diff --git a/scripts/debug-fb-www.js b/scripts/debug-fb-www.js
index ceb67189f9..18e8ab0625 100644
--- a/scripts/debug-fb-www.js
+++ b/scripts/debug-fb-www.js
@@ -46,7 +46,6 @@ let prepackOptions = {
   reactVerbose: true,
   inlineExpressions: true,
   omitInvariants: true,
-  abstractEffectsInAdditionalFunctions: true,
   simpleClosures: true,
   abstractValueImpliesMax: 1000,
 };
diff --git a/scripts/test-error-handler.js b/scripts/test-error-handler.js
index 98fb7ce6b9..259e379d4b 100644
--- a/scripts/test-error-handler.js
+++ b/scripts/test-error-handler.js
@@ -55,7 +55,6 @@ function runTest(name: string, code: string): boolean {
 
   let recover = code.includes("// recover-from-errors");
   let delayUnsupportedRequires = code.includes("// delay unsupported requires");
-  let abstractEffects = code.includes("// abstract effects");
   let compatibility = code.includes("// jsc") ? "jsc-600-1-4-17" : undefined;
 
   let expectedErrors = code.match(/\/\/\s*expected errors:\s*(.*)/);
@@ -74,7 +73,6 @@ function runTest(name: string, code: string): boolean {
       errorHandler: errorHandler.bind(null, recover ? "Recover" : "Fail", errors),
       serialize: true,
       initializeMoreModules: false,
-      abstractEffectsInAdditionalFunctions: abstractEffects,
       compatibility,
     };
     prepackFileSync([name], options);
diff --git a/scripts/test-react.js b/scripts/test-react.js
index c9f2e20cd7..4557b9d37c 100644
--- a/scripts/test-react.js
+++ b/scripts/test-react.js
@@ -80,7 +80,6 @@ function runTestSuite(outputJsx, shouldTranspileSource) {
     reactOutput: outputJsx ? "jsx" : "create-element",
     inlineExpressions: true,
     omitInvariants: true,
-    abstractEffectsInAdditionalFunctions: true,
     stripFlow: true,
   };
 
diff --git a/scripts/test-runner.js b/scripts/test-runner.js
index f065618f60..3199980495 100644
--- a/scripts/test-runner.js
+++ b/scripts/test-runner.js
@@ -268,7 +268,6 @@ function runTest(name, code, options: PrepackOptions, args) {
   if (code.includes("// do not inline expressions")) options.inlineExpressions = false;
   if (code.includes("// omit invariants")) options.omitInvariants = true;
   if (code.includes("// emit concrete model")) options.emitConcreteModel = true;
-  if (code.includes("// abstract effects")) options.abstractEffectsInAdditionalFunctions = true;
   if (code.includes("// exceeds stack limit")) options.maxStackDepth = 10;
   if (code.includes("// react")) {
     options.reactEnabled = true;
diff --git a/src/options.js b/src/options.js
index 4c7c7d826b..ba614b2c90 100644
--- a/src/options.js
+++ b/src/options.js
@@ -50,7 +50,6 @@ export type RealmOptions = {
   reactOutput?: ReactOutputTypes,
   reactVerbose?: boolean,
   stripFlow?: boolean,
-  abstractEffectsInAdditionalFunctions?: boolean,
   abstractValueImpliesMax?: number,
 };
 
