On Fri, 18 Sep 2020, Patrick Palka wrote:
> On Fri, 18 Sep 2020, Jason Merrill wrote:
>
> > On 9/18/20 4:07 PM, Patrick Palka wrote:
> > > With r10-8077 we stopped passing the argified current_template_parms to
> > > normalize_constraint_expression from finish_nested_requirement, and
> > > instead tweaked map_arguments to perform a self-mapping of parameters
> > > when args is NULL. We're currently not handling parameter packs and
> > > BOUND_TEMPLATE_TEMPLATE_PARMs properly during this self-mapping, which
> > > leads to ICEs later during satisfaction.
> > >
> > > To fix the self-mapping of a parameter pack, this patch makes
> > > map_arguments use template_parm_to_arg which already does the right
> > > thing for parameter packs.
> > >
> > > Before r10-8077, a BOUND_TEMPLATE_TEMPLATE_PARM would get mapped to the
> > > corresponding TEMPLATE_TEMPLATE_PARM. We could restore this behavior in
> > > map_arguments, but since a BOUND_TEMPLATE_TEMPLATE_PARM is not really a
> > > template parameter it seems better to make keep_template_parm not give
> > > us a BOUND_TEMPLATE_TEMPLATE_PARM in the first place. I think what we
> > > actually want is to map the TEMPLATE_TEMPLATE_PARM to itself, so this
> > > patch adjusts keep_template_parm to give us the corresponding
> > > TEMPLATE_TEMPLATE_PARM of a BOUND_TEMPLATE_TEMPLATE_PARM instead.
> > >
> > > Tested on x86_64-pc-linux-gnu, and also tested with the cmcstl2 library.
> > > Does this look OK for trunk/10?
> > >
> > > gcc/cp/ChangeLog:
> > >
> > > PR c++/96531
> > > PR c++/97103
> > > * constraint.cc (map_arguments): Call template_parm_to_arg
> > > appropriately when doing a self-mapping.
> > > * pt.c (keep_template_parm): Don't record a
> > > BOUND_TEMPLATE_TEMPLATE_PARM, instead record its corresponding
> > > TEMPLATE_TEMPLATE_PARM.
> > >
> > > gcc/testsuite/ChangeLog:
> > >
> > > PR c++/96531
> > > PR c++/97103
> > > * g++.dg/cpp2a/concepts-ttp2.C: New test.
> > > * g++.dg/cpp2a/concepts-variadic1.C: New test.
> > > ---
> > > gcc/cp/constraint.cc | 27 ++++++++++++------
> > > gcc/cp/pt.c | 5 ++++
> > > gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C | 11 ++++++++
> > > .../g++.dg/cpp2a/concepts-variadic1.C | 28 +++++++++++++++++++
> > > 4 files changed, 62 insertions(+), 9 deletions(-)
> > > create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
> > > create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
> > >
> > > diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> > > index 0aab3073cc1..43336d191d9 100644
> > > --- a/gcc/cp/constraint.cc
> > > +++ b/gcc/cp/constraint.cc
> > > @@ -546,15 +546,24 @@ static tree
> > > map_arguments (tree parms, tree args)
> > > {
> > > for (tree p = parms; p; p = TREE_CHAIN (p))
> > > - if (args)
> > > - {
> > > - int level;
> > > - int index;
> > > - template_parm_level_and_index (TREE_VALUE (p), &level, &index);
> > > - TREE_PURPOSE (p) = TMPL_ARG (args, level, index);
> > > - }
> > > - else
> > > - TREE_PURPOSE (p) = TREE_VALUE (p);
> > > + {
> > > + tree parm = TREE_VALUE (p);
> > > + if (args)
> > > + {
> > > + int level;
> > > + int index;
> > > + template_parm_level_and_index (parm, &level, &index);
> > > + TREE_PURPOSE (p) = TMPL_ARG (args, level, index);
> > > + }
> > > + else
> > > + {
> > > + tree tpi = (TYPE_P (parm)
> > > + ? TEMPLATE_TYPE_PARM_INDEX (parm) : parm);
> > > + TREE_PURPOSE (p)
> > > + = template_parm_to_arg (build_tree_list (NULL_TREE,
> > > + TEMPLATE_PARM_DECL
> > > (tpi)));
> >
> > Doesn't passing 'p' to template_parm_to_arg work?
