diff --git a/AST.cpp b/AST.cpp
index 4b10fb0..cecdabd 100644
--- a/AST.cpp
+++ b/AST.cpp
@@ -86,8 +86,8 @@
     return mPackage;
 }
 
-bool AST::isInterface(std::string *ifaceName) const {
-    return mRootScope->containsSingleInterface(ifaceName);
+bool AST::isInterface() const {
+    return mRootScope->getInterface() != nullptr;
 }
 
 bool AST::containsInterfaces() const {
@@ -530,8 +530,7 @@
 }
 
 bool AST::isJavaCompatible() const {
-    std::string ifaceName;
-    if (!AST::isInterface(&ifaceName)) {
+    if (!AST::isInterface()) {
         for (const auto *type : mRootScope->getSubTypes()) {
             if (!type->isJavaCompatible()) {
                 return false;
@@ -559,4 +558,10 @@
     return mRootScope->getInterface();
 }
 
+std::string AST::getBaseName() const {
+    const Interface *iface = mRootScope->getInterface();
+
+    return iface ? iface->getBaseName() : "types";
+}
+
 }  // namespace android;
diff --git a/AST.h b/AST.h
index e510cbe..1efb78d 100644
--- a/AST.h
+++ b/AST.h
@@ -48,7 +48,7 @@
 
     // package and version really.
     FQName package() const;
-    bool isInterface(std::string *ifaceName) const;
+    bool isInterface() const;
     bool containsInterfaces() const;
 
     void enterScope(Scope *container);
@@ -118,8 +118,12 @@
 
     bool isIBase() const;
 
+    // or nullptr if not isInterface
     const Interface *getInterface() const;
 
+    // types or Interface base name (e.x. Foo)
+    std::string getBaseName() const;
+
 private:
     const Coordinator *mCoordinator;
     std::string mPath;
diff --git a/Coordinator.cpp b/Coordinator.cpp
index 1ec0554..9b31c77 100644
--- a/Coordinator.cpp
+++ b/Coordinator.cpp
@@ -122,17 +122,16 @@
 
         err = UNKNOWN_ERROR;
     } else {
-        std::string ifaceName;
-        if (ast->isInterface(&ifaceName)) {
+        if (ast->isInterface()) {
             if (fqName.name() == "types") {
                 fprintf(stderr,
                         "ERROR: File at '%s' declares an interface '%s' "
                         "instead of the expected types common to the package.\n",
                         path.c_str(),
-                        ifaceName.c_str());
+                        ast->getInterface()->localName().c_str());
 
                 err = UNKNOWN_ERROR;
-            } else if (ifaceName != fqName.name()) {
+            } else if (ast->getInterface()->localName() != fqName.name()) {
                 fprintf(stderr,
                         "ERROR: File at '%s' does not declare interface type "
                         "'%s'.\n",
diff --git a/Scope.cpp b/Scope.cpp
index aad55c9..b2414b3 100644
--- a/Scope.cpp
+++ b/Scope.cpp
@@ -95,17 +95,6 @@
     return NULL;
 }
 
-bool Scope::containsSingleInterface(std::string *ifaceName) const {
-    Interface *iface = getInterface();
-
-    if (iface != NULL) {
-        *ifaceName = iface->localName();
-        return true;
-    }
-
-    return false;
-}
-
 bool Scope::containsInterfaces() const {
     for (const NamedType *type : mTypes) {
         if (type->isInterface()) {
diff --git a/Scope.h b/Scope.h
index de53974..122520b 100644
--- a/Scope.h
+++ b/Scope.h
@@ -47,7 +47,6 @@
     // Returns the single interface or NULL.
     Interface *getInterface() const;
 
-    bool containsSingleInterface(std::string *ifaceName) const;
     bool containsInterfaces() const;
 
     status_t emitTypeDeclarations(Formatter &out) const override;
diff --git a/generateCpp.cpp b/generateCpp.cpp
index fb0c2c1..cb6039f 100644
--- a/generateCpp.cpp
+++ b/generateCpp.cpp
@@ -371,17 +371,12 @@
 }
 
 status_t AST::generateInterfaceHeader(const std::string &outputPath) const {
+    const Interface *iface = getInterface();
+    std::string ifaceName = iface ? iface->localName() : "types";
 
     std::string path = outputPath;
     path.append(mCoordinator->convertPackageRootToPath(mPackage));
     path.append(mCoordinator->getPackagePath(mPackage, true /* relative */));
-
-    std::string ifaceName;
-    bool isInterface = true;
-    if (!AST::isInterface(&ifaceName)) {
-        ifaceName = "types";
-        isInterface = false;
-    }
     path.append(ifaceName);
     path.append(".h");
 
