diff --git a/lib/compress.js b/lib/compress.js
index ad4c28ab..3c680401 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -3240,9 +3240,11 @@ merge(Compressor.prototype, {
                                 if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) {
                                     compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name));
                                     if (def.value) {
+                                        var ref = make_node(AST_SymbolRef, def.name, def.name);
+                                        sym.references.push(ref);
                                         var assign = make_node(AST_Assign, def, {
                                             operator: "=",
-                                            left: make_node(AST_SymbolRef, def.name, def.name),
+                                            left: ref,
                                             right: def.value
                                         });
                                         if (fixed_ids[sym.id] === def) {
@@ -3694,8 +3696,10 @@ merge(Compressor.prototype, {
             while (left instanceof AST_PropAccess) {
                 left = left.expression;
             }
-            if (left instanceof AST_Symbol) return this;
-            return this.right.drop_side_effect_free(compressor);
+            if (left.is_constant_expression(compressor.find_parent(AST_Scope))) {
+                return this.right.drop_side_effect_free(compressor);
+            }
+            return this;
         });
         def(AST_Conditional, function(compressor){
             var consequent = this.consequent.drop_side_effect_free(compressor);
diff --git a/lib/scope.js b/lib/scope.js
index be4ad02b..7b2e4c02 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -411,7 +411,7 @@ AST_Scope.DEFMETHOD("find_variable", function(name){
 
 AST_Scope.DEFMETHOD("def_function", function(symbol, init){
     var def = this.def_variable(symbol, init);
-    if (!def.init) def.init = init;
+    if (!def.init || def.init instanceof AST_Defun) def.init = init;
     this.functions.set(symbol.name, def);
     return def;
 });
diff --git a/package.json b/package.json
index be6cbf19..a36cae3b 100644
--- a/package.json
+++ b/package.json
@@ -4,7 +4,7 @@
   "homepage": "https://github.com/mishoo/UglifyJS2/tree/harmony",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.3.8",
+  "version": "3.3.9",
   "engines": {
     "node": ">=0.8.0"
   },
diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index 0324d722..4f629e51 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -2066,3 +2066,30 @@ issue_2768: {
     }
     expect_stdout: "PASS undefined"
 }
+
+issue_2846: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f(a, b) {
+            var a = 0;
+            b && b(a);
+            return a++;
+        }
+        var c = f();
+        console.log(c);
+    }
+    expect: {
+        var c = function(a, b) {
+            a = 0;
+            b && b(a);
+            return a++;
+        }();
+        console.log(c);
+    }
+    expect_stdout: "0"
+}
diff --git a/test/compress/pure_getters.js b/test/compress/pure_getters.js
index 55fce16e..9a9a7816 100644
--- a/test/compress/pure_getters.js
+++ b/test/compress/pure_getters.js
@@ -818,3 +818,30 @@ issue_2678: {
     }
     expect_stdout: "PASS"
 }
+
+issue_2838: {
+    options = {
+        pure_getters: true,
+        side_effects: true,
+    }
+    input: {
+        function f(a, b) {
+            (a || b).c = "PASS";
+            (function() {
+                return f(a, b);
+            }).prototype.foo = "bar";
+        }
+        var o = {};
+        f(null, o);
+        console.log(o.c);
+    }
+    expect: {
+        function f(a, b) {
+            (a || b).c = "PASS";
+        }
+        var o = {};
+        f(null, o);
+        console.log(o.c);
+    }
+    expect_stdout: "PASS"
+}
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index 5194f242..311ad7c4 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -5950,3 +5950,26 @@ issue_2799_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_2836: {
+    options = {
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            return "FAIL";
+        }
+        console.log(f());
+        function f() {
+            return "PASS";
+        }
+    }
+    expect: {
+        console.log(function() {
+            return "PASS";
+        }());
+    }
+    expect_stdout: "PASS"
+}