From b1bef15a1e05587f7b6a3471003ad2b773453b1f Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Mon, 14 Mar 2016 15:11:27 -0700
Subject: [PATCH] Removing 'T?' type notation (use 'T | null | undefined'
 instead)

---
 src/compiler/checker.ts | 24 +-----------------------
 src/compiler/parser.ts  | 23 ++++++-----------------
 src/compiler/types.ts   |  9 +--------
 3 files changed, 8 insertions(+), 48 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 10e4d50d930..5360cb558f8 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2414,7 +2414,6 @@ namespace ts {
                     case SyntaxKind.UnionType:
                     case SyntaxKind.IntersectionType:
                     case SyntaxKind.ParenthesizedType:
-                    case SyntaxKind.NullableType:
                         return isDeclarationVisible(<Declaration>node.parent);
 
                     // Default binding, import specifier and namespace import is visible
@@ -4779,14 +4778,6 @@ namespace ts {
             return links.resolvedType;
         }
 
-        function getTypeFromNullableTypeNode(node: NullableTypeNode): Type {
-            const links = getNodeLinks(node);
-            if (!links.resolvedType) {
-                links.resolvedType = getNullableType(getTypeFromTypeNode(node.type));
-            }
-            return links.resolvedType;
-        }
-
         interface TypeSet extends Array<Type> {
             containsAny?: boolean;
             containsUndefined?: boolean;
@@ -5029,8 +5020,6 @@ namespace ts {
                     return getTypeFromUnionTypeNode(<UnionTypeNode>node);
                 case SyntaxKind.IntersectionType:
                     return getTypeFromIntersectionTypeNode(<IntersectionTypeNode>node);
-                case SyntaxKind.NullableType:
-                    return getTypeFromNullableTypeNode(<NullableTypeNode>node);
                 case SyntaxKind.ParenthesizedType:
                 case SyntaxKind.JSDocNullableType:
                 case SyntaxKind.JSDocNonNullableType:
@@ -6546,16 +6535,6 @@ namespace ts {
             return getNullableKind(type) === TypeFlags.Nullable;
         }
 
-        function getNullableType(type: Type): Type {
-            if (!strictNullChecks) {
-                return type;
-            }
-            if (!type.nullableType) {
-                type.nullableType = isNullableType(type) ? type : getUnionType([type, undefinedType, nullType]);
-            }
-            return type.nullableType;
-        }
-
         function addNullableKind(type: Type, kind: TypeFlags): Type {
             if ((getNullableKind(type) & kind) !== kind) {
                 const types = [type];
@@ -15792,8 +15771,7 @@ namespace ts {
                 case SyntaxKind.IntersectionType:
                     return checkUnionOrIntersectionType(<UnionOrIntersectionTypeNode>node);
                 case SyntaxKind.ParenthesizedType:
-                case SyntaxKind.NullableType:
-                    return checkSourceElement((<ParenthesizedTypeNode | NullableTypeNode>node).type);
+                    return checkSourceElement((<ParenthesizedTypeNode>node).type);
                 case SyntaxKind.FunctionDeclaration:
                     return checkFunctionDeclaration(<FunctionDeclaration>node);
                 case SyntaxKind.Block:
diff --git a/src/compiler/parser.ts b/src/compiler/parser.ts
index 0ff1dafc78b..a08c5755a3f 100644
--- a/src/compiler/parser.ts
+++ b/src/compiler/parser.ts
@@ -127,8 +127,7 @@ namespace ts {
             case SyntaxKind.IntersectionType:
                 return visitNodes(cbNodes, (<UnionOrIntersectionTypeNode>node).types);
             case SyntaxKind.ParenthesizedType:
-            case SyntaxKind.NullableType:
-                return visitNode(cbNode, (<ParenthesizedTypeNode | NullableTypeNode>node).type);
+                return visitNode(cbNode, (<ParenthesizedTypeNode>node).type);
             case SyntaxKind.ObjectBindingPattern:
             case SyntaxKind.ArrayBindingPattern:
                 return visitNodes(cbNodes, (<BindingPattern>node).elements);
@@ -2426,21 +2425,11 @@ namespace ts {
 
         function parseArrayTypeOrHigher(): TypeNode {
             let type = parseNonArrayType();
-            while (!scanner.hasPrecedingLineBreak()) {
-                if (parseOptional(SyntaxKind.OpenBracketToken)) {
-                    parseExpected(SyntaxKind.CloseBracketToken);
-                    const node = <ArrayTypeNode>createNode(SyntaxKind.ArrayType, type.pos);
-                    node.elementType = type;
-                    type = finishNode(node);
-                }
-                else if (parseOptional(SyntaxKind.QuestionToken)) {
-                    const node = <NullableTypeNode>createNode(SyntaxKind.NullableType, type.pos);
-                    node.type = type;
-                    type = finishNode(node);
-                }
-                else {
-                    break;
-                }
+            while (!scanner.hasPrecedingLineBreak() && parseOptional(SyntaxKind.OpenBracketToken)) {
+                parseExpected(SyntaxKind.CloseBracketToken);
+                const node = <ArrayTypeNode>createNode(SyntaxKind.ArrayType, type.pos);
+                node.elementType = type;
+                type = finishNode(node);
             }
             return type;
         }
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 12ff2673564..3c7a16da59f 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -210,7 +210,6 @@ namespace ts {
         ParenthesizedType,
         ThisType,
         StringLiteralType,
-        NullableType,
         // Binding patterns
         ObjectBindingPattern,
         ArrayBindingPattern,
@@ -357,7 +356,7 @@ namespace ts {
         FirstFutureReservedWord = ImplementsKeyword,
         LastFutureReservedWord = YieldKeyword,
         FirstTypeNode = TypePredicate,
-        LastTypeNode = NullableType,
+        LastTypeNode = StringLiteralType,
         FirstPunctuation = OpenBraceToken,
         LastPunctuation = CaretEqualsToken,
         FirstToken = Unknown,
@@ -785,11 +784,6 @@ namespace ts {
         _stringLiteralTypeBrand: any;
     }
 
-    // @kind(SyntaxKind.NullableType)
-    export interface NullableTypeNode extends TypeNode {
-        type: TypeNode;
-    }
-
     // @kind(SyntaxKind.StringLiteral)
     export interface StringLiteral extends LiteralExpression {
         _stringLiteralBrand: any;
@@ -2152,7 +2146,6 @@ namespace ts {
         /* @internal */ id: number;      // Unique ID
         symbol?: Symbol;                 // Symbol associated with type (if any)
         pattern?: DestructuringPattern;  // Destructuring pattern represented by type (if any)
-        nullableType?: Type;             // Cached nullable form of this type
     }
 
     /* @internal */