,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
                 End Get
             End Property
 
-            Private ReadOnly _conditionalMap As IDictionary(Of DirectiveTriviaSyntax, IEnumerable(Of DirectiveTriviaSyntax))
+            Private ReadOnly _conditionalMap As IDictionary(Of DirectiveTriviaSyntax, IReadOnlyList(Of DirectiveTriviaSyntax))
 
             ''' <summary>
             ''' Maps a #If/#ElseIf/#Else/#EndIf directive to its list of matching #If/#ElseIf/#Else/#End directives.
             ''' </summary>
-            Public ReadOnly Property ConditionalMap As IDictionary(Of DirectiveTriviaSyntax, IEnumerable(Of DirectiveTriviaSyntax))
+            Public ReadOnly Property ConditionalMap As IDictionary(Of DirectiveTriviaSyntax, IReadOnlyList(Of DirectiveTriviaSyntax))
                 Get
                     Return _conditionalMap
                 End Get
@@ -51,7 +51,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
             End Property
 
             Public Sub New(startEndMap As IDictionary(Of DirectiveTriviaSyntax, DirectiveTriviaSyntax),
-                           conditionalMap As IDictionary(Of DirectiveTriviaSyntax, IEnumerable(Of DirectiveTriviaSyntax)),
+                           conditionalMap As IDictionary(Of DirectiveTriviaSyntax, IReadOnlyList(Of DirectiveTriviaSyntax)),
                            inactiveRegionLines As ISet(Of Tuple(Of Integer, Integer)))
                 _startEndMap = startEndMap
                 _conditionalMap = conditionalMap
@@ -66,7 +66,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
             Dim info = s_rootToDirectiveInfo.GetValue(root,
                             Function(r)
                                 Dim startEndMap = New Dictionary(Of DirectiveTriviaSyntax, DirectiveTriviaSyntax)(DirectiveSyntaxEqualityComparer.Instance)
-                                Dim conditionalMap = New Dictionary(Of DirectiveTriviaSyntax, IEnumerable(Of DirectiveTriviaSyntax))(DirectiveSyntaxEqualityComparer.Instance)
+                                Dim conditionalMap = New Dictionary(Of DirectiveTriviaSyntax, IReadOnlyList(Of DirectiveTriviaSyntax))(DirectiveSyntaxEqualityComparer.Instance)
                                 Dim walker = New DirectiveWalker(startEndMap, conditionalMap, cancellationToken)
                                 walker.Visit(r)
                                 walker.Finish()
@@ -120,14 +120,14 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
         ''' </summary>
         <Extension()>
         Public Function GetMatchingConditionalDirectives(directive As DirectiveTriviaSyntax,
-                                                         cancellationToken As CancellationToken) As IEnumerable(Of DirectiveTriviaSyntax)
+                                                         cancellationToken As CancellationToken) As IReadOnlyList(Of DirectiveTriviaSyntax)
             If directive Is Nothing Then
                 Throw New ArgumentNullException(NameOf(directive))
             End If
 
-            Dim result As IEnumerable(Of DirectiveTriviaSyntax) = Nothing
+            Dim result As IReadOnlyList(Of DirectiveTriviaSyntax) = Nothing
             If Not GetDirectiveInfo(directive, cancellationToken).ConditionalMap.TryGetValue(directive, result) Then
-                Return SpecializedCollections.EmptyEnumerable(Of DirectiveTriviaSyntax)()
+                Return SpecializedCollections.EmptyReadOnlyList(Of DirectiveTriviaSyntax)()
             End If
             Return result
         End Function

src/Workspaces/VisualBasic/Portable/Extensions/SyntaxNodeExtensions.vb

@@ -394,31 +394,27 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
             ' Also, keep track of those spans so that if we see #else/#elif we
             ' can tell if they belong to a pp span that is entirely within the
             ' node.
-            Dim ifEndIfSpans = SimpleIntervalTree.Create(TextSpanIntervalIntrospector.Instance)
             Dim span = node.Span
-
-            Return node.DescendantTokens().Any(Function(token) ContainsInterleavedDirective(span, token, cancellationToken, ifEndIfSpans))
+            Return node.DescendantTokens().Any(Function(token) ContainsInterleavedDirective(span, token, cancellationToken))
         End Function
 