diff --git a/src/prepack-cli.js b/src/prepack-cli.js
index 253e04a39f..139010c1ff 100644
--- a/src/prepack-cli.js
+++ b/src/prepack-cli.js
@@ -48,7 +48,6 @@ function run(
     --srcmapOut              The output sourcemap filename.
     --maxStackDepth          Specify the maximum call stack depth.
     --timeout                The amount of time in seconds until Prepack should time out.
-    --abstractEffectsInAdditionalFunctions Experimental flag to allow abstract effectful function calls.
     --lazyObjectsRuntime     Enable lazy objects feature and specify the JS runtime that support this feature.
     --debugNames             Changes the output of Prepack so that for named functions and variables that get emitted into
                              Prepack's output, the original name is appended as a suffix to Prepack's generated identifier.
@@ -97,7 +96,6 @@ function run(
     emitConcreteModel: false,
     inlineExpressions: false,
     simpleClosures: false,
-    abstractEffectsInAdditionalFunctions: false,
     logStatistics: false,
     logModules: false,
     delayInitializations: false,
diff --git a/src/prepack-options.js b/src/prepack-options.js
index 5f9fc16235..0a541f440d 100644
--- a/src/prepack-options.js
+++ b/src/prepack-options.js
@@ -16,7 +16,6 @@ import invariant from "./invariant.js";
 
 export type PrepackOptions = {|
   additionalGlobals?: Realm => void,
-  abstractEffectsInAdditionalFunctions?: boolean,
   lazyObjectsRuntime?: string,
   heapGraphFormat?: "DotLanguage" | "VISJS",
   compatibility?: Compatibility,
@@ -59,7 +58,6 @@ export type PrepackOptions = {|
 |};
 
