diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 9c1e0cfe4b9..6f1de3677e7 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -1838,6 +1838,12 @@ namespace ts {
                 transformFlags |= TransformFlags.AssertJsx;
                 break;
 
+            case SyntaxKind.ExportKeyword:
+                // This node is both ES6 and TypeScript syntax.
+                transformFlags |= TransformFlags.AssertES6 | TransformFlags.TypeScript;
+                break;
+
+            case SyntaxKind.DefaultKeyword:
             case SyntaxKind.NoSubstitutionTemplateLiteral:
             case SyntaxKind.TemplateHead:
             case SyntaxKind.TemplateMiddle:
@@ -1965,20 +1971,6 @@ namespace ts {
 
                 break;
 
-            case SyntaxKind.ExpressionStatement:
-                if (nodeIsSynthesized(node)) {
-                    const expression = (<ExpressionStatement>node).expression;
-                    if (nodeIsSynthesized(expression)
-                        && isCallExpression(expression)
-                        && expression.expression.kind === SyntaxKind.SuperKeyword) {
-                        // A synthesized call to `super` should be transformed to a cleaner emit
-                        // when transpiling to ES5/3.
-                        transformFlags |= TransformFlags.AssertES6;
-                    }
-                }
-
-                break;
-
             case SyntaxKind.BinaryExpression:
                 if (isDestructuringAssignment(node)) {
                     // Destructuring assignments are ES6 syntax.
@@ -2087,7 +2079,7 @@ namespace ts {
             case SyntaxKind.VariableDeclarationList:
                 // If a VariableDeclarationList is `let` or `const`, then it is ES6 syntax.
                 if (node.flags & NodeFlags.BlockScoped) {
-                    transformFlags |= TransformFlags.AssertES6;
+                    transformFlags |= TransformFlags.AssertES6 | TransformFlags.ContainsBlockScopedBinding;
                 }
 
                 break;
@@ -2100,6 +2092,26 @@ namespace ts {
 
                 break;
 
+            case SyntaxKind.LabeledStatement:
+                // A labeled statement containing a block scoped binding *may* need to be transformed from ES6.
+                if (subtreeFlags & TransformFlags.ContainsBlockScopedBinding
+                    && isIterationStatement(this, /*lookInLabeledStatements*/ true)) {
+                    transformFlags |= TransformFlags.AssertES6;
+                }
+
+                break;
+
+            case SyntaxKind.DoStatement:
+            case SyntaxKind.WhileStatement:
+            case SyntaxKind.ForStatement:
+            case SyntaxKind.ForInStatement:
+                // A loop containing a block scoped binding *may* need to be transformed from ES6.
+                if (subtreeFlags & TransformFlags.ContainsBlockScopedBinding) {
+                    transformFlags |= TransformFlags.AssertES6;
+                }
+
+                break;
+
             case SyntaxKind.ClassDeclaration:
             case SyntaxKind.ClassExpression:
                 // A ClassDeclarations or ClassExpression is ES6 syntax.
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index e3d6ecae27d..e3c44e51a20 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -2760,6 +2760,7 @@ namespace ts {
         ContainsParameterPropertyAssignments = 1 << 13,
         ContainsSpreadElementExpression = 1 << 14,
         ContainsComputedPropertyName = 1 << 15,
+        ContainsBlockScopedBinding = 1 << 16,
 
         // Assertions
         // - Bitmasks that are used to assert facts about the syntax of a node and its subtree.
@@ -2772,12 +2773,12 @@ namespace ts {
         // - Bitmasks that exclude flags from propagating out of a specific context
         //   into the subtree flags of their container.
         NodeExcludes = TypeScript | Jsx | ES7 | ES6,
-        ArrowFunctionExcludes = ContainsDecorators | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsParameterPropertyAssignments,
-        FunctionExcludes = ContainsDecorators | ContainsDefaultValueAssignments | ContainsCapturedLexicalThis | ContainsLexicalThis | ContainsParameterPropertyAssignments,
-        ConstructorExcludes = ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsParameterPropertyAssignments,
-        MethodOrAccessorExcludes = ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis,
+        ArrowFunctionExcludes = ContainsDecorators | ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding,
+        FunctionExcludes = ContainsDecorators | ContainsDefaultValueAssignments | ContainsCapturedLexicalThis | ContainsLexicalThis | ContainsParameterPropertyAssignments | ContainsBlockScopedBinding,
+        ConstructorExcludes = ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding,
+        MethodOrAccessorExcludes = ContainsDefaultValueAssignments | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding,
         ClassExcludes = ContainsDecorators | ContainsPropertyInitializer | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsComputedPropertyName | ContainsParameterPropertyAssignments,
-        ModuleExcludes = ContainsDecorators | ContainsLexicalThis | ContainsCapturedLexicalThis,
+        ModuleExcludes = ContainsDecorators | ContainsLexicalThis | ContainsCapturedLexicalThis | ContainsBlockScopedBinding,
         TypeExcludes = ~ContainsTypeScript,
         ObjectLiteralExcludes = ContainsDecorators | ContainsComputedPropertyName,
         ArrayLiteralOrCallOrNewExcludes = ContainsSpreadElementExpression,