diff --git a/include/hermes/IR/IR.h b/include/hermes/IR/IR.h
index a85815c075f..dddfe2d7bbf 100644
--- a/include/hermes/IR/IR.h
+++ b/include/hermes/IR/IR.h
@@ -1773,7 +1773,8 @@ class Function : public llvh::ilist_node_with_parent<Function, Module>,
 
   enum class DefinitionKind {
     ES5Function,
-    ES6Constructor,
+    ES6BaseConstructor,
+    ES6DerivedConstructor,
     ES6Arrow,
     ES6Method,
     // This corresponds to the synthetic function we create in IRGen, which is
diff --git a/lib/IR/IR.cpp b/lib/IR/IR.cpp
index cf58449badd..eb2da0e969d 100644
--- a/lib/IR/IR.cpp
+++ b/lib/IR/IR.cpp
@@ -162,7 +162,8 @@ static Type functionNewTargetType(Function::DefinitionKind defKind) {
   switch (defKind) {
     case Function::DefinitionKind::ES5Function:
       return Type::unionTy(Type::createObject(), Type::createUndefined());
-    case Function::DefinitionKind::ES6Constructor:
+    case Function::DefinitionKind::ES6BaseConstructor:
+    case Function::DefinitionKind::ES6DerivedConstructor:
       return Type::createObject();
     case Function::DefinitionKind::ES6Arrow:
     case Function::DefinitionKind::GeneratorInnerArrow:
@@ -229,8 +230,10 @@ std::string Function::getDefinitionKindStr(bool isDescriptive) const {
   switch (definitionKind_) {
     case Function::DefinitionKind::ES5Function:
       return "function";
-    case Function::DefinitionKind::ES6Constructor:
-      return "constructor";
+    case Function::DefinitionKind::ES6BaseConstructor:
+      return "base constructor";
+    case Function::DefinitionKind::ES6DerivedConstructor:
+      return "derived constructor";
     case Function::DefinitionKind::ES6Arrow:
       return isDescriptive ? "arrow function" : "arrow";
     case Function::DefinitionKind::ES6Method:
@@ -283,7 +286,8 @@ llvh::Optional<llvh::StringRef> Function::getSourceRepresentationStr() const {
 
 Function::ProhibitInvoke Function::getProhibitInvoke() const {
   // ES6 constructors must be invoked as constructors.
-  if (definitionKind_ == DefinitionKind::ES6Constructor)
+  if (definitionKind_ == DefinitionKind::ES6BaseConstructor ||
+      definitionKind_ == DefinitionKind::ES6DerivedConstructor)
     return ProhibitInvoke::ProhibitCall;
 
   // Generators, async functions, methods, and arrow functions may not be
diff --git a/lib/IR/IRVerifier.cpp b/lib/IR/IRVerifier.cpp
index 5ed018ae109..10818cebca9 100644
--- a/lib/IR/IRVerifier.cpp
+++ b/lib/IR/IRVerifier.cpp
@@ -1481,7 +1481,8 @@ bool Verifier::visitGetNewTargetInst(GetNewTargetInst const &Inst) {
   AssertIWithMsg(
       Inst,
       definitionKind == Function::DefinitionKind::ES5Function ||
-          definitionKind == Function::DefinitionKind::ES6Constructor ||
+          definitionKind == Function::DefinitionKind::ES6BaseConstructor ||
+          definitionKind == Function::DefinitionKind::ES6DerivedConstructor ||
           definitionKind == Function::DefinitionKind::ES6Method,
       "GetNewTargetInst can only be used in ES6 constructors, ES5 functions, and ES6 methods");
   AssertIWithMsg(
diff --git a/lib/IRGen/ESTreeIRGen-expr.cpp b/lib/IRGen/ESTreeIRGen-expr.cpp
index 8663c44a4f8..a8ba742a5c3 100644
--- a/lib/IRGen/ESTreeIRGen-expr.cpp
+++ b/lib/IRGen/ESTreeIRGen-expr.cpp
@@ -2476,7 +2476,8 @@ Value *ESTreeIRGen::genNewTarget() {
 
