diff --git a/lib/validate.js b/lib/validate.js
index dc95adf..72a2aa1 100644
--- a/lib/validate.js
+++ b/lib/validate.js
@@ -794,6 +794,7 @@ Vp.expression = function expression(e) {
 
         when({
             type: 'AssignmentExpression',
+            operator: '=',
             left: match.var('left', { type: match.some('Identifier', 'MemberExpression') }),
             right: match.var('right')
         }, function(vars) {
diff --git a/test/index.js b/test/index.js
index a787115..6a540b6 100644
--- a/test/index.js
+++ b/test/index.js
@@ -354,3 +354,11 @@ exports.testForWithoutUpdate = asmAssert.one(
         }
     },
     { pass: true });
+
+exports.testCompoundAssignment = asmAssert.one(
+    "compound assignment operations such as += are disallowed",
+    function f() {
+        var x = 0;
+        x += 1;
+    },
+    { pass: false });