@@ -407,7 +402,7 @@
         out << "\n";
     }
 
-    if (isInterface) {
+    if (iface) {
         if (isIBase()) {
             out << "// skipped #include IServiceNotification.h\n\n";
         } else {
@@ -418,7 +413,7 @@
     out << "#include <hidl/HidlSupport.h>\n";
     out << "#include <hidl/MQDescriptor.h>\n";
 
-    if (isInterface) {
+    if (iface) {
         out << "#include <hidl/Status.h>\n";
     }
 
@@ -428,11 +423,10 @@
     enterLeaveNamespace(out, true /* enter */);
     out << "\n";
 
-    if (isInterface) {
+    if (iface) {
         out << "struct "
             << ifaceName;
 
-        const Interface *iface = mRootScope->getInterface();
         const Interface *superType = iface->superType();
 
         if (superType == NULL) {
@@ -454,9 +448,7 @@
         return err;
     }
 
-    if (isInterface) {
-        const Interface *iface = mRootScope->getInterface();
-
+    if (iface) {
         out << "virtual bool isRemote() const ";
         if (!isIBase()) {
             out << "override ";
@@ -530,7 +522,7 @@
         }
     }
 
-    if (isInterface) {
+    if (iface) {
         out.unindent();
 
         out << "};\n\n";
@@ -551,17 +543,8 @@
 }
 
 status_t AST::generateHwBinderHeader(const std::string &outputPath) const {
-    std::string ifaceName;
-    bool isInterface = AST::isInterface(&ifaceName);
-    const Interface *iface = nullptr;
-    std::string klassName{};
-
-    if(isInterface) {
-        iface = mRootScope->getInterface();
-        klassName = iface->getHwName();
-    } else {
-        klassName = "hwtypes";
-    }
+    const Interface *iface = getInterface();
+    std::string klassName = iface ? iface->getHwName() : "hwtypes";
 
     std::string path = outputPath;
     path.append(mCoordinator->convertPackageRootToPath(mPackage));
@@ -581,11 +564,7 @@
     out << "#ifndef " << guard << "\n";
     out << "#define " << guard << "\n\n";
 
-    if (isInterface) {
-        generateCppPackageInclude(out, mPackage, ifaceName);
-    } else {
-        generateCppPackageInclude(out, mPackage, "types");
-    }
+    generateCppPackageInclude(out, mPackage, iface ? iface->localName() : "types");
 
     out << "\n";
 
@@ -787,7 +766,6 @@
 }
 
 status_t AST::generateMethods(Formatter &out, MethodGenerator gen) const {
-
     const Interface *iface = mRootScope->getInterface();
 
     const Interface *prevIterface = nullptr;
@@ -817,8 +795,7 @@
 }
 
 status_t AST::generateStubHeader(const std::string &outputPath) const {
-    std::string ifaceName;
-    if (!AST::isInterface(&ifaceName)) {
+    if (!AST::isInterface()) {
         // types.hal does not get a stub header.
         return OK;
     }
@@ -866,11 +843,11 @@
     out.indent();
     out << "explicit "
         << klassName
-        << "(const ::android::sp<" << ifaceName << "> &_hidl_impl);"
+        << "(const ::android::sp<" << iface->localName() << "> &_hidl_impl);"
         << "\n";
     out << "explicit "
         << klassName
-        << "(const ::android::sp<" << ifaceName << "> &_hidl_impl,"
+        << "(const ::android::sp<" << iface->localName() << "> &_hidl_impl,"
         << " const std::string& HidlInstrumentor_package,"
         << " const std::string& HidlInstrumentor_interface);"
         << "\n\n";
@@ -885,7 +862,7 @@
     out.unindent();
     out.unindent();
 
-    out << "::android::sp<" << ifaceName << "> getImpl() { return _hidl_mImpl; };\n";
+    out << "::android::sp<" << iface->localName() << "> getImpl() { return _hidl_mImpl; };\n";
     out.unindent();
     out << "private:\n";
     out.indent();
@@ -910,7 +887,7 @@
         return err;
     }
 
-    out << "::android::sp<" << ifaceName << "> _hidl_mImpl;\n";
+    out << "::android::sp<" << iface->localName() << "> _hidl_mImpl;\n";
     out.unindent();
     out << "};\n\n";
 
