From 441a4880cba0908e58a102b068095e4ac2bb46cc Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Tue, 13 Sep 2022 09:48:04 -0400
Subject: [PATCH] c++: some missing-SFINAE fixes
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 in the usual way, by passing complain and
propagating error_mark_node appropriately.
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 | 4 +++-
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, 42 insertions(+), 3 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 936f1cf0197a..5404d7e084cc 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);
return expr;
}
diff --git a/gcc/cp/except.cc b/gcc/cp/except.cc
index 7fdbc747c228..4d7f0ce102da 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 1c6f4b84612b..074179288b60 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
@@ -14312,6 +14312,8 @@ 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 (spec == error_mark_node)
+ return error_mark_node;
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 000000000000..491df4d58b77
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/noexcept-type26.C
@@ -0,0 +1,12 @@
+// Verify a non-constant conditional noexcept-specifier in a function type
+// respects SFINAE.
+// { 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 000000000000..47903813680a
--- /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 000000000000..dc43116128ba
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/integer-pack6.C
@@ -0,0 +1,13 @@
+// Verify a non-constant argument to __integer_pack respects SFINAE.
+// { 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);
+}
--
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