[Issue 7542] inout parameter contravariant should be allowed

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=7542


timon.gehr at gmx.ch changed:

           What    |Removed                     |Added
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                 CC|                            |timon.gehr at gmx.ch


--- Comment #2 from timon.gehr at gmx.ch 2012-02-19 05:05:58 PST ---
This pull breaks the type system:

void main(){
    // conversion from void function(int*) to void function(inout(int)*):
    void function(inout(int)*) wfp = function(int*)(*p = 1;}
    immutable int x = 0;
    wfp(&x); // mutates x
}

The title of the bug report is correct though, contravariance is safe.

Those are the safe conversions:
mfp = wfp; // match inout as mutable
wfp = cfp; // inout is a subtype of const
cfp = wfp; // match inout as const
ifp = wfp; // match inout as immutable

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