diff --git a/internal/js_parser/js_parser_lower.go b/internal/js_parser/js_parser_lower.go
index 79e49f69..f86f013f 100644
--- a/internal/js_parser/js_parser_lower.go
+++ b/internal/js_parser/js_parser_lower.go
@@ -508,11 +508,18 @@ flatten:
 
 	// Stop now if we can strip the whole chain as dead code. Since the chain is
 	// lazily evaluated, it's safe to just drop the code entirely.
-	if isNullOrUndefined, sideEffects, ok := toNullOrUndefinedWithSideEffects(expr.Data); ok && isNullOrUndefined {
-		if sideEffects == couldHaveSideEffects {
-			return js_ast.JoinWithComma(p.simplifyUnusedExpr(expr), valueWhenUndefined), exprOut{}
+	if p.options.mangleSyntax {
+		if isNullOrUndefined, sideEffects, ok := toNullOrUndefinedWithSideEffects(expr.Data); ok && isNullOrUndefined {
+			if sideEffects == couldHaveSideEffects {
+				return js_ast.JoinWithComma(p.simplifyUnusedExpr(expr), valueWhenUndefined), exprOut{}
+			}
+			return valueWhenUndefined, exprOut{}
+		}
+	} else {
+		switch expr.Data.(type) {
+		case *js_ast.ENull, *js_ast.EUndefined:
+			return valueWhenUndefined, exprOut{}
 		}
-		return valueWhenUndefined, exprOut{}
 	}
 
 	// We need to lower this if this is an optional call off of a private name
diff --git a/internal/js_parser/js_parser_lower_test.go b/internal/js_parser/js_parser_lower_test.go
index 2585719f..4daa6914 100644
--- a/internal/js_parser/js_parser_lower_test.go
+++ b/internal/js_parser/js_parser_lower_test.go
@@ -429,13 +429,13 @@ func TestLowerOptionalChain(t *testing.T) {
 	expectPrintedTarget(t, 2019, "delete undefined?.[x]", "true;\n")
 	expectPrintedTarget(t, 2019, "delete undefined?.(x)", "true;\n")
 
-	expectPrintedTarget(t, 2019, "(foo(), null)?.x", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2019, "(foo(), null)?.[x]", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2019, "(foo(), null)?.(x)", "foo(), void 0;\n")
+	expectPrintedMangleTarget(t, 2019, "(foo(), null)?.x; y = (bar(), null)?.x", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2019, "(foo(), null)?.[x]; y = (bar(), null)?.[x]", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2019, "(foo(), null)?.(x); y = (bar(), null)?.(x)", "foo(), y = (bar(), void 0);\n")
 
-	expectPrintedTarget(t, 2019, "(foo(), void 0)?.x", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2019, "(foo(), void 0)?.[x]", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2019, "(foo(), void 0)?.(x)", "foo(), void 0;\n")
+	expectPrintedMangleTarget(t, 2019, "(foo(), void 0)?.x; y = (bar(), void 0)?.x", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2019, "(foo(), void 0)?.[x]; y = (bar(), void 0)?.[x]", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2019, "(foo(), void 0)?.(x); y = (bar(), void 0)?.(x)", "foo(), y = (bar(), void 0);\n")
 
 	expectPrintedTarget(t, 2020, "x?.y", "x?.y;\n")
 	expectPrintedTarget(t, 2020, "x?.[y]", "x?.[y];\n")
@@ -449,13 +449,21 @@ func TestLowerOptionalChain(t *testing.T) {
 	expectPrintedTarget(t, 2020, "undefined?.[x]", "void 0;\n")
 	expectPrintedTarget(t, 2020, "undefined?.(x)", "void 0;\n")
 
-	expectPrintedTarget(t, 2020, "(foo(), null)?.x", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2020, "(foo(), null)?.[x]", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2020, "(foo(), null)?.(x)", "foo(), void 0;\n")
+	expectPrintedTarget(t, 2020, "(foo(), null)?.x", "(foo(), null)?.x;\n")
+	expectPrintedTarget(t, 2020, "(foo(), null)?.[x]", "(foo(), null)?.[x];\n")
+	expectPrintedTarget(t, 2020, "(foo(), null)?.(x)", "(foo(), null)?.(x);\n")
 
-	expectPrintedTarget(t, 2020, "(foo(), void 0)?.x", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2020, "(foo(), void 0)?.[x]", "foo(), void 0;\n")
-	expectPrintedTarget(t, 2020, "(foo(), void 0)?.(x)", "foo(), void 0;\n")
+	expectPrintedTarget(t, 2020, "(foo(), void 0)?.x", "(foo(), void 0)?.x;\n")
+	expectPrintedTarget(t, 2020, "(foo(), void 0)?.[x]", "(foo(), void 0)?.[x];\n")
+	expectPrintedTarget(t, 2020, "(foo(), void 0)?.(x)", "(foo(), void 0)?.(x);\n")
+
+	expectPrintedMangleTarget(t, 2020, "(foo(), null)?.x; y = (bar(), null)?.x", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2020, "(foo(), null)?.[x]; y = (bar(), null)?.[x]", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2020, "(foo(), null)?.(x); y = (bar(), null)?.(x)", "foo(), y = (bar(), void 0);\n")
+
+	expectPrintedMangleTarget(t, 2020, "(foo(), void 0)?.x; y = (bar(), void 0)?.x", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2020, "(foo(), void 0)?.[x]; y = (bar(), void 0)?.[x]", "foo(), y = (bar(), void 0);\n")
+	expectPrintedMangleTarget(t, 2020, "(foo(), void 0)?.(x); y = (bar(), void 0)?.(x)", "foo(), y = (bar(), void 0);\n")
 
 	expectPrintedTarget(t, 2019, "a?.b()", "a == null ? void 0 : a.b();\n")
 	expectPrintedTarget(t, 2019, "a?.[b]()", "a == null ? void 0 : a[b]();\n")