diff --git a/src/com/google/javascript/jscomp/ChainCalls.java b/src/com/google/javascript/jscomp/ChainCalls.java
index bf3696c2eea..6281e87ca0b 100644
--- a/src/com/google/javascript/jscomp/ChainCalls.java
+++ b/src/com/google/javascript/jscomp/ChainCalls.java
@@ -21,7 +21,6 @@
 import com.google.javascript.jscomp.NodeTraversal.ScopedCallback;
 import com.google.javascript.jscomp.graph.DiGraph.DiGraphEdge;
 import com.google.javascript.rhino.Node;
-
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
diff --git a/src/com/google/javascript/jscomp/DefinitionUseSiteFinder.java b/src/com/google/javascript/jscomp/DefinitionUseSiteFinder.java
index d38d148803d..fbadff39f00 100644
--- a/src/com/google/javascript/jscomp/DefinitionUseSiteFinder.java
+++ b/src/com/google/javascript/jscomp/DefinitionUseSiteFinder.java
@@ -22,7 +22,6 @@
 import com.google.javascript.jscomp.DefinitionsRemover.Definition;
 import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
 import com.google.javascript.rhino.Node;
-
 import java.util.Collection;
 
 /**
diff --git a/src/com/google/javascript/jscomp/DefinitionsRemover.java b/src/com/google/javascript/jscomp/DefinitionsRemover.java
index a27a993e15f..b1bad2a63ee 100644
--- a/src/com/google/javascript/jscomp/DefinitionsRemover.java
+++ b/src/com/google/javascript/jscomp/DefinitionsRemover.java
@@ -21,7 +21,6 @@
 import com.google.javascript.rhino.IR;
 import com.google.javascript.rhino.Node;
 import com.google.javascript.rhino.Token;
-
 import java.util.Set;
 
 /**
@@ -156,6 +155,10 @@ public void remove() {
     public boolean isExtern() {
       return isExtern;
     }
+
+    public String toString() {
+      return getLValue().getQualifiedName() + " = " + getRValue().toString();
+    }
   }
 
   /**
diff --git a/src/com/google/javascript/jscomp/MarkNoSideEffectCalls.java b/src/com/google/javascript/jscomp/MarkNoSideEffectCalls.java
index 7a62aa8702a..b70683e24a7 100644
--- a/src/com/google/javascript/jscomp/MarkNoSideEffectCalls.java
+++ b/src/com/google/javascript/jscomp/MarkNoSideEffectCalls.java
@@ -21,7 +21,6 @@
 import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
 import com.google.javascript.rhino.JSDocInfo;
 import com.google.javascript.rhino.Node;
-
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
diff --git a/test/com/google/javascript/jscomp/NameBasedDefinitionProviderTest.java b/test/com/google/javascript/jscomp/NameBasedDefinitionProviderTest.java
index eadac983656..5d0b771057b 100644
--- a/test/com/google/javascript/jscomp/NameBasedDefinitionProviderTest.java
+++ b/test/com/google/javascript/jscomp/NameBasedDefinitionProviderTest.java
@@ -22,7 +22,6 @@
 import com.google.javascript.jscomp.DefinitionsRemover.Definition;
 import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
 import com.google.javascript.rhino.Node;
-
 import java.util.Collection;
 import java.util.Set;
 import java.util.TreeSet;
diff --git a/test/com/google/javascript/jscomp/PureFunctionIdentifierTest.java b/test/com/google/javascript/jscomp/PureFunctionIdentifierTest.java
index 1f35e2cb09c..f3f0c0f6a54 100644
--- a/test/com/google/javascript/jscomp/PureFunctionIdentifierTest.java
+++ b/test/com/google/javascript/jscomp/PureFunctionIdentifierTest.java
@@ -23,7 +23,6 @@
 import com.google.javascript.jscomp.CompilerOptions.LanguageMode;
 import com.google.javascript.jscomp.NodeTraversal.AbstractPostOrderCallback;
 import com.google.javascript.rhino.Node;
-
 import java.util.ArrayList;
 import java.util.List;
 
@@ -668,6 +667,37 @@ public void testCall() throws Exception {
                      ImmutableList.of("f.call"));
   }
 
