diff --git a/attribute-order.conf b/attribute-order.conf
index 44dd18d..e1eab14 100644
--- a/attribute-order.conf
+++ b/attribute-order.conf
@@ -138,6 +138,7 @@ test
 declaration
 
 [ExportAllFrom]
+name
 moduleSpecifier
 
 [ExportDeclaration]
@@ -234,6 +235,9 @@ moduleSpecifier
 [ImportDeclaration]
 moduleSpecifier
 
+[ImportExpression]
+source
+
 [ImportNamespace]
 defaultBinding
 namespaceBinding
@@ -250,6 +254,10 @@ body
 label
 body
 
+[LiteralBigIntExpression]
+bigint
+value
+
 [LiteralBooleanExpression]
 value
 
@@ -300,7 +308,9 @@ name
 callee
 arguments
 
-[NewTargetExpression]
+[MetaProperty]
+meta
+property
 
 [Node]
 
@@ -317,6 +327,13 @@ properties
 
 [ObjectProperty]
 
+[OptionalChainingExpression]
+expression
+
+[OptionalMemberExpression]
+object
+property 
+
 [Program]
 
 [PropertyName]
diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..95094f5
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,48 @@
+{
+  "name": "shift-spec-idl",
+  "version": "2020.0.0",
+  "lockfileVersion": 2,
+  "requires": true,
+  "packages": {
+    "": {
+      "name": "shift-spec-idl",
+      "version": "2020.0.0",
+      "license": "Apache-2.0",
+      "devDependencies": {
+        "shift-spec-consumer": "^1.0.0"
+      }
+    },
+    "node_modules/shift-spec-consumer": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/shift-spec-consumer/-/shift-spec-consumer-1.0.1.tgz",
+      "integrity": "sha1-9nZS3vwYgGeAqOBLT58IoP/iOpw=",
+      "dev": true,
+      "dependencies": {
+        "webidl2": "^2.0.11"
+      }
+    },
+    "node_modules/webidl2": {
+      "version": "2.4.0",
+      "resolved": "https://registry.npmjs.org/webidl2/-/webidl2-2.4.0.tgz",
+      "integrity": "sha1-Wm8oK3K0ec6grsIisUuDM325cpA=",
+      "dev": true
+    }
+  },
+  "dependencies": {
+    "shift-spec-consumer": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/shift-spec-consumer/-/shift-spec-consumer-1.0.1.tgz",
+      "integrity": "sha1-9nZS3vwYgGeAqOBLT58IoP/iOpw=",
+      "dev": true,
+      "requires": {
+        "webidl2": "^2.0.11"
+      }
+    },
+    "webidl2": {
+      "version": "2.4.0",
+      "resolved": "https://registry.npmjs.org/webidl2/-/webidl2-2.4.0.tgz",
+      "integrity": "sha1-Wm8oK3K0ec6grsIisUuDM325cpA=",
+      "dev": true
+    }
+  }
+}
diff --git a/package.json b/package.json
index 74ae6b8..f477748 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "shift-spec-idl",
-  "version": "2019.0.0",
+  "version": "2020.0.0",
   "description": "Shift AST specification IDL files",
   "author": "Shape Security",
   "homepage": "https://github.com/shapesecurity/shift-spec",
diff --git a/spec.idl b/spec.idl
index b44524f..8b0f264 100644
--- a/spec.idl
+++ b/spec.idl
@@ -47,7 +47,7 @@ enum CompoundAssignmentOperator {
 };
 enum BinaryOperator {
   "==", "!=", "===", "!==", "<", "<=", ">", ">=", "in", "instanceof", "<<",
-  ">>", ">>>", "+", "-", "*", "/", "%", "**", ",", "||", "&&", "|", "^", "&"
+  ">>", ">>>", "+", "-", "*", "/", "%", "**", ",", "||", "&&", "|", "^", "&", "??"
 };
 enum UnaryOperator { "+", "-", "!", "~", "typeof", "void", "delete" };
 enum UpdateOperator { "++", "--" };
@@ -255,8 +255,9 @@ interface ImportSpecifier : Node {
   attribute BindingIdentifier binding;
 };
 
-// `export * FromClause;`
+// `export * FromClause;`, `export * as IdentifierName FromClause`
 interface ExportAllFrom : ExportDeclaration {
+  attribute IdentifierName? name;
   attribute string moduleSpecifier;
 };
 
@@ -349,6 +350,12 @@ interface StaticPropertyName : PropertyName {
 
 // literals
 
+// `BigIntLiteral`
+interface LiteralBigIntExpression : Expression {
+  attribute string bigint;
+  attribute double value;
+};
+
 // `BooleanLiteral`
 interface LiteralBooleanExpression : Expression {
   attribute boolean value;
@@ -412,7 +419,7 @@ interface AssignmentExpression : Expression {
   attribute Expression expression;
 };
 
-// `ExponentiationExpression`, `MultiplicativeExpression`, `AdditiveExpression`, `ShiftExpression`, `RelationalExpression`, `EqualityExpression`, `BitwiseANDExpression`, `BitwiseXORExpression`, `BitwiseORExpression`, `LogicalANDExpression`, `LogicalORExpression`
+// `ExponentiationExpression`, `MultiplicativeExpression`, `AdditiveExpression`, `ShiftExpression`, `RelationalExpression`, `EqualityExpression`, `BitwiseANDExpression`, `BitwiseXORExpression`, `BitwiseORExpression`, `LogicalANDExpression`, `LogicalORExpression`, `NullishCoalescingExpression`
 interface BinaryExpression : Expression {
   attribute BinaryOperator operator;
   // The expression before the operator.
@@ -459,17 +466,34 @@ FunctionExpression implements Function;
 interface IdentifierExpression : Expression { };
 IdentifierExpression implements VariableReference;
 
+// `ImportExpression`
+interface ImportExpression : Expression {
+  attribute Expression source;
+};
+
+// `import.meta`, `new.target`
+interface MetaProperty: Expression {
+  attribute Identifier meta;
+  attribute Identifier property;
+};
+
 interface NewExpression : Expression {
   attribute Expression callee;
   attribute Arguments arguments;
 };
 
-interface NewTargetExpression : Expression { };
-
 interface ObjectExpression : Expression {
   attribute ObjectProperty[] properties;
 };
 
+interface OptionalChainingExpression: Expression {
+  attribute Expression expression;
+};
+
+interface OptionalMemberExpression: MemberExpression {
+  attribute IdentifierName property;
+};
+
 interface UnaryExpression : Expression {
   attribute UnaryOperator operator;
   attribute Expression operand;