 export function getRealmOptions({
-  abstractEffectsInAdditionalFunctions = false,
   compatibility = "browser",
   debugNames = false,
   errorHandler,
@@ -80,7 +78,6 @@ export function getRealmOptions({
   abstractValueImpliesMax,
 }: PrepackOptions): RealmOptions {
   return {
-    abstractEffectsInAdditionalFunctions,
     compatibility,
     debugNames,
     errorHandler,
diff --git a/src/realm.js b/src/realm.js
index 0012136877..6a9248d005 100644
--- a/src/realm.js
+++ b/src/realm.js
@@ -152,7 +152,6 @@ export class Realm {
   constructor(opts: RealmOptions) {
     this.isReadOnly = false;
     this.useAbstractInterpretation = !!opts.serialize || !!opts.residual || !!opts.check;
-    this.trackLeaks = !!opts.abstractEffectsInAdditionalFunctions;
     this.ignoreLeakLogic = false;
     this.isInPureTryStatement = false;
     if (opts.mathRandomSeed !== undefined) {
@@ -227,7 +226,6 @@ export class Realm {
   isReadOnly: boolean;
   isStrict: boolean;
   useAbstractInterpretation: boolean;
-  trackLeaks: boolean;
   debugNames: void | boolean;
   isInPureTryStatement: boolean; // TODO(1264): Remove this once we implement proper exception handling in abstract calls.
   abstractValueImpliesMax: number;
@@ -508,9 +506,6 @@ export class Realm {
   // also won't have effects on any objects or bindings that weren't created in this
   // call.
   evaluatePure<T>(f: () => T) {
-    if (!this.trackLeaks) {
-      return f();
-    }
     let saved_createdObjectsTrackedForLeaks = this.createdObjectsTrackedForLeaks;
     // Track all objects (including function closures) created during
     // this call. This will be used to make the assumption that every
diff --git a/test/serializer/abstract/ObjectAssign10.js b/test/serializer/abstract/ObjectAssign10.js
index 1807755412..4911a7de07 100644
--- a/test/serializer/abstract/ObjectAssign10.js
+++ b/test/serializer/abstract/ObjectAssign10.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 var copyOfCopyOfObj;
@@ -10,6 +8,6 @@ __evaluatePureFunction(() => {
   copyOfObj.x = 10;
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfCopyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign11.js b/test/serializer/abstract/ObjectAssign11.js
index 8caaa3d8c0..665eaa3ecf 100644
--- a/test/serializer/abstract/ObjectAssign11.js
+++ b/test/serializer/abstract/ObjectAssign11.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -10,6 +8,6 @@ __evaluatePureFunction(() => {
   copyOfObj.x = 10;
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign12.js b/test/serializer/abstract/ObjectAssign12.js
index 380cb783fe..b74e4432f5 100644
--- a/test/serializer/abstract/ObjectAssign12.js
+++ b/test/serializer/abstract/ObjectAssign12.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({foo: __abstract('number')}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -10,6 +8,6 @@ __evaluatePureFunction(() => {
   copyOfObj.foo = 2;
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign13.js b/test/serializer/abstract/ObjectAssign13.js
index ed11114f9a..beb98ca2af 100644
--- a/test/serializer/abstract/ObjectAssign13.js
+++ b/test/serializer/abstract/ObjectAssign13.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -15,6 +13,6 @@ __evaluatePureFunction(() => {
   });
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign14.js b/test/serializer/abstract/ObjectAssign14.js
index 380cb783fe..b74e4432f5 100644
--- a/test/serializer/abstract/ObjectAssign14.js
+++ b/test/serializer/abstract/ObjectAssign14.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({foo: __abstract('number')}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -10,6 +8,6 @@ __evaluatePureFunction(() => {
   copyOfObj.foo = 2;
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign15.js b/test/serializer/abstract/ObjectAssign15.js
index 3cbbbb6dce..d77bfb2c30 100644
--- a/test/serializer/abstract/ObjectAssign15.js
+++ b/test/serializer/abstract/ObjectAssign15.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({foo: __abstract('number')}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -17,6 +15,6 @@ __evaluatePureFunction(() => {
   });
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(y);
 }
diff --git a/test/serializer/abstract/ObjectAssign16.js b/test/serializer/abstract/ObjectAssign16.js
index b21de38d63..03c7764ab4 100644
--- a/test/serializer/abstract/ObjectAssign16.js
+++ b/test/serializer/abstract/ObjectAssign16.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({foo: __abstract('number')}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -10,6 +8,6 @@ __evaluatePureFunction(() => {
   delete copyOfObj.foo;
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign17.js b/test/serializer/abstract/ObjectAssign17.js
index d03f266e2a..4950553c71 100644
--- a/test/serializer/abstract/ObjectAssign17.js
+++ b/test/serializer/abstract/ObjectAssign17.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -21,6 +19,6 @@ __evaluatePureFunction(() => {
   copyOfObj.__proto__ = proto;
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(y);
 }
diff --git a/test/serializer/abstract/ObjectAssign19.js b/test/serializer/abstract/ObjectAssign19.js
index 042b6abed6..82c3af322d 100644
--- a/test/serializer/abstract/ObjectAssign19.js
+++ b/test/serializer/abstract/ObjectAssign19.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 
diff --git a/test/serializer/abstract/ObjectAssign6.js b/test/serializer/abstract/ObjectAssign6.js
index 471f6d7f26..f466167933 100644
--- a/test/serializer/abstract/ObjectAssign6.js
+++ b/test/serializer/abstract/ObjectAssign6.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -8,6 +6,6 @@ __evaluatePureFunction(() => {
   copyOfObj = Object.assign({}, obj, {foo: 2});
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign7.js b/test/serializer/abstract/ObjectAssign7.js
index f243f3d589..0d43e2ebdf 100644
--- a/test/serializer/abstract/ObjectAssign7.js
+++ b/test/serializer/abstract/ObjectAssign7.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 var copyOfObj;
@@ -8,6 +6,6 @@ __evaluatePureFunction(() => {
   copyOfObj = Object.assign({}, {foo: 2}, obj);
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(copyOfObj);
 }
diff --git a/test/serializer/abstract/ObjectAssign8.js b/test/serializer/abstract/ObjectAssign8.js
index 841bebd277..7f32bbabc8 100644
--- a/test/serializer/abstract/ObjectAssign8.js
+++ b/test/serializer/abstract/ObjectAssign8.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 var obj = global.__abstract && global.__makePartial && global.__makeSimple ? __makeSimple(__makePartial(__abstract({}, "({foo:1})"))) : {foo:1};
 var x;
@@ -11,6 +9,6 @@ __evaluatePureFunction(() => {
   y.foo = 2;
 });
 
