diff --git a/package.json b/package.json
index 5b10eed..38c4d2a 100644
--- a/package.json
+++ b/package.json
@@ -48,7 +48,7 @@
     "eslint": "^2.9.0",
     "estree-walker": "^0.2.0",
     "istanbul": "^0.4.0",
-    "magic-string": "^0.10.1",
+    "magic-string": "^0.15.1",
     "mocha": "^2.3.3",
     "remap-istanbul": "^0.5.1",
     "rollup": "^0.26.2",
diff --git a/src/Bundle.js b/src/Bundle.js
index f16d105..9fc7c01 100644
--- a/src/Bundle.js
+++ b/src/Bundle.js
@@ -1,4 +1,4 @@
-import MagicString from 'magic-string';
+import { Bundle as MagicStringBundle } from 'magic-string';
 import first from './utils/first.js';
 import { blank, forOwn, keys } from './utils/object.js';
 import Module from './Module.js';
@@ -282,7 +282,7 @@ export default class Bundle {
 		// Determine export mode - 'default', 'named', 'none'
 		const exportMode = getExportMode( this, options.exports, options.moduleName );
 
-		let magicString = new MagicString.Bundle({ separator: '\n\n' });
+		let magicString = new MagicStringBundle({ separator: '\n\n' });
 		let usedModules = [];
 
 		this.orderedModules.forEach( module => {
diff --git a/src/Module.js b/src/Module.js
index cde624c..9786374 100644
--- a/src/Module.js
+++ b/src/Module.js
@@ -488,15 +488,16 @@ export default class Module {
 						const declaration = this.declarations[ name ];
 
 						if ( declaration.exportName && declaration.isReassigned ) {
-							magicString.insert( statement.end, `;\nexports.${name} = ${declaration.render( es6 )}` );
+							magicString.insertLeft( statement.end, `;\nexports.${name} = ${declaration.render( es6 )}` );
 						}
 					});
 				}
 
 				if ( statement.node.isSynthetic ) {
 					// insert `var/let/const` if necessary
-					magicString.insert( statement.start, `${statement.node.kind} ` );
-					magicString.overwrite( statement.end, statement.next, ';\n' ); // TODO account for trailing newlines
+					magicString.insertRight( statement.start, `${statement.node.kind} ` );
+					magicString.insertLeft( statement.end, ';' );
+					magicString.overwrite( statement.end, statement.next, '\n' ); // TODO account for trailing newlines
 				}
 			}
 
