Equality operator chaining?

[bearophile]

Few days ago I have suggested a small language enhancement:
http://d.puremagic.com/issues/show_bug.cgi?id=11410


In Python this code is allowed:

>>> x = 3
>>> y = 4
>>> z = 5
>>> x < y < z
True



It is compilable in C too:


int main() {
     int x = 3;
     int y = 4;
     int z = 5;
     int b = x < y < z;
     return 0;
}


But GCC tells us with a warning that code doesn't work as 
expected by a Python programmer:

test.c:5:15: warning: comparisons like 'X<=Y<=Z' do not have 
their mathematical meaning [-Wparentheses]
      int b = x < y < z;


So D disallows that code, giving:

test.d(5): Error: semicolon expected, not '<'
test.d(5): Error: found '<' instead of statement

- - - - - - - - - - - - - -

GCC accepts this code:


int main() {
     int x = 4;
     int y = 4;
     int z = 4;
     int b = x == y == z;
     return 0;
}


With a warning:

test.c:5:15: warning: suggest parentheses around comparison in 
operand of '=='
[-Wparentheses]
      int b = x == y == z;


While DMD refuses that code:

test.d(5): Error: semicolon expected, not '=='
test.d(5): Error: found '==' instead of statement


In D I find several situations where a chained equality is handy:

if (n == foo(n) == bar(n) && ...

It avoids code like this, that needs an auxiliary variable:

aux = foo(n);
if (n == aux && aux == bar(n) && ...


Is this idea going to cause troubles with operator overloading or 
something else? Do you like it? Is it important enough?

Bye,
bearophile