On Tue, 13 Sep 2022, Jason Merrill wrote:
> On 9/13/22 07:45, Patrick Palka wrote:
> > It looks like we aren't respecting SFINAE for:
> >
> > * an invalid/non-constant conditional explicit-specifier
> > * a non-constant conditional noexcept-specifier
> > * a non-constant argument to __integer_pack
> >
> > This patch fixes these issues in the usual way, by passing complain
> > and propagating error_mark_node appropriately.
> >
> > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> > trunk?
> >
> > gcc/cp/ChangeLog:
> >
> > * decl.cc (build_explicit_specifier): Pass complain to
> > cxx_constant_value.
> > * except.cc (build_noexcept_spec): Likewise.
> > * pt.cc (expand_integer_pack): Likewise.
> > (tsubst_function_decl): Propagate error_mark_node returned
> > from build_explicit_specifier.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/cpp1z/noexcept-type26.C: New test.
> > * g++.dg/cpp2a/explicit19.C: New test.
> > * g++.dg/ext/integer-pack6.C: New test.
> > ---
> > gcc/cp/decl.cc | 2 +-
> > gcc/cp/except.cc | 2 +-
> > gcc/cp/pt.cc | 6 ++++--
> > gcc/testsuite/g++.dg/cpp1z/noexcept-type26.C | 12 ++++++++++++
> > gcc/testsuite/g++.dg/cpp2a/explicit19.C | 12 ++++++++++++
> > gcc/testsuite/g++.dg/ext/integer-pack6.C | 13 +++++++++++++
> > 6 files changed, 43 insertions(+), 4 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/cpp1z/noexcept-type26.C
> > create mode 100644 gcc/testsuite/g++.dg/cpp2a/explicit19.C
> > create mode 100644 gcc/testsuite/g++.dg/ext/integer-pack6.C
> >
> > diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> > index 936f1cf0197..5404d7e084c 100644
> > --- a/gcc/cp/decl.cc
> > +++ b/gcc/cp/decl.cc
> > @@ -18557,7 +18557,7 @@ build_explicit_specifier (tree expr, tsubst_flags_t
> > complain)
> > expr = build_converted_constant_bool_expr (expr, complain);
> > expr = instantiate_non_dependent_expr (expr, complain);
> > - expr = cxx_constant_value (expr);
> > + expr = cxx_constant_value (expr, NULL_TREE, complain);
>
> The patch is OK, but perhaps we want another overload that omits the object
> parameter?
Thanks -- sounds good, like the following incremental patch?
-- >8 --
Subject: [PATCH] c++: two-parameter version of cxx_constant_value
Since some callers need the complain parameter but not the object
parameter, let's introduce and use an overload of cxx_constant_value
that omits the latter.
gcc/cp/ChangeLog:
* cp-tree.h (cxx_constant_value): Define two-parameter version
that omits the object parameter.
* decl.cc (build_explicit_specifier): Omit NULL_TREE object
argument to cxx_constant_value.
* except.cc (build_noexcept_spec): Likewise.
* pt.cc (expand_integer_pack): Likewise.
(fold_targs_r): Likewise.
* semantics.cc (finish_if_stmt_cond): Likewise.
---
gcc/cp/cp-tree.h | 2 ++
gcc/cp/decl.cc | 2 +-
gcc/cp/except.cc | 2 +-
gcc/cp/pt.cc | 4 ++--
gcc/cp/semantics.cc | 2 +-
5 files changed, 7 insertions(+), 5 deletions(-)
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 2ba44e80e20..1eb176d4a50 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -8414,6 +8414,8 @@ extern bool require_rvalue_constant_expression (tree);
extern bool require_potential_rvalue_constant_expression (tree);
extern tree cxx_constant_value (tree, tree = NULL_TREE,
tsubst_flags_t = tf_error);
+inline tree cxx_constant_value (tree t, tsubst_flags_t complain)
+{ return cxx_constant_value (t, NULL_TREE, complain); }
extern void cxx_constant_dtor (tree, tree);
extern tree cxx_constant_init (tree, tree = NULL_TREE);
extern tree maybe_constant_value (tree, tree = NULL_TREE, bool =
false);
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 5404d7e084c..006e9affcba 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -18557,7 +18557,7 @@ build_explicit_specifier (tree expr, tsubst_flags_t
complain)
expr = build_converted_constant_bool_expr (expr, complain);
expr = instantiate_non_dependent_expr (expr, complain);
- expr = cxx_constant_value (expr, NULL_TREE, complain);
+ expr = cxx_constant_value (expr, complain);
return expr;
}
diff --git a/gcc/cp/except.cc b/gcc/cp/except.cc
index 4d7f0ce102d..048612de400 100644
--- a/gcc/cp/except.cc
+++ b/gcc/cp/except.cc
@@ -1257,7 +1257,7 @@ build_noexcept_spec (tree expr, tsubst_flags_t complain)
{
expr = build_converted_constant_bool_expr (expr, complain);
expr = instantiate_non_dependent_expr (expr, complain);
- expr = cxx_constant_value (expr, NULL_TREE, complain);
+ expr = cxx_constant_value (expr, complain);
}
if (TREE_CODE (expr) == INTEGER_CST)
{