         Private Function ContainsInterleavedDirective(
             textSpan As TextSpan,
             token As SyntaxToken,
-            cancellationToken As CancellationToken,
-            ByRef ifEndIfSpans As SimpleIntervalTree(Of TextSpan)) As Boolean
+            cancellationToken As CancellationToken) As Boolean
 
-            Return ContainsInterleavedDirective(textSpan, token.LeadingTrivia, cancellationToken, ifEndIfSpans) OrElse
-                ContainsInterleavedDirective(textSpan, token.TrailingTrivia, cancellationToken, ifEndIfSpans)
+            Return ContainsInterleavedDirective(textSpan, token.LeadingTrivia, cancellationToken) OrElse
+                ContainsInterleavedDirective(textSpan, token.TrailingTrivia, cancellationToken)
         End Function
 
         Private Function ContainsInterleavedDirective(
             textSpan As TextSpan,
             list As SyntaxTriviaList,
-            cancellationToken As CancellationToken,
-            ByRef ifEndIfSpans As SimpleIntervalTree(Of TextSpan)) As Boolean
+            cancellationToken As CancellationToken) As Boolean
 
             For Each trivia In list
                 If textSpan.Contains(trivia.Span) Then
-                    If ContainsInterleavedDirective(textSpan, trivia, cancellationToken, ifEndIfSpans) Then
+                    If ContainsInterleavedDirective(textSpan, trivia, cancellationToken) Then
                         Return True
                     End If
                 End If
@@ -430,8 +426,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
         Private Function ContainsInterleavedDirective(
             textSpan As TextSpan,
             trivia As SyntaxTrivia,
-            cancellationToken As CancellationToken,
-            ByRef ifEndIfSpans As SimpleIntervalTree(Of TextSpan)) As Boolean
+            cancellationToken As CancellationToken) As Boolean
 
             If trivia.HasStructure AndAlso TypeOf trivia.GetStructure() Is DirectiveTriviaSyntax Then
                 Dim parentSpan = trivia.GetStructure().Span
@@ -445,18 +440,16 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Extensions
                             ' this node.
                             Return True
                         End If
-
-                        If directiveSyntax.IsKind(SyntaxKind.IfDirectiveTrivia, SyntaxKind.EndIfDirectiveTrivia) Then
-                            Dim ppSpan = TextSpan.FromBounds(Math.Min(parentSpan.Start, matchSpan.Start), Math.Max(parentSpan.End, matchSpan.End))
-
-                            ifEndIfSpans = ifEndIfSpans.AddInterval(ppSpan)
-                        End If
                     End If
                 ElseIf directiveSyntax.IsKind(SyntaxKind.ElseDirectiveTrivia, SyntaxKind.ElseIfDirectiveTrivia) Then
-                    If Not ifEndIfSpans.IntersectsWith(parentSpan.Start) Then
-                        ' This else/elif belongs to a pp span that isn't 
-                        ' entirely within this node.
-                        Return True
+                    Dim directives = directiveSyntax.GetMatchingConditionalDirectives(cancellationToken)
+                    If directives IsNot Nothing AndAlso directives.Count > 0 Then
+                        If Not textSpan.Contains(directives(0).SpanStart) OrElse
+                           Not textSpan.Contains(directives(directives.Count - 1).SpanStart) Then
+                            ' This else/elif belongs to a pp span that isn't 
+                            ' entirely within this node.
+                            Return True
+                        End If
                     End If
                 End If
             End If

src/Workspaces/VisualBasic/Portable/Utilities/DirectiveWalker.vb

@@ -18,14 +18,14 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Utilities
         Inherits VisualBasicSyntaxWalker
 
         Private ReadOnly _startEndMap As Dictionary(Of DirectiveTriviaSyntax, DirectiveTriviaSyntax)
-        Private ReadOnly _conditionalMap As Dictionary(Of DirectiveTriviaSyntax, IEnumerable(Of DirectiveTriviaSyntax))
+        Private ReadOnly _conditionalMap As Dictionary(Of DirectiveTriviaSyntax, IReadOnlyList(Of DirectiveTriviaSyntax))
         Private ReadOnly _cancellationToken As CancellationToken
 
