[PATCH] c++: Include the constraint parameter mapping in diagnostic constraint contexts
Patrick Palka
ppalka@redhat.com
Fri Mar 20 14:23:22 GMT 2020
On Thu, 19 Mar 2020, Jason Merrill wrote:
> On 3/19/20 12:50 PM, Patrick Palka wrote:
> > On Thu, 19 Mar 2020, Jason Merrill wrote:
> >
> > > On 3/18/20 3:26 PM, Patrick Palka wrote:
> > > > + if (map)
> > > > + {
> > > > + pp_cxx_whitespace (pp);
> > > > + pp_cxx_left_bracket (pp);
> > > > + pp->translate_string ("with");
> > > > + pp_cxx_whitespace (pp);
> > > > + pp_cxx_parameter_mapping (pp, map);
> > > > + pp_cxx_right_bracket (pp);
> > > > + }
> > >
> > > Perhaps we should move the [with ] bits into pp_cxx_parameter_mapping
> > > rather
> > > than duplicate them here.
> >
> > Like this?
> >
> > -- >8 --
> >
> > gcc/cp/ChangeLog:
> >
> > * cxx-pretty-print.c (pp_cxx_parameter_mapping): Make extern. Move
> > the "[with ]" bits to here from ...
> > (pp_cxx_atomic_constraint): ... here.
> > * cxx-pretty-print.h (pp_cxx_parameter_mapping): Declare.
> > * error.c (rebuild_concept_check): Delete.
> > (print_concept_check_info): Print the dependent form of the constraint
> > and the
> > preferably substituted parameter mapping alongside it.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/concepts/diagnostic6.C: New test.
> > ---
> > gcc/cp/cxx-pretty-print.c | 12 ++++---
> > gcc/cp/cxx-pretty-print.h | 1 +
> > gcc/cp/error.c | 36 +++++++--------------
> > gcc/testsuite/g++.dg/concepts/diagnostic6.C | 14 ++++++++
> > 4 files changed, 33 insertions(+), 30 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/concepts/diagnostic6.C
> >
> > diff --git a/gcc/cp/cxx-pretty-print.c b/gcc/cp/cxx-pretty-print.c
> > index 100154e400f..15d8b7eb609 100644
> > --- a/gcc/cp/cxx-pretty-print.c
> > +++ b/gcc/cp/cxx-pretty-print.c
> > @@ -2878,9 +2878,13 @@ pp_cxx_check_constraint (cxx_pretty_printer *pp, tree
> > t)
> > /* Output the "[with ...]" clause for a parameter mapping of an atomic
> > constraint. */
> > -static void
> > +void
> > pp_cxx_parameter_mapping (cxx_pretty_printer *pp, tree map)
> > {
> > + pp_cxx_left_bracket (pp);
> > + pp->translate_string ("with");
> > + pp_cxx_whitespace (pp);
> > +
> > for (tree p = map; p; p = TREE_CHAIN (p))
> > {
> > tree parm = TREE_VALUE (p);
> > @@ -2903,6 +2907,8 @@ pp_cxx_parameter_mapping (cxx_pretty_printer *pp, tree
> > map)
> > if (TREE_CHAIN (p) != NULL_TREE)
> > pp_cxx_separate_with (pp, ';');
> > }
> > +
> > + pp_cxx_right_bracket (pp);
> > }
> > void
> > @@ -2915,12 +2921,8 @@ pp_cxx_atomic_constraint (cxx_pretty_printer *pp,
> > tree t)
> > tree map = ATOMIC_CONSTR_MAP (t);
> > if (map && map != error_mark_node)
> > {
> > - pp_cxx_whitespace (pp);
> > - pp_cxx_left_bracket (pp);
> > - pp->translate_string ("with");
> > pp_cxx_whitespace (pp);
>
> Is there a reason not to move the initial whitespace as well, like in
> dump_substitution? OK with that change.
No good reason :) Thanks, patch committed with that change.