@@ -922,8 +899,7 @@
 }
 
 status_t AST::generateProxyHeader(const std::string &outputPath) const {
-    std::string ifaceName;
-    if (!AST::isInterface(&ifaceName)) {
+    if (!AST::isInterface()) {
         // types.hal does not get a proxy header.
         return OK;
     }
@@ -1005,25 +981,12 @@
 }
 
 status_t AST::generateCppSources(const std::string &outputPath) const {
+    std::string baseName = getBaseName();
+    const Interface *iface = getInterface();
 
     std::string path = outputPath;
     path.append(mCoordinator->convertPackageRootToPath(mPackage));
     path.append(mCoordinator->getPackagePath(mPackage, true /* relative */));
-
-    std::string ifaceName;
-    std::string baseName;
-
-    const Interface *iface = nullptr;
-    bool isInterface;
-    if (!AST::isInterface(&ifaceName)) {
-        baseName = "types";
-        isInterface = false;
-    } else {
-        iface = mRootScope->getInterface();
-        baseName = iface->getBaseName();
-        isInterface = true;
-    }
-
     path.append(baseName);
 
     if (baseName != "types") {
@@ -1048,7 +1011,7 @@
     out << "#include <android/log.h>\n";
     out << "#include <cutils/trace.h>\n";
     out << "#include <hidl/HidlTransportSupport.h>\n\n";
-    if (isInterface) {
+    if (iface) {
         // This is a no-op for IServiceManager itself.
         out << "#include <android/hidl/manager/1.0/IServiceManager.h>\n";
 
@@ -1076,9 +1039,9 @@
     enterLeaveNamespace(out, true /* enter */);
     out << "\n";
 
-    status_t err = generateTypeSource(out, ifaceName);
+    status_t err = generateTypeSource(out, iface ? iface->localName() : "");
 
-    if (err == OK && isInterface) {
+    if (err == OK && iface) {
         const Interface *iface = mRootScope->getInterface();
 
         // need to be put here, generateStubSource is using this.
@@ -1137,19 +1100,19 @@
         err = generateInterfaceSource(out);
     }
 
-    if (err == OK && isInterface) {
+    if (err == OK && iface) {
         err = generateProxySource(out, iface->fqName());
     }
 
-    if (err == OK && isInterface) {
+    if (err == OK && iface) {
         err = generateStubSource(out, iface);
     }
 
-    if (err == OK && isInterface) {
+    if (err == OK && iface) {
         err = generatePassthroughSource(out);
     }
 
-    if (err == OK && isInterface) {
+    if (err == OK && iface) {
         const Interface *iface = mRootScope->getInterface();
 
         if (isIBase()) {
@@ -1807,13 +1770,13 @@
 }
 
 status_t AST::generatePassthroughHeader(const std::string &outputPath) const {
-    std::string ifaceName;
-    if (!AST::isInterface(&ifaceName)) {
+    if (!AST::isInterface()) {
         // types.hal does not get a stub header.
         return OK;
     }
 
     const Interface *iface = mRootScope->getInterface();
+    CHECK(iface != nullptr);
 
     const std::string klassName = iface->getPassthroughName();
 
@@ -1847,7 +1810,7 @@
     out << "#include <cutils/trace.h>\n";
     out << "#include <future>\n";
 
-    generateCppPackageInclude(out, mPackage, ifaceName);
+    generateCppPackageInclude(out, mPackage, iface->localName());
     out << "\n";
 
     out << "#include <hidl/HidlPassthroughSupport.h>\n";
@@ -1860,14 +1823,14 @@
 
     out << "struct "
         << klassName
-        << " : " << ifaceName
+        << " : " << iface->localName()
         << ", ::android::hardware::details::HidlInstrumentor {\n";
 
     out.indent();
     out << "explicit "
         << klassName
         << "(const ::android::sp<"
-        << ifaceName
+        << iface->localName()
         << "> impl);\n";
 
     status_t err = generateMethods(out, [&](const Method *method, const Interface *) {
@@ -1881,7 +1844,7 @@
     out.unindent();
     out << "private:\n";
     out.indent();
-    out << "const ::android::sp<" << ifaceName << "> mImpl;\n";
+    out << "const ::android::sp<" << iface->localName() << "> mImpl;\n";
 
     if (supportOneway) {
         out << "::android::hardware::details::TaskRunner mOnewayQueue;\n";
diff --git a/generateCppImpl.cpp b/generateCppImpl.cpp
index 874743b..7025a87 100644
--- a/generateCppImpl.cpp
+++ b/generateCppImpl.cpp
@@ -80,14 +80,12 @@
 }
 
 status_t AST::generateStubImplHeader(const std::string &outputPath) const {
-    std::string ifaceName;
-    if (!AST::isInterface(&ifaceName)) {
+    if (!AST::isInterface()) {
         // types.hal does not get a stub header.
         return OK;
     }
 
     const Interface *iface = mRootScope->getInterface();
-
     const std::string baseName = iface->getBaseName();
 
     std::string path = outputPath;
@@ -129,7 +127,7 @@
     out << "struct "
         << baseName
         << " : public "
-        << ifaceName
+        << iface->localName()
         << " {\n";
 
