I searched range's source (php4/ext/standard/array.c)

It seems that problem is in string 

for (; *low <= *high; (*low) += (unsigned int)lstep) {
    add_next_index_stringl(return_value, low, 1, 1);
}

+= increments not pointer, but value, to which low points.
Therefore for(;;) iterates values between first characters of high and low strings.

Confirmed in 4.3.0.  If they are strings, $a turns into 40!  If $a is integer, it stays 20 as expected.  Btw if we have '$a = "$a = "24"; $b = "140";' then $a turns into 04.  There seems to be sort of a pattern but it's kinda weird :)  The second argument ($b) does not get modified and the following behavoir exists:

range(20, "30");   // okay in 4.3.0-dev
range("20", "30"); // not okay in 4.3.0-dev

And as a holiday bonus, in HEAD either use results in a segfault with the following backtrace for CLI:

rock:/tmp# php range.php
a1: 20
FATAL:  erealloc():  Unable to allocate 1515870815 bytes
Segmentation fault (core dumped)

#0  0x400b9c51 in kill () from /lib/libc.so.6
#1  0x0815f28c in _erealloc (ptr=0x8360cdc, size=1515870815, allow_failure=0, __zend_filename=0x81b8100 "/cvs/php4/Zend/zend_operators.c", __zend_lineno=1013, __zend_orig_filename=0x0, __zend_orig_lineno=0)
    at /cvs/php4/Zend/zend_alloc.c:298
#2  0x0816fb47 in add_string_to_string (result=0xbfffd5f4, op1=0xbfffd5f4, op2=0xbfffd748) at /cvs/php4/Zend/zend_operators.c:1013
#3  0x0818766b in execute (op_array=0x83677c4) at /cvs/php4/Zend/zend_execute.c:1463
#4  0x08174924 in zend_execute_scripts (type=8, retval=0x0, file_count=3) at /cvs/php4/Zend/zend.c:931
#5  0x08139553 in php_execute_script (primary_file=0xbffffa2c) at /cvs/php4/main/main.c:1693
#6  0x0818e817 in main (argc=2, argv=0xbffffaa4) at /cvs/php4/sapi/cli/php_cli.c:744

range.php looks like this:

<?php
$a = "20"; $b = "30";
echo "a1: $a\n";
$result = range($a, $b);
echo "a2: $a : type : " . gettype($a) . "\n";
?>

This bug has been fixed in CVS.

In case this was a PHP problem, snapshots of the sources are packaged
every three hours; this change will be in the next snapshot. You can
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In case this was a documentation problem, the fix will show up soon at
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