diff --git a/infer/src/quandary/CppTrace.ml b/infer/src/quandary/CppTrace.ml
index 17da8819a..04f5f87c9 100644
--- a/infer/src/quandary/CppTrace.ml
+++ b/infer/src/quandary/CppTrace.ml
@@ -73,6 +73,9 @@ module CppSource = struct
     | pname ->
         failwithf "Non-C++ procname %a in C++ analysis@." Procname.pp pname
 
+  let to_callee t callee_site =
+    { t with site = callee_site; }
+
   let compare src1 src2 =
     SourceKind.compare src1.kind src2.kind
     |> next CallSite.compare src1.site src2.site
diff --git a/infer/src/quandary/JavaTrace.ml b/infer/src/quandary/JavaTrace.ml
index 4c37805c9..376b754fe 100644
--- a/infer/src/quandary/JavaTrace.ml
+++ b/infer/src/quandary/JavaTrace.ml
@@ -81,6 +81,9 @@ module JavaSource = struct
     | pname when BuiltinDecl.is_declared pname -> None
     | pname -> failwithf "Non-Java procname %a in Java analysis@." Procname.pp pname
 
+  let to_callee t callee_site =
+    { t with site = callee_site; }
+
   let compare src1 src2 =
     SourceKind.compare src1.kind src2.kind
     |> next CallSite.compare src1.site src2.site
diff --git a/infer/src/quandary/Sink.ml b/infer/src/quandary/Sink.ml
index 3be9b8a2f..26ec12592 100644
--- a/infer/src/quandary/Sink.ml
+++ b/infer/src/quandary/Sink.ml
@@ -23,8 +23,6 @@ let make_sink_param sink index ~report_reachable =
 module type S = sig
   include TraceElem.S
 
-  val to_callee : t -> CallSite.t -> t
-
   (** return the parameter index and sink kind for the given call site with the given actuals *)
   val get : CallSite.t -> (Exp.t * Typ.t) list -> t parameter list
 end
diff --git a/infer/src/quandary/Trace.ml b/infer/src/quandary/Trace.ml
index a77f34629..bc38bc0ad 100644
--- a/infer/src/quandary/Trace.ml
+++ b/infer/src/quandary/Trace.ml
@@ -156,24 +156,38 @@ module Make (Spec : Spec) = struct
     if is_empty callee_trace
     then caller_trace
     else
+      let non_footprint_callee_sources =
+        Sources.filter (fun source -> not (Source.is_footprint source)) callee_trace.sources in
       let sources =
-        Sources.filter (fun source -> not (Source.is_footprint source)) callee_trace.sources
-        |> Sources.union caller_trace.sources in
-      let sinks, passthroughs =
-        if Sinks.for_all (fun sink -> Sinks.mem sink caller_trace.sinks) callee_trace.sinks
+        if Sources.subset non_footprint_callee_sources caller_trace.sources
         then
-          (* this callee didn't add any new sinks; it's just a passthrough *)
-          let passthroughs =
-            Passthroughs.add (Passthrough.make callee_site) caller_trace.passthroughs in
-          caller_trace.sinks, passthroughs
+          caller_trace.sources
         else
-          (* this callee added a new sink *)
-          let callee_sinks =
-            IList.map
-              (fun sink -> Sink.to_callee sink callee_site)
-              (Sinks.elements callee_trace.sinks)
-            |> Sinks.of_list in
-          Sinks.union caller_trace.sinks callee_sinks, caller_trace.passthroughs in
+          IList.map
+            (fun sink -> Source.to_callee sink callee_site)
+            (Sources.elements non_footprint_callee_sources)
+          |> Sources.of_list
+          |> Sources.union caller_trace.sources in
+
+      let sinks =
+        if Sinks.subset callee_trace.sinks caller_trace.sinks
+        then
+          caller_trace.sinks
+        else
+          IList.map
+            (fun sink -> Sink.to_callee sink callee_site)
+            (Sinks.elements callee_trace.sinks)
+          |> Sinks.of_list
+          |> Sinks.union caller_trace.sinks in
+
+      let passthroughs =
+        if sources == caller_trace.sources && sinks == caller_trace.sinks
+        then
+          (* this callee didn't add any new sources or any news sinks; it's just a passthrough *)
+          Passthroughs.add (Passthrough.make callee_site) caller_trace.passthroughs
+        else
+          caller_trace.passthroughs in
+
       { sources; sinks; passthroughs; }
 
   let initial =
diff --git a/infer/src/quandary/TraceElem.ml b/infer/src/quandary/TraceElem.ml
index 1e4952cba..b4fd49907 100644
--- a/infer/src/quandary/TraceElem.ml
+++ b/infer/src/quandary/TraceElem.ml
@@ -17,6 +17,7 @@ module type S = sig
   val kind : t -> kind
 
   val make : kind -> CallSite.t -> t
+  val to_callee : t -> CallSite.t -> t
 
   val compare : t -> t -> int
   val equal : t -> t -> bool
diff --git a/infer/src/unit/TraceTests.ml b/infer/src/unit/TraceTests.ml
index 4f5f85965..058a29479 100644
--- a/infer/src/unit/TraceTests.ml
+++ b/infer/src/unit/TraceTests.ml
@@ -133,9 +133,9 @@ let tests =
         "Appended trace should contain source and sink"
         (MockTrace.equal (MockTrace.append source_trace footprint_trace call_site) expected_trace);
 
