Description:
------------
//When i type this code,

<?php
	//FOR Function
	for ($a = a;$a <= x;$a++){
		echo "$a ";
	}
?>

//it appears : a b c d e f g h i j k l m n o p q r s t u v w x y

//but when i type the code like this,

<?php
	//FOR Function
	for ($a = a;$a <= z;$a++){
		echo "$a ";
	}
?>

/*
it appears :

a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai 
aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj 
bk bl bm bn bo bp bq br bs bt bu bv bw bx by bz ca cb cc cd ce cf cg ch ci cj ck 
cl cm cn co cp cq cr cs ct cu cv cw cx cy cz da db dc dd de df dg dh di dj dk dl 
dm dn do dp dq dr ds dt du dv dw dx dy dz ea eb ec ed ee ef eg eh ei ej ek el em 
en eo ep eq er es et eu ev ew ex ey ez fa fb fc fd fe ff fg fh fi fj fk fl fm fn 
fo fp fq fr fs ft fu fv fw fx fy fz ga gb gc gd ge gf gg gh gi gj gk gl gm gn go 
gp gq gr gs gt gu gv gw gx gy gz ha hb hc hd he hf hg hh hi hj hk hl hm hn ho hp 
hq hr hs ht hu hv hw hx hy hz ia ib ic id ie if ig ih ii ij ik il im in io ip iq 
ir is it iu iv iw ix iy iz ja jb jc jd je jf jg jh ji jj jk jl jm jn jo jp jq jr 
js jt ju jv jw jx jy jz ka kb kc kd ke kf kg kh ki kj kk kl km kn ko kp kq kr ks 
kt ku kv kw kx ky kz la lb lc ld le lf lg lh li lj lk ll lm ln lo lp lq lr ls lt 
lu lv lw lx ly lz ma mb mc md me mf mg mh mi mj mk ml mm mn mo mp mq mr ms mt mu 
mv mw mx my mz na nb nc nd ne nf ng nh ni nj nk nl nm nn no np nq nr ns nt nu nv 
nw nx ny nz oa ob oc od oe of og oh oi oj ok ol om on oo op oq or os ot ou ov ow 
ox oy oz pa pb pc pd pe pf pg ph pi pj pk pl pm pn po pp pq pr ps pt pu pv pw px 
py pz qa qb qc qd qe qf qg qh qi qj qk ql qm qn qo qp qq qr qs qt qu qv qw qx qy 
qz ra rb rc rd re rf rg rh ri rj rk rl rm rn ro rp rq rr rs rt ru rv rw rx ry rz 
sa sb sc sd se sf sg sh si sj sk sl sm sn so sp sq sr ss st su sv sw sx sy sz ta 
tb tc td te tf tg th ti tj tk tl tm tn to tp tq tr ts tt tu tv tw tx ty tz ua ub 
uc ud ue uf ug uh ui uj uk ul um un uo up uq ur us ut uu uv uw ux uy uz va vb vc 
vd ve vf vg vh vi vj vk vl vm vn vo vp vq vr vs vt vu vv vw vx vy vz wa wb wc wd 
we wf wg wh wi wj wk wl wm wn wo wp wq wr ws wt wu wv ww wx wy wz xa xb xc xd xe 
xf xg xh xi xj xk xl xm xn xo xp xq xr xs xt xu xv xw xx xy xz ya yb yc yd ye yf 
yg yh yi yj yk yl ym yn yo yp yq yr ys yt yu yv yw yx yy yz
*/

#i dunno if this is really a bug, i just wanna know
#Thanks Before

Test script:
---------------
<?php
	//FOR Function
	for ($a = a;$a <= y;$a++){
		echo "$a ";
	}
?>
<?php
	//FOR Error Function
	for ($a = a;$a <= z;$a++){
		echo "$a ";
	}
?>

Expected result:
----------------
a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai 
aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc bd be bf bg bh bi bj 
bk bl bm bn bo bp bq br bs bt bu bv bw bx by bz ca cb cc cd ce cf cg ch ci cj ck 
cl cm cn co cp cq cr cs ct cu cv cw cx cy cz da db dc dd de df dg dh di dj dk dl 
dm dn do dp dq dr ds dt du dv dw dx dy dz ea eb ec ed ee ef eg eh ei ej ek el em 
en eo ep eq er es et eu ev ew ex ey ez fa fb fc fd fe ff fg fh fi fj fk fl fm fn 
fo fp fq fr fs ft fu fv fw fx fy fz ga gb gc gd ge gf gg gh gi gj gk gl gm gn go 
gp gq gr gs gt gu gv gw gx gy gz ha hb hc hd he hf hg hh hi hj hk hl hm hn ho hp 
hq hr hs ht hu hv hw hx hy hz ia ib ic id ie if ig ih ii ij ik il im in io ip iq 
ir is it iu iv iw ix iy iz ja jb jc jd je jf jg jh ji jj jk jl jm jn jo jp jq jr 
js jt ju jv jw jx jy jz ka kb kc kd ke kf kg kh ki kj kk kl km kn ko kp kq kr ks 
kt ku kv kw kx ky kz la lb lc ld le lf lg lh li lj lk ll lm ln lo lp lq lr ls lt 
lu lv lw lx ly lz ma mb mc md me mf mg mh mi mj mk ml mm mn mo mp mq mr ms mt mu 
mv mw mx my mz na nb nc nd ne nf ng nh ni nj nk nl nm nn no np nq nr ns nt nu nv 
nw nx ny nz oa ob oc od oe of og oh oi oj ok ol om on oo op oq or os ot ou ov ow 
ox oy oz pa pb pc pd pe pf pg ph pi pj pk pl pm pn po pp pq pr ps pt pu pv pw px 
py pz qa qb qc qd qe qf qg qh qi qj qk ql qm qn qo qp qq qr qs qt qu qv qw qx qy 
qz ra rb rc rd re rf rg rh ri rj rk rl rm rn ro rp rq rr rs rt ru rv rw rx ry rz 
sa sb sc sd se sf sg sh si sj sk sl sm sn so sp sq sr ss st su sv sw sx sy sz ta 
tb tc td te tf tg th ti tj tk tl tm tn to tp tq tr ts tt tu tv tw tx ty tz ua ub 
uc ud ue uf ug uh ui uj uk ul um un uo up uq ur us ut uu uv uw ux uy uz va vb vc 
vd ve vf vg vh vi vj vk vl vm vn vo vp vq vr vs vt vu vv vw vx vy vz wa wb wc wd 
we wf wg wh wi wj wk wl wm wn wo wp wq wr ws wt wu wv ww wx wy wz xa xb xc xd xe 
xf xg xh xi xj xk xl xm xn xo xp xq xr xs xt xu xv xw xx xy xz ya yb yc yd ye yf 
yg yh yi yj yk yl ym yn yo yp yq yr ys yt yu yv yw yx yy yz

Actual result:
--------------
a b c d e f g h i j k l m n o p q r s t u v w x y z