@@ -527,7 +528,7 @@ export default class Module {
 					}
 
 					if ( reference.isShorthandProperty ) {
-						magicString.insert( end, `: ${name}` );
+						magicString.insertLeft( end, `: ${name}` );
 					} else {
 						magicString.overwrite( start, end, name, true );
 					}
diff --git a/test/cli/multiple-targets-shared-config/_expected/cjs.js.map b/test/cli/multiple-targets-shared-config/_expected/cjs.js.map
index 7010396..d88316a 100644
--- a/test/cli/multiple-targets-shared-config/_expected/cjs.js.map
+++ b/test/cli/multiple-targets-shared-config/_expected/cjs.js.map
@@ -1 +1 @@
-{"version":3,"file":"cjs.js","sources":["../main.js"],"sourcesContent":["export default 0;\n"],"names":[],"mappings":";;WAAe,CAAC,CAAC,;;"}
\ No newline at end of file
+{"version":3,"file":"cjs.js","sources":["../main.js"],"sourcesContent":["export default 0;\n"],"names":[],"mappings":";;AAAA,WAAe,CAAC,CAAC,;;"}
diff --git a/test/cli/multiple-targets-shared-config/_expected/es6.js.map b/test/cli/multiple-targets-shared-config/_expected/es6.js.map
index ba7fc9c..8b3e60e 100644
--- a/test/cli/multiple-targets-shared-config/_expected/es6.js.map
+++ b/test/cli/multiple-targets-shared-config/_expected/es6.js.map
@@ -1 +1 @@
-{"version":3,"file":"es6.js","sources":["../main.js"],"sourcesContent":["export default 0;\n"],"names":[],"mappings":"WAAe,CAAC,CAAC,;;"}
\ No newline at end of file
+{"version":3,"file":"es6.js","sources":["../main.js"],"sourcesContent":["export default 0;\n"],"names":[],"mappings":"AAAA,WAAe,CAAC,CAAC,;;"}
diff --git a/test/form/sourcemaps/_config.js b/test/form/sourcemaps-external/_config.js
similarity index 100%
rename from test/form/sourcemaps/_config.js
rename to test/form/sourcemaps-external/_config.js
diff --git a/test/form/sourcemaps/_expected/amd.js b/test/form/sourcemaps-external/_expected/amd.js
similarity index 100%
rename from test/form/sourcemaps/_expected/amd.js
rename to test/form/sourcemaps-external/_expected/amd.js
diff --git a/test/form/sourcemaps/_expected/amd.js.map b/test/form/sourcemaps-external/_expected/amd.js.map
similarity index 100%
rename from test/form/sourcemaps/_expected/amd.js.map
rename to test/form/sourcemaps-external/_expected/amd.js.map
diff --git a/test/form/sourcemaps/_expected/cjs.js b/test/form/sourcemaps-external/_expected/cjs.js
similarity index 100%
rename from test/form/sourcemaps/_expected/cjs.js
rename to test/form/sourcemaps-external/_expected/cjs.js
diff --git a/test/form/sourcemaps/_expected/cjs.js.map b/test/form/sourcemaps-external/_expected/cjs.js.map
similarity index 100%
rename from test/form/sourcemaps/_expected/cjs.js.map
rename to test/form/sourcemaps-external/_expected/cjs.js.map
diff --git a/test/form/sourcemaps/_expected/es6.js b/test/form/sourcemaps-external/_expected/es6.js
similarity index 100%
rename from test/form/sourcemaps/_expected/es6.js
rename to test/form/sourcemaps-external/_expected/es6.js
diff --git a/test/form/sourcemaps/_expected/es6.js.map b/test/form/sourcemaps-external/_expected/es6.js.map
similarity index 100%
rename from test/form/sourcemaps/_expected/es6.js.map
rename to test/form/sourcemaps-external/_expected/es6.js.map
diff --git a/test/form/sourcemaps/_expected/iife.js b/test/form/sourcemaps-external/_expected/iife.js
similarity index 100%
rename from test/form/sourcemaps/_expected/iife.js
rename to test/form/sourcemaps-external/_expected/iife.js
diff --git a/test/form/sourcemaps/_expected/iife.js.map b/test/form/sourcemaps-external/_expected/iife.js.map
similarity index 100%
rename from test/form/sourcemaps/_expected/iife.js.map
rename to test/form/sourcemaps-external/_expected/iife.js.map
diff --git a/test/form/sourcemaps/_expected/umd.js b/test/form/sourcemaps-external/_expected/umd.js
similarity index 100%
rename from test/form/sourcemaps/_expected/umd.js
rename to test/form/sourcemaps-external/_expected/umd.js
diff --git a/test/form/sourcemaps/_expected/umd.js.map b/test/form/sourcemaps-external/_expected/umd.js.map
similarity index 100%
rename from test/form/sourcemaps/_expected/umd.js.map
rename to test/form/sourcemaps-external/_expected/umd.js.map
diff --git a/test/form/sourcemaps/bar.js b/test/form/sourcemaps-external/bar.js
similarity index 100%
rename from test/form/sourcemaps/bar.js
rename to test/form/sourcemaps-external/bar.js
diff --git a/test/form/sourcemaps/foo.js b/test/form/sourcemaps-external/foo.js
similarity index 100%
rename from test/form/sourcemaps/foo.js
rename to test/form/sourcemaps-external/foo.js
diff --git a/test/form/sourcemaps/main.js b/test/form/sourcemaps-external/main.js
similarity index 100%
rename from test/form/sourcemaps/main.js
rename to test/form/sourcemaps-external/main.js
diff --git a/test/test.js b/test/test.js
index af44baa..1df5666 100644
--- a/test/test.js
+++ b/test/test.js
@@ -13,7 +13,6 @@ var FUNCTION = path.resolve( __dirname, 'function' );
 var FORM = path.resolve( __dirname, 'form' );
 var SOURCEMAPS = path.resolve( __dirname, 'sourcemaps' );
 var CLI = path.resolve( __dirname, 'cli' );
-var INCREMENTAL = path.resolve( __dirname, 'incremental' );
 
 var PROFILES = [
 	{ format: 'amd' },