diff --git a/include/swift/AST/Module.h b/include/swift/AST/Module.h
index bcfabeda77447..e4f878f1742ef 100644
--- a/include/swift/AST/Module.h
+++ b/include/swift/AST/Module.h
@@ -244,8 +244,11 @@ class ModuleDecl : public DeclContext, public TypeDecl {
     declaredCrossImports;
 
   std::unique_ptr<SourceLookupCache> Cache;
+
+public:
   SourceLookupCache &getSourceLookupCache() const;
 
+private:
   /// Tracks the file that will generate the module's entry point, either
   /// because it contains a class marked with \@UIApplicationMain
   /// or \@NSApplicationMain, or because it is a script file.
diff --git a/include/swift/AST/SourceFile.h b/include/swift/AST/SourceFile.h
index fa3bee62f5245..ec776ae072490 100644
--- a/include/swift/AST/SourceFile.h
+++ b/include/swift/AST/SourceFile.h
@@ -210,11 +210,7 @@ class SourceFile final : public FileUnit {
 public:
   /// Appends the given declaration to the end of the top-level decls list. Do
   /// not add any additional uses of this function.
-  void addTopLevelDecl(Decl *d) {
-    // Force decl parsing if we haven't already.
-    (void)getTopLevelDecls();
-    Decls->push_back(d);
-  }
+  void addTopLevelDecl(Decl *d);
 
   /// Prepends a declaration to the top-level decls list.
   ///
@@ -394,8 +390,6 @@ class SourceFile final : public FileUnit {
   void cacheVisibleDecls(SmallVectorImpl<ValueDecl *> &&globals) const;
   const SmallVectorImpl<ValueDecl *> &getCachedVisibleDecls() const;
 
-  void addVisibleDecl(ValueDecl *decl);
-
   virtual void lookupValue(DeclName name, NLKind lookupKind,
                            SmallVectorImpl<ValueDecl*> &result) const override;
 
diff --git a/lib/AST/Module.cpp b/lib/AST/Module.cpp
index d071cab0d6843..c779298e4255b 100644
--- a/lib/AST/Module.cpp
+++ b/lib/AST/Module.cpp
@@ -156,7 +156,10 @@ class swift::SourceLookupCache {
     }
   };
 
+public:
   ValueDeclMap TopLevelValues;
+
+private:
   ValueDeclMap ClassMembers;
   bool MemberCachePopulated = false;
 
@@ -216,6 +219,8 @@ class swift::SourceLookupCache {
                          DeclName name,
                          SmallVectorImpl<ValueDecl*> &results);
 
+  void addTopLevelDecl(ValueDecl *decl);
+
   SmallVector<ValueDecl *, 0> AllVisibleValues;
 };
 SourceLookupCache &SourceFile::getCache() const {
@@ -322,6 +327,10 @@ SourceLookupCache::SourceLookupCache(const ModuleDecl &M) {
   }
 }
 
+void SourceLookupCache::addTopLevelDecl(ValueDecl *decl) {
+  TopLevelValues.add(decl);
+}
+
 void SourceLookupCache::lookupValue(DeclName Name, NLKind LookupKind,
                                     SmallVectorImpl<ValueDecl*> &Result) {
   auto I = TopLevelValues.find(Name);
@@ -2232,9 +2241,15 @@ SourceFile::getCachedVisibleDecls() const {
   return getCache().AllVisibleValues;
 }
 
-void SourceFile::addVisibleDecl(ValueDecl *decl) {
-  Decls->push_back(decl);
-  getCache().AllVisibleValues.push_back(decl);
+void SourceFile::addTopLevelDecl(Decl *d) {
+  // Force decl parsing if we haven't already.
+  (void)getTopLevelDecls();
+  Decls->push_back(d);
+  // Update caches.
+  if (auto *valueDecl = dyn_cast<ValueDecl>(d)) {
+    getCache().TopLevelValues.add(valueDecl);
+    getParentModule()->getSourceLookupCache().TopLevelValues.add(valueDecl);
+  }
 }
 
 static void performAutoImport(
diff --git a/lib/SILOptimizer/Utils/Differentiation/LinearMapInfo.cpp b/lib/SILOptimizer/Utils/Differentiation/LinearMapInfo.cpp
index bb0032fa00069..555e7392e9c5f 100644
--- a/lib/SILOptimizer/Utils/Differentiation/LinearMapInfo.cpp
+++ b/lib/SILOptimizer/Utils/Differentiation/LinearMapInfo.cpp
@@ -159,7 +159,7 @@ EnumDecl *LinearMapInfo::createBranchingTraceDecl(
   computeAccessLevel(branchingTraceDecl, original->getEffectiveSymbolLinkage());
   branchingTraceDecl->getInterfaceType();
   assert(branchingTraceDecl->hasInterfaceType());
-  file.addVisibleDecl(branchingTraceDecl);
+  file.addTopLevelDecl(branchingTraceDecl);
   // Add basic block enum cases.
   for (auto *predBB : originalBB->getPredecessorBlocks()) {
     auto bbId = "bb" + std::to_string(predBB->getDebugID());
@@ -233,7 +233,7 @@ LinearMapInfo::createLinearMapStruct(SILBasicBlock *originalBB,
   computeAccessLevel(linearMapStruct, original->getEffectiveSymbolLinkage());
   linearMapStruct->getInterfaceType();
   assert(linearMapStruct->hasInterfaceType());
-  file.addVisibleDecl(linearMapStruct);
+  file.addTopLevelDecl(linearMapStruct);
   return linearMapStruct;
 }
 
diff --git a/test/AutoDiff/compiler_crashers/tf1232-autodiff-generated-declaration-mangling.swift b/test/AutoDiff/compiler_crashers_fixed/tf1232-autodiff-generated-declaration-mangling.swift
similarity index 96%
rename from test/AutoDiff/compiler_crashers/tf1232-autodiff-generated-declaration-mangling.swift
rename to test/AutoDiff/compiler_crashers_fixed/tf1232-autodiff-generated-declaration-mangling.swift
index 2189f4f454934..61bc8ac3abdcc 100644
--- a/test/AutoDiff/compiler_crashers/tf1232-autodiff-generated-declaration-mangling.swift
+++ b/test/AutoDiff/compiler_crashers_fixed/tf1232-autodiff-generated-declaration-mangling.swift
@@ -1,4 +1,4 @@
-// RUN: not %target-build-swift -g %s
+// RUN: %target-build-swift -g %s
 // REQUIRES: asserts
 
 // TF-1232: IRGenDebugInfo crash due to lack of proper mangling for