fix corner case in functions (#3365)

fixes #3364

test/compress/functions.js

@@ -2916,3 +2916,68 @@ issue_2485: {
     }
     expect_stdout: "6"
 }
+
+issue_3364: {
+    options = {
+        functions: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    mangle = {}
+    input: {
+        var s = 2, a = 100, b = 10, c = 0;
+        function f(p, e, r) {
+            try {
+                for (var i = 1; i-- > 0;)
+                    var a = function(x) {
+                        function g(y) {
+                            y && y[a++];
+                        }
+                        var x = g(--s >= 0 && f(c++));
+                        for (var j = 1; --j > 0;);
+                    }();
+            } catch (e) {
+                try {
+                    return;
+                } catch (z) {
+                    for (var k = 1; --k > 0;) {
+                        for (var l = 1; l > 0; --l) {
+                            var n = function() {};
+                            for (var k in n)
+                                var o = (n, k);
+                        }
+                    }
+                }
+            }
+        }
+        var r = f();
+        console.log(c);
+    }
+    expect: {
+        var s = 2, c = 0;
+        (function n(r, o, a) {
+            try {
+                for (var f = 1; f-- >0;)
+                    var t = function(r) {
+                        (function(r) {
+                            r && r[t++];
+                        })(--s >= 0 && n(c++));
+                        for (var o = 1; --o > 0;);
+                    }();
+            } catch (o) {
+                try {
+                    return;
+                } catch (r) {
+                    for (var v = 1; --v > 0;)
+                        for (var i = 1; i > 0;--i) {
+                            function u() {}
+                            for (var v in u);
+                        }
+                }
+            }
+        })();
+        console.log(c);
+    }
+    expect_stdout: "2"
+}