-inspect = function() {  
+inspect = function() {
   return JSON.stringify(x);
 }
diff --git a/test/serializer/abstract/ObjectAssign9.js b/test/serializer/abstract/ObjectAssign9.js
index fe04dd51a7..e3fe7f438c 100644
--- a/test/serializer/abstract/ObjectAssign9.js
+++ b/test/serializer/abstract/ObjectAssign9.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
 __evaluatePureFunction(() => {
   let dims = global.__abstract ? __abstract({
diff --git a/test/serializer/additional-functions/possible_throw_object_assign.js b/test/serializer/additional-functions/possible_throw_object_assign.js
index 13ec580a87..a7f1546d88 100644
--- a/test/serializer/additional-functions/possible_throw_object_assign.js
+++ b/test/serializer/additional-functions/possible_throw_object_assign.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 global.f = function(x, y) {
     if (y) Object.assign({}, x); else throw new Error();
 };
diff --git a/test/serializer/pure-functions/AbstractCall.js b/test/serializer/pure-functions/AbstractCall.js
index d385e5b9ff..9c9045c528 100644
--- a/test/serializer/pure-functions/AbstractCall.js
+++ b/test/serializer/pure-functions/AbstractCall.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let forEach = global.__abstract ? __abstract('function', '(function(callback) { callback("a", 0); callback("b", 1); })') : function(callback) { callback("a", 0); callback("b", 1); };
 let set = global.__abstract ? __abstract('function', '(function(obj, name, value) { obj[name] = value; })') : function(obj, name, value) { obj[name] = value; };
 
diff --git a/test/serializer/pure-functions/AbstractCallUnknownType.js b/test/serializer/pure-functions/AbstractCallUnknownType.js
index 81bde6cde8..6add7d3a07 100644
--- a/test/serializer/pure-functions/AbstractCallUnknownType.js
+++ b/test/serializer/pure-functions/AbstractCallUnknownType.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj = global.__abstract ? __abstract('object', '({foo: function() { return 1; }})') : {foo: function() { return 1; }};
 if (global.__makeSimple) {
   __makeSimple(obj);
diff --git a/test/serializer/pure-functions/AbstractCallUnknownType2.js b/test/serializer/pure-functions/AbstractCallUnknownType2.js
index 7adc9d29c7..d2dbc8ada7 100644
--- a/test/serializer/pure-functions/AbstractCallUnknownType2.js
+++ b/test/serializer/pure-functions/AbstractCallUnknownType2.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj = {};
 if (global.__makeSimple) {
   __makeSimple(obj);
diff --git a/test/serializer/pure-functions/AbstractPropertyRead.js b/test/serializer/pure-functions/AbstractPropertyRead.js
index 52b1cbf370..5e26dd6e08 100644
--- a/test/serializer/pure-functions/AbstractPropertyRead.js
+++ b/test/serializer/pure-functions/AbstractPropertyRead.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj1 = global.__abstract ? __abstract('object', '({get foo() { return "bar"; }})') : {get foo() { return "bar"; }};
 let obj2 = global.__abstract ? __abstract('object', '({foo:{bar:"baz"}})') : {foo:{bar:"baz"}};
 if (global.__makeSimple) {
diff --git a/test/serializer/pure-functions/AbstractPropertyRead2.js b/test/serializer/pure-functions/AbstractPropertyRead2.js
index d5b7be0938..2b9ec5a62d 100644
--- a/test/serializer/pure-functions/AbstractPropertyRead2.js
+++ b/test/serializer/pure-functions/AbstractPropertyRead2.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj1 = global.__abstract ? __abstract('object', '({get foo() { return "bar"; }})') : {get foo() { return "bar"; }};
 let obj2 = global.__abstract ? __abstract('object', '({foo:{extends:"baz"}})') : {foo:{"extends":"baz"}};
 if (global.__makeSimple) {
diff --git a/test/serializer/pure-functions/AbstractPropertyRead3.js b/test/serializer/pure-functions/AbstractPropertyRead3.js
index 46c2dc4e73..e65df3c956 100644
--- a/test/serializer/pure-functions/AbstractPropertyRead3.js
+++ b/test/serializer/pure-functions/AbstractPropertyRead3.js
@@ -1,4 +1,3 @@
-// abstract effects
 // does contain: "barone"
 
