diff --git a/lib/6to5/types/alias-keys.json b/lib/6to5/types/alias-keys.json
index 19cec9ca23..56ad154225 100644
--- a/lib/6to5/types/alias-keys.json
+++ b/lib/6to5/types/alias-keys.json
@@ -17,23 +17,23 @@
   "ExportDeclaration":   ["Statement", "Declaration"],
   "ImportDeclaration":   ["Statement", "Declaration"],
 
-  "ArrowFunctionExpression": ["Scope", "Function"],
+  "ArrowFunctionExpression": ["Scope", "Function", "Expression"],
   "FunctionDeclaration":     ["Statement", "Declaration", "Scope", "Function"],
-  "FunctionExpression":      ["Scope", "Function"],
+  "FunctionExpression":      ["Scope", "Function", "Expression"],
 
   "BlockStatement": ["Statement", "Scope"],
   "Program":        ["Scope"],
   "CatchClause":    ["Scope"],
 
-  "LogicalExpression": ["Binary"],
-  "BinaryExpression":  ["Binary"],
+  "LogicalExpression": ["Binary", "Expression"],
+  "BinaryExpression":  ["Binary", "Expression"],
 
-  "UnaryExpression": ["UnaryLike"],
+  "UnaryExpression": ["UnaryLike", "Expression"],
   "SpreadProperty":  ["UnaryLike"],
   "SpreadElement":   ["UnaryLike"],
 
   "ClassDeclaration": ["Statement", "Declaration", "Class"],
-  "ClassExpression":  ["Class"],
+  "ClassExpression":  ["Class", "Expression"],
 
   "ForOfStatement": ["Statement", "For", "Scope", "Loop"],
   "ForInStatement": ["Statement", "For", "Scope", "Loop"],
@@ -43,5 +43,27 @@
   "ArrayPattern":  ["Pattern"],
 
   "Property": ["UserWhitespacable"],
-  "XJSElement": ["UserWhitespacable"]
+  "XJSElement": ["UserWhitespacable", "Expression"],
+
+  "ArrayExpression": ["Expression"],
+  "AssignmentExpression": ["Expression"],
+  "AwaitExpression": ["Expression"],
+  "BindFunctionExpression": ["Expression"],
+  "BindMemberExpression": ["Expression"],
+  "CallExpression": ["Expression"],
+  "ComprehensionExpression": ["Expression"],
+  "ConditionalExpression": ["Expression"],
+  "Identifier": ["Expression"],
+  "Literal": ["Expression"],
+  "MemberExpression": ["Expression"],
+  "NewExpression": ["Expression"],
+  "ObjectExpression": ["Expression"],
+  "SequenceExpression": ["Expression"],
+  "TaggedTemplateExpression": ["Expression"],
+  "ThisExpression": ["Expression"],
+  "UpdateExpression": ["Expression"],
+  "VirtualPropertyExpression": ["Expression"],
+  "XJSEmptyExpression": ["Expression"],
+  "XJSMemberExpression": ["Expression"],
+  "YieldExpression": ["Expression"]
 }
diff --git a/lib/6to5/types/index.js b/lib/6to5/types/index.js
index 16ae144200..c5d66ecb1f 100644
--- a/lib/6to5/types/index.js
+++ b/lib/6to5/types/index.js
@@ -66,14 +66,6 @@ _.each(t.FLIPPED_ALIAS_KEYS, function (types, type) {
 
 //
 
-t.isExpression = function (node) {
-  return !t.isStatement(node);
-};
-
-addAssert("Expression", t.isExpression);
-
-//
-
 t.isFalsyExpression = function (node) {
   if (t.isLiteral(node)) {
     return !node.value;
diff --git a/test/fixtures/generation/comments/computed-property-comments-2/expected.js b/test/fixtures/generation/comments/computed-property-comments-2/expected.js
index 285ad050f3..abfa5fb5c4 100644
--- a/test/fixtures/generation/comments/computed-property-comments-2/expected.js
+++ b/test/fixtures/generation/comments/computed-property-comments-2/expected.js
@@ -3,8 +3,8 @@ var test = {
    * Before bracket init
    */
   ["a"]: "1",
-  [/*
-    * Inside bracket init
-    */
-  "b"]: "2"
+  [( /*
+      * Inside bracket init
+      */
+  "b")]: "2"
 }, ok = 42;
diff --git a/test/fixtures/generation/comments/computed-property-comments/expected.js b/test/fixtures/generation/comments/computed-property-comments/expected.js
index c6ffd441f8..177f5a9146 100644
--- a/test/fixtures/generation/comments/computed-property-comments/expected.js
+++ b/test/fixtures/generation/comments/computed-property-comments/expected.js
@@ -4,10 +4,10 @@ var test = {
    */
   ["a"]: "1",
 
-  [/*
-    * Inside bracket init
-    */
-  "b"]: "2",
+  [( /*
+      * Inside bracket init
+      */
+  "b")]: "2",
 
   ["c"
   /*
@@ -17,9 +17,9 @@ var test = {
   // Before bracket, line comment
   ["d"]: "4",
 
-  [
+  [(
   // Inside bracket, line comment
-  "e"]: "5",
+  "e")]: "5",
 
   ["f"
   // After bracket, line comment