On Thu Jan 30 2014 at 2:38:44 PM, Ismail Pazarbasi < ismail.pazarb...@gmail.com> wrote:
> Hi rsmith, > > PR18127: misparse of 'new struct S < ...' where S is not a template-name > > If clang sees '<' token after an elaborated-type-specifier, it assumes > elaborated-type-specifier refers to a template name, and then issues > diagnostics concerning missing '>'. > > We try to find corresponding '>' for diagnostics location purpose, and > perform name lookup. Parser knows that it is not parsing a template. If > name lookup doesn't find a name, we will keep issuing `explicit > instantiation/specialization of non-template class` error. > > http://llvm-reviews.chandlerc.com/D2662 > > Files: > lib/Parse/ParseDeclCXX.cpp > test/Parser/cxx-template-argument.cpp > > Index: lib/Parse/ParseDeclCXX.cpp > =================================================================== > --- lib/Parse/ParseDeclCXX.cpp > +++ lib/Parse/ParseDeclCXX.cpp > @@ -24,6 +24,8 @@ > #include "clang/Sema/Scope.h" > #include "clang/Sema/SemaDiagnostic.h" > #include "llvm/ADT/SmallString.h" > +#include "clang/Sema/Lookup.h" > + > using namespace clang; > > /// ParseNamespace - We know that the current token is a namespace > keyword. This > @@ -1230,38 +1232,39 @@ > // a class (or template thereof). > TemplateArgList TemplateArgs; > SourceLocation LAngleLoc, RAngleLoc; > - if (ParseTemplateIdAfterTemplateName(TemplateTy(), NameLoc, SS, > - true, LAngleLoc, > - TemplateArgs, RAngleLoc)) { > - // We couldn't parse the template argument list at all, so don't > - // try to give any location information for the list. > - LAngleLoc = RAngleLoc = SourceLocation(); > - } > - > - Diag(NameLoc, diag::err_explicit_spec_non_template) > - << (TemplateInfo.Kind == ParsedTemplateInfo:: > ExplicitInstantiation) > - << TagTokKind << Name << SourceRange(LAngleLoc, RAngleLoc); > + LAngleLoc = ConsumeToken(); > + if (SkipUntil(tok::greater, StopBeforeMatch | StopAtSemi)) > + RAngleLoc = ConsumeToken(); > + // If a name was not found, this might be an explicit instantiation > or > + // specialization attempt. If a name was found, that name does not > refer > + // to a template name. > + LookupResult Result(Actions, Name, NameLoc, Sema::LookupTagName); > + Actions.LookupName(Result, getCurScope()); > This is using too low-level an interface from the Parser into Sema. Also, I'm not convinced this'll do the right thing if it finds an injected-class-name for a class template. Can you use Sema::isTemplateName here? > + if (Result.getResultKind() != LookupResult::Found) > + Diag(NameLoc, diag::err_explicit_spec_non_template) > This is the wrong diagnostic in many cases (including the "new X < blah" case). This is fine if you have TemplateInfo telling you that we had template-parameter-lists, but otherwise, you should stop parsing before the '<'. In particular: bool k = new struct IDontExist < 0; ... should only diagnose allocation of an incomplete type, and struct A { template<typename T> operator T(); }; bool b = sizeof &A::operator struct Foo < 8; ... should be accepted without any diagnostics. + << (TemplateInfo.Kind == ParsedTemplateInfo:: > ExplicitInstantiation) > + << TagTokKind << Name << SourceRange(LAngleLoc, RAngleLoc); > > // Strip off the last template parameter list if it was empty, since > // we've removed its template argument list. > if (TemplateParams && TemplateInfo.LastParameterListWasEmpty) { > if (TemplateParams && TemplateParams->size() > 1) { > TemplateParams->pop_back(); > } else { > TemplateParams = 0; > - const_cast<ParsedTemplateInfo&>(TemplateInfo).Kind > - = ParsedTemplateInfo::NonTemplate; > + const_cast<ParsedTemplateInfo &>(TemplateInfo).Kind = > + ParsedTemplateInfo::NonTemplate; > } > - } else if (TemplateInfo.Kind > - == ParsedTemplateInfo::ExplicitInstantiation) > { > + } else if (TemplateInfo.Kind == > + ParsedTemplateInfo::ExplicitInstantiation) { > // Pretend this is just a forward declaration. > TemplateParams = 0; > - const_cast<ParsedTemplateInfo&>(TemplateInfo).Kind > - = ParsedTemplateInfo::NonTemplate; > - const_cast<ParsedTemplateInfo&>(TemplateInfo).TemplateLoc > - = SourceLocation(); > - const_cast<ParsedTemplateInfo&>(TemplateInfo).ExternLoc > - = SourceLocation(); > + const_cast<ParsedTemplateInfo &>(TemplateInfo).Kind = > + ParsedTemplateInfo::NonTemplate; > + const_cast<ParsedTemplateInfo &>(TemplateInfo).TemplateLoc = > + SourceLocation(); > + const_cast<ParsedTemplateInfo &>(TemplateInfo).ExternLoc = > + SourceLocation(); > } > } > } else if (Tok.is(tok::annot_template_id)) { > Index: test/Parser/cxx-template-argument.cpp > =================================================================== > --- test/Parser/cxx-template-argument.cpp > +++ test/Parser/cxx-template-argument.cpp > @@ -106,3 +106,21 @@ > { }; > > } > + > +namespace PR18127 { > + struct A {} *a; > + bool f = new struct A < 0; > + bool g = new struct A < a; > + > + template<typename T> > + struct B { }; > + > + bool h = new struct B < 0; // expected-error{{expected '>'}} > + bool i = new struct B<int> < 0; > + bool operator<(const struct O &, const struct O &); > + struct O { } *p; > + bool j = *(new struct O) < *p; > + bool k = new struct IDontExist < 0; // expected-error{{explicit > specialization of non-template struct 'IDontExist'}} > + // expected-error@-1{{allocation of incomplete type 'struct > IDontExist'}} > + // expected-note@-2{{forward declaration of 'PR18127::IDontExist'}} > +} >
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