 var __evaluatePureFunction = this.__evaluatePureFunction || (f => f());
diff --git a/test/serializer/pure-functions/AbstractPropertyRead4.js b/test/serializer/pure-functions/AbstractPropertyRead4.js
index c46f4f040b..53b49ee5ca 100644
--- a/test/serializer/pure-functions/AbstractPropertyRead4.js
+++ b/test/serializer/pure-functions/AbstractPropertyRead4.js
@@ -1,4 +1,3 @@
-// abstract effects
 // does contain: "barone"
 // does not contain: "23"
 
diff --git a/test/serializer/pure-functions/BinaryExpressions.js b/test/serializer/pure-functions/BinaryExpressions.js
index 327bf5264f..5a5336052c 100644
--- a/test/serializer/pure-functions/BinaryExpressions.js
+++ b/test/serializer/pure-functions/BinaryExpressions.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj1 = global.__abstract ? __abstract('object', '({foo: {valueOf() { return 42; }}})') : {foo: {valueOf() { return 42; }}};
 let obj2 = global.__abstract ? __abstract('object', '({foo: {bar: {valueOf() { return 42; }}}})') : {foo: {bar: {valueOf() { return 42; }}}};
 
diff --git a/test/serializer/pure-functions/BinaryExpressions2.js b/test/serializer/pure-functions/BinaryExpressions2.js
index 3a46f7b97b..287c2dcc2d 100644
--- a/test/serializer/pure-functions/BinaryExpressions2.js
+++ b/test/serializer/pure-functions/BinaryExpressions2.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj1 = global.__abstract ? __abstract('object', '({foo: {valueOf() { return 42; }}})') : {foo: {valueOf() { return 42; }}};
 let obj2 = global.__abstract ? __abstract('object', '({foo: {bar: {valueOf() { return 42; }}}})') : {foo: {bar: {valueOf() { return 42; }}}};
 
diff --git a/test/serializer/pure-functions/BinaryExpressions3.js b/test/serializer/pure-functions/BinaryExpressions3.js
index 69c55bf492..aff6e47e94 100644
--- a/test/serializer/pure-functions/BinaryExpressions3.js
+++ b/test/serializer/pure-functions/BinaryExpressions3.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj1 = global.__abstract ? __abstract('object', '({valueOf() { this.x = 10; return 42; }})') : {valueOf() { this.x = 10; return 42; }};
 
 function additional1() {
@@ -12,7 +10,7 @@ function additional2() {
   var x = {
     valueOf:
       (global.__abstract
-        ? __abstract('function', '(function() { this.foo++; return 10; })') 
+        ? __abstract('function', '(function() { this.foo++; return 10; })')
         : function() { this.foo++; return 10; }
       ),
     foo: 0
diff --git a/test/serializer/pure-functions/CastStringOnUnknown.js b/test/serializer/pure-functions/CastStringOnUnknown.js
index 159326cca9..42a496b78c 100644
--- a/test/serializer/pure-functions/CastStringOnUnknown.js
+++ b/test/serializer/pure-functions/CastStringOnUnknown.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj1 = global.__abstract ? __abstract('object', '({get foo() { return "bar"; }})') : {get foo() { return "bar"; }};
 let obj2 = global.__abstract ? __abstract('object', '({foo:{bar:"baz"}})') : {foo:{bar:"baz"}};
 if (global.__makeSimple) {
diff --git a/test/serializer/pure-functions/Invariants.js b/test/serializer/pure-functions/Invariants.js
index 1ea69355b9..97f557e3ab 100644
--- a/test/serializer/pure-functions/Invariants.js
+++ b/test/serializer/pure-functions/Invariants.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var invariant = function(condition, message) {
   if (condition) return;
   throw new Error(message);
@@ -10,8 +8,8 @@ if (!global.__evaluatePureFunction) {
 }
 
