Description:
------------
When inserting (the name of) a lambda function provided by create_function into a string that will be used to create a second lambda function, the second function fails to parse. The parse error message makes what appears to be a spurious complaint about the code; only Test 5's error message makes sense (plus, it seems there is no "callable" version of a lambda function's name).

(Cf. bug #10721 - parser chokes on lambda function names in eval'd code)


Reproduce code:
---------------
I made five distinct tests to bracket the issue:
TEST 1:
// Creating a function that calls an ordinary function (explict name)
function always_true(){return true;}
$afun = create_function('', 'return !always_true();');
echo "Calling $afun() " . ($afun() ? "returns true\n" : "returns false\n");

TEST 2:
// Creating a function that calls an ordinary function (variable name)
function always_true(){return true;}
$b1 = 'always_true';
$bfun = create_function('','return !'.$b1.'();');
echo "Calling $bfun() " . ($bfun() ? "returns true\n" : "returns false\n");

TEST 3:
// Creating a function that calls an anonymous function (explicit name);
$c1 = create_function('','return true;');
$cfun = create_function('','return !'.chr(0).'lambda_3();');
echo "Calling $cfun() " . ($cfun() ? "returns true\n" : "returns false\n");

TEST 4:
// Creating a function that calls an anonymous function (variable name)
$d1 = create_function('','return true;');
$dfun = create_function('','return !'.$d1.'();');
echo "Calling $dfun() " . ($dfun() ? "returns true\n" : "returns false\n");

TEST 5:
// Using is_callable to get a callable version of anonymous function name
$e1 = create_function('', 'return true;');
if(!is_callable($e1,false,$callable_e1)) die("Couldn't call anonymous function.");
echo "Using $callable_e1 as name of anonymous function\n";
$efun = create_function('','return !'.$callable_e1.'();');
echo "Calling $efun() " . ($efun() ? "returns true\n" : "returns false\n");



Expected result:
----------------
TEST 1:
Calling  lambda_1() returns false

TEST 2:
Calling  lambda_1() returns false

TEST 3:
Calling  lambda_2() returns false

TEST 4:
Calling  lambda_2() returns false

TEST 5:
Using  lambda_1 as name of anonymous function  [?]
Calling  lambda_2() returns false


Actual result:
--------------
Actual Results:
TEST 1:
Calling  lambda_1() returns false

TEST 2:
Calling  lambda_1() returns false

TEST 3:
Parse error: parse error, unexpected '}' in test.php : runtime-created function on line 1
Fatal error: Function name must be a string in test.php on line 4

TEST 4:
Parse error: parse error, unexpected '}' in test.php : runtime-created function on line 1
Fatal error: Function name must be a string in test.php on line 4

TEST 5:
Using  as name of anonymous function
Parse error: parse error, unexpected ')' in test.php : runtime-created function on line 1
Fatal error: Function name must be a string in test.php on line 6