From 9bc6b23d11697545e8a951ccd60691b1e58b98c2 Mon Sep 17 00:00:00 2001
From: Patrick Palka <ppalka@redhat.com>
Date: Wed, 14 Feb 2024 10:20:31 -0500
Subject: [PATCH] c++: synthesized_method_walk context independence [PR113908]
In the second testcase below, during ahead of time checking of the
non-dependent new-expr we synthesize B's copy ctor, which we expect to
get defined as deleted since A's copy ctor is inaccessible. But during
access checking thereof, enforce_access incorrectly decides to defer it
since we're in a template context according to current_template_parms
(before r14-557 it checked processing_template_decl which got cleared
from implicitly_declare_fn), which leads to the access check leaking out
to the template context that triggered the synthesization, and B's copy
ctor getting declared as non-deleted.
This patch fixes this by using maybe_push_to_top_level to clear the
context (including current_template_parms) before proceeding with the
synthesization. We could do this from implicitly_declare_fn, but it's
better to do it more generally from synthesized_method_walk for sake of
its other callers.
This turns out to fix PR113332 as well: there the lambda context
triggering synthesization was causing maybe_dummy_object to misbehave,
but now synthesization is sufficiently context-independent.
PR c++/113908
PR c++/113332
gcc/cp/ChangeLog:
* method.cc (synthesized_method_walk): Use maybe_push_to_top_level.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/lambda/lambda-nsdmi11.C: New test.
* g++.dg/template/non-dependent31.C: New test.
Reviewed-by: Jason Merrill <jason@redhat.com>
---
gcc/cp/method.cc | 2 ++
.../g++.dg/cpp0x/lambda/lambda-nsdmi11.C | 20 +++++++++++++++++++
.../g++.dg/template/non-dependent31.C | 18 +++++++++++++++++
3 files changed, 40 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/lambda/lambda-nsdmi11.C
create mode 100644 gcc/testsuite/g++.dg/template/non-dependent31.C
diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
index 957496d3e180..98c10e6a8b5b 100644
--- a/gcc/cp/method.cc
+++ b/gcc/cp/method.cc
@@ -2760,6 +2760,7 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
return;
}
+ bool push_to_top = maybe_push_to_top_level (TYPE_NAME (ctype));
++cp_unevaluated_operand;
++c_inhibit_evaluation_warnings;
push_deferring_access_checks (dk_no_deferred);
@@ -2857,6 +2858,7 @@ synthesized_method_walk (tree ctype, special_function_kind sfk, bool const_p,
pop_deferring_access_checks ();
--cp_unevaluated_operand;
--c_inhibit_evaluation_warnings;
+ maybe_pop_from_top_level (push_to_top);
}
/* DECL is a defaulted function whose exception specification is now
diff --git a/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-nsdmi11.C b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-nsdmi11.C
new file mode 100644
index 000000000000..246654c5b502
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/lambda/lambda-nsdmi11.C
@@ -0,0 +1,20 @@
+// PR c++/113332
+// { dg-do compile { target c++11 } }
+
+struct tuple {
+ template<class _Tp>
+ static constexpr bool __is_implicitly_default_constructible() { return true; }
+
+ template<class _Tp = void,
+ bool = __is_implicitly_default_constructible<_Tp>()>
+ tuple();
+};
+
+struct DBusStruct {
+private:
+ tuple data_;
+};
+
+struct IBusService {
+ int m = [] { DBusStruct{}; return 42; }();
+};
diff --git a/gcc/testsuite/g++.dg/template/non-dependent31.C b/gcc/testsuite/g++.dg/template/non-dependent31.C
new file mode 100644
index 000000000000..3fa68f40fe11
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/non-dependent31.C
@@ -0,0 +1,18 @@
+// PR c++/113908
+// { dg-do compile { target c++11 } }
+
+struct A {
+ A();
+private:
+ A(const A&);
+};
+
+struct B {
+ A a;
+
+ template<class T>
+ static void f() { new B(); }
+};
+
+template void B::f<int>();
+static_assert(!__is_constructible(B, const B&), "");
--
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