+  public void testApplyToUnknownDefinition() throws Exception {
+    checkMarkedCalls(
+        "var dict = {'func': function() {}};"
+            + "function f() { var s = dict['func'];}"
+            + "f.apply()",
+        ImmutableList.of("f.apply"));
+
+    // Not marked becuase the definition cannot be found so unknown side effects.
+    checkMarkedCalls(
+        "var dict = {'func': function() {}};"
+            + "function f() { var s = dict['func'].apply();}"
+            + "f.apply()",
+        ImmutableList.<String>of());
+
+    // Not marked becuase the definition cannot be found so unknown side effects.
+    checkMarkedCalls(
+        "var pure = function() {};"
+            + "var dict = {'func': function() {}};"
+            + "function f() { var s = (dict['func'] || pure)();}"
+            + "f()",
+        ImmutableList.<String>of());
+
+    // Not marked becuase the definition cannot be found so unknown side effects.
+    checkMarkedCalls(
+        "var pure = function() {};"
+            + "var dict = {'func': function() {}};"
+            + "function f() { var s = (condition ? dict['func'] : pure)();}"
+            + "f()",
+        ImmutableList.<String>of());
+  }
+
   public void testInference1() throws Exception {
     checkMarkedCalls("function f() {return g()}" +
                      "function g() {return 42}" +
@@ -1036,6 +1066,51 @@ public void testInheritance2() throws Exception {
     checkMarkedCalls(source, ImmutableList.of("goog.inherits", "I", "A"));
   }
 
+  public void testAmbiguousDefinitions() throws Exception {
+    String s =
+        "var globalVar = 1;"
+            + "A.f = function() {globalVar = 2;};"
+            + "A.f = function() {};"
+            + "function sideEffectCaller() { A.f() };"
+            + "sideEffectCaller();";
+    // Can't tell which f is being called so it assumes both.
+    checkMarkedCalls(s, ImmutableList.<String>of());
+  }
+
+  public void testAmbiguousDefinitionsCall() throws Exception {
+    String s =
+        "var globalVar = 1;"
+            + "A.f = function() {globalVar = 2;};"
+            + "A.f = function() {};"
+            + "function sideEffectCaller() { A.f.call(null); };"
+            + "sideEffectCaller();";
+    // Can't tell which f is being called so it assumes both.
+    checkMarkedCalls(s, ImmutableList.<String>of());
+  }
+
+  public void testAmbiguousDefinitionsAllPropagationTypes() throws Exception {
+    String s =
+        "var globalVar = 1;"
+            + "/**@constructor*/A.f = function() { this.x = 5; };"
+            + "/**@constructor*/B.f = function() {};"
+            + "function sideEffectCaller() { new C.f() };"
+            + "sideEffectCaller();";
+    // Can't tell which f is being called so it assumes both.
+    checkMarkedCalls(s, ImmutableList.<String>of("C.f", "sideEffectCaller"));
+  }
+
+  public void testAmbiguousDefinitionsCallWithThis() throws Exception {
+    String s =
+        "var globalVar = 1;"
+            + "A.modifiesThis = function() { this.x = 5; };"
+            + "/**@constructor*/function Constructor() { Constructor.modifiesThis.call(this); };"
+            + "Constructor.prototype.modifiesThis = function() {};"
+            + "new Constructor();"
+            + "A.modifiesThis();";
+    // Can't tell which modifiesThis is being called so it assumes both.
+    checkMarkedCalls(s, ImmutableList.<String>of("Constructor"));
+  }
+
   public void testCallBeforeDefinition() throws Exception {
     checkMarkedCalls("f(); function f(){}",
                      ImmutableList.of("f"));
@@ -1199,7 +1274,7 @@ public void testCallFunctionForGorH() throws Exception {
     checkMarkedCalls(source, ImmutableList.of("(f : (g || h))", "i"));
   }
 
-  public void testCallFunctionFOrGWithSideEffects() throws Exception {
+  public void testCallFunctionForGWithSideEffects() throws Exception {
     String source = "var x = 0;\n" +
         "function f(){x = 10}\n" +
         "function g(){}\n" +