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digitalmars.D.bugs - [Issue 8857] New: [CTFE] Referring to a wrong member of a sruct in CTFE with -inline

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=8857

           Summary: [CTFE] Referring to a wrong member of a sruct in CTFE
                    with -inline
           Product: D
           Version: D2
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody puremagic.com
        ReportedBy: youxkei gmail.com


--- Comment #0 from Hisayuki Mima <youxkei gmail.com> 2012-10-20 23:27:56 JST
---
Code:

struct Result{ bool match; string next; }

void func1()(){
    auto r = func2();
    if(r.match){ // line 5
        auto next = r.next;
    }
}

Result func2(){
    Result result;
    result.match = true;
    return result;
}

static assert({
    func1();
    return true;
}());

void main(){}



Compilation Output:

bug.d(5): Error: Result(true,null).next does not evaluate to a boolean.



The above code doesn't compiled by dmd 2.060 with -inline.
At the line 5, I surely wrote "r.match", but dmd seems to have recognized
"r.match" as "r.next".
This means that dmd is referring to a wrong member of the struct "Result".

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next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=8857


Don <clugdbug yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|[CTFE] Referring to a wrong |[CTFE] does not evaluate to
                   |member of a sruct in CTFE   |a boolean, only with
                   |with -inline                |-inline


--- Comment #1 from Don <clugdbug yahoo.com.au> 2012-11-06 11:46:53 PST ---
Original title:
[CTFE] Referring to a wrong member of a struct in CTFE with -inline

Actually it isn't using a wrong struct member. What happens is that the inliner
changes
if(r.match){ // line 5
        auto next = r.next;
}

into:
  r.match && (string next = r.next);

The CTFE engine cannot currently cope with this expression, and gives an error.
It's the wrong line number, though this hardly matters since it's really an
internal compiler error.

It's quite an obscure bug, in that it is only triggered with -inline (the code
after inlining is not valid D code) + a true condition + an assignment where
the value is null.

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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 2012-11-10 12:14:56 PST ---
Commit pushed to master at https://github.com/D-Programming-Language/dmd

https://github.com/D-Programming-Language/dmd/commit/517c80e609208e38b36be621642d8c8032038971
Fix issue 8857 [CTFE] does not evaluate to a boolean, only with -inline

This is a situation where we've evaluated an Lvalue, but we actually
need an Rvalue. The bug report is one of the few circumstances where
it matters.

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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
            Version|D2                          |D1 & D2
         Resolution|                            |FIXED


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