fix pre-existing issues

- reference counting on assignment
- walking of anonymous functions

lib/compress.js

@@ -298,6 +298,7 @@ merge(Compressor.prototype, {
                     && node.left instanceof AST_SymbolRef) {
                     var d = node.left.definition();
                     if (HOP(safe_ids, d.id) && safe_to_assign(d, node.right)) {
+                        d.references.push(node.left);
                         d.fixed = function() {
                             return node.right;
                         };
@@ -321,13 +322,11 @@ merge(Compressor.prototype, {
                     safe_ids = save_ids;
                     return true;
                 }
-                var iife;
-                if (node instanceof AST_Function
-                    && (iife = tw.parent()) instanceof AST_Call
-                    && iife.expression === node) {
-                    if (node.name) {
-                        node.name.definition().fixed = node;
-                    } else {
+                if (node instanceof AST_Function) {
+                    var iife;
+                    if (!node.name
+                        && (iife = tw.parent()) instanceof AST_Call
+                        && iife.expression === node) {
                         // Virtually turn IIFE parameters into variable definitions:
                         //   (function(a,b) {...})(c,d) => (function() {var a=c,b=d; ...})()
                         // So existing transformation rules can work on them.
@@ -339,6 +338,10 @@ merge(Compressor.prototype, {
                             mark(d, true);
                         });
                     }
+                    push();
+                    descend();
+                    pop();
+                    return true;
                 }
                 if (node instanceof AST_Binary
                     && (node.operator == "&&" || node.operator == "||")) {

test/compress/collapse_vars.js

@@ -1592,3 +1592,25 @@ var_side_effects_3: {
     }
     expect_stdout: true
 }
+
+reduce_vars_assign: {
+    options = {
+        collapse_vars: true,
+        reduce_vars: true,
+    }
+    input: {
+        !function() {
+            var a = 1;
+            a = [].length,
+            console.log(a);
+        }();
+    }
+    expect: {
+        !function() {
+            var a = 1;
+            a = [].length,
+            console.log(a);
+        }();
+    }
+    expect_stdout: "0"
+}

test/compress/reduce_vars.js

@@ -2258,3 +2258,34 @@ cond_assign: {
     }
     expect_stdout: "undefined"
 }
+
+iife_assign: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        !function() {
+            var a = 1, b = 0;
+            !function() {
+                b++;
+                return;
+                a = 2;
+            }();
+            console.log(a);
+        }();
+    }
+    expect: {
+        !function() {
+            var a = 1, b = 0;
+            !function() {
+                b++;
+                return;
+                a = 2;
+            }();
+            console.log(a);
+        }();
+    }
+    expect_stdout: "1"
+}