     out.indent();
@@ -155,9 +153,9 @@
 
     out << "// FIXME: most likely delete, this is only for passthrough implementations\n"
         << "// extern \"C\" "
-        << ifaceName
+        << iface->localName()
         << "* ";
-    generateFetchSymbol(out, ifaceName);
+    generateFetchSymbol(out, iface->localName());
     out << "(const char* name);\n\n";
 
     out << "}  // namespace implementation\n";
@@ -169,8 +167,7 @@
 }
 
 status_t AST::generateStubImplSource(const std::string &outputPath) const {
-    std::string ifaceName;
-    if (!AST::isInterface(&ifaceName)) {
+    if (!AST::isInterface()) {
         // types.hal does not get a stub header.
         return OK;
     }
@@ -205,9 +202,9 @@
     }
 
     out.setLinePrefix("//");
-    out << ifaceName
+    out << iface->localName()
         << "* ";
-    generateFetchSymbol(out, ifaceName);
+    generateFetchSymbol(out, iface->localName());
     out << "(const char* /* name */) {\n";
     out.indent();
     out << "return new " << baseName << "();\n";
diff --git a/generateJava.cpp b/generateJava.cpp
index c0f8768..9f8f1dd 100644
--- a/generateJava.cpp
+++ b/generateJava.cpp
@@ -108,12 +108,12 @@
         return UNKNOWN_ERROR;
     }
 
-    std::string ifaceName;
-    if (!AST::isInterface(&ifaceName)) {
+    if (!AST::isInterface()) {
         return generateJavaTypes(outputPath, limitToType);
     }
 
     const Interface *iface = mRootScope->getInterface();
+    std::string ifaceName = iface->localName();
 
     const std::string baseName = iface->getBaseName();
 
diff --git a/generateVts.cpp b/generateVts.cpp
index b7e2e2b..f695bec 100644
--- a/generateVts.cpp
+++ b/generateVts.cpp
@@ -30,49 +30,36 @@
 namespace android {
 
 status_t AST::emitVtsTypeDeclarations(Formatter &out) const {
-  std::string ifaceName;
-  if (AST::isInterface(&ifaceName)) {
-    const Interface *iface = mRootScope->getInterface();
-    status_t status = iface->emitVtsAttributeDeclaration(out);
-    if (status != OK) {
-      return status;
+    if (AST::isInterface()) {
+      const Interface *iface = mRootScope->getInterface();
+      return iface->emitVtsAttributeDeclaration(out);
     }
-  } else {
+
     for (const auto &type : mRootScope->getSubTypes()) {
-      // Skip for TypeDef as it is just an alias of a defined type.
-      if (type->isTypeDef()) {
-        continue;
-      }
-      out << "attribute: {\n";
-      out.indent();
-      status_t status = type->emitVtsTypeDeclarations(out);
-      if (status != OK) {
-        return status;
-      }
-      out.unindent();
-      out << "}\n\n";
+        // Skip for TypeDef as it is just an alias of a defined type.
+        if (type->isTypeDef()) {
+            continue;
+        }
+        out << "attribute: {\n";
+        out.indent();
+        status_t status = type->emitVtsTypeDeclarations(out);
+        if (status != OK) {
+            return status;
+        }
+        out.unindent();
+        out << "}\n\n";
     }
-  }
-  return OK;
+
+    return OK;
 }
 
 status_t AST::generateVts(const std::string &outputPath) const {
+    std::string baseName = AST::getBaseName();
+    const Interface *iface = AST::getInterface();
+
     std::string path = outputPath;
     path.append(mCoordinator->convertPackageRootToPath(mPackage));
     path.append(mCoordinator->getPackagePath(mPackage, true /* relative */));
-
-    std::string ifaceName;
-    std::string baseName;
-
-    bool isInterface = true;
-    if (!AST::isInterface(&ifaceName)) {
-        baseName = "types";
-        isInterface = false;
-    } else {
-        const Interface *iface = mRootScope->getInterface();
-        baseName = iface->getBaseName();
-    }
-
     path.append(baseName);
     path.append(".vts");
 
@@ -89,7 +76,7 @@
     out << "component_type_version: " << mPackage.version()
         << "\n";
     out << "component_name: \""
-        << (isInterface ? ifaceName : "types")
+        << (iface ? iface->localName() : "types")
         << "\"\n\n";
 
     out << "package: \"" << mPackage.package() << "\"\n\n";
@@ -106,7 +93,7 @@
 
     out << "\n";
 
-    if (isInterface) {
+    if (isInterface()) {
         const Interface *iface = mRootScope->getInterface();
         out << "interface: {\n";
         out.indent();