   switch (curFunction()->function->getDefinitionKind()) {
     case Function::DefinitionKind::ES5Function:
-    case Function::DefinitionKind::ES6Constructor:
+    case Function::DefinitionKind::ES6BaseConstructor:
+    case Function::DefinitionKind::ES6DerivedConstructor:
       value = Builder.createGetNewTargetInst(
           curFunction()->function->getNewTargetParam());
       break;
diff --git a/lib/IRGen/ESTreeIRGen-func.cpp b/lib/IRGen/ESTreeIRGen-func.cpp
index fdd850d5e9b..3bcf6c767a9 100644
--- a/lib/IRGen/ESTreeIRGen-func.cpp
+++ b/lib/IRGen/ESTreeIRGen-func.cpp
@@ -403,33 +403,33 @@ NormalFunction *ESTreeIRGen::genBasicFunction(
           parentScope);
     }
 
-    if (functionKind == Function::DefinitionKind::ES6Constructor) {
-      if (curFunction()->hasLegacyClassContext()) {
-        if (curFunction()->getSemInfo()->constructorKind ==
-            sema::FunctionInfo::ConstructorKind::Derived) {
-          // Initialize the 'checked this' in derived class constructors.
-          newFunctionContext.capturedState.thisVal = Builder.createVariable(
-              curFunction()->curScope->getVariableScope(),
-              Builder.createIdentifier("?CHECKED_this"),
-              Type::unionTy(Type::createObject(), Type::createEmpty()),
-              true);
-          Builder.createStoreFrameInst(
-              curFunction()->curScope,
-              Builder.getLiteralEmpty(),
-              newFunctionContext.capturedState.thisVal);
-        } else {
-          // We generate this call after calling super for derived classes.
-          emitLegacyInstanceElementsInitCall();
-        }
-      } else {
+    if (curFunction()->hasLegacyClassContext()) {
+      if (functionKind == Function::DefinitionKind::ES6BaseConstructor) {
+        // We only need to generate this here for base classes. It's not
+        // required for derived because they generate this call after calling
+        // super().
+        emitLegacyInstanceElementsInitCall();
+      } else if (
+          functionKind == Function::DefinitionKind::ES6DerivedConstructor) {
+        // Initialize the 'checked this' in derived class constructors.
+        newFunctionContext.capturedState.thisVal = Builder.createVariable(
+            curFunction()->curScope->getVariableScope(),
+            Builder.createIdentifier("?CHECKED_this"),
+            Type::unionTy(Type::createObject(), Type::createEmpty()),
+            true);
+        Builder.createStoreFrameInst(
+            curFunction()->curScope,
+            Builder.getLiteralEmpty(),
+            newFunctionContext.capturedState.thisVal);
+      }
+    } else {
+      if (functionKind == Function::DefinitionKind::ES6BaseConstructor) {
         assert(
             curFunction()->hasTypedClassContext() &&
             "ES6Constructor has no valid class context");
-        // If we're compiling a typed constructor with no superclass, emit the
-        // field inits at the start.
-        if (superClassNode == nullptr) {
-          emitTypedFieldInitCall(typedClassContext.type);
-        }
+        // If we're compiling a typed base class constructor, emit the field
+        // inits at the start.
+        emitTypedFieldInitCall(typedClassContext.type);
       }
     }
 