>
> > pp_cxx_parameter_mapping (pp, map);
> > - pp_cxx_right_bracket (pp);
> > }
> > }
> > diff --git a/gcc/cp/cxx-pretty-print.h b/gcc/cp/cxx-pretty-print.h
> > index 7c7347f57ba..494f3fdde59 100644
> > --- a/gcc/cp/cxx-pretty-print.h
> > +++ b/gcc/cp/cxx-pretty-print.h
> > @@ -112,5 +112,6 @@ void pp_cxx_conjunction (cxx_pretty_printer *, tree);
> > void pp_cxx_disjunction (cxx_pretty_printer *, tree);
> > void pp_cxx_constraint (cxx_pretty_printer *, tree);
> > void pp_cxx_constrained_type_spec (cxx_pretty_printer *, tree);
> > +void pp_cxx_parameter_mapping (cxx_pretty_printer *, tree);
> > #endif /* GCC_CXX_PRETTY_PRINT_H */
> > diff --git a/gcc/cp/error.c b/gcc/cp/error.c
> > index cc51b6ffe13..9f19e9bbaa4 100644
> > --- a/gcc/cp/error.c
> > +++ b/gcc/cp/error.c
> > @@ -3680,27 +3680,6 @@ print_location (diagnostic_context *context,
> > location_t loc)
> > "locus", xloc.file, xloc.line);
> > }
> > -/* Instantiate the concept check for the purpose of diagnosing an error.
> > */
> > -
> > -static tree
> > -rebuild_concept_check (tree expr, tree map, tree args)
> > -{
> > - /* Instantiate the parameter mapping for the template-id. */
> > - map = tsubst_parameter_mapping (map, args, tf_none, NULL_TREE);
> > - if (map == error_mark_node)
> > - return error_mark_node;
> > - args = get_mapped_args (map);
> > -
> > - /* Rebuild the template id using substituted arguments. Substituting
> > - directly through the expression will trigger recursive satisfaction,
> > - so don't do that. */
> > - tree id = unpack_concept_check (expr);
> > - args = tsubst_template_args (TREE_OPERAND (id, 1), args, tf_none,
> > NULL_TREE);
> > - if (args == error_mark_node)
> > - return error_mark_node;
> > - return build_nt (TEMPLATE_ID_EXPR, TREE_OPERAND (id, 0), args);
> > -}
> > -
> > static void
> > print_constrained_decl_info (diagnostic_context *context, tree decl)
> > {
> > @@ -3717,12 +3696,19 @@ print_concept_check_info (diagnostic_context
> > *context, tree expr, tree map, tree
> > tree tmpl = TREE_OPERAND (id, 0);
> > if (OVL_P (tmpl))
> > tmpl = OVL_FIRST (tmpl);
> > - tree check = rebuild_concept_check (expr, map, args);
> > - if (check == error_mark_node)
> > - check = expr;
> > print_location (context, DECL_SOURCE_LOCATION (tmpl));
> > - pp_verbatim (context->printer, "required for the satisfaction of %qE\n",
> > check);
> > +
> > + cxx_pretty_printer *pp = (cxx_pretty_printer *)context->printer;
> > + pp_verbatim (pp, "required for the satisfaction of %qE", expr);
> > + if (map)
> > + {
> > + tree subst_map = tsubst_parameter_mapping (map, args, tf_none,
> > NULL_TREE);
> > + pp_cxx_whitespace (pp);
> > + pp_cxx_parameter_mapping (pp, (subst_map != error_mark_node
> > + ? subst_map : map));
> > + }
> > + pp_newline (pp);
> > }
> > /* Diagnose the entry point into the satisfaction error. Returns the
> > next
> > diff --git a/gcc/testsuite/g++.dg/concepts/diagnostic6.C
> > b/gcc/testsuite/g++.dg/concepts/diagnostic6.C
> > new file mode 100644
> > index 00000000000..06b17caccbe
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/concepts/diagnostic6.C
> > @@ -0,0 +1,14 @@
> > +// { dg-do compile { target c++2a } }
> > +
> > +template<typename T>
> > + concept C = requires (T t) { t + 0; };
> > +// { dg-message "satisfaction of .C<T>. .with T = typename T::type." "" {
> > target *-*-* } .-1 }
> > +
> > +template<typename T>
> > + concept D = C<T>;
> > +// { dg-message "satisfaction of .D<typename T::type>. .with T = int." "" {
> > target *-*-* } .-1 }
> > +
> > +template<typename T>
> > + concept E = D<typename T::type>;
> > +
> > +static_assert(E<int>); // { dg-error "static assertion failed|not a class"
> > }
> >
>
>
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