-      let appended_trace = MockTrace.append MockTrace.initial source_trace call_site in
+      let appended_trace = MockTrace.append source_trace source_trace call_site in
       assert_bool
-        "Appending a trace without a sink should add a passthrough"
+        "Appending a trace that doesn't add a new source/sink should add a passthrough"
         (MockTrace.Passthroughs.mem
            (Passthrough.make call_site) (MockTrace.passthroughs appended_trace)) in
     "append">::append_ in
diff --git a/infer/tests/codetoanalyze/cpp/quandary/issues.exp b/infer/tests/codetoanalyze/cpp/quandary/issues.exp
index 2a5cd8681..9538ea4fe 100644
--- a/infer/tests/codetoanalyze/cpp/quandary/issues.exp
+++ b/infer/tests/codetoanalyze/cpp/quandary/issues.exp
@@ -1,5 +1,5 @@
 basics.cpp:28: ERROR: QUANDARY_TAINT_ERROR Error: Other(__infer_taint_source at [line 27]) -> Other(__infer_taint_sink at [line 28]) via {  }
-basics.cpp:33: ERROR: QUANDARY_TAINT_ERROR Error: Other(__infer_taint_source at [line 20]) -> Other(__infer_taint_sink at [line 33]) via { basics::returnSource at [line 32] }
+basics.cpp:33: ERROR: QUANDARY_TAINT_ERROR Error: Other(basics::returnSource at [line 32]) -> Other(__infer_taint_sink at [line 33]) via {  }
 basics.cpp:38: ERROR: QUANDARY_TAINT_ERROR Error: Other(__infer_taint_source at [line 37]) -> Other(basics::callSink at [line 38]) via {  }
 basics.cpp:44: ERROR: QUANDARY_TAINT_ERROR Error: Other(__infer_taint_source at [line 42]) -> Other(basics::callSink at [line 44]) via { basics::id at [line 43] }
 execs.cpp:52: ERROR: QUANDARY_TAINT_ERROR Error: EnvironmentVariable(getenv at [line 47]) -> ShellExec(execl at [line 52]) via {  }
diff --git a/infer/tests/codetoanalyze/java/quandary/issues.exp b/infer/tests/codetoanalyze/java/quandary/issues.exp
index 2a289c281..ed624349f 100644
--- a/infer/tests/codetoanalyze/java/quandary/issues.exp
+++ b/infer/tests/codetoanalyze/java/quandary/issues.exp
@@ -25,15 +25,15 @@ Basics.java:160: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.infe
 Basics.java:166: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 164]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 166]) via {  }
 Basics.java:209: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 206]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 209]) via {  }
 Basics.java:218: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 214]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 218]) via {  }
-DynamicDispatch.java:77: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 25]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 77]) via { Object DynamicDispatch$BadInterfaceImpl1.returnSource() at [line 76], Object DynamicDispatch$BadInterfaceImpl2.returnSource() at [line 76] }
-DynamicDispatch.java:77: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 42]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 77]) via { Object DynamicDispatch$BadInterfaceImpl1.returnSource() at [line 76], Object DynamicDispatch$BadInterfaceImpl2.returnSource() at [line 76] }
+DynamicDispatch.java:77: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object DynamicDispatch$BadInterfaceImpl1.returnSource() at [line 76]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 77]) via {  }
+DynamicDispatch.java:77: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object DynamicDispatch$BadInterfaceImpl2.returnSource() at [line 76]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 77]) via {  }
 DynamicDispatch.java:82: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 81]) -> Other(void DynamicDispatch$BadInterfaceImpl1.callSink(Object) at [line 82]) via {  }
 DynamicDispatch.java:82: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 81]) -> Other(void DynamicDispatch$BadInterfaceImpl2.callSink(Object) at [line 82]) via {  }
 DynamicDispatch.java:88: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 86]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 88]) via { Object DynamicDispatch$BadInterfaceImpl1.propagate(Object) at [line 87], Object DynamicDispatch$BadInterfaceImpl2.propagate(Object) at [line 87] }
-DynamicDispatch.java:135: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 119]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 135]) via { Object DynamicDispatch$BadSubtype.returnSource() at [line 134] }
+DynamicDispatch.java:135: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object DynamicDispatch$BadSubtype.returnSource() at [line 134]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 135]) via {  }
 DynamicDispatch.java:140: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 139]) -> Other(void DynamicDispatch$BadSubtype.callSink(Object) at [line 140]) via {  }
 DynamicDispatch.java:146: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 144]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 146]) via { Object DynamicDispatch$BadSubtype.propagate(Object) at [line 145] }
-DynamicDispatch.java:154: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 119]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 154]) via { Object DynamicDispatch$BadSubtype.returnSource() at [line 153] }
+DynamicDispatch.java:154: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object DynamicDispatch$BadSubtype.returnSource() at [line 153]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 154]) via {  }
 DynamicDispatch.java:157: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 156]) -> Other(void DynamicDispatch$BadSubtype.callSink(Object) at [line 157]) via {  }
 DynamicDispatch.java:160: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 156]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 160]) via { Object DynamicDispatch$BadSubtype.propagate(Object) at [line 159] }
