Description:
------------
One reason we are not using compact() in our production code is that it is hard to search for variable references because $foo is simply called 'foo' in compact()

Suggestion: Strip off a leading $ before looking up variables, i.e. make compact('$foo') equivalent to compact('foo').

It's clear that people can shoot themselves in the foot if they try compact("$foo") but it would possibly make code using compact() a little easier to maintain.

Patch:
Index: ext/standard/array.c
===================================================================
--- ext/standard/array.c        (revision 289696)
+++ ext/standard/array.c        (working copy)
@@ -1488,7 +1488,7 @@
 {
        zstr key;
        int key_len;
-       zend_bool free_key = 0;
+       void *free_key = NULL;
        zval **value_ptr, *value, *data;

        if (Z_TYPE_P(entry) == IS_STRING || Z_TYPE_P(entry) == IS_UNICODE) {
@@ -1505,9 +1505,19 @@
                        } else if (norm != key.u) {
                                key.u = norm;
                                key_len = norm_len;
-                               free_key = 1;
+                               free_key = norm;
                        }
+                       if (*key.u == '$') {
+                               key.u++;
+                               key_len--;
+                       }
                }
+               else {
+                       if (*key.s == '$') {
+                               key.s++;
+                               key_len--;
+                       }
+               }
                if (zend_u_hash_find(eg_active_symbol_table, Z_TYPE_P(entry), key, key_len + 1, (void **)&value_ptr) != FAILURE) {
                        value = *value_ptr;
                        ALLOC_ZVAL(data);
@@ -1518,7 +1528,7 @@
                        zend_u_hash_update(Z_ARRVAL_P(return_value), Z_TYPE_P(entry), key, key_len + 1, &data, sizeof(zval *), NULL);
                }
                if (free_key) {
-                       efree(key.v);
+                       efree(free_key);
                }
        }
        else if (Z_TYPE_P(entry) == IS_ARRAY) {


Reproduce code:
---------------
sapi/cli/php -r '$foo = "FOO"; var_dump(compact("\$foo"));'

Expected result:
----------------
array(1) {
  [u"foo"]=>
  unicode(3) "FOO"
}


Actual result:
--------------
array(0) {
}