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

[Nathan Wilson]

On Fri, Jul 24, 2015 at 2:43 PM, Aaron Ballman <aaron at aaronballman.com>
wrote:

> On Fri, Jul 24, 2015 at 3:43 PM, Hubert Tong
> <hubert.reinterpretcast at gmail.com> wrote:
> > Thanks Aaron for copying the similar messages here. I'd still like the
> use
> > "definition of", but with Aaron's suggestion as the base.
> > I considered using plural nouns instead of singular ones to match the
> > existing messages better, but the result was clunky.
> >
> > "'concept' can only appear on the definition of a function template or
> > variable template"
>
> Perfect!
>

Thanks guys. I'll update the patch.


>
> ~Aaron
>
> >
> > On Fri, Jul 24, 2015 at 3:37 PM, Aaron Ballman <aaron at aaronballman.com>
> > wrote:
> >>
> >> On Fri, Jul 24, 2015 at 3:27 PM, Nathan Wilson <nwilson20 at gmail.com>
> >> wrote:
> >> >
> >> >
> >> > 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"
> >>
> >> I don't have a strong preference, but I think "specifier may only be"
> >> is kind of wordy without adding much value. For comparison:
> >>
> >> def err_inline_non_function : Error<
> >>   "'inline' can only appear on functions">;
> >> def err_noreturn_non_function : Error<
> >>   "'_Noreturn' can only appear on functions">;
> >> def err_virtual_non_function : Error<
> >>   "'virtual' can only appear on non-static member functions">;
> >> def err_explicit_non_function : Error<
> >>   "'explicit' can only appear on non-static member functions">;
> >>
> >> ~Aaron
> >>
> >> >
> >> >>
> >> >>
> >> >> >  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<
> >> >> >
> >> >> >
> >> >> >
> >> >> > _______________________________________________
> >> >> > cfe-commits mailing list
> >> >> > cfe-commits at cs.uiuc.edu
> >> >> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
> >> >> >
> >> >
> >> >
> >
> >
>
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