 Exceptions.java:23: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 19]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 23]) via {  }
@@ -80,13 +80,13 @@ Intents.java:51: ERROR: QUANDARY_TAINT_ERROR Error: Intent(Intent Intent.parseIn
 Intents.java:51: ERROR: QUANDARY_TAINT_ERROR Error: Intent(Intent Intent.parseUri(String,int) at [line 31]) -> Intent(void Activity.startActivityFromFragment(Fragment,Intent,int) at [line 51]) via {  }
 Intents.java:52: ERROR: QUANDARY_TAINT_ERROR Error: Intent(Intent Intent.parseIntent(Resources,XmlPullParser,AttributeSet) at [line 34]) -> Intent(ComponentName ContextWrapper.startService(Intent) at [line 52]) via {  }
 Intents.java:52: ERROR: QUANDARY_TAINT_ERROR Error: Intent(Intent Intent.parseUri(String,int) at [line 31]) -> Intent(ComponentName ContextWrapper.startService(Intent) at [line 52]) via {  }
-Interprocedural.java:39: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 31]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 39]) via { Object Interprocedural.returnSourceDirect() at [line 39] }
-Interprocedural.java:44: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 31]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 44]) via { Object Interprocedural.returnSourceDirect() at [line 43] }
-Interprocedural.java:48: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 35]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 48]) via { Object Interprocedural.returnSourceIndirect() at [line 48] }
-Interprocedural.java:58: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 53]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 58]) via { Interprocedural$Obj Interprocedural.returnSourceViaField() at [line 58] }
-Interprocedural.java:67: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 62]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 67]) via { void Interprocedural.returnSourceViaParameter1(Interprocedural$Obj) at [line 66] }
+Interprocedural.java:39: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object Interprocedural.returnSourceDirect() at [line 39]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 39]) via {  }
+Interprocedural.java:44: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object Interprocedural.returnSourceDirect() at [line 43]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 44]) via {  }
+Interprocedural.java:48: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object Interprocedural.returnSourceIndirect() at [line 48]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 48]) via {  }
+Interprocedural.java:58: ERROR: QUANDARY_TAINT_ERROR Error: Other(Interprocedural$Obj Interprocedural.returnSourceViaField() at [line 58]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 58]) via {  }
+Interprocedural.java:67: ERROR: QUANDARY_TAINT_ERROR Error: Other(void Interprocedural.returnSourceViaParameter1(Interprocedural$Obj) at [line 66]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 67]) via {  }
 Interprocedural.java:77: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 75]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 77]) via { void Interprocedural.returnSourceViaParameter2(Interprocedural$Obj,Interprocedural$Obj) at [line 76] }
-Interprocedural.java:92: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 87]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 92]) via { void Interprocedural.returnSourceViaGlobal() at [line 91] }
+Interprocedural.java:92: ERROR: QUANDARY_TAINT_ERROR Error: Other(void Interprocedural.returnSourceViaGlobal() at [line 91]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 92]) via {  }
 Interprocedural.java:108: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 108]) -> Other(void Interprocedural.callSinkParam1(Object,Object) at [line 108]) via {  }
 Interprocedural.java:120: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 120]) -> Other(void Interprocedural.callSinkParam2(Object,Object) at [line 120]) via {  }
 Interprocedural.java:133: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 132]) -> Other(void Interprocedural.callSinkOnFieldDirect() at [line 133]) via {  }
@@ -99,7 +99,7 @@ Interprocedural.java:201: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferT
 Interprocedural.java:202: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 200]) -> Other(void Interprocedural.callSinkParam2(Object,Object) at [line 202]) via {  }
 Interprocedural.java:210: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 208]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 210]) via { Object Interprocedural.id(Object) at [line 209] }
 Interprocedural.java:217: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 214]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 217]) via { Object Interprocedural.id(Object) at [line 215], Object Interprocedural.id(Object) at [line 216] }
-Interprocedural.java:228: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 223]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 228]) via { Object Interprocedural.returnSourceConditional(boolean) at [line 228] }
+Interprocedural.java:228: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object Interprocedural.returnSourceConditional(boolean) at [line 228]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 228]) via {  }
 Interprocedural.java:239: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 237]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 239]) via {  }
 Interprocedural.java:251: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 251]) -> Other(void Interprocedural.callSinkVariadic(java.lang.Object[]) at [line 251]) via {  }
 Interprocedural.java:262: ERROR: QUANDARY_TAINT_ERROR Error: Other(Object InferTaint.inferSecretSource() at [line 260]) -> Other(void InferTaint.inferSensitiveSink(Object) at [line 262]) via {  }