diff --git a/src/ExternalModule.js b/src/ExternalModule.js
index 757d56d..01a00d0 100644
--- a/src/ExternalModule.js
+++ b/src/ExternalModule.js
@@ -45,4 +45,6 @@ export default class ExternalModule {
 			return reference.call( this.exports, name );
 		};
 	}
+
+	markExport () {}
 }
diff --git a/src/Module.js b/src/Module.js
index 3f489cb..5cd9ca4 100644
--- a/src/Module.js
+++ b/src/Module.js
@@ -435,7 +435,7 @@ export default class Module {
 			else {
 				// Be sure to mark the default export for the entry module.
 				if ( isEntryModule && statement.node.type === 'ExportDefaultDeclaration' ) {
-					this.markExport( 'default', null, this );
+					this.markExport( 'default', this );
 				}
 
 				statement.mark();
@@ -449,7 +449,7 @@ export default class Module {
 		});
 	}
 
-	markExport ( name, suggestedName, importer ) {
+	markExport ( name, importer ) {
 		const id = this.exports.lookup( name );
 
 		if ( id ) {
diff --git a/src/Statement.js b/src/Statement.js
index 56f218d..420e96b 100644
--- a/src/Statement.js
+++ b/src/Statement.js
@@ -266,7 +266,7 @@ export default class Statement {
 			const otherModule = this.module.getModule( this.node.source.value );
 
 			this.node.specifiers.forEach( specifier => {
-				otherModule.markExport( specifier.local.name, null, this.module );
+				otherModule.markExport( specifier.local.name, this.module );
 			});
 
 			return;