[PATCH] D11490: [Concepts] Add diagnostic: non template declaration

[Nathan Wilson]

On Fri, Jul 24, 2015 at 2:14 PM, Aaron Ballman <aaron at aaronballman.com>
wrote:

> On Fri, Jul 24, 2015 at 2:43 PM, Nathan Wilson <nwilson20 at gmail.com>
> wrote:
> > nwilson created this revision.
> > nwilson added reviewers: rsmith, faisalv, fraggamuffin,
> hubert.reinterpretcast.
> > nwilson added a subscriber: cfe-commits.
> >
> > Adding diagnostic for concepts declared as non template (function or
> variable)
> >
> > http://reviews.llvm.org/D11490
> >
> > Files:
> >   include/clang/Basic/DiagnosticSemaKinds.td
> >   lib/Sema/SemaDecl.cpp
> >   test/SemaCXX/cxx-concept-declaration.cpp
> >
> > Index: test/SemaCXX/cxx-concept-declaration.cpp
> > ===================================================================
> > --- test/SemaCXX/cxx-concept-declaration.cpp
> > +++ test/SemaCXX/cxx-concept-declaration.cpp
> > @@ -15,3 +15,7 @@
> >  struct C {
> >    template<typename T> static concept bool D3 = true; // expected-error
> {{concept declarations may only appear in namespace scope}}
> >  };
> > +
> > +concept bool D4() { return true; } // expected-error {{concept can only
> be applied to a function or variable template definition}}
> > +
> > +concept bool D5 = true; // expected-error {{concept can only be applied
> to a function or variable template definition}}
> > Index: lib/Sema/SemaDecl.cpp
> > ===================================================================
> > --- lib/Sema/SemaDecl.cpp
> > +++ lib/Sema/SemaDecl.cpp
> > @@ -4865,6 +4865,12 @@
> >      // C++ Concepts TS [dcl.spec.concept]p1: The concept specifier
> shall be
> >      // applied only to the definition of a function template or variable
> >      // template, declared in namespace scope
> > +    if (!TemplateParamLists.size()) {
> > +      Diag(D.getDeclSpec().getConceptSpecLoc(),
> > +           diag::err_concept_decl_non_template);
> > +      return nullptr;
> > +    }
> > +
> >      if (!DC->getRedeclContext()->isFileContext()) {
> >        Diag(D.getIdentifierLoc(),
> >             diag::err_concept_decls_may_only_appear_in_namespace_scope);
> > Index: include/clang/Basic/DiagnosticSemaKinds.td
> > ===================================================================
> > --- include/clang/Basic/DiagnosticSemaKinds.td
> > +++ include/clang/Basic/DiagnosticSemaKinds.td
> > @@ -1966,6 +1966,8 @@
> >    "use __attribute__((visibility(\"hidden\"))) attribute instead">;
> >
> >  // C++ Concepts TS
> > +def err_concept_decl_non_template : Error<
> > +  "concept can only be applied to a function or variable template
> definition">;
>
> Since we are using "concept" as a grammar term, I think we want to
> quote it. Similar diagnostics suggest phrasing like:
>
> "'concept' can only appear on a function template or variable template
> definition"
>
> This also reduces some ambiguity over how "function or variable template"
> binds.
>
> ~Aaron
>

May we apply both this suggestion and Hubert's? So it would be:

"the 'concept' specifier may only be applied to the definition of a
function or variable template"


>
> >  def err_concept_decls_may_only_appear_in_namespace_scope : Error<
> >    "concept declarations may only appear in namespace scope">;
> >  def err_function_concept_not_defined : Error<
> >
> >
> >
> > _______________________________________________
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> > cfe-commits at cs.uiuc.edu
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> >
>
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