diff --git a/README.md b/README.md
index 3b99441b..b6abc379 100644
--- a/README.md
+++ b/README.md
@@ -350,6 +350,11 @@ to set `true`; it's effectively a shortcut for `foo=true`).
   compressor from discarding unused function arguments.  You need this
   for code which relies on `Function.length`.
 
+- `keep_fnames` -- default `false`.  Pass `true` to prevent the
+  compressor from mangling/discarding function names.  Useful for code relying on
+  `Function.prototype.name`.
+
+
 ### The `unsafe` option
 
 It enables some transformations that *might* break code logic in certain
diff --git a/lib/compress.js b/lib/compress.js
index 646476df..cbd1caee 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -2308,7 +2308,15 @@ merge(Compressor.prototype, {
     });
 
     OPT(AST_SymbolRef, function(self, compressor){
-        if (self.undeclared()) {
+        function isLHS(symbol, parent) {
+            return (
+                parent instanceof AST_Binary &&
+                parent.operator === '=' &&
+                parent.left === symbol
+            );
+        }
+
+        if (self.undeclared() && !isLHS(self, compressor.parent())) {
             var defines = compressor.option("global_defs");
             if (defines && defines.hasOwnProperty(self.name)) {
                 return make_node_from_constant(compressor, defines[self.name], self);
diff --git a/lib/propmangle.js b/lib/propmangle.js
index 086709e6..840bda91 100644
--- a/lib/propmangle.js
+++ b/lib/propmangle.js
@@ -83,6 +83,7 @@ function mangle_properties(ast, options) {
     var regex = options.regex;
 
     var names_to_mangle = [];
+    var unmangleable = [];
 
     // step 1: find candidates to mangle
     ast.walk(new TreeWalker(function(node){
@@ -108,20 +109,14 @@ function mangle_properties(ast, options) {
     // step 2: transform the tree, renaming properties
     return ast.transform(new TreeTransformer(function(node){
         if (node instanceof AST_ObjectKeyVal) {
-            if (should_mangle(node.key)) {
-                node.key = mangle(node.key);
-            }
+            node.key = mangle(node.key);
         }
         else if (node instanceof AST_ObjectProperty) {
             // setter or getter
-            if (should_mangle(node.key.name)) {
-                node.key.name = mangle(node.key.name);
-            }
+            node.key.name = mangle(node.key.name);
         }
         else if (node instanceof AST_Dot) {
-            if (should_mangle(node.property)) {
-                node.property = mangle(node.property);
-            }
+            node.property = mangle(node.property);
         }
         else if (node instanceof AST_Sub) {
             node.property = mangleStrings(node.property);
@@ -143,6 +138,7 @@ function mangle_properties(ast, options) {
     // only function declarations after this line
 
     function can_mangle(name) {
+        if (unmangleable.indexOf(name) >= 0) return false;
         if (reserved.indexOf(name) >= 0) return false;
         if (options.only_cache) {
             return cache.props.has(name);
@@ -161,9 +157,17 @@ function mangle_properties(ast, options) {
     function add(name) {
         if (can_mangle(name))
             push_uniq(names_to_mangle, name);
+
+        if (!should_mangle(name)) {
+            push_uniq(unmangleable, name);
+        }
     }
 
     function mangle(name) {
+        if (!should_mangle(name)) {
+            return name;
+        }
+
         var mangled = cache.props.get(name);
         if (!mangled) {
             do {
@@ -206,9 +210,7 @@ function mangle_properties(ast, options) {
                 node.cdr = mangleStrings(node.cdr);
             }
             else if (node instanceof AST_String) {
-                if (should_mangle(node.value)) {
-                    node.value = mangle(node.value);
-                }
+                node.value = mangle(node.value);
             }
             else if (node instanceof AST_Conditional) {
                 node.consequent = mangleStrings(node.consequent);
diff --git a/test/compress/issue-208.js b/test/compress/issue-208.js
new file mode 100644
index 00000000..14752b8a
--- /dev/null
+++ b/test/compress/issue-208.js
@@ -0,0 +1,11 @@
+do_not_update_lhs: {
+    options = { global_defs: { DEBUG: false } };
+    input: { DEBUG = false; }
+    expect: { DEBUG = false; }
+}
+
+do_update_rhs: {
+    options = { global_defs: { DEBUG: false } };
+    input: { MY_DEBUG = DEBUG; }
+    expect: { MY_DEBUG = false; }
+}
diff --git a/test/compress/issue-747.js b/test/compress/issue-747.js
new file mode 100644
index 00000000..0a4e4502
--- /dev/null
+++ b/test/compress/issue-747.js
@@ -0,0 +1,37 @@
+dont_reuse_prop: {
+    mangle_props = {
+        regex: /asd/
+    };
+
+    input: {
+        var obj = {};
+        obj.a = 123;
+        obj.asd = 256;
+        console.log(obj.a);
+    }
+    expect: {
+        var obj = {};
+        obj.a = 123;
+        obj.b = 256;
+        console.log(obj.a);
+    }
+}
+
+unmangleable_props_should_always_be_reserved: {
+    mangle_props = {
+        regex: /asd/
+    };
+
+    input: {
+        var obj = {};
+        obj.asd = 256;
+        obj.a = 123;
+        console.log(obj.a);
+    }
+    expect: {
+        var obj = {};
+        obj.b = 256;
+        obj.a = 123;
+        console.log(obj.a);
+    }
+}
\ No newline at end of file
diff --git a/test/run-tests.js b/test/run-tests.js
index 92b153ee..ea8d03e4 100755
--- a/test/run-tests.js
+++ b/test/run-tests.js
@@ -96,6 +96,9 @@ function run_compress_tests() {
             }
             var input = as_toplevel(test.input);
             var input_code = make_code(test.input);
+            if (test.mangle_props) {
+                input = U.mangle_properties(input, test.mangle_props);
+            }
             var output = input.transform(cmp);
             output.figure_out_scope();
             output = make_code(output, false);
diff --git a/tools/node.js b/tools/node.js
index cbe49e39..29d5632d 100644
--- a/tools/node.js
+++ b/tools/node.js
@@ -73,17 +73,20 @@ exports.minify = function(files, options) {
     } else {
         if (typeof files == "string")
             files = [ files ];
-        files.forEach(function(file){
+        files.forEach(function(file, i){
             var code = options.fromString
                 ? file
                 : fs.readFileSync(file, "utf8");
             sourcesContent[file] = code;
             toplevel = UglifyJS.parse(code, {
-                filename: options.fromString ? "?" : file,
+                filename: options.fromString ? i : file,
                 toplevel: toplevel
             });
         });
     }
+    if (options.wrap) {
+      toplevel = toplevel.wrap_commonjs(options.wrap, options.exportAll);
+    }
 
     // 2. compress
     if (options.compress) {