diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index d5e5b5c67e4..261924dd9a4 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -2516,10 +2516,11 @@ module ts {
             }
         }
 
-        function getDeclaredTypeOfClass(symbol: Symbol): InterfaceType {
+        function getDeclaredTypeOfClassOrInterface(symbol: Symbol): InterfaceType {
             let links = getSymbolLinks(symbol);
             if (!links.declaredType) {
-                let type = links.declaredType = <InterfaceType>createObjectType(TypeFlags.Class, symbol);
+                let kind = symbol.flags & SymbolFlags.Class ? TypeFlags.Class : TypeFlags.Interface;
+                let type = links.declaredType = <InterfaceType>createObjectType(kind, symbol);
                 let typeParameters = getTypeParametersOfClassOrInterface(symbol);
                 if (typeParameters) {
                     type.flags |= TypeFlags.Reference;
@@ -2529,35 +2530,6 @@ module ts {
                     (<GenericType>type).target = <GenericType>type;
                     (<GenericType>type).typeArguments = type.typeParameters;
                 }
-                
-                type.declaredProperties = getNamedMembers(symbol.members);
-                type.declaredCallSignatures = emptyArray;
-                type.declaredConstructSignatures = emptyArray;
-                type.declaredStringIndexType = getIndexTypeOfSymbol(symbol, IndexKind.String);
-                type.declaredNumberIndexType = getIndexTypeOfSymbol(symbol, IndexKind.Number);
-            }
-            return <InterfaceType>links.declaredType;
-        }
-
-        function getDeclaredTypeOfInterface(symbol: Symbol): InterfaceType {
-            let links = getSymbolLinks(symbol);
-            if (!links.declaredType) {
-                let type = links.declaredType = <InterfaceType>createObjectType(TypeFlags.Interface, symbol);
-                let typeParameters = getTypeParametersOfClassOrInterface(symbol);
-                if (typeParameters) {
-                    type.flags |= TypeFlags.Reference;
-                    type.typeParameters = typeParameters;
-                    (<GenericType>type).instantiations = {};
-                    (<GenericType>type).instantiations[getTypeListId(type.typeParameters)] = <GenericType>type;
-                    (<GenericType>type).target = <GenericType>type;
-                    (<GenericType>type).typeArguments = type.typeParameters;
-                }
-
-                type.declaredProperties = getNamedMembers(symbol.members);
-                type.declaredCallSignatures = getSignaturesOfSymbol(symbol.members["__call"]);
-                type.declaredConstructSignatures = getSignaturesOfSymbol(symbol.members["__new"]);
-                type.declaredStringIndexType = getIndexTypeOfSymbol(symbol, IndexKind.String);
-                type.declaredNumberIndexType = getIndexTypeOfSymbol(symbol, IndexKind.Number);
             }
             return <InterfaceType>links.declaredType;
         }
@@ -2613,11 +2585,8 @@ module ts {
 
         function getDeclaredTypeOfSymbol(symbol: Symbol): Type {
             Debug.assert((symbol.flags & SymbolFlags.Instantiated) === 0);
-            if (symbol.flags & SymbolFlags.Class) {
-                return getDeclaredTypeOfClass(symbol);
-            }
-            if (symbol.flags & SymbolFlags.Interface) {
-                return getDeclaredTypeOfInterface(symbol);
+            if (symbol.flags & (SymbolFlags.Class | SymbolFlags.Interface)) {
+                return getDeclaredTypeOfClassOrInterface(symbol);
             }
             if (symbol.flags & SymbolFlags.TypeAlias) {
                 return getDeclaredTypeOfTypeAlias(symbol);
@@ -2666,7 +2635,24 @@ module ts {
             }
         }
 