>
> Unfortunately not, template_parm_to_arg expects a TREE_LIST node whose
> TREE_VALUE is the corresponding *_DECL for the template parm (i.e. it
> expects node from current_template_parms), and 'p' is a
> TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE PARM or TEMPLATE_PARM_INDEX (given
> to us by find_template_parameters).
Oops, 'p' is of course a TREE_LIST of a TEMPLATE_PARM_P node.
But template_parm_to_arg wants a TREE_LIST of a DECL_TEMPLATE_PARM_P
node.
>
> Would it be appropriate to adjust template_parm_to_arg to accept the
> latter inputs as well?
This version extends template_parm_to_arg to handle TEMPLATE_PARM_P
nodes alongside its existing DECL_TEMPLATE_PARM_P handling, which allows
us to simply pass 'p' to template_parm_to_arg from map_arguments.
Bootstrapped and regtested on x86_64-pc-linux-gnu and tested on cmcstl2
and range-v3.
-- >8 --
Subject: [PATCH] c++: Fix self-mapping in map_arguments [PR96531, PR97103]
With r10-8077 we stopped passing the argified current_template_parms to
normalize_constraint_expression from finish_nested_requirement, and
instead made map_arguments perform a self-mapping of parameters when
args is NULL. But we're currently not handling parameter packs and
BOUND_TEMPLATE_TEMPLATE_PARMs properly during this self-mapping, which
leads to ICEs later during satisfaction.
To properly handle self-mapping of a parameter pack, this patch
extends template_parm_to_arg to handle TEMPLATE_PARM_P nodes, and
makes map_arguments use it. This change revealed that the call to
template_parm_to_arg in convert_generic_types_to_packs is a no-op
because 't' is never a TREE_LIST, so this patch additionally removes
this call.
As for bound ttps, map_arguments before r10-8077 would map a
BOUND_TEMPLATE_TEMPLATE_PARM not to itself but to its underlying
TEMPLATE_TEMPLATE_PARM. We could restore this behavior in
map_arguments, but since a bound ttp is not really a template parameter
it seems better to make keep_template_parm not give us a bound ttp in
the first place. So this patch makes keep_template_parm return the
underlying ttp instead of the bound ttp itself.
gcc/cp/ChangeLog:
PR c++/96531
PR c++/97103
* constraint.cc (map_arguments): Call template_parm_to_arg
in the self-mapping case.
(finish_shorthand_constraint): No need to build a TREE_LIST
before calling template_parm_to_arg.
* pt.c (template_parm_to_arg): Rewrite to handle TEMPLATE_PARM_P
nodes as well as DECL_TEMPLATE_PARM_P nodes, and to make the
overlying TREE_LIST node optional.
(keep_template_parm): Don't record a BOUND_TEMPLATE_TEMPLATE_PARM,
instead record its corresponding TEMPLATE_TEMPLATE_PARM.
(convert_generic_types_to_packs): Don't call
template_parm_to_arg.
gcc/testsuite/ChangeLog:
PR c++/96531
PR c++/97103
* g++.dg/cpp2a/concepts-ttp2.C: New test.
* g++.dg/cpp2a/concepts-variadic1.C: New test.
