diff --git a/package.json b/package.json
index cf2ec6af2..6ecbc79f8 100644
--- a/package.json
+++ b/package.json
@@ -69,8 +69,7 @@
       "tests/typescript/conformance/es6/Symbols/jsfmt.spec.js",
       "tests/typescript/conformance/classes/jsfmt.spec.js",
       "tests/typescript/conformance/classes/constructorDeclarations/constructorParameters/jsfmt.spec.js",
-      "tests/typescript/custom/module/jsfmt.spec.js",
-      "tests/typescript/conformance/interfaces/interfaceDeclarations/jsfmt.spec.js"
+      "tests/typescript/custom/module/jsfmt.spec.js"
     ]
   }
 }
diff --git a/src/printer.js b/src/printer.js
index b1d780022..4a7caab73 100644
--- a/src/printer.js
+++ b/src/printer.js
@@ -770,10 +770,10 @@ function genericPrintNoParens(path, options, print, args) {
         " "
       );
       
-      if (n.heritageClauses) {
-        prefix.push(
+      if (n.heritage.length) {
+        parts.push(
           "extends ",
-          join(", ", path.map(print, "heritageClauses")),
+          join(", ", path.map(print, "heritage")),
           " "
         );
       }
@@ -857,12 +857,11 @@ function genericPrintNoParens(path, options, print, args) {
       let content;
       if (props.length === 0 && !n.typeAnnotation) {
         if (!hasDanglingComments(n)) {
-          return concat([concat(prefix), leftBrace, rightBrace]);
+          return concat([leftBrace, rightBrace]);
         }
 
         content = group(
           concat([
-            concat(prefix),
             leftBrace,
             comments.printDanglingComments(path, options),
             softline,
@@ -871,7 +870,6 @@ function genericPrintNoParens(path, options, print, args) {
         );
       } else {
         content = concat([
-          concat(prefix),
           leftBrace,
           indent(
             align(
@@ -1628,6 +1626,8 @@ function genericPrintNoParens(path, options, print, args) {
       }
       parts.push(concat(printClass(path, options, print)));
       return concat(parts);
+    case "TSInterfaceHeritage":
+      return path.call(print, "id");
     case "TSHeritageClause":
       return join(", ", path.map(print, "types"));
     case "TSExpressionWithTypeArguments":
diff --git a/src/typescript-ast-nodes.js b/src/typescript-ast-nodes.js
index 7c4353594..b270f9b03 100644
--- a/src/typescript-ast-nodes.js
+++ b/src/typescript-ast-nodes.js
@@ -155,7 +155,12 @@ module.exports = function(fork) {
   def("TSInterfaceDeclaration")
     .build("name", "members")
     .field("name", def("Identifier"))
-    .field("members", [def("TSMethodSignature")]);
+    .field("members", [def("TSMethodSignature")])
+    .bases("Declaration");
+    
+  def("TSInterfaceBody")
+    .build("body")
+    .bases("Node");
 
   def("TSModuleDeclaration")
     .build("modifiers", "name", "body")
diff --git a/tests/typescript/conformance/interfaces/interfaceDeclarations/__snapshots__/jsfmt.spec.js.snap b/tests/typescript/conformance/interfaces/interfaceDeclarations/__snapshots__/jsfmt.spec.js.snap
index 73647566d..320e5d519 100644
--- a/tests/typescript/conformance/interfaces/interfaceDeclarations/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/typescript/conformance/interfaces/interfaceDeclarations/__snapshots__/jsfmt.spec.js.snap
@@ -17,14 +17,13 @@ interface Derived extends Base, Base2 {
     x: { b: string }
 }
 
-interface Derived2 extends Base, Base2 { // error
+interface Derived2 extends Base, Base2 {
     x: { a: number; b: string }
 }
 
 interface Derived3 extends Base, Base2 {
     x: { a: string; b: string }
 }
-
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 interface Base {
   x: {
@@ -44,7 +43,7 @@ interface Derived extends Base, Base2 {
   x: { b: string };
 }
 
-interface Derived2 extends Base, Base2 { // error
+interface Derived2 extends Base, Base2 {
   x: { a: number, b: string };
 }
 
diff --git a/tests/typescript/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBaseTypes2.ts b/tests/typescript/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBaseTypes2.ts
index 4ff83a669..4e44c20c7 100644
--- a/tests/typescript/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBaseTypes2.ts
+++ b/tests/typescript/conformance/interfaces/interfaceDeclarations/interfaceWithMultipleBaseTypes2.ts
@@ -14,11 +14,10 @@ interface Derived extends Base, Base2 {
     x: { b: string }
 }
 
-interface Derived2 extends Base, Base2 { // error
+interface Derived2 extends Base, Base2 {
     x: { a: number; b: string }
 }
 
 interface Derived3 extends Base, Base2 {
     x: { a: string; b: string }
 }
-