[PATCH] D139705: [clang] fix zero-initialization fix-it for variable template

[Aaron Ballman via Phabricator via cfe-commits]

aaron.ballman added inline comments.


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Comment at: clang/lib/Sema/SemaInit.cpp:3863
 
+  SourceLocation EndLoc = VD->getEndLoc();
+  if (const auto *VTSD = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
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erichkeane wrote:
> v1nh1shungry wrote:
> > aaron.ballman wrote:
> > > erichkeane wrote:
> > > > Hmm... it is strange to me that the variables 'endloc' is the end of the identifier and not the end of the variable declaration.  I unfortunately don't have a good feeling as to the 'correct' behavior for that (Aaron is typically the one who understands source locations better than me!), so hopefully he can come along and see.  
> > > I don't think we should have to do this dance here, this is something that `getEndLoc()` should be able to tell us. The way that source locations work is that AST nodes can override `getSourceRange()` to produce the correct range information for the node, and then they expose different accessors for any other source location information. In this case, I think `VarTemplateSpecializationDecl` isn't overloading `getSourceRange()` and so we're getting the default behavior from `VarDecl`.
> > Sorry! I'm confused here. Do you mean we should use `getEndLoc()` directly as the location where the fix-hint insert? But isn't the original code using `getEndLoc()`, it turns out to add the fix-hint after the end of the identifier instead of the right angle of `VarTemplateSpecializationDecl`.
> Right, we should use `getEndLoc` directly for hte fixit location, and 'fix' `getEndLoc` by having `VarTemplateSpecializationDecl` override `getSourceRange` to have the right `end loc`.
> Sorry! I'm confused here. Do you mean we should use getEndLoc() directly as the location where the fix-hint insert? But isn't the original code using getEndLoc(), it turns out to add the fix-hint after the end of the identifier instead of the right angle of VarTemplateSpecializationDecl.

Thanks for asking for clarification! I think the code here in SemaInit.cpp is correct as-is and we should instead be implementing `VarTemplateSpecializationDecl::getSourceRange()` to calculate the correct begin and end location for the variable declaration. This should fix SemaInit.cpp because `getEndLoc()` is implemented by calling `getSourceRange()` and returning the end location: https://github.com/llvm/llvm-project/blob/main/clang/include/clang/AST/DeclBase.h#L428


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