diff --git a/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp b/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp
index 03d4917f93f13..1e857fc6eb266 100644
--- a/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp
+++ b/lib/SILOptimizer/IPO/CrossModuleOptimization.cpp
@@ -625,7 +625,8 @@ bool CrossModuleOptimization::canSerializeFieldsByInstructionKind(
         [&](SILDeclRef method) {
           if (method.isForeign)
             canUse = false;
-          else if (isPackageCMOEnabled(method.getModuleContext())) {
+          else if (canUse &&
+                   isPackageCMOEnabled(method.getModuleContext())) {
             // If the referenced keypath is internal, do not
             // serialize.
             auto methodScope = method.getDecl()->getFormalAccessScope(
diff --git a/test/SILOptimizer/package-cmo-cast-internal-dst b/test/SILOptimizer/package-cmo-cast-internal-dst
deleted file mode 100644
index 2281532f4aaa0..0000000000000
--- a/test/SILOptimizer/package-cmo-cast-internal-dst
+++ /dev/null
@@ -1,29 +0,0 @@
-// RUN: %empty-directory(%t)
-// RUN: split-file %s %t
-
-// RUN: %target-swift-frontend -emit-sil %t/Lib.swift -package-name pkg \
-// RUN:   -wmo -allow-non-resilient-access -package-cmo \
-// RUN:   -enable-library-evolution -swift-version 5 \
-// RUN:   -Xllvm -sil-print-function=topFunc -o %t/Lib.sil
-
-// RUN: %FileCheck %s < %t/Lib.sil
-
-/// Verify that `InternalKlass` is visited and the instruction containing it is not serialized.
-// CHECK: sil @$s3Lib7topFuncySiAA3PubCF : $@convention(thin) (@guaranteed Pub) -> Int {
-// CHECK:   checked_cast_br Pub in %0 : $Pub to InternalKlass
-
-
-//--- Lib.swift
-public class Pub {
-  public var pubVar: Int
-  public init(_ arg: Int) {
-    pubVar = arg
-  }
-}
-
-class InternalKlass: Pub {}
-
-public func topFunc(_ arg: Pub) -> Int {
-  let x = arg as? InternalKlass
-  return x != nil ? 1 : 0
-}
diff --git a/test/SILOptimizer/package-cmo-check-cast-dst.swift b/test/SILOptimizer/package-cmo-check-cast-dst.swift
new file mode 100644
index 0000000000000..2857bf4c2164e
--- /dev/null
+++ b/test/SILOptimizer/package-cmo-check-cast-dst.swift
@@ -0,0 +1,124 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+/// Verify a function with a cast instruction with an internal decl as dst
+/// does not get serialized with PackageCMO in both scenarios below.
+
+/// Scenario 1.
+// RUN: %target-swift-frontend -emit-sil %t/Lib.swift -package-name pkg \
+// RUN:   -wmo -allow-non-resilient-access -package-cmo \
+// RUN:   -enable-library-evolution -swift-version 5 \
+// RUN:   -Xllvm -sil-print-function=topFunc -o %t/Lib.sil
+// RUN: %FileCheck %s < %t/Lib.sil
+
+/// Scenario 2.
+// RUN: %target-build-swift %t/Mod.swift \
+// RUN: -module-name=Mod -package-name pkg \
+// RUN: -parse-as-library -emit-module -emit-module-path %t/Mod.swiftmodule -I%t \
+// RUN: -Xfrontend -experimental-package-cmo -Xfrontend -experimental-allow-non-resilient-access \
+// RUN: -O -wmo -enable-library-evolution
+// RUN: %target-sil-opt -enable-sil-verify-all %t/Mod.swiftmodule -o %t/Mod.sil
+// RUN: %FileCheck %s --check-prefix=CHECK-MOD < %t/Mod.sil
+
+
+//--- Lib.swift
+public class Pub {
+  public var pubVar: Int
+  public init(_ arg: Int) {
+    pubVar = arg
+  }
+}
+
+class InternalKlass: Pub {}
+
+/// Verify that `InternalKlass` is visited and the instruction containing it is not serialized.
+// CHECK: sil @$s3Lib7topFuncySiAA3PubCF : $@convention(thin) (@guaranteed Pub) -> Int {
+// CHECK:   checked_cast_br Pub in %0 to InternalKlass
+public func topFunc(_ arg: Pub) -> Int {
+  let x = arg as? InternalKlass
+  return x != nil ? 1 : 0
+}
+
+
+//--- Mod.swift
+struct SymmetricTextChildQuery<Provider: PubProto> {
+  var source: Text
+  init(_ arg: Text) {
+    source = arg
+  }
+  /// This function references isCollapsible(), which contains an internal decl.
+  /// If isCollapsible() were serialized, building a client of this module would fail
+  /// due to a linker error: undefined symbol `CollapsibleTextModifier`.
+  mutating func updateValue() {
+    let resolvedSource = ResolvedStyledText.styledText(canCollapse: source.isCollapsible())
+  }
+}
+
+@frozen
+public struct Text: Equatable, Sendable {
+  public init() {}
+  @frozen
+  @usableFromInline
+  package enum Modifier: Equatable {
+    case font
+    case anyTextModifier(AnyTextModifier)
+    
+    @usableFromInline
+    package static func ==(lhs: Modifier, rhs: Modifier) -> Bool {
+      return true
+    }
+  }
+  
+  @usableFromInline
+  package var modifiers = [Modifier]()
+  
+}
+
+extension Text {
+  /// Verify that function containing an internal decl CollapsibleTextModifier is
+  /// not serialized with Package CMO.
