Bug 176381 – [Win] Compile errors in Document::updateTitleElement.

• Component: WebCore Misc.
• Status: RESOLVED FIXED

[Per Arne Vollan]

c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1570): error C2446: ':': no conversion from 'WebCore::Document::updateTitleElement::<lambda_16b62001404c23de7212dde0d19dd8c0>' to 'WebCore::Document::updateTitleElement::<lambda_8c64903d313d33c5fcf4c4945dc4e7bd>' (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp) [C:\cygwin\home\buildbot\slave\win-release\build\WebKitBuild\Release\Source\WebCore\WebCore.vcxproj]
  c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1570): note: No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp)
c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1571): error C2446: ':': no conversion from 'WebCore::Document::updateTitleElement::<lambda_b90aca9775183a3a847bb0f92fa5dde7>' to 'WebCore::Document::updateTitleElement::<lambda_5bf19252f147055cda21dc9527885b1b>' (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp) [C:\cygwin\home\buildbot\slave\win-release\build\WebKitBuild\Release\Source\WebCore\WebCore.vcxproj]
  c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1571): note: No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp)
c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1572): error C2446: ':': no conversion from 'WebCore::Document::updateTitleElement::<lambda_7d10b9bb64b9bf807f86fa41f4b56cfc>' to 'WebCore::Document::updateTitleElement::<lambda_a2b965e941c6d63acb9048aedb2d8536>' (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp) [C:\cygwin\home\buildbot\slave\win-release\build\WebKitBuild\Release\Source\WebCore\WebCore.vcxproj]
  c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1572): note: No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp)
c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1574): error C2064: term does not evaluate to a function taking 1 arguments (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp) [C:\cygwin\home\buildbot\slave\win-release\build\WebKitBuild\Release\Source\WebCore\WebCore.vcxproj]
c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1581): error C2064: term does not evaluate to a function taking 1 arguments (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp) [C:\cygwin\home\buildbot\slave\win-release\build\WebKitBuild\Release\Source\WebCore\WebCore.vcxproj]
c:\cygwin\home\buildbot\slave\win-release\build\source\webcore\dom\Document.cpp(1585): error C2064: term does not evaluate to a function taking 1 arguments (compiling source file C:\cygwin\home\buildbot\slave\win-release\build\Source\WebCore\dom\DOMAllInOne.cpp) [C:\cygwin\home\buildbot\slave\win-release\build\WebKitBuild\Release\Source\WebCore\WebCore.vcxproj]

[Per Arne Vollan]

Created attachment 319915 [details]
Patch

[Per Arne Vollan]

Created attachment 319916 [details]
Patch

[Per Arne Vollan]

This has already been fixed.

[Per Arne Vollan]

I am seeing this compile error again, now.

[Darin Adler]

Comment on attachment 319916 [details]
Patch

This change makes things less efficient and less elegant. But maybe there is no other way to work around the limitations of the Windows compiler.

[Darin Adler]

Comment on attachment 319916 [details]
Patch

A better way to work around this unfortunate limitation of the Windows compiler it is to convert all 6 of the lambdas into plain old functions, outside Document::updateTitleElement, just local functions like:

    static Element* findHTMLTitle(Document& document)
    {
    }

[Per Arne Vollan]

(In reply to Darin Adler from comment #6)
> Comment on attachment 319916 [details]
> Patch
> 
> A better way to work around this unfortunate limitation of the Windows
> compiler it is to convert all 6 of the lambdas into plain old functions,
> outside Document::updateTitleElement, just local functions like:
> 
>     static Element* findHTMLTitle(Document& document)
>     {
>     }

Thanks for reviewing! I will update the patch.

[Per Arne Vollan]

Created attachment 320034 [details]
Patch

[Alex Christensen]

Comment on attachment 320034 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=320034&action=review

> Source/WebCore/dom/Document.cpp:1567
> +static bool isSVGTitle(Element& element)
> +{
> +    return is<SVGTitleElement>(element);

Can we not just use is<SVGTitleElement> where we use isSVGTitle instead of making a wrapper?  Same with isHTMLTitle

[Per Arne Vollan]

Committed r221684: <https://trac.webkit.org/changeset/221684/webkit>

[Per Arne Vollan]

(In reply to Alex Christensen from comment #9)
> Comment on attachment 320034 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=320034&action=review
> 
> > Source/WebCore/dom/Document.cpp:1567
> > +static bool isSVGTitle(Element& element)
> > +{
> > +    return is<SVGTitleElement>(element);
> 
> Can we not just use is<SVGTitleElement> where we use isSVGTitle instead of
> making a wrapper?  Same with isHTMLTitle

isSVGTitle and isHTMLTitle is only used when assigning one of the function pointers to a local variable, I don't think we can use is<SVGTitleElement> there, if I understand you correctly?

Thanks for reviewing!

[Darin Adler]

Comment on attachment 320034 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=320034&action=review

>>> Source/WebCore/dom/Document.cpp:1567
>>> +    return is<SVGTitleElement>(element);
>> 
>> Can we not just use is<SVGTitleElement> where we use isSVGTitle instead of making a wrapper?  Same with isHTMLTitle
> 
> isSVGTitle and isHTMLTitle is only used when assigning one of the function pointers to a local variable, I don't think we can use is<SVGTitleElement> there, if I understand you correctly?
> 
> Thanks for reviewing!

I think we can use is<SVGTitleElement> and is<HTMLTitleElement>. Those are functions--template functions are functions--and can be turned into function pointers. Did you try it?

[Per Arne Vollan]

(In reply to Darin Adler from comment #12)
> Comment on attachment 320034 [details]
> Patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=320034&action=review
> 
> >>> Source/WebCore/dom/Document.cpp:1567
> >>> +    return is<SVGTitleElement>(element);
> >> 
> >> Can we not just use is<SVGTitleElement> where we use isSVGTitle instead of making a wrapper?  Same with isHTMLTitle
> > 
> > isSVGTitle and isHTMLTitle is only used when assigning one of the function pointers to a local variable, I don't think we can use is<SVGTitleElement> there, if I understand you correctly?
> > 
> > Thanks for reviewing!
> 
> I think we can use is<SVGTitleElement> and is<HTMLTitleElement>. Those are
> functions--template functions are functions--and can be turned into function
> pointers. Did you try it?

Yes, I tried it, but this also gave compile errors. MSVC was not able to resolve, since is<> has several overloads.

[Darin Adler]

I thought of another way to write this that would be slightly more elegant. Working on a patch for that.

[Per Arne Vollan]

<rdar://problem/34373638>