On Wed, 11 Aug 2021, Jason Merrill wrote:
> On 8/9/21 1:16 PM, Patrick Palka wrote:
> > It looks like we still don't recognize class-scope non-template
> > deduction guides even after r12-2260. This is because deduction guides
> > are handled in cp_parser_init_declarator after calling
> > cp_parser_declarator, but in the class-scope non-template case we call
> > cp_parser_declarator directly from cp_parser_member_declaration.
> >
> > This patch makes us handle deduction guides in cp_parser_member_declaration
> > as well.
> >
> > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> > trunk?
> >
> > PR c++/79501
> >
> > gcc/cp/ChangeLog:
> >
> > * parser.c (cp_parser_maybe_adjust_declarator_for_dguide): New,
> > split out from ...
> > (cp_parser_init_declarator): ... here.
> > (cp_parser_member_declaration): Use it.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/cpp1z/class-deduction98.C: New test.
> > ---
> > gcc/cp/parser.c | 54 +++++++++++++------
> > .../g++.dg/cpp1z/class-deduction98.C | 10 ++++
> > 2 files changed, 49 insertions(+), 15 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction98.C
> >
> > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> > index d4da25ca703..04fdeec32ab 100644
> > --- a/gcc/cp/parser.c
> > +++ b/gcc/cp/parser.c
> > @@ -21869,6 +21869,30 @@ warn_about_ambiguous_parse (const
> > cp_decl_specifier_seq *decl_specifiers,
> > }
> > }
> > +/* If the function declarator DECLARATOR names a class template, adjust
> > + it to name its deduction guides and return true. Otherwise return
> > false. */
> > +
> > +static bool
> > +cp_parser_maybe_adjust_declarator_for_dguide (cp_parser *parser,
> > + cp_declarator *declarator)
> > +{
> > + gcc_assert (function_declarator_p (declarator));
> > +
> > + cp_declarator *id = get_id_declarator (declarator);
> > + tree name = id->u.id.unqualified_name;
> > + parser->scope = id->u.id.qualifying_scope;
> > + tree tmpl = cp_parser_lookup_name_simple (parser, name, id->id_loc);
> > + if (tmpl
> > + && (DECL_CLASS_TEMPLATE_P (tmpl)
> > + || DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl)))
> > + {
> > + id->u.id.unqualified_name = dguide_name (tmpl);
> > + id->u.id.sfk = sfk_deduction_guide;
> > + return true;
> > + }
> > + return false;
> > +}
> > +
> > /* Declarators [gram.dcl.decl] */
> > /* Parse an init-declarator.
> > @@ -22045,25 +22069,16 @@ cp_parser_init_declarator (cp_parser* parser,
> > if (function_declarator_p (declarator))
> > {
> > - /* Handle C++17 deduction guides. */
> > + /* Handle C++17 deduction guides. Note that class-scope
> > + non-template deduction guides are handled in
> > + cp_parser_member_declaration. */
> > if (!decl_specifiers->type
> > && !decl_specifiers->any_type_specifiers_p
> > && ctor_dtor_or_conv_p <= 0
> > && cxx_dialect >= cxx17)
> > - {
> > - cp_declarator *id = get_id_declarator (declarator);
> > - tree name = id->u.id.unqualified_name;
> > - parser->scope = id->u.id.qualifying_scope;
> > - tree tmpl = cp_parser_lookup_name_simple (parser, name, id->id_loc);
> > - if (tmpl
> > - && (DECL_CLASS_TEMPLATE_P (tmpl)
> > - || DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl)))
> > - {
> > - id->u.id.unqualified_name = dguide_name (tmpl);
> > - id->u.id.sfk = sfk_deduction_guide;
> > - ctor_dtor_or_conv_p = 1;
> > - }
> > - }
> > + if (cp_parser_maybe_adjust_declarator_for_dguide (parser,
> > + declarator))
> > + ctor_dtor_or_conv_p = 1;
> > if (!member_p && !cp_parser_error_occurred (parser))
> > warn_about_ambiguous_parse (decl_specifiers, declarator);
> > @@ -26719,6 +26734,15 @@ cp_parser_member_declaration (cp_parser* parser)
> > cp_lexer_consume_token (parser->lexer);
> > goto out;
> > }
> > + /* Handle class-scope non-template C++17 deduction guides. */
> > + if (function_declarator_p (declarator)
> > + && !decl_specifiers.type
> > + && !decl_specifiers.any_type_specifiers_p
> > + && ctor_dtor_or_conv_p <= 0
> > + && cxx_dialect >= cxx17)
>
> Looks like you could factor more of the tests into the new function.
That works nicely, like so? Bootstrap and regtesting in progress.
