diff --git a/include/swift/AST/DebuggerClient.h b/include/swift/AST/DebuggerClient.h
index b21d96be80312..b51207788b51d 100644
--- a/include/swift/AST/DebuggerClient.h
+++ b/include/swift/AST/DebuggerClient.h
@@ -61,6 +61,25 @@ class DebuggerClient {
                                SourceLoc Loc, bool IsTypeLookup,
                                ResultVector &RV) = 0;
 
+  /// The following functions allow the debugger to modify the results of a
+  /// qualfied lookup as needed. These methods may add, remove or modify the
+  /// entries in `decls`. See the corresponding DeclContext::lookupInXYZ
+  /// functions defined in NameLookup.cpp for more context.
+  ///
+
+  virtual void finishLookupInNominals(const DeclContext *dc,
+                                      ArrayRef<NominalTypeDecl *> types,
+                                      DeclName member, NLOptions options,
+                                      SmallVectorImpl<ValueDecl *> &decls) {}
+
+  virtual void finishLookupInModule(const DeclContext *dc, ModuleDecl *module,
+                                    DeclName member, NLOptions options,
+                                    SmallVectorImpl<ValueDecl *> &decls) {}
+
+  virtual void finishLookupInAnyObject(const DeclContext *dc, DeclName member,
+                                       NLOptions options,
+                                       SmallVectorImpl<ValueDecl *> &decls) {}
+
   /// When evaluating an expression in the context of an existing source file,
   /// we may want to prefer declarations from that source file.
   /// The DebuggerClient can return a private-discriminator to tell lookup to
diff --git a/include/swift/AST/NameLookup.h b/include/swift/AST/NameLookup.h
index 263286989282d..18851ddca2299 100644
--- a/include/swift/AST/NameLookup.h
+++ b/include/swift/AST/NameLookup.h
@@ -367,10 +367,10 @@ void forAllVisibleModules(const DeclContext *DC, const Fn &fn) {
         ->forAllVisibleModules(ModuleDecl::AccessPathTy(), fn);
 }
 
-/// Only name lookup has gathered a set of results, perform any necessary
+/// Once name lookup has gathered a set of results, perform any necessary
 /// steps to prune the result set before returning it to the caller.
-bool finishLookup(const DeclContext *dc, NLOptions options,
-                  SmallVectorImpl<ValueDecl *> &decls);
+void pruneLookupResultSet(const DeclContext *dc, NLOptions options,
+                          SmallVectorImpl<ValueDecl *> &decls);
 
 /// Do nothing if debugClient is null.
 template <typename Result>
diff --git a/lib/AST/NameLookup.cpp b/lib/AST/NameLookup.cpp
index 9180840fffe26..b7b8e0e062a2a 100644
--- a/lib/AST/NameLookup.cpp
+++ b/lib/AST/NameLookup.cpp
@@ -1356,8 +1356,8 @@ static bool isAcceptableLookupResult(const DeclContext *dc,
   return true;
 }
 
-bool namelookup::finishLookup(const DeclContext *dc, NLOptions options,
-                              SmallVectorImpl<ValueDecl *> &decls) {
+void namelookup::pruneLookupResultSet(const DeclContext *dc, NLOptions options,
+                                      SmallVectorImpl<ValueDecl *> &decls) {
   // If we're supposed to remove overridden declarations, do so now.
   if (options & NL_RemoveOverridden)
     removeOverriddenDecls(decls);
@@ -1368,9 +1368,6 @@ bool namelookup::finishLookup(const DeclContext *dc, NLOptions options,
     removeShadowedDecls(decls, M);
 
   filterForDiscriminator(decls, M->getDebugClient());
-
-  // We're done. Report success/failure.
-  return !decls.empty();
 }
 
 /// Inspect the given type to determine which nominal type declarations it
@@ -1574,7 +1571,13 @@ bool DeclContext::lookupQualified(ArrayRef<NominalTypeDecl *> typeDecls,
     }
   }
 
-  return finishLookup(this, options, decls);
+  pruneLookupResultSet(this, options, decls);
+  if (auto *debugClient = this->getParentModule()->getDebugClient()) {
+    debugClient->finishLookupInNominals(this, typeDecls, member, options,
+                                        decls);
+  }
+  // We're done. Report success/failure.
+  return !decls.empty();
 }
 
 bool DeclContext::lookupQualified(ModuleDecl *module, DeclName member,
@@ -1626,7 +1629,13 @@ bool DeclContext::lookupQualified(ModuleDecl *module, DeclName member,
     return !knownDecls.insert(vd).second;
   }), decls.end());
 
-  return finishLookup(this, options, decls);
+  pruneLookupResultSet(this, options, decls);
+
+  if (auto *debugClient = this->getParentModule()->getDebugClient()) {
+    debugClient->finishLookupInModule(this, module, member, options, decls);
+  }
+  // We're done. Report success/failure.
+  return !decls.empty();
 }
 
 bool DeclContext::lookupAnyObject(DeclName member, NLOptions options,
@@ -1681,7 +1690,12 @@ bool DeclContext::lookupAnyObject(DeclName member, NLOptions options,
       decls.push_back(decl);
   }
 
-  return finishLookup(this, options, decls);
+  pruneLookupResultSet(this, options, decls);
+  if (auto *debugClient = this->getParentModule()->getDebugClient()) {
+    debugClient->finishLookupInAnyObject(this, member, options, decls);
+  }
+  // We're done. Report success/failure.
+  return !decls.empty();
 }
 
 void DeclContext::lookupAllObjCMethods(