diff --git a/compiler/forget/src/HIR/HIR.ts b/compiler/forget/src/HIR/HIR.ts
index 4f0db335aa..15441ed018 100644
--- a/compiler/forget/src/HIR/HIR.ts
+++ b/compiler/forget/src/HIR/HIR.ts
@@ -522,3 +522,7 @@ function objectTypeEquals(tA: Type, tB: Type): boolean {
 function funcTypeEquals(tA: Type, tB: Type): boolean {
   return tA.kind === "Function" && tB.kind === "Function";
 }
+
+export function isObjectType(id: Identifier): boolean {
+  return id.type.kind === "Object";
+}
diff --git a/compiler/forget/src/HIR/InferReferenceEffects.ts b/compiler/forget/src/HIR/InferReferenceEffects.ts
index 82f83a23e9..d055726331 100644
--- a/compiler/forget/src/HIR/InferReferenceEffects.ts
+++ b/compiler/forget/src/HIR/InferReferenceEffects.ts
@@ -14,6 +14,7 @@ import {
   HIRFunction,
   IdentifierId,
   InstructionValue,
+  isObjectType,
   Phi,
   Place,
   ValueKind,
@@ -585,12 +586,14 @@ function inferBlock(env: Environment, block: BasicBlock) {
             // redefine lvalue: `a = b.c.d`
             env.initialize(instrValue, env.kind(instrValue));
             env.define(lvalue.place, instrValue);
-          } else if (instrValue.memberPath === null) {
-            // no-op: `a.b.c = d`
-            env.reference(lvalue.place, Effect.Store);
           } else {
+            // no-op: `a.b.c = d`
+            // or
             // no-op: `a.b.c = d.e.f`
-            env.reference(lvalue.place, Effect.Store);
+            const effect = isObjectType(lvalue.place.identifier)
+              ? Effect.Store
+              : Effect.Mutate;
+            env.reference(lvalue.place, effect);
           }
         }
         continue;
diff --git a/compiler/forget/src/__tests__/fixtures/hir/assignment-variations.expect.md b/compiler/forget/src/__tests__/fixtures/hir/assignment-variations.expect.md
index 93a6fce6ee..a65ad7961e 100644
--- a/compiler/forget/src/__tests__/fixtures/hir/assignment-variations.expect.md
+++ b/compiler/forget/src/__tests__/fixtures/hir/assignment-variations.expect.md
@@ -63,8 +63,8 @@ function f$0() {
 ```
 bb0:
   [1] Const mutate $6:TPrimitive = 1
-  [2] Const mutate $7_@0:TPrimitive[0:6] = Binary read a$5_@0.b.c + read $6:TPrimitive
-  [3] Reassign store a$5_@0.b.c[0:6] = read $7_@0:TPrimitive
+  [2] Const mutate $7:TPrimitive = Binary read a$5_@0.b.c + read $6:TPrimitive
+  [3] Reassign read a$5_@0.b.c[0:6] = read $7:TPrimitive
   [4] Const mutate $8:TPrimitive = 2
   [5] Reassign mutate a$5_@0.b.c[0:6] = Binary read a$5_@0.b.c * read $8:TPrimitive
   [6] Return
@@ -77,8 +77,8 @@ function g(
   a,
 ) {
   [1] Const mutate $6:TPrimitive = 1
-  [2] Const mutate $7_@0:TPrimitive[0:6] = Binary read a$5_@0.b.c + read $6:TPrimitive
-  [3] Reassign store a$5_@0.b.c[0:6] = read $7_@0:TPrimitive
+  [2] Const mutate $7:TPrimitive = Binary read a$5_@0.b.c + read $6:TPrimitive
+  [3] Reassign read a$5_@0.b.c[0:6] = read $7:TPrimitive
   [4] Const mutate $8:TPrimitive = 2
   [5] Reassign mutate a$5_@0.b.c[0:6] = Binary read a$5_@0.b.c * read $8:TPrimitive
   return