cynecx added a comment.
Hi :),
First of all, I would like to say that I am new into all the clang stuff
(software architecture/internal concepts) but I wanted to start hacking clang
so I went here to check out some ##trivial## clang bugs to fix so I can learn
internal stuff about clang, with internal stuff I mean how AST/Sema are
implemented and kinda these things.
So basically, I tried all the day long to find a better approach as @rjmccall
explained that the key issue is that you can't copy-construct a ##W## from a
##volatile W&##. The issue might be in ##SemaInit.cpp## ->
##ResolveConstructorOverload## because when the ##NamedDecl*## loop reaches the
##const S&## constructor it doesn't know that it's actually copy-constructed so
it's not setting ##SuppressUserConversions## to ##true##. This has the effect
that ##AddTemplateOverloadCandidate## also includes user-conversion functions,
so in this case: ##S(volatile W)## and this is actually what causes the
infinity loop: ##PerformCopyInitialization -> InitializationSequence::Perform
->CompleteConstructorCall -> GatherArgumentsForCall -> ...##.
While debugging I basically changed the ##SuppressUserConversions## variable to
true for the ##W (const S&)## constructor and this solved the infinity-loop
problem and produced a gcc similar diagnostic message:
simplified.cpp:13:7: error: no matching constructor for initialization of 'W'
S s(*w);
^~
simplified.cpp:3:8: note: candidate constructor (the implicit copy
constructor) not viable: 1st argument ('volatile W')
would lose volatile qualifier
struct W {
^
simplified.cpp:3:8: note: candidate constructor (the implicit move
constructor) not viable: 1st argument ('volatile W')
would lose volatile qualifier
struct W {
^
simplified.cpp:4:3: note: candidate constructor not viable: no known
conversion from 'volatile W' to 'const S &' for
1st argument
W( const S& ) {}
^
simplified.cpp:8:15: note: passing argument to parameter here
S(volatile W) {}
It would be nice if anyone could check if this is a right approach for fixing
this issue.
Thank you.
http://reviews.llvm.org/D10881
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