         Private ReadOnly _regionStack As New Stack(Of DirectiveTriviaSyntax)()
         Private ReadOnly _ifStack As New Stack(Of DirectiveTriviaSyntax)()
 
         Public Sub New(startEndMap As Dictionary(Of DirectiveTriviaSyntax, DirectiveTriviaSyntax),
-                       conditionalMap As Dictionary(Of DirectiveTriviaSyntax, IEnumerable(Of DirectiveTriviaSyntax)),
+                       conditionalMap As Dictionary(Of DirectiveTriviaSyntax, IReadOnlyList(Of DirectiveTriviaSyntax)),
                        cancellationToken As CancellationToken)
             MyBase.New(SyntaxWalkerDepth.StructuredTrivia)
 
@@ -68,35 +68,45 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Utilities
         End Sub
 
         Public Overrides Sub VisitEndIfDirectiveTrivia(directive As EndIfDirectiveTriviaSyntax)
-            If Not _ifStack.IsEmpty() Then
-                Dim condDirectives As New List(Of DirectiveTriviaSyntax)
-                condDirectives.Add(directive)
-
-                Do
-                    Dim poppedDirective = _ifStack.Pop()
-                    condDirectives.Add(poppedDirective)
-                    If poppedDirective.Kind = SyntaxKind.IfDirectiveTrivia Then
-                        Exit Do
-                    End If
-                Loop Until _ifStack.IsEmpty()
-
-                condDirectives.Sort(Function(n1, n2) n1.SpanStart.CompareTo(n2.SpanStart))
-
-                For Each cond In condDirectives
-                    _conditionalMap.Add(cond, condDirectives)
-                Next
-
-                ' #If should be the first one in sorted order
-                Dim ifDirective = condDirectives.First()
-                Contract.Assert(ifDirective.Kind = SyntaxKind.IfDirectiveTrivia OrElse
+            FinishIf(directive)
+
+            MyBase.VisitEndIfDirectiveTrivia(directive)
+        End Sub
+
+        Private Sub FinishIf(directiveOpt As EndIfDirectiveTriviaSyntax)
+            If _ifStack.IsEmpty() Then
+                Return
+            End If
+
+            Dim condDirectives As New List(Of DirectiveTriviaSyntax)
+            If directiveOpt IsNot Nothing Then
+                condDirectives.Add(directiveOpt)
+            End If
+
+            Do
+                Dim poppedDirective = _ifStack.Pop()
+                condDirectives.Add(poppedDirective)
+                If poppedDirective.Kind = SyntaxKind.IfDirectiveTrivia Then
+                    Exit Do
+                End If
+            Loop Until _ifStack.IsEmpty()
+
+            condDirectives.Sort(Function(n1, n2) n1.SpanStart.CompareTo(n2.SpanStart))
+
+            For Each cond In condDirectives
+                _conditionalMap.Add(cond, condDirectives)
+            Next
+
+            ' #If should be the first one in sorted order
+            Dim ifDirective = condDirectives.First()
+            Contract.Assert(ifDirective.Kind = SyntaxKind.IfDirectiveTrivia OrElse
                             ifDirective.Kind = SyntaxKind.ElseIfDirectiveTrivia OrElse
                             ifDirective.Kind = SyntaxKind.ElseDirectiveTrivia)
 
-                _startEndMap.Add(directive, ifDirective)
-                _startEndMap.Add(ifDirective, directive)
+            If directiveOpt IsNot Nothing Then
+                _startEndMap.Add(directiveOpt, ifDirective)
+                _startEndMap.Add(ifDirective, directiveOpt)
             End If
-
-            MyBase.VisitEndIfDirectiveTrivia(directive)
         End Sub
 
         Public Overrides Sub VisitEndRegionDirectiveTrivia(directive As EndRegionDirectiveTriviaSyntax)
@@ -114,6 +124,10 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Utilities
             While _regionStack.Count > 0
                 _startEndMap.Add(_regionStack.Pop(), Nothing)
             End While
+
+            While _ifStack.Count > 0
+                FinishIf(directiveOpt:=Nothing)
+            End While
         End Sub
     End Class
 End Namespace