diff --git a/src/ast/Node.js b/src/ast/Node.js
index 4f65871..6a80ede 100644
--- a/src/ast/Node.js
+++ b/src/ast/Node.js
@@ -66,6 +66,12 @@ export default class Node {
 		this.eachChild( child => child.initialise( this.scope || scope ) );
 	}
 
+	insertSemicolon ( code ) {
+		if ( code.original[ this.end - 1 ] !== ';' ) {
+			code.insertLeft( this.end, ';' );
+		}
+	}
+
 	locate () {
 		// useful for debugging
 		const location = getLocation( this.module.code, this.start );
diff --git a/src/ast/nodes/ExpressionStatement.js b/src/ast/nodes/ExpressionStatement.js
index 237441a..7198541 100644
--- a/src/ast/nodes/ExpressionStatement.js
+++ b/src/ast/nodes/ExpressionStatement.js
@@ -1,5 +1,8 @@
 import Statement from './shared/Statement.js';
 
 export default class ExpressionStatement extends Statement {
-
+	render ( code, es ) {
+		super.render( code, es );
+		if ( this.shouldInclude ) this.insertSemicolon( code );
+	}
 }
diff --git a/src/ast/nodes/VariableDeclaration.js b/src/ast/nodes/VariableDeclaration.js
index e1be1a0..77f4433 100644
--- a/src/ast/nodes/VariableDeclaration.js
+++ b/src/ast/nodes/VariableDeclaration.js
@@ -14,7 +14,7 @@ function getSeparator ( code, start ) {
 	return `;\n${lineStart}`;
 }
 
-const forStatement = /^For(?:Of|In)Statement/;
+const forStatement = /^For(?:Of|In)?Statement/;
 
 export default class VariableDeclaration extends Node {
 	initialise ( scope ) {
@@ -92,9 +92,16 @@ export default class VariableDeclaration extends Node {
 
 		if ( treeshake && empty ) {
 			code.remove( this.leadingCommentStart || this.start, this.next || this.end );
-		} else if ( this.end > c ) {
-			const hasSemicolon = code.original[ this.end - 1 ] === ';';
-			code.overwrite( c, this.end, hasSemicolon ? ';' : '' );
+		} else {
+			// always include a semi-colon (https://github.com/rollup/rollup/pull/1013),
+			// unless it's a var declaration in a loop head
+			const needsSemicolon = !forStatement.test( this.parent.type );
+
+			if ( this.end > c ) {
+				code.overwrite( c, this.end, needsSemicolon ? ';' : '' );
+			} else if ( needsSemicolon  ) {
+				this.insertSemicolon( code );
+			}
 		}
 	}
 }
diff --git a/test/function/adds-semicolons-if-necessary-b/_config.js b/test/function/adds-semicolons-if-necessary-b/_config.js
new file mode 100644
index 0000000..bb17123
--- /dev/null
+++ b/test/function/adds-semicolons-if-necessary-b/_config.js
@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'adds semi-colons if necessary'
+};
diff --git a/test/function/adds-semicolons-if-necessary-b/foo.js b/test/function/adds-semicolons-if-necessary-b/foo.js
new file mode 100644
index 0000000..b2602d2
--- /dev/null
+++ b/test/function/adds-semicolons-if-necessary-b/foo.js
@@ -0,0 +1 @@
+assert.ok( true )
diff --git a/test/function/adds-semicolons-if-necessary-b/main.js b/test/function/adds-semicolons-if-necessary-b/main.js
new file mode 100644
index 0000000..c6ddba4
--- /dev/null
+++ b/test/function/adds-semicolons-if-necessary-b/main.js
@@ -0,0 +1,3 @@
+import './foo.js';
+
+(function bar() {})();
diff --git a/test/function/adds-semicolons-if-necessary/_config.js b/test/function/adds-semicolons-if-necessary/_config.js
new file mode 100644
index 0000000..bb17123
--- /dev/null
+++ b/test/function/adds-semicolons-if-necessary/_config.js
@@ -0,0 +1,3 @@
+module.exports = {
+	description: 'adds semi-colons if necessary'
+};
diff --git a/test/function/adds-semicolons-if-necessary/foo.js b/test/function/adds-semicolons-if-necessary/foo.js
new file mode 100644
index 0000000..14d0105
--- /dev/null
+++ b/test/function/adds-semicolons-if-necessary/foo.js
@@ -0,0 +1,3 @@
+export var foo = function () {
+	return 42;
+}
diff --git a/test/function/adds-semicolons-if-necessary/main.js b/test/function/adds-semicolons-if-necessary/main.js
new file mode 100644
index 0000000..2a031e5
--- /dev/null
+++ b/test/function/adds-semicolons-if-necessary/main.js
@@ -0,0 +1,7 @@
+import { foo } from './foo.js';
+
+(function bar() {
+	assert.ok( true );
+})();
+
+assert.equal( foo(), 42 );