From c16c7d56c0a4e9f7e11dd134cffcdbb1eef5916c Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Fri, 20 Jan 2017 09:17:14 -0800
Subject: [PATCH] Allow base constructor types to be intersections

---
 src/compiler/checker.ts | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 6de1b5aa624..a5058bdf7f2 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3810,7 +3810,7 @@ namespace ts {
         }
 
         function isConstructorType(type: Type): boolean {
-            return type.flags & TypeFlags.Object && getSignaturesOfType(type, SignatureKind.Construct).length > 0;
+            return isValidBaseType(type) && getSignaturesOfType(type, SignatureKind.Construct).length > 0;
         }
 
         function getBaseTypeNodeOfClass(type: InterfaceType): ExpressionWithTypeArguments {
@@ -3849,7 +3849,7 @@ namespace ts {
                     return unknownType;
                 }
                 const baseConstructorType = checkExpression(baseTypeNode.expression);
-                if (baseConstructorType.flags & TypeFlags.Object) {
+                if (baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection)) {
                     // Resolving the members of a class requires us to resolve the base class of that class.
                     // We force resolution here such that we catch circularities now.
                     resolveStructuredTypeMembers(<ObjectType>baseConstructorType);
@@ -3890,7 +3890,7 @@ namespace ts {
         function resolveBaseTypesOfClass(type: InterfaceType): void {
             type.resolvedBaseTypes = type.resolvedBaseTypes || emptyArray;
             const baseConstructorType = <ObjectType>getBaseConstructorTypeOfClass(type);
-            if (!(baseConstructorType.flags & TypeFlags.Object)) {
+            if (!(baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection))) {
                 return;
             }
             const baseTypeNode = getBaseTypeNodeOfClass(type);
@@ -4591,9 +4591,9 @@ namespace ts {
                         constructSignatures = getDefaultConstructSignatures(classType);
                     }
                     const baseConstructorType = getBaseConstructorTypeOfClass(classType);
-                    if (baseConstructorType.flags & TypeFlags.Object) {
+                    if (baseConstructorType.flags & (TypeFlags.Object | TypeFlags.Intersection)) {
                         members = createSymbolTable(getNamedMembers(members));
-                        addInheritedMembers(members, getPropertiesOfObjectType(baseConstructorType));
+                        addInheritedMembers(members, getPropertiesOfType(baseConstructorType));
                     }
                 }
                 const numberIndexInfo = symbol.flags & SymbolFlags.Enum ? enumNumberIndexInfo : undefined;