 __evaluatePureFunction(() => {
-  var x = global.__abstract 
-    ? __abstract("object", "({foo: {foo2: {}}, bar: {bar2: {}}})") 
+  var x = global.__abstract
+    ? __abstract("object", "({foo: {foo2: {}}, bar: {bar2: {}}})")
     : {foo: {foo2: {}}, bar: {bar2: {}}};
 
   if (global.__makeSimple) {
@@ -26,4 +24,4 @@ __evaluatePureFunction(() => {
 
   foo2 || invariant(0, "Should not error 1!");
   bar2 || invariant(0, "Should not error 2!");
-});
\ No newline at end of file
+});
diff --git a/test/serializer/pure-functions/NewExpression.js b/test/serializer/pure-functions/NewExpression.js
index 99d2817567..444c920949 100644
--- a/test/serializer/pure-functions/NewExpression.js
+++ b/test/serializer/pure-functions/NewExpression.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var Foo = global.__abstract ? __abstract(undefined, "(function () { this.x = 10 })") : function () { this.x = 10 };
 
 function additional1() {
diff --git a/test/serializer/pure-functions/ObjectAssign.js b/test/serializer/pure-functions/ObjectAssign.js
index b04dfe506c..d47c7682ac 100644
--- a/test/serializer/pure-functions/ObjectAssign.js
+++ b/test/serializer/pure-functions/ObjectAssign.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var obj = global.__abstract && global.__makePartial ? __makePartial(__abstract({}, "({foo:1})")) : {foo:1};
 
 function additional1() {
diff --git a/test/serializer/pure-functions/UnaryExpressions.js b/test/serializer/pure-functions/UnaryExpressions.js
index 280cbbe71c..fa83d15c85 100644
--- a/test/serializer/pure-functions/UnaryExpressions.js
+++ b/test/serializer/pure-functions/UnaryExpressions.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 let obj1 = global.__abstract ? __abstract('object', '({foo: {valueOf() { return 42; }}})') : {foo: {valueOf() { return 42; }}};
 let obj2 = global.__abstract ? __abstract('object', '({foo: {bar: {valueOf() { return 42; }}}})') : {foo: {bar: {valueOf() { return 42; }}}};
 
diff --git a/test/serializer/pure-functions/hasOwnProperty.js b/test/serializer/pure-functions/hasOwnProperty.js
index bf217ef609..44254e35ce 100644
--- a/test/serializer/pure-functions/hasOwnProperty.js
+++ b/test/serializer/pure-functions/hasOwnProperty.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var obj = global.__abstract && global.__makePartial ? __makePartial(__abstract({}, "({foo:1})")) : {foo:1};
 if (global.__makeSimple) __makeSimple(obj);
 
diff --git a/test/serializer/pure-functions/hasOwnProperty2.js b/test/serializer/pure-functions/hasOwnProperty2.js
index 0c41419d1e..22bb72c2a7 100644
--- a/test/serializer/pure-functions/hasOwnProperty2.js
+++ b/test/serializer/pure-functions/hasOwnProperty2.js
@@ -1,5 +1,3 @@
-// abstract effects
-
 var obj = global.__abstract && global.__makePartial ? __makePartial(__abstract({}, "({foo:1})")) : {foo:1};
 if (global.__makeSimple) __makeSimple(obj);
 
diff --git a/website/js/repl.js b/website/js/repl.js
index e31d9711d1..60b660d68f 100644
--- a/website/js/repl.js
+++ b/website/js/repl.js
@@ -75,12 +75,6 @@ var optionsConfig = [
     defaultVal: true,
     description: "Removes Flow type annotations from the output."
   },
-  {
-    type: "boolean",
-    name: "abstractEffectsInAdditionalFunctions",
-    defaultVal: true,
-    description: "Allows abstract effects in pure functions and React components."
-  },
 ];
 
 var demos = [];