diff --git a/src/completions.js b/src/completions.js
index f16009e970..ca8b2dd2a9 100644
--- a/src/completions.js
+++ b/src/completions.js
@@ -88,6 +88,9 @@ export class BreakCompletion extends AbruptCompletion {
 export class ReturnCompletion extends AbruptCompletion {
   constructor(value: Value, precedingEffects: void | Effects, location: ?BabelNodeSourceLocation) {
     super(value, precedingEffects, location);
+    if (value instanceof EmptyValue) {
+      this.value = value.$Realm.intrinsics.undefined;
+    }
   }
 }
 
diff --git a/src/methods/join.js b/src/methods/join.js
index 599b794c36..126378f97b 100644
--- a/src/methods/join.js
+++ b/src/methods/join.js
@@ -334,87 +334,11 @@ export class JoinImplementation {
     }
   }
 
-  updatePossiblyNormalCompletionWithConditionalSimpleNormalCompletion(
+  joinNormalCompletions(
     realm: Realm,
     joinCondition: AbstractValue,
-    pnc: PossiblyNormalCompletion,
-    nc: SimpleNormalCompletion
-  ): void {
-    let v = nc.value;
-    if (pnc.consequent instanceof AbruptCompletion) {
-      if (pnc.alternate instanceof SimpleNormalCompletion) {
-        nc.value = AbstractValue.createFromConditionalOp(realm, joinCondition, pnc.alternate.value, v);
-        pnc.alternateEffects.result = nc;
-        nc.effects = pnc.alternateEffects;
-        pnc.alternate = nc;
-      } else {
-        invariant(pnc.alternate instanceof PossiblyNormalCompletion);
-        this.updatePossiblyNormalCompletionWithConditionalSimpleNormalCompletion(
-          realm,
-          joinCondition,
-          pnc.alternate,
-          nc
-        );
-      }
-    } else {
-      if (pnc.consequent instanceof SimpleNormalCompletion) {
-        nc.value = AbstractValue.createFromConditionalOp(realm, joinCondition, pnc.consequent.value, v);
-        pnc.consequentEffects.result = nc;
-        nc.effects = pnc.consequentEffects;
-        pnc.consequent = nc;
-      } else {
-        invariant(pnc.consequent instanceof PossiblyNormalCompletion);
-        this.updatePossiblyNormalCompletionWithConditionalSimpleNormalCompletion(
-          realm,
-          joinCondition,
-          pnc.consequent,
-          nc
-        );
-      }
-    }
-  }
-
-  updatePossiblyNormalCompletionWithInverseConditionalSimpleNormalCompletion(
-    realm: Realm,
-    joinCondition: AbstractValue,
-    pnc: PossiblyNormalCompletion,
-    nc: SimpleNormalCompletion
-  ): void {
-    let v = nc.value;
-    if (pnc.consequent instanceof AbruptCompletion) {
-      if (pnc.alternate instanceof SimpleNormalCompletion) {
-        nc.value = AbstractValue.createFromConditionalOp(realm, joinCondition, v, pnc.alternate.value);
-        pnc = pnc.updateAlternateKeepingCurrentEffects(nc);
-      } else {
-        invariant(pnc.alternate instanceof PossiblyNormalCompletion);
-        this.updatePossiblyNormalCompletionWithInverseConditionalSimpleNormalCompletion(
-          realm,
-          joinCondition,
-          pnc.alternate,
-          nc
-        );
-      }
-    } else {
-      if (pnc.consequent instanceof SimpleNormalCompletion) {
-        nc.value = AbstractValue.createFromConditionalOp(realm, joinCondition, v, pnc.consequent.value);
-        pnc = pnc.updateConsequentKeepingCurrentEffects(nc);
-      } else {
-        invariant(pnc.consequent instanceof PossiblyNormalCompletion);
-        this.updatePossiblyNormalCompletionWithInverseConditionalSimpleNormalCompletion(
-          realm,
-          joinCondition,
-          pnc.consequent,
-          nc
-        );
-      }
-    }
-  }
-
-  joinPossiblyNormalCompletions(
-    realm: Realm,
-    joinCondition: AbstractValue,
-    c: PossiblyNormalCompletion,
-    a: PossiblyNormalCompletion
+    c: NormalCompletion,
+    a: NormalCompletion
   ): PossiblyNormalCompletion {
     let getAbstractValue = (v1: void | Value, v2: void | Value): Value => {
       if (v1 instanceof EmptyValue) return v2 || realm.intrinsics.undefined;
@@ -633,8 +557,8 @@ export class JoinImplementation {
     if (result1 instanceof AbruptCompletion && result2 instanceof AbruptCompletion) {
       return new ForkedAbruptCompletion(realm, joinCondition, result1, e1, result2, e2);
     }
-    if (result1 instanceof PossiblyNormalCompletion && result2 instanceof PossiblyNormalCompletion) {
-      return this.joinPossiblyNormalCompletions(realm, joinCondition, result1, result2);
+    if (result1 instanceof NormalCompletion && result2 instanceof NormalCompletion) {
+      return this.joinNormalCompletions(realm, joinCondition, result1, result2);
     }
     if (result1 instanceof AbruptCompletion) {
       let completion = result2;
@@ -678,21 +602,6 @@ export class JoinImplementation {
         savedEffects
       );
     }
-    if (result1 instanceof PossiblyNormalCompletion) {
-      invariant(result2 instanceof SimpleNormalCompletion);
-      this.updatePossiblyNormalCompletionWithConditionalSimpleNormalCompletion(realm, joinCondition, result1, result2);
-      return result1;
-    }
-    if (result2 instanceof PossiblyNormalCompletion) {
-      invariant(result1 instanceof SimpleNormalCompletion);
-      this.updatePossiblyNormalCompletionWithInverseConditionalSimpleNormalCompletion(
-        realm,
-        joinCondition,
-        result2,
-        result1
-      );
-      return result2;
-    }
     invariant(false);
   }
 
