http://d.puremagic.com/issues/show_bug.cgi?id=5373

           Summary: Regression (2.051) CTFE and std.string.replace()
                    causes "Bad binary function q{a == b}..
           Product: D
           Version: D2
          Platform: Other
        OS/Version: Mac OS X
            Status: NEW
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: soul8o8@gmail.com


--- Comment #0 from Heywood Floyd <soul8o8@gmail.com> 2010-12-24 21:31:04 PST ---
Using replace() in a mixin doesn't seem to work if the mixin is placed inside a
class. (I have no idea what's going on here.)

Isolated example:

// - - - - 8< - - - - - - - - - - - -

import std.stdio, std.string;
version(bug)
{
    class Foo
    {
        mixin(anint("a"));
        this()
        {
            a = 9;
        }
    }
}


void main()
{
    version(bug)
    {
        auto a = new Foo;
        writeln("a:", a.a);
    }
    else //works
    {
        mixin(anint("a"));
        a = 9;
        writeln("a:",a);
    }
}

string anint(string name)
{
    return replace("int $name;", "$name", name);
}

// - - - - 8< - - - - - - - - - - - -

# dmd -run testmixin.d
a:9
# dmd -version=bug -run testmixin.d
/Library/Compilers/dmd2/osx/bin/../../src/phobos/std/functional.d(177): Error:
static assert  "Bad binary function q{a == b}. You need to use a valid D
expression using symbols a of type dchar and b of type const(char)[]."
/Library/Compilers/dmd2/osx/bin/../../src/phobos/std/functional.d(180):
instantiated from here: Body!(dchar,const(char)[])
/Library/Compilers/dmd2/osx/bin/../../src/phobos/std/algorithm.d(2149):
instantiated from here: result!(dchar,const(char)[])
# _

// - - - - 8< - - - - - - - - - - - -

I'm pretty sure this worked in 2.050, or at least 2.049. (Some program I'm working on started emitting these errors today. Didn't before. Not entirely sure when I last built it. Sorry.)

BR
/HF

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Trass3r <mrmocool@gmx.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |rejects-valid
                 CC|                            |mrmocool@gmx.de
           Platform|Other                       |All
         OS/Version|Mac OS X                    |All


--- Comment #1 from Trass3r <mrmocool@gmx.de> 2011-01-19 11:26:36 PST ---
Very interesting that you got code like that as well.
I also use replace in a mixin inside a class in cl4d.

This error was introduced in 2.051 I think.

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--- Comment #2 from Trass3r <mrmocool@gmx.de> 2011-01-19 12:14:40 PST ---
Ok I tested different revisions of dmd with phobos etc. of 2.050 Seems like r809 introduced it. Can anybody confirm?

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--- Comment #3 from Trass3r <mrmocool@gmx.de> 2011-01-19 12:42:42 PST ---
Yeah it was introduced with 2.051.
The release date in the changelog is wrong.
2.051 probably contains dmd r810 and the bug was introduced in r809.

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Rob Jacques <sandford@jhu.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sandford@jhu.edu


--- Comment #4 from Rob Jacques <sandford@jhu.edu> 2011-02-03 14:58:36 PST ---
*** Issue 5406 has been marked as a duplicate of this issue. ***

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--- Comment #5 from Rob Jacques <sandford@jhu.edu> 2011-02-03 15:00:16 PST ---
This is the patch from Issue 5406. It appear to solve both issue's test cases.

template binaryFunImpl(alias fun, string parm1Name, string parm2Name) {
    static if (is(typeof(fun) : string)) {
        enum testAsExpression = "{ ElementType1 "
            ~parm1Name~"; ElementType2 "
            ~parm2Name~"; return ("~fun~");}()";

        typeof(mixin(testAsExpression))
        result(ElementType1, ElementType2)(ElementType1 __a, ElementType2 __b)
            if(__traits(compiles, mixin(testAsExpression)))
        {
            mixin("alias __a "~parm1Name~";");
            mixin("alias __b "~parm2Name~";");
            mixin("return (" ~ fun ~ ");");
        }
    } else {
        alias fun result;
    }
}

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--- Comment #6 from Trass3r <mrmocool@gmx.de> 2011-02-03 15:16:34 PST ---
Well the other bug report was purely about phobos.
The question is if this is just a workaround for an issue that actually needs
to be addressed in dmd.

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Rob Jacques <sandford@jhu.edu> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|rejects-valid               |patch
           Priority|P2                          |P3
          Component|DMD                         |Phobos
           Severity|normal                      |regression


--- Comment #7 from Rob Jacques <sandford@jhu.edu> 2011-02-03 16:38:01 PST ---
(In reply to comment #6)
> Well the other bug report was purely about phobos.
> The question is if this is just a workaround for an issue that actually needs
> to be addressed in dmd.

_Not_ a Phobos bug? *sigh* Here's the bug in all it's detail:

//Reduction 1
import std.string;
pragma(msg, replace(int.stringof,"int","real"));

//Reduction 2
pragma(msg, indexOf("int","real")  );

//Reduction 3
pragma(msg, is(typeof(startsWith!"a == b"("int","real")))  );

//Reduction 4
bool startsWith2(alias pred = "a == b", R, E)
(R doesThisStart, E withThis)
if (is(typeof(binaryFun!pred(doesThisStart.front, withThis))))
{
    return true;
}
pragma(msg, is(typeof(startsWith2!"a == b"("int","real")))  );

//Final Reduction
pragma(msg, is(typeof(binaryFun!"a == b"("int".front, "real"))) );

So what's happening here is that DMD is trying to execute replace at
compile-time. Replace calls indexOf, which calls startsWith. Now startsWith has
three overload sets which differ by their template constraints. So DMD
evaluates each constraint in turn. Which then causes in invalid binaryFun call,
which triggers a static assert. And static assert stops compilation then and
there. As this is per spec (AssignExpression is evaluated at compile time, and
converted to a boolean value. If the value is true, the static assert is
ignored. If the value is false, an error diagnostic is issued and the compile
fails.
Unlike AssertExpressions, StaticAsserts are always checked and evaluted by the
compiler unless they appear in an unsatisfied conditional.) This isn't a
regression in DMD; it's a regression in Phobos due to better conformance of DMD
to the spec. Now, there does appear to be an inconsistency between static
assert's behavior during CTFE vs Non-CTFE, but that's more of an issue with the
Non-CTFE behavior vs the CTFE behavior.

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--- Comment #8 from Trass3r <mrmocool@gmx.de> 2011-02-21 08:16:16 PST ---
Well, as of 2.052 replace() has moved to std.array and can't be called at compile-time anymore at all cause of Appender using pointers.

I've opened a new report: http://d.puremagic.com/issues/show_bug.cgi?id=5632

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Trass3r <mrmocool@gmx.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


--- Comment #9 from Trass3r <mrmocool@gmx.de> 2011-07-12 05:21:13 PDT ---
I think we can close this one now.

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