+        function getDeclaredPropertiesOfClassOrInterface(type: InterfaceType): Symbol[] {
+            resolveDeclaredMembers(type);
+            return type.declaredProperties;
+        }
+
+        function resolveDeclaredMembers(type: InterfaceType) {
+            if (!type.declaredProperties) {
+                var symbol = type.symbol;
+                type.declaredProperties = getNamedMembers(symbol.members);
+                type.declaredCallSignatures = getSignaturesOfSymbol(symbol.members["__call"]);
+                type.declaredConstructSignatures = getSignaturesOfSymbol(symbol.members["__new"]);
+                type.declaredStringIndexType = getIndexTypeOfSymbol(symbol, IndexKind.String);
+                type.declaredNumberIndexType = getIndexTypeOfSymbol(symbol, IndexKind.Number);
+            }
+        }
+
         function resolveClassOrInterfaceMembers(type: InterfaceType): void {
+            resolveDeclaredMembers(type);
             let members = type.symbol.members;
             let callSignatures = type.declaredCallSignatures;
             let constructSignatures = type.declaredConstructSignatures;
@@ -2688,6 +2674,7 @@ module ts {
 
         function resolveTypeReferenceMembers(type: TypeReference): void {
             let target = type.target;
+            resolveDeclaredMembers(target);
             let mapper = createTypeMapper(target.typeParameters, type.typeArguments);
             let members = createInstantiatedSymbolTable(target.declaredProperties, mapper);
             let callSignatures = instantiateList(target.declaredCallSignatures, mapper, instantiateSignature);
@@ -2843,7 +2830,7 @@ module ts {
                     callSignatures = getSignaturesOfSymbol(symbol);
                 }
                 if (symbol.flags & SymbolFlags.Class) {
-                    let classType = getDeclaredTypeOfClass(symbol);
+                    let classType = getDeclaredTypeOfClassOrInterface(symbol);
                     constructSignatures = getSignaturesOfSymbol(symbol.members["__constructor"]);
                     if (!constructSignatures.length) {
                         constructSignatures = getDefaultConstructSignatures(classType);
@@ -3084,7 +3071,7 @@ module ts {
         function getSignatureFromDeclaration(declaration: SignatureDeclaration): Signature {
             let links = getNodeLinks(declaration);
             if (!links.resolvedSignature) {
-                let classType = declaration.kind === SyntaxKind.Constructor ? getDeclaredTypeOfClass((<ClassDeclaration>declaration.parent).symbol) : undefined;
+                let classType = declaration.kind === SyntaxKind.Constructor ? getDeclaredTypeOfClassOrInterface((<ClassDeclaration>declaration.parent).symbol) : undefined;
                 let typeParameters = classType ? classType.typeParameters :
                     declaration.typeParameters ? getTypeParametersFromDeclaration(declaration.typeParameters) : undefined;
                 let parameters: Symbol[] = [];
@@ -10152,7 +10139,7 @@ module ts {
             }
 
             let seen: Map<{ prop: Symbol; containingType: Type }> = {};
-            forEach(type.declaredProperties, p => { seen[p.name] = { prop: p, containingType: type }; });
+            forEach(getDeclaredPropertiesOfClassOrInterface(type), p => { seen[p.name] = { prop: p, containingType: type }; });
             let ok = true;
 
             for (let base of baseTypes) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index bff15a1ab9d..54f2e5e2bd4 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -1485,11 +1485,11 @@ module ts {
     // Class and interface types (TypeFlags.Class and TypeFlags.Interface)
     export interface InterfaceType extends ObjectType {
         typeParameters: TypeParameter[];           // Type parameters (undefined if non-generic)
-        declaredProperties: Symbol[];              // Declared members
-        declaredCallSignatures: Signature[];       // Declared call signatures
-        declaredConstructSignatures: Signature[];  // Declared construct signatures
-        declaredStringIndexType: Type;             // Declared string index type
-        declaredNumberIndexType: Type;             // Declared numeric index type
+        declaredProperties: Symbol[];              // Declared members (computed by resolveDeclaredMembers)
+        declaredCallSignatures: Signature[];       // Declared call signatures (computed by resolveDeclaredMembers)
+        declaredConstructSignatures: Signature[];  // Declared construct signatures (computed by resolveDeclaredMembers)
+        declaredStringIndexType: Type;             // Declared string index type (computed by resolveDeclaredMembers)
+        declaredNumberIndexType: Type;             // Declared numeric index type (computed by resolveDeclaredMembers)
     }
 
     export interface InterfaceTypeWithBaseTypes extends InterfaceType {