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digitalmars.D.bugs - [Issue 7295] New: Alias This + Pure + pointsTo = rejects-valid

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7295

           Summary: Alias This + Pure + pointsTo = rejects-valid
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Windows
            Status: NEW
          Keywords: rejects-valid
          Severity: critical
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: dsimcha yahoo.com



import std.exception;

struct RefCounted(T) {
    T payload;

    T refCountedPayload() { return payload;}
    alias refCountedPayload this;
}

void main() {
    RefCounted!int x;
    doPure(x);
}

void doPure(ref RefCounted!int lhs) pure {
    std.exception.pointsTo(lhs, lhs);
}

test.d(16): Error: pure function 'doPure' cannot call impure function
'refCountedPayload'

Marking as critical because this breaks std.algorithm.swap for ref counted
types, though there may be an easy workaround:  refCountedPayload() should
probably be pure.

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Jan 15 2012
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7295




One thing I forgot to note:  This bug appears cross-module only.  If I copy and
paste pointsTo() into test.d, the bug goes away.

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Jan 15 2012
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7295


Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |clugdbug yahoo.com.au



Reduced test case:
struct S
{
    int member;
     property ref int refCountedPayload() { return member; }
    alias refCountedPayload this;
}


// If you remove this next line, it works.
void foo(S)(immutable S t, int qq) pure { }
void foo(S)(S s) pure { }

void bar() pure
{
    S b;
    foo!int(b);
}
-------------------

The bug is in template.c, deduceFunctionTemplateMatch().
If a parameter fails to match (the immutable S above), it tries alias this. The
first is to run semantic on the alias this, which causes the error. Those error
messages should be suppressed.

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Jan 25 2012
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=7295


Walter Bright <bugzilla digitalmars.com> changed:

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



00:45:17 PST ---
https://github.com/D-Programming-Language/dmd/commit/2357f7771b7a5bdd560c2e8e9656d4194e8388d9

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Jan 26 2012