+  // CHECK-MOD-NOT: sil package [serialized_for_package] [canonical] @$s3Mod4TextV13isCollapsibleSbyF : $@convention(method) (@guaranteed Text) -> Bool {
+  // CHECK-MOD-NOT: checked_cast_br AnyTextModifier in {{.*}} : $AnyTextModifier to CollapsibleTextModifier
+  package func isCollapsible() -> Bool {
+    modifiers.contains { modifier in
+      guard case .anyTextModifier(let anyModifier) = modifier
+      else { return false }
+      return anyModifier is CollapsibleTextModifier
+    }
+  }
+}
+
+final class CollapsibleTextModifier: AnyTextModifier {
+  override func isEqual(to other: AnyTextModifier) -> Bool {
+    other is CollapsibleTextModifier
+  }
+}
+
+public protocol PubProto {
+  var pubVar: String { get set }
+}
+
+public struct PubStruct {
+  public static func makeView<P: PubProto>(_ type: P.Type, _ arg: Text) {
+    var child = SymmetricTextChildQuery<P>(arg)
+    child.updateValue()
+  }
+}
+
+public class ResolvedStyledText {
+  package var canCollapse: Bool
+  package init(_ arg: Bool) {
+    canCollapse = arg
+  }
+}
+
+extension ResolvedStyledText {
+  package static func styledText(canCollapse: Bool) -> ResolvedStyledText {
+    return ResolvedStyledText(canCollapse)
+  }
+}
+
+@usableFromInline
+package class AnyTextModifier {
+  func isEqual(to other: AnyTextModifier) -> Bool { fatalError() }
+}
diff --git a/test/SILOptimizer/package-cmo-keypath.swift b/test/SILOptimizer/package-cmo-keypath.swift
new file mode 100644
index 0000000000000..9023e5e666d0c
--- /dev/null
+++ b/test/SILOptimizer/package-cmo-keypath.swift
@@ -0,0 +1,41 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-build-swift %t/Lib.swift \
+// RUN: -module-name=Lib -package-name Pkg \
+// RUN: -parse-as-library -emit-module -emit-module-path %t/Lib.swiftmodule -I%t \
+// RUN: -Xfrontend -experimental-package-cmo -Xfrontend -experimental-allow-non-resilient-access \
+// RUN: -O -wmo -enable-library-evolution
+// RUN: %target-sil-opt -enable-sil-verify-all %t/Lib.swiftmodule -o %t/Lib.sil
+
+// RUN: %FileCheck %s < %t/Lib.sil
+
+// REQUIRES: swift_in_compiler
+
+//--- Lib.swift
+package protocol PkgProto {
+    var pkgVar: String { get }
+}
+
+package struct Foo: PkgProto {
+    package var pkgVar: String {
+      return "Foo pkgVar"
+    }
+}
+
+// testKeyPath<A>(_:)
+// CHECK-NOT: sil package [serialized_for_package] [canonical] @$s3Lib11testKeyPathys0cD0CyxSSGSayxGAA8PkgProtoRzlF : $@convention(thin) <T where T : PkgProto> (@guaranteed Array<T>) -> @owned KeyPath<T, String> {
+// CHECK-NOT: keypath $KeyPath<T, String>, <τ_0_0 where τ_0_0 : PkgProto> (root $τ_0_0; gettable_property $String,  id #PkgProto.pkgVar!getter : <Self where Self : PkgProto> (Self) -> () -> String, getter @$s3Lib8PkgProtoP6pkgVarSSvpAaBRzlxTK : $@convention(keypath_accessor_getter) <τ_0_0 where τ_0_0 : PkgProto> (@in_guaranteed τ_0_0) -> @out String) <T>
+// CHECK-NOT: } // end sil function '$s3Lib11testKeyPathys0cD0CyxSSGSayxGAA8PkgProtoRzlF'
+package func testKeyPath<T: PkgProto>(_ array: [T]) -> KeyPath<T, String> {
+  return \T.pkgVar
+}
+
+// key path getter for PkgProto.pkgVar : <A>A
+// CHECK-NOT: sil [serialized_for_package] [thunk] [canonical] @$s3Lib8PkgProtoP6pkgVarSSvpAaBRzlxTK : $@convention(keypath_accessor_getter) <T where T : PkgProto> (@in_guaranteed T) -> @out String {
+// CHECK-NOT: witness_method $T, #PkgProto.pkgVar!getter : <Self where Self : PkgProto> (Self) -> () -> String : $@convention(witness_method: PkgProto) <τ_0_0 where τ_0_0 : PkgProto> (@in_guaranteed τ_0_0) -> @owned String // user: %3
+// CHECK-NOT: // end sil function '$s3Lib8PkgProtoP6pkgVarSSvpAaBRzlxTK'
+
+// CHECK: sil_witness_table package [serialized_for_package] Foo: PkgProto module Lib {
+// CHECK:  method #PkgProto.pkgVar!getter: <Self where Self : PkgProto> (Self) -> () -> String : @$s3Lib3FooVAA8PkgProtoA2aDP6pkgVarSSvgTW
+