---
gcc/cp/constraint.cc | 4 +-
gcc/cp/pt.c | 43 ++++++++++++-------
gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C | 11 +++++
.../g++.dg/cpp2a/concepts-variadic1.C | 28 ++++++++++++
4 files changed, 68 insertions(+), 18 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 0aab3073cc1..2827d3f91b3 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -554,7 +554,7 @@ map_arguments (tree parms, tree args)
TREE_PURPOSE (p) = TMPL_ARG (args, level, index);
}
else
- TREE_PURPOSE (p) = TREE_VALUE (p);
+ TREE_PURPOSE (p) = template_parm_to_arg (p);
return parms;
}
@@ -1492,7 +1492,7 @@ finish_shorthand_constraint (tree decl, tree constr)
/* Get the argument and overload used for the requirement
and adjust it if we're going to expand later. */
- tree arg = template_parm_to_arg (build_tree_list (NULL_TREE, decl));
+ tree arg = template_parm_to_arg (decl);
if (apply_to_each_p && declared_pack_p)
arg = PACK_EXPANSION_PATTERN (TREE_VEC_ELT (ARGUMENT_PACK_ARGS (arg), 0));
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index cfe5ff4a94f..93706543d93 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -4704,29 +4704,37 @@ end_template_decl (void)
current_template_parms = TREE_CHAIN (current_template_parms);
}
-/* Takes a TREE_LIST representing a template parameter and convert it
- into an argument suitable to be passed to the type substitution
- functions. Note that If the TREE_LIST contains an error_mark
- node, the returned argument is error_mark_node. */
+/* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
+ thereof, and converts it into an argument suitable to be passed to
+ the type substitution functions. Note that if the TREE_LIST contains
+ an error_mark node, the returned argument is error_mark_node. */
tree
template_parm_to_arg (tree t)
{
-
- if (t == NULL_TREE
- || TREE_CODE (t) != TREE_LIST)
+ if (t == NULL_TREE)
return t;
- if (error_operand_p (TREE_VALUE (t)))
- return error_mark_node;
+ if (TREE_CODE (t) == TREE_LIST)
+ t = TREE_VALUE (t);
- t = TREE_VALUE (t);
+ if (error_operand_p (t))
+ return error_mark_node;
- if (TREE_CODE (t) == TYPE_DECL
- || TREE_CODE (t) == TEMPLATE_DECL)
+ if (DECL_P (t) && DECL_TEMPLATE_PARM_P (t))
{
- t = TREE_TYPE (t);
+ if (TREE_CODE (t) == TYPE_DECL
+ || TREE_CODE (t) == TEMPLATE_DECL)
+ t = TREE_TYPE (t);
+ else
+ t = DECL_INITIAL (t);
+ }
+
+ gcc_assert (TEMPLATE_PARM_P (t));
+ if (TREE_CODE (t) == TEMPLATE_TYPE_PARM
+ || TREE_CODE (t) == TEMPLATE_TEMPLATE_PARM)
+ {
if (TEMPLATE_TYPE_PARAMETER_PACK (t))
{
/* Turn this argument into a TYPE_ARGUMENT_PACK
@@ -4743,8 +4751,6 @@ template_parm_to_arg (tree t)
}
else
{
- t = DECL_INITIAL (t);
-
if (TEMPLATE_PARM_PARAMETER_PACK (t))
{
/* Turn this argument into a NONTYPE_ARGUMENT_PACK
@@ -10539,6 +10545,11 @@ keep_template_parm (tree t, void* data)
if (level > ftpi->max_depth)
return 0;
+ if (TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM)
+ /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
+ BOUND_TEMPLATE_TEMPLATE_PARM itself. */
+ t = TREE_TYPE (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t));
+
/* Arguments like const T yield parameters like const T. This means that
a template-id like X<T, const T> would yield two distinct parameters:
T and const T. Adjust types to their unqualified versions. */
@@ -29448,7 +29459,7 @@ convert_generic_types_to_packs (tree parm, int
start_idx, int end_idx)
if (tree constr = TEMPLATE_PARM_CONSTRAINTS (node))
{
tree id = unpack_concept_check (constr);
- TREE_VEC_ELT (TREE_OPERAND (id, 1), 0) = template_parm_to_arg (t);
+ TREE_VEC_ELT (TREE_OPERAND (id, 1), 0) = t;
tree fold = finish_left_unary_fold_expr (constr, TRUTH_ANDIF_EXPR);
TEMPLATE_PARM_CONSTRAINTS (node) = fold;
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