@@ -701,10 +701,8 @@ void ESTreeIRGen::initCaptureStateInES5FunctionHelper() {
   // `this` is managed separately in the case of a legacy derived class
   // constructor.
   if (!(curFunction()->function->getDefinitionKind() ==
-            Function::DefinitionKind::ES6Constructor &&
-        curFunction()->hasLegacyClassContext() &&
-        semCtx_.nearestNonArrow(curFunction()->getSemInfo())->constructorKind ==
-            sema::FunctionInfo::ConstructorKind::Derived)) {
+            Function::DefinitionKind::ES6DerivedConstructor &&
+        curFunction()->hasLegacyClassContext())) {
     auto *th = Builder.createVariable(
         scope,
         genAnonymousLabelName("this"),
diff --git a/lib/IRGen/ESTreeIRGen-legacy-class.cpp b/lib/IRGen/ESTreeIRGen-legacy-class.cpp
index 72c52f8cb80..880cccd433e 100644
--- a/lib/IRGen/ESTreeIRGen-legacy-class.cpp
+++ b/lib/IRGen/ESTreeIRGen-legacy-class.cpp
@@ -112,7 +112,8 @@ CreateClassInst *ESTreeIRGen::genLegacyClassLike(
         llvh::cast<ESTree::FunctionExpressionNode>(consMethodNode->_value),
         curScope->getVariableScope(),
         superClassNode,
-        Function::DefinitionKind::ES6Constructor,
+        superClassNode ? Function::DefinitionKind::ES6DerivedConstructor
+                       : Function::DefinitionKind::ES6BaseConstructor,
         clsPrototypeVar,
         consMethodNode);
   }
@@ -385,7 +386,9 @@ NormalFunction *ESTreeIRGen::genLegacyImplicitConstructor(
 
   auto *consFunc = Builder.createFunction(
       className,
-      Function::DefinitionKind::ES6Constructor,
+      funcInfo->constructorKind == sema::FunctionInfo::ConstructorKind::Derived
+          ? Function::DefinitionKind::ES6DerivedConstructor
+          : Function::DefinitionKind::ES6BaseConstructor,
       /* strictMode */ true,
       funcInfo->customDirectives);
 
diff --git a/lib/IRGen/ESTreeIRGen-typed-class.cpp b/lib/IRGen/ESTreeIRGen-typed-class.cpp
index 5e7f6b20c5b..32ffcb81458 100644
--- a/lib/IRGen/ESTreeIRGen-typed-class.cpp
+++ b/lib/IRGen/ESTreeIRGen-typed-class.cpp
@@ -99,7 +99,8 @@ void ESTreeIRGen::genClassDeclaration(ESTree::ClassDeclarationNode *node) {
         llvh::cast<ESTree::FunctionExpressionNode>(consMethod->_value),
         consName,
         node->_superClass,
-        Function::DefinitionKind::ES6Constructor);
+        node->_superClass ? Function::DefinitionKind::ES6DerivedConstructor
+                          : Function::DefinitionKind::ES6BaseConstructor);
   } else {
     // The constructor is implicit.
     consFunction = genTypedImplicitConstructor(consName, superClass);
diff --git a/test/IRGen/flow/class-constructor-super.js b/test/IRGen/flow/class-constructor-super.js
index a922e33cd2d..ae2778c8b81 100644
--- a/test/IRGen/flow/class-constructor-super.js
+++ b/test/IRGen/flow/class-constructor-super.js
@@ -73,7 +73,7 @@ new D();
 
 // CHECK:scope %VS2 []
 
-// CHECK:constructor C(): any [typed]
+// CHECK:base constructor C(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
 // CHECK-NEXT:  %1 = CreateScopeInst (:environment) %VS2: any, %0: environment
@@ -82,7 +82,7 @@ new D();
 
 // CHECK:scope %VS3 []
 
-// CHECK:constructor D(): any [typed]
+// CHECK:derived constructor D(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
diff --git a/test/IRGen/flow/class-method-inherited.js b/test/IRGen/flow/class-method-inherited.js
index 9f2903b9ecb..2503e7369e0 100644
--- a/test/IRGen/flow/class-method-inherited.js
+++ b/test/IRGen/flow/class-method-inherited.js
@@ -99,7 +99,7 @@ new D().inherited();
 
 // CHECK:scope %VS4 []
 
