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digitalmars.D.bugs - [Issue 8099] New: Inner class's outer pointer matches constancy of inner, but can be set to object of arbitrary constancy

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=8099

           Summary: Inner class's outer pointer matches constancy of
                    inner, but can be set to object of arbitrary constancy
           Product: D
           Version: D2
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Keywords: accepts-invalid
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: smjg iname.com
            Blocks: 2573


--- Comment #0 from Stewart Gordon <smjg iname.com> 2012-05-15 08:16:32 PDT ---
An inner class considers the pointer to the outer object to have the same
constancy as itself.  (This doesn't seem to be stated in the spec, but by
const-transitivity rules it would have to be the same or stronger.  See issue
8098 comment 1.)

Nonetheless, when instantiating the inner class it totally disregards the
constancy of the outer with which it is instantiated.  This means that the
inner class can be viewing a mutable outer object as immutable, or vice versa.

----------
import std.stdio;

class Outer {
    class Inner {}
}

void test(X, Y)(X x, Y y) {
    writefln("%-20s  %-20s  %s", X.stringof, Y.stringof,
typeof(y.outer).stringof);
}

void main() {
    auto m = new Outer;
    auto c = new const(Outer);
    auto i = new immutable(Outer);

    auto mm = m.new Inner;             test(m, mm);  // m -> m  OK
    auto mc = m.new const(Inner);      test(m, mc);  // m -> c  OK
    auto mi = m.new immutable(Inner);  test(m, mi);  // m -> i  bad

    auto cm = c.new Inner;             test(c, cm);  // c -> m  bad
    auto cc = c.new const(Inner);      test(c, cc);  // c -> c  OK
    auto ci = c.new immutable(Inner);  test(c, ci);  // c -> i  bad

    auto im = i.new Inner;             test(i, im);  // i -> m  bad
    auto ic = i.new const(Inner);      test(i, ic);  // i -> c  OK
    auto ii = i.new immutable(Inner);  test(i, ii);  // i -> i  OK
}
----------
C:\Users\Stewart\Documents\Programming\D\Tests>inner_const_2
Outer                 Inner                 Outer
Outer                 const(Inner)          const(Outer)
Outer                 immutable(Inner)      immutable(Outer)
const(Outer)          Inner                 Outer
const(Outer)          const(Inner)          const(Outer)
const(Outer)          immutable(Inner)      immutable(Outer)
immutable(Outer)      Inner                 Outer
immutable(Outer)      const(Inner)          const(Outer)
immutable(Outer)      immutable(Inner)      immutable(Outer)
----------
(DMD 2.059 Win32)

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=8099


Kenji Hara <k.hara.pg gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull
           Platform|x86                         |All
         OS/Version|Windows                     |All


--- Comment #1 from Kenji Hara <k.hara.pg gmail.com> 2012-05-25 00:27:02 PDT ---
https://github.com/D-Programming-Language/dmd/pull/965

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prev sibling next sibling parent d-bugmail puremagic.com writes:
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--- Comment #2 from github-bugzilla puremagic.com 2012-05-25 15:13:01 PDT ---
Commits pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/6499c5cf306745c799748c9ea733e57c855c5918
fix Issue 8099 - Inner class's outer pointer matches constancy of inner, but
can be set to object of arbitrary constancy

https://github.com/D-Programming-Language/dmd/commit/4c9b4742011f5febd7313fe25672bffa70758597
Merge pull request #965 from 9rnsr/fix8099

Issue 8099 - Inner class's outer pointer matches constancy of inner, but can be
set to object of arbitrary constancy

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prev sibling parent d-bugmail puremagic.com writes:
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Walter Bright <bugzilla digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla digitalmars.com
         Resolution|                            |FIXED


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