b/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
new file mode 100644
index 00000000000..7f4883754dd
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
@@ -0,0 +1,11 @@
+// PR c++/97103
+// { dg-do compile { target c++20 } }
+
+template<typename R, typename Rep>
+class quantity {};
+
+template<template<typename, typename> typename Q>
+inline constexpr bool valid_template_arguments = requires {
+ requires requires { typename Q<int, int>; };
+};
+static_assert(valid_template_arguments<quantity>);
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
b/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
new file mode 100644
index 00000000000..deab028ca3c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
@@ -0,0 +1,28 @@
+// PR c++/96531
+// { dg-do compile { target c++20 } }
+
+template<typename T>
+concept is_bool = __is_same(bool, T);
+
+template <typename... Ts>
+concept C = requires {
+ requires (is_bool<Ts> || ...);
+};
+
+template <bool... Bs>
+concept D = requires {
+ requires (Bs || ...);
+};
+
+template <typename... Ts>
+requires C<Ts...>
+void bar() {}
+
+template <bool... Bs>
+requires D<Bs...>
+void baz() {}
+
+int main() {
+ bar<int, char, bool>();
+ baz<false, true, false>();
+}
--
2.28.0.497.g54e85e7af1
>
> >
> > > + }
> > > + }
> > > return parms;
> > > }
> > > diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
> > > index cfe5ff4a94f..55d8060b911 100644
> > > --- a/gcc/cp/pt.c
> > > +++ b/gcc/cp/pt.c
> > > @@ -10539,6 +10539,11 @@ keep_template_parm (tree t, void* data)
> > > if (level > ftpi->max_depth)
> > > return 0;
> > > + if (TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM)
> > > + /* A BOUND_TEMPLATE_TEMPLATE_PARM isn't a template parameter. What
> > > we
> > > + really want is the corresponding TEMPLATE_TEMPLATE_PARM. */
> > > + t = TREE_TYPE (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t));
> > > +
> > > /* Arguments like const T yield parameters like const T. This means
> > > that
> > > a template-id like X<T, const T> would yield two distinct
> > > parameters:
> > > T and const T. Adjust types to their unqualified versions. */
> > > diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
> > > b/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
> > > new file mode 100644
> > > index 00000000000..7f4883754dd
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C
> > > @@ -0,0 +1,11 @@
> > > +// PR c++/97103
> > > +// { dg-do compile { target c++20 } }
> > > +
> > > +template<typename R, typename Rep>
> > > +class quantity {};
> > > +
> > > +template<template<typename, typename> typename Q>
> > > +inline constexpr bool valid_template_arguments = requires {
> > > + requires requires { typename Q<int, int>; };
> > > +};
> > > +static_assert(valid_template_arguments<quantity>);
> > > diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
> > > b/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
> > > new file mode 100644
> > > index 00000000000..deab028ca3c
> > > --- /dev/null
> > > +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C
> > > @@ -0,0 +1,28 @@
> > > +// PR c++/96531
> > > +// { dg-do compile { target c++20 } }
> > > +
> > > +template<typename T>
> > > +concept is_bool = __is_same(bool, T);
> > > +
> > > +template <typename... Ts>
> > > +concept C = requires {
> > > + requires (is_bool<Ts> || ...);
> > > +};
> > > +
> > > +template <bool... Bs>
> > > +concept D = requires {
> > > + requires (Bs || ...);
> > > +};
> > > +
> > > +template <typename... Ts>
> > > +requires C<Ts...>
> > > +void bar() {}
> > > +
> > > +template <bool... Bs>
> > > +requires D<Bs...>
> > > +void baz() {}
> > > +
> > > +int main() {
> > > + bar<int, char, bool>();
> > > + baz<false, true, false>();
> > > +}
> > >
> >
> >
>
