Hello, I found a fondamental bug in Squeak and Pharo. The next code 11 / 2 gives the fraction (11/2). It's correct. But the next code (SmallInteger>>#/) valueWithReceiver: 11 arguments: {2} gives 1 ! The problem is the method valueWithReceiver:arguements: is used hugely with method wrappers... After long time of debugging, I found a point to debug: this method don't have the good behavior with compiled methods having a primitive that fails and executes some code after (as in SmallInteger>>#/ method when the division don't give a whole integer). In fact, when I send this message, the vm executes normally the compiled method but, in place of returns simply the good result, seems to rerun the the compiled method with other arguments (completly wrong) and returns so a wrong result. For example, (SmallInteger>>#/) valueWithReceiver: 11 arguments: {2} has the following execution trace : 2 isZero | 2 = 0 | returns: false returns: false 2 isMemberOf: SmallInteger | 2 class | returns: SmallInteger | SmallInteger == SmallInteger | returns: true returns: true Fraction numerator: 101 denominator: 2 | Fraction new | | Fraction basicNew | | returns: a Fraction instance | | (a Fraction instance) initialize | | returns: a Fraction instance | returns: a Fraction instance | a Fraction instance setNumerator: 101 denominator: 2 | | 2 = 0 | | returns: false | | 101 asInteger | | returns: 101 | | 2 asInteger | | returns: 2 | | 2 abs | | | 2 < 0 | | | returns: false | | returns: 2 | | 2 < 0 | | returns: false | returns: (101/2) returns: (101/2) (101/2) reduced | 101 = 0 | returns: false | 101 gcd: 2 | | 101 = 0 | | returns: false | | 2 \\ 101 | | returns: 2 | | 2 = 0 | | returns: false | | 101 \\ 2 | | returns: 1 | | 1 = 0 | | returns: false | | 2 \\ 1 | | returns: 0 | | 0 = 0 | | returns: true | | 1 abs | | | 1 < 0 | | | returns: false | | returns: 1 | returns: 1 | 101 // 1 | returns: 101 | 2 // 1 | returns: 2 | 2 = 1 | returns: false | Fraction numerator: 101 denominator: 2 | | Fraction new | | | Fraction basicNew | | | returns: a Fraction instance | | | (a Fraction instance) initialize | | | returns: a Fraction instance | | returns: a Fraction instance | | (a Fraction instance) setNumerator: 101 denominator: 2 | | | 2 = 0 | | | returns: false | | | 101 asInteger | | | returns: 101 | | | 2 asInteger | | | returns: 2 | | | 2 abs | | | | 2 < 0 | | | | returns: false | | | returns: 2 | | | 2 < 0 | | | returns: false | | returns: (101/2) | returns: (101/2) returns: (101/2) 2 isZero | 2 = 0 | returns: false returns: false false isMemberOf: SmallInteger | false class | returns: False | False == SmallInteger | returns: false returns: false Please help me to fix this bug. I really need it works fine ! Fréd -- Frédéric Pluquet Université Libre de Bruxelles (ULB) Assistant http://www.ulb.ac.be/di/fpluquet