-// CHECK:constructor D(): any [typed]
+// CHECK:derived constructor D(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
diff --git a/test/IRGen/flow/class-method-override.js b/test/IRGen/flow/class-method-override.js
index 854992b6661..935570d9b0b 100644
--- a/test/IRGen/flow/class-method-override.js
+++ b/test/IRGen/flow/class-method-override.js
@@ -142,7 +142,7 @@ function foo(c: C, d: D){
 
 // CHECK:scope %VS6 []
 
-// CHECK:constructor D(): any [typed]
+// CHECK:derived constructor D(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
diff --git a/test/IRGen/flow/class-super-method.js b/test/IRGen/flow/class-super-method.js
index 4b94f9d63ed..15c61a01014 100644
--- a/test/IRGen/flow/class-super-method.js
+++ b/test/IRGen/flow/class-super-method.js
@@ -79,7 +79,7 @@ class B extends A {
 
 // CHECK:scope %VS2 [x: any]
 
-// CHECK:constructor A(x: number): any [typed]
+// CHECK:base constructor A(x: number): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
@@ -107,7 +107,7 @@ class B extends A {
 
 // CHECK:scope %VS4 [x: any]
 
-// CHECK:constructor B(x: number): any [typed]
+// CHECK:derived constructor B(x: number): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
diff --git a/test/IRGen/flow/class-super-prop.js b/test/IRGen/flow/class-super-prop.js
index 4e162b99986..611b1716d12 100644
--- a/test/IRGen/flow/class-super-prop.js
+++ b/test/IRGen/flow/class-super-prop.js
@@ -74,7 +74,7 @@ class B extends A {
 
 // CHECK:scope %VS2 [x: any]
 
-// CHECK:constructor A(x: number): any [typed]
+// CHECK:base constructor A(x: number): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
@@ -89,7 +89,7 @@ class B extends A {
 
 // CHECK:scope %VS3 [x: any]
 
-// CHECK:constructor B(x: number): any [typed]
+// CHECK:derived constructor B(x: number): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
diff --git a/test/IRGen/flow/class1.js b/test/IRGen/flow/class1.js
index 55b262f9089..099453d3e56 100644
--- a/test/IRGen/flow/class1.js
+++ b/test/IRGen/flow/class1.js
@@ -56,7 +56,7 @@ return [dotProduct, Vec2D];
 // CHECK-NEXT:       ReturnInst %8: number
 // CHECK-NEXT:function_end
 
-// CHECK:constructor Vec2D(x: number, y: number): undefined [typed]
+// CHECK:base constructor Vec2D(x: number, y: number): undefined [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = LoadParamInst (:number) %y: number
diff --git a/test/IRGen/flow/field-inits.js b/test/IRGen/flow/field-inits.js
index 47a35f4934a..1bf9615b846 100644
--- a/test/IRGen/flow/field-inits.js
+++ b/test/IRGen/flow/field-inits.js
@@ -164,7 +164,7 @@ function f(i: number): number {
 
 // CHECK:scope %VS4 []
 
-// CHECK:constructor A(): any [typed]
+// CHECK:base constructor A(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
@@ -194,7 +194,7 @@ function f(i: number): number {
 
 // CHECK:scope %VS6 []
 
-// CHECK:constructor B(): any [typed]
+// CHECK:base constructor B(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
@@ -259,7 +259,7 @@ function f(i: number): number {
 
 // CHECK:scope %VS11 []
 
-// CHECK:constructor C1(): any [typed]
+// CHECK:derived constructor C1(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
@@ -290,7 +290,7 @@ function f(i: number): number {
 
 // CHECK:scope %VS13 []
 
-// CHECK:constructor "A 1#"(): any [typed]
+// CHECK:base constructor "A 1#"(): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS2: any, %parentScope: environment
diff --git a/test/IRGen/flow/generic-class-id.js b/test/IRGen/flow/generic-class-id.js
index 5a5cbf48975..3aa48eedfb6 100644
--- a/test/IRGen/flow/generic-class-id.js
+++ b/test/IRGen/flow/generic-class-id.js
@@ -79,7 +79,7 @@ const s: string = i2.val;
 