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 074179288b6..db4e808adec 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -3869,7 +3869,7 @@ expand_integer_pack (tree call, tree args, tsubst_flags_t
complain,
else
{
hi = instantiate_non_dependent_expr (hi, complain);
- hi = cxx_constant_value (hi, NULL_TREE, complain);
+ hi = cxx_constant_value (hi, complain);
int len = valid_constant_size_p (hi) ? tree_to_shwi (hi) : -1;
/* Calculate the largest value of len that won't make the size of the vec
@@ -20121,7 +20121,7 @@ fold_targs_r (tree targs, tsubst_flags_t complain)
&& !glvalue_p (elt)
&& !TREE_CONSTANT (elt))
{
- elt = cxx_constant_value (elt, NULL_TREE, complain);
+ elt = cxx_constant_value (elt, complain);
if (elt == error_mark_node)
return false;
}
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 3edefb2fca2..4f189978484 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -1042,7 +1042,7 @@ finish_if_stmt_cond (tree orig_cond, tree if_stmt)
{
maybe_warn_for_constant_evaluated (cond, /*constexpr_if=*/true);
cond = instantiate_non_dependent_expr (cond);
- cond = cxx_constant_value (cond, NULL_TREE);
+ cond = cxx_constant_value (cond);
}
else
{
--
2.37.3.542.gdd3f6c4cae
>
> > return expr;
> > }
> > diff --git a/gcc/cp/except.cc b/gcc/cp/except.cc
> > index 7fdbc747c22..4d7f0ce102d 100644
> > --- a/gcc/cp/except.cc
> > +++ b/gcc/cp/except.cc
> > @@ -1257,7 +1257,7 @@ build_noexcept_spec (tree expr, tsubst_flags_t
> > complain)
> > {
> > expr = build_converted_constant_bool_expr (expr, complain);
> > expr = instantiate_non_dependent_expr (expr, complain);
> > - expr = cxx_constant_value (expr);
> > + expr = cxx_constant_value (expr, NULL_TREE, complain);
> > }
> > if (TREE_CODE (expr) == INTEGER_CST)
> > {
> > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> > index 1c6f4b84612..f16f5ffca20 100644
> > --- a/gcc/cp/pt.cc
> > +++ b/gcc/cp/pt.cc
> > @@ -3869,7 +3869,7 @@ expand_integer_pack (tree call, tree args,
> > tsubst_flags_t complain,
> > else
> > {
> > hi = instantiate_non_dependent_expr (hi, complain);
> > - hi = cxx_constant_value (hi);
> > + hi = cxx_constant_value (hi, NULL_TREE, complain);
> > int len = valid_constant_size_p (hi) ? tree_to_shwi (hi) : -1;
> > /* Calculate the largest value of len that won't make the size of
> > the vec
> > @@ -14312,7 +14312,9 @@ tsubst_function_decl (tree t, tree args,
> > tsubst_flags_t complain,
> > /*function_p=*/false,
> > /*i_c_e_p=*/true);
> > spec = build_explicit_specifier (spec, complain);
> > - if (instantiation_dependent_expression_p (spec))
> > + if (spec == error_mark_node)
> > + return error_mark_node;
> > + else if (instantiation_dependent_expression_p (spec))
> > store_explicit_specifier (r, spec);
> > else
> > {
> > diff --git a/gcc/testsuite/g++.dg/cpp1z/noexcept-type26.C
> > b/gcc/testsuite/g++.dg/cpp1z/noexcept-type26.C
> > new file mode 100644
> > index 00000000000..73058395f0a
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/cpp1z/noexcept-type26.C
> > @@ -0,0 +1,12 @@
> > +// Verify a non-constant conditional noexcept-specifier of a function type
> > +// is a SFINAE error.
> > +// { dg-do compile { target c++17 } }
> > +
> > +template<class T> void f(void() noexcept(T::value)) = delete;
> > +template<class T> void f(...);
> > +
> > +struct B { static bool value; };
> > +
> > +int main() {
> > + f<B>(nullptr);
> > +}
> > diff --git a/gcc/testsuite/g++.dg/cpp2a/explicit19.C
> > b/gcc/testsuite/g++.dg/cpp2a/explicit19.C
> > new file mode 100644
> > index 00000000000..47903813680
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/cpp2a/explicit19.C
> > @@ -0,0 +1,12 @@
> > +// Verify a conditional explicit-specifier is a SFINAE context.
> > +// { dg-do compile { target c++20 } }
> > +
> > +struct A {
> > + template<class T> explicit(T::value) A(T) = delete;
> > + A(...);
> > +};
> > +
> > +struct B { static bool value; };
> > +
> > +A x(0);
> > +A y(B{});
> > diff --git a/gcc/testsuite/g++.dg/ext/integer-pack6.C
> > b/gcc/testsuite/g++.dg/ext/integer-pack6.C
> > new file mode 100644
> > index 00000000000..7e16bc44b40
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/integer-pack6.C
> > @@ -0,0 +1,13 @@
> > +// Verify a non-constant argument to __integer_pack is a SFINAE error.
> > +// { dg-do compile { target c++11 } }
> > +
> > +template<int...> struct A { };
> > +
> > +template<class T> auto f(int) -> A<__integer_pack(T::value)...> = delete;
> > +template<class T> void f(...);
> > +
> > +struct B { static int value; };
> > +
> > +int main() {
> > + f<B>(0);
> > +}
>
>
