From 51c76ac35128adba8a760fc08092e0035a1b5cd5 Mon Sep 17 00:00:00 2001
From: Arthur Ozga <aozgaa-ms@outlook.com>
Date: Mon, 8 May 2017 18:17:17 -0700
Subject: [PATCH] fix malformed nodes

---
 src/compiler/checker.ts   | 6 +++---
 src/compiler/factory.ts   | 4 ++++
 src/compiler/utilities.ts | 2 +-
 3 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 658bad82f83..9ac1dc2d615 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2752,7 +2752,7 @@ namespace ts {
 
             function indexInfoToIndexSignatureDeclarationHelper(indexInfo: IndexInfo, kind: IndexKind, context: NodeBuilderContext): IndexSignatureDeclaration {
                 const indexerTypeNode = createKeywordTypeNode(kind === IndexKind.String ? SyntaxKind.StringKeyword : SyntaxKind.NumberKeyword);
-                const name = getNameFromIndexInfo(indexInfo);
+                const name = getNameFromIndexInfo(indexInfo) || "x";
 
                 const indexingParameter = createParameter(
                     /*decorators*/ undefined,
@@ -2830,8 +2830,8 @@ namespace ts {
                     initializer = parameterDeclaration.initializer;
                 }
                 const parameterNode = createParameter(
-                    parameterDeclaration.decorators,
-                    parameterDeclaration.modifiers,
+                    /*decorators*/ undefined,
+                    cloneNodeArray(parameterDeclaration.modifiers),
                     (parameterDeclaration ? isRestParameter(parameterDeclaration) : isTransientSymbol(parameterSymbol) && parameterSymbol.isRestParameter) ?
                         createToken(SyntaxKind.DotDotDotToken) :
                         undefined,
diff --git a/src/compiler/factory.ts b/src/compiler/factory.ts
index 172710f39aa..45b09892bb0 100644
--- a/src/compiler/factory.ts
+++ b/src/compiler/factory.ts
@@ -89,6 +89,10 @@ namespace ts {
         return nodeIsSynthesized(clone) ? clone : getSynthesizedClone(clone);
     }
 
+    export function cloneNodeArray<T extends Node>(nodeArray: NodeArray<T>) {
+        return nodeArray && nodeArray.map(getDeepSynthesizedClone);
+    }
+
     // Literals
 
     export function createLiteral(value: string): StringLiteral;
diff --git a/src/compiler/utilities.ts b/src/compiler/utilities.ts
index cd63ebfb690..baa83697fba 100644
--- a/src/compiler/utilities.ts
+++ b/src/compiler/utilities.ts
@@ -466,7 +466,7 @@ namespace ts {
         return getFullWidth(name) === 0 ? "(Missing)" : getTextOfNode(name);
     }
 
-    export function getNameFromIndexInfo(info: IndexInfo) {
+    export function getNameFromIndexInfo(info: IndexInfo): string | undefined {
         return info.declaration ? declarationNameToString(info.declaration.parameters[0].name) : undefined;
     }