diff --git a/lib/SILPasses/Link.cpp b/lib/SILPasses/Link.cpp
index 39325f47e14..81b84ff1403 100644
--- a/lib/SILPasses/Link.cpp
+++ b/lib/SILPasses/Link.cpp
@@ -91,11 +91,12 @@ void swift::performSILLinking(SILModule *M) {
         if (ApplyInst *AI = dyn_cast<ApplyInst>(I)) {
           SILValue Callee = AI->getCallee();
           // Handles FunctionRefInst only.
-          if (FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(Callee.getDef()))
+          if (FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(Callee.getDef())) {
             CalleeFunction = FRI->getReferencedFunction();
-
-          // When EnableLinkAll is true, we always link the Callee.
-          TryLinking = EnableLinkAll ? true : AI->isTransparent();
+            // When EnableLinkAll is true, we always link the Callee.
+            TryLinking = EnableLinkAll || AI->isTransparent() ||
+                         CalleeFunction->getLinkage() == SILLinkage::Private;
+          }
         }
         else if (PartialApplyInst *PAI = dyn_cast<PartialApplyInst>(I)) {
           SILValue Callee = PAI->getCallee();
@@ -103,7 +104,8 @@ void swift::performSILLinking(SILModule *M) {
           if (FunctionRefInst *FRI = dyn_cast<FunctionRefInst>(Callee.getDef())) {
             CalleeFunction = FRI->getReferencedFunction();
             // When EnableLinkAll is true, we always link the Callee.
-            TryLinking = EnableLinkAll ? true : CalleeFunction->isTransparent();
+            TryLinking = EnableLinkAll || CalleeFunction->isTransparent() ||
+                         CalleeFunction->getLinkage() == SILLinkage::Private;
           } else {
             continue;
           }
diff --git a/lib/Serialization/SerializeSIL.cpp b/lib/Serialization/SerializeSIL.cpp
index fbdb5acbd7e..58799760be8 100644
--- a/lib/Serialization/SerializeSIL.cpp
+++ b/lib/Serialization/SerializeSIL.cpp
@@ -1333,8 +1333,12 @@ void SILSerializer::writeAllSILFunctions(const SILModule *SILMod) {
 
     // Helper function for whether to emit a function body.
     auto shouldEmitFunctionBody = [&](const SILFunction &F) {
+      // Emit function body if a private function is referenced in this module.
+      // This is needed for body of closure.
       return (!F.empty() &&
-              (EnableSerializeAll || F.isTransparent()));
+              (EnableSerializeAll || F.isTransparent()  ||
+               (F.getLinkage() == SILLinkage::Private &&
+                FuncsToDeclare.count(&F))));
     };
 
     // Go through all the SILFunctions in SILMod and write out any
diff --git a/test/Serialization/Inputs/def_basic.sil b/test/Serialization/Inputs/def_basic.sil
index 800835d2d42..3142d58f7a1 100644
--- a/test/Serialization/Inputs/def_basic.sil
+++ b/test/Serialization/Inputs/def_basic.sil
@@ -872,6 +872,30 @@ entry(%f : $@thin (@out Int, Int) -> (), %x : $Int):
   return %y : $Int
 }
 
+// Make sure we serialize the body of closure even without -sil-serialize-all.
+// CHECK_DECL-LABEL:  @partial_apply_with_closure
+sil [transparent] @partial_apply_with_closure : $@thin (@owned @callee_owned () -> Bool, @owned String, CString, Int64) -> () {
+bb0(%0 : $@callee_owned () -> Bool, %1 : $String, %2 : $CString, %3 : $Int64):
+  %17 = function_ref @closure_body : $@thin (CString, CString, Int64) -> ()
+// CHECK_DECL: function_ref @closure_body
+  %18 = partial_apply %17(%2, %3) : $@thin (CString, CString, Int64) -> ()
+// CHECK_DECL: partial_apply
+  %30 = tuple ()
+  return %30 : $()
+}
+
+// CHECK_DECL-LABEL: @closure_body : $@thin (CString, CString, Int64) -> () {
+sil private @closure_body : $@thin (CString, CString, Int64) -> () {
+bb0(%0 : $CString, %1 : $CString, %2 : $Int64):
+// CHECK_DECL: function_ref @assert_fail
+  %3 = function_ref @assert_fail : $@thin (CString, CString, Int64) -> ()
+  %4 = apply %3(%0, %1, %2) : $@thin (CString, CString, Int64) -> ()
+  %5 = tuple ()
+  return %5 : $()
+}
+
+sil @assert_fail : $@thin (CString, CString, Int64) -> ()
+
 @fragile
 class Foo {
   subscript (x: Int, y: Int) -> Int
@@ -964,7 +988,7 @@ sil_witness_table ConformingAssoc: AssocReqt module def_basic {
   method #AssocReqt.requiredMethod!1: @_TTWV14witness_tables15ConformingAssocS_9AssocReqtS_FS1_14requiredMethodU_fRQPS1_FT_T_
 }
 
-sil @_TF9def_basic13serialize_allFT_T_ : $@thin () -> () {
+sil [transparent] @_TF9def_basic13serialize_allFT_T_ : $@thin () -> () {
 bb0:
   %1 = function_ref @_TFV18lazy_global_access4Type10staticPropSia : $@thin () -> Builtin.RawPointer
   %2 = function_ref @test1 : $@thin () -> ()
@@ -1022,6 +1046,7 @@ bb0:
 
   %120 = function_ref @test_forward_ref : $@thin (UInt8, UInt8) -> UInt8
   %121 = function_ref @partial_apply : $@thin (@thin (@out Int, Int) -> (), Int) -> Int
+  %122 = function_ref @partial_apply_with_closure : $@thin (@owned @callee_owned () -> Bool, @owned String, CString, Int64) -> ()
 
   %119 = tuple ()
   return %119 : $()