 // CHECK:scope %VS2 [val: any]
 
-// CHECK:constructor ID(val: number): any [typed]
+// CHECK:base constructor ID(val: number): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
@@ -94,7 +94,7 @@ const s: string = i2.val;
 
 // CHECK:scope %VS3 [val: any]
 
-// CHECK:constructor "ID 1#"(val: string): any [typed]
+// CHECK:base constructor "ID 1#"(val: string): any [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
diff --git a/test/Optimizer/flow/inline-constructor-small.js b/test/Optimizer/flow/inline-constructor-small.js
index bfe0e80cc55..e9cd4d2f323 100644
--- a/test/Optimizer/flow/inline-constructor-small.js
+++ b/test/Optimizer/flow/inline-constructor-small.js
@@ -38,7 +38,7 @@ print(p1.x, p2.x);
 // CHECK-NEXT:       ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 
-// CHECK:constructor Point(x: number, y: number): undefined [typed]
+// CHECK:base constructor Point(x: number, y: number): undefined [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = LoadParamInst (:number) %x: number
diff --git a/test/Optimizer/object-with-object-field-alloc.js b/test/Optimizer/object-with-object-field-alloc.js
index 642bab9e546..5f8d1476d4e 100644
--- a/test/Optimizer/object-with-object-field-alloc.js
+++ b/test/Optimizer/object-with-object-field-alloc.js
@@ -51,7 +51,7 @@ new Foo();
 // CHECK-NEXT:        ReturnInst %12: undefined
 // CHECK-NEXT:function_end
 
-// CHECK:constructor O(): undefined [typed]
+// CHECK:base constructor O(): undefined [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = HBCLoadConstInst (:number) 7: number
 // CHECK-NEXT:  %1 = LoadParamInst (:object) %<this>: object
@@ -60,7 +60,7 @@ new Foo();
 // CHECK-NEXT:       ReturnInst %3: undefined
 // CHECK-NEXT:function_end
 
-// CHECK:constructor Foo(): undefined [typed]
+// CHECK:base constructor Foo(): undefined [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment
diff --git a/test/Optimizer/typed-object-promotion.js b/test/Optimizer/typed-object-promotion.js
index 45aadd2500e..58c120c54c4 100644
--- a/test/Optimizer/typed-object-promotion.js
+++ b/test/Optimizer/typed-object-promotion.js
@@ -38,7 +38,7 @@ print(foo.x, foo.y);
 // CHECK-NEXT:       ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 
-// CHECK:constructor Foo(x: number, y: number): undefined [typed]
+// CHECK:base constructor Foo(x: number, y: number): undefined [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = LoadParamInst (:number) %x: number
diff --git a/test/Optimizer/uninit-prop-access-opt.js b/test/Optimizer/uninit-prop-access-opt.js
index 154042a956c..127c69febe8 100644
--- a/test/Optimizer/uninit-prop-access-opt.js
+++ b/test/Optimizer/uninit-prop-access-opt.js
@@ -85,14 +85,14 @@ print(f());
 // CHECK-NEXT:       ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 
-// CHECK:constructor O(): undefined [typed]
+// CHECK:base constructor O(): undefined [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:       PrStoreInst 7: number, %0: object, 0: number, "i": string, true: boolean
 // CHECK-NEXT:       ReturnInst undefined: undefined
 // CHECK-NEXT:function_end
 
-// CHECK:constructor Foo(): undefined [typed]
+// CHECK:base constructor Foo(): undefined [typed]
 // CHECK-NEXT:%BB0:
 // CHECK-NEXT:  %0 = LoadParamInst (:object) %<this>: object
 // CHECK-NEXT:  %1 = GetParentScopeInst (:environment) %VS1: any, %parentScope: environment