diff --git a/src/types.js b/src/types.js
index 445cd8ef6e..79ae1b9278 100644
--- a/src/types.js
+++ b/src/types.js
@@ -32,7 +32,6 @@ import {
   AbruptCompletion,
   Completion,
   ForkedAbruptCompletion,
-  SimpleNormalCompletion,
   PossiblyNormalCompletion,
   NormalCompletion,
 } from "./completions.js";
@@ -741,20 +740,6 @@ export type JoinType = {
     e: Effects
   ): ForkedAbruptCompletion,
 
-  updatePossiblyNormalCompletionWithConditionalSimpleNormalCompletion(
-    realm: Realm,
-    joinCondition: AbstractValue,
-    pnc: PossiblyNormalCompletion,
-    nc: SimpleNormalCompletion
-  ): void,
-
-  updatePossiblyNormalCompletionWithInverseConditionalSimpleNormalCompletion(
-    realm: Realm,
-    joinCondition: AbstractValue,
-    pnc: PossiblyNormalCompletion,
-    nc: SimpleNormalCompletion
-  ): void,
-
   extractAndJoinCompletionsOfType(CompletionType: typeof AbruptCompletion, realm: Realm, c: AbruptCompletion): Effects,
 
   joinForkOrChoose(realm: Realm, joinCondition: Value, e1: Effects, e2: Effects): Effects,
diff --git a/test/serializer/abstract/Throw10.js b/test/serializer/abstract/Throw10.js
new file mode 100644
index 0000000000..29dbe3ef9b
--- /dev/null
+++ b/test/serializer/abstract/Throw10.js
@@ -0,0 +1,14 @@
+let c1 = global.__abstract ? __abstract("boolean", "true") : true;
+let c2 = global.__abstract ? __abstract("boolean", "false") : false;
+
+function foo(cond) {
+  if (cond) throw "I am an error too!";
+}
+
+if (c2) {
+  foo(c1);
+}
+
+inspect = function() {
+  return "success";
+};