* [pushed] c++: Fix invalid pointer-to-member in requires [PR67825]
@ 2020-04-04 15:06 Jason Merrill
0 siblings, 0 replies; only message in thread
From: Jason Merrill @ 2020-04-04 15:06 UTC (permalink / raw)
To: gcc-patches
A recent change to cmcstl2 led to two tests failing due to this bug: our
valid expression checking in the context of a requires-expression wasn't
catching that an expression of member function type can only appear as the
function operand of a call expression. Fixed by using convert_to_void to do
the same checking as a discarded-value expression.
This patch also fixes 67825, which already had a testcase, but the testcase
was testing for the wrong behavior.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog
2020-04-04 Jason Merrill <jason@redhat.com>
PR c++/67825
* constraint.cc (tsubst_valid_expression_requirement): Call
convert_to_void.
---
gcc/cp/constraint.cc | 5 ++++-
gcc/testsuite/g++.dg/cpp2a/concepts-pmf1.C | 22 +++++++++++++++++++
gcc/testsuite/g++.dg/cpp2a/concepts-pr67825.C | 2 +-
3 files changed, 27 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-pmf1.C
diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
index 9c21ce80256..e5308414879 100644
--- a/gcc/cp/constraint.cc
+++ b/gcc/cp/constraint.cc
@@ -1864,7 +1864,10 @@ hash_placeholder_constraint (tree c)
static tree
tsubst_valid_expression_requirement (tree t, tree args, subst_info info)
{
- return tsubst_expr (t, args, info.complain, info.in_decl, false);
+ tree r = tsubst_expr (t, args, info.complain, info.in_decl, false);
+ if (convert_to_void (r, ICV_STATEMENT, info.complain) == error_mark_node)
+ return error_mark_node;
+ return r;
}
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-pmf1.C b/gcc/testsuite/g++.dg/cpp2a/concepts-pmf1.C
new file mode 100644
index 00000000000..30d2b2d4a48
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-pmf1.C
@@ -0,0 +1,22 @@
+// Make sure that the requirement fails because a .* expression of function
+// type can only be used in a call.
+
+// { dg-do compile { target concepts } }
+
+template<class D, class T>
+constexpr decltype(auto) invoke(D (T::*pmd), T&& t)
+ noexcept(noexcept(t.*pmd))
+ requires requires { t.*pmd; }
+ { return t.*pmd; }
+
+char invoke(...);
+
+struct A
+{
+ int f();
+};
+
+int main()
+{
+ static_assert(sizeof(invoke (&A::f, A())) == 1);
+}
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-pr67825.C b/gcc/testsuite/g++.dg/cpp2a/concepts-pr67825.C
index 95698e99978..fff414b8eb2 100644
--- a/gcc/testsuite/g++.dg/cpp2a/concepts-pr67825.C
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-pr67825.C
@@ -15,6 +15,6 @@ template <class X> concept bool C() {
}
int main() {
- static_assert(C<A>());
+ static_assert(!C<A>());
return 0;
}
base-commit: bab8d9625f4cdeaf9bb45e28ab62abe47c3827f9
--
2.18.1
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