-- >8 --
Subject: [PATCH] c++: recognize class-scope non-template dguides [PR79501]
It looks like we still don't recognize class-scope non-template
deduction guides even after r12-2260. This is because deduction guides
are tagged as such in cp_parser_init_declarator after calling
cp_parser_declarator, but in cp_parser_member_declaration we call
cp_parser_declarator directly.
This patch makes us handle deduction guides in cp_parser_member_declaration
as well.
PR c++/79501
gcc/cp/ChangeLog:
* parser.c (maybe_adjust_declarator_for_dguide): New, split out
from ...
(cp_parser_init_declarator): ... here.
(cp_parser_member_declaration): Use it.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1z/class-deduction98.C: New test.
---
gcc/cp/parser.c | 63 +++++++++++++------
.../g++.dg/cpp1z/class-deduction98.C | 10 +++
2 files changed, 54 insertions(+), 19 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction98.C
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index b2ddfe4f181..27bb7178464 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -22081,6 +22081,37 @@ warn_about_ambiguous_parse (const
cp_decl_specifier_seq *decl_specifiers,
}
}
+/* If DECLARATOR with DECL_SPECS is a function declarator that has
+ the form of a deduction guide, tag it as such. CTOR_DTOR_OR_CONV_P
+ has the same meaning as in cp_parser_declarator. */
+
+static void
+cp_parser_maybe_adjust_declarator_for_dguide (cp_parser *parser,
+ cp_decl_specifier_seq *decl_specs,
+ cp_declarator *declarator,
+ int *ctor_dtor_or_conv_p)
+{
+ if (cxx_dialect >= cxx17
+ && *ctor_dtor_or_conv_p <= 0
+ && !decl_specs->type
+ && !decl_specs->any_type_specifiers_p
+ && function_declarator_p (declarator))
+ {
+ cp_declarator *id = get_id_declarator (declarator);
+ tree name = id->u.id.unqualified_name;
+ parser->scope = id->u.id.qualifying_scope;
+ tree tmpl = cp_parser_lookup_name_simple (parser, name, id->id_loc);
+ if (tmpl
+ && (DECL_CLASS_TEMPLATE_P (tmpl)
+ || DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl)))
+ {
+ id->u.id.unqualified_name = dguide_name (tmpl);
+ id->u.id.sfk = sfk_deduction_guide;
+ *ctor_dtor_or_conv_p = 1;
+ }
+ }
+}
+
/* Declarators [gram.dcl.decl] */
/* Parse an init-declarator.
@@ -22257,25 +22288,13 @@ cp_parser_init_declarator (cp_parser* parser,
if (function_declarator_p (declarator))
{
- /* Handle C++17 deduction guides. */
- if (!decl_specifiers->type
- && !decl_specifiers->any_type_specifiers_p
- && ctor_dtor_or_conv_p <= 0
- && cxx_dialect >= cxx17)
- {
- cp_declarator *id = get_id_declarator (declarator);
- tree name = id->u.id.unqualified_name;
- parser->scope = id->u.id.qualifying_scope;
- tree tmpl = cp_parser_lookup_name_simple (parser, name, id->id_loc);
- if (tmpl
- && (DECL_CLASS_TEMPLATE_P (tmpl)
- || DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl)))
- {
- id->u.id.unqualified_name = dguide_name (tmpl);
- id->u.id.sfk = sfk_deduction_guide;
- ctor_dtor_or_conv_p = 1;
- }
- }
+ /* Handle C++17 deduction guides. Note that class-scope
+ non-template deduction guides are instead handled in
+ cp_parser_member_declaration. */
+ cp_parser_maybe_adjust_declarator_for_dguide (parser,
+ decl_specifiers,
+ declarator,
+ &ctor_dtor_or_conv_p);
if (!member_p && !cp_parser_error_occurred (parser))
warn_about_ambiguous_parse (decl_specifiers, declarator);
@@ -26959,6 +26978,12 @@ cp_parser_member_declaration (cp_parser* parser)
goto out;
}
+ /* Handle class-scope non-template C++17 deduction guides. */
+ cp_parser_maybe_adjust_declarator_for_dguide (parser,
+ &decl_specifiers,
+ declarator,
+
&ctor_dtor_or_conv_p);
+
if (declares_class_or_enum & 2)
cp_parser_check_for_definition_in_return_type
(declarator, decl_specifiers.type,
diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction98.C
b/gcc/testsuite/g++.dg/cpp1z/class-deduction98.C
new file mode 100644
index 00000000000..bee0ce433ee
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction98.C
@@ -0,0 +1,10 @@
+// PR c++/79501
+// { dg-do compile { target c++17 } }
+
+template<class T>
+struct A {
+ template<class U> struct B { template<class V> B(V); };
+ B(T) -> B<T>;
+};
+
+A<int>::B b(0);
--
2.33.0.rc1
