From: Jason Merrill <jason@redhat.com>
To: gcc-patches@gcc.gnu.org
Subject: [C++ PATCH] PR c++/88875 - error with explicit list constructor.
Date: Fri, 18 Jan 2019 20:35:00 -0000 [thread overview]
Message-ID: <20190118203548.29886-1-jason@redhat.com> (raw)
In my patch for CWG issue 2267, I changed reference_binding to clear
CONSTRUCTOR_IS_DIRECT_INIT on the argument init-list. But that breaks if
there's another candidate for which CONSTRUCTOR_IS_DIRECT_INIT is correct.
So instead, let's encode in the conversion that we want to override the
flag.
Tested x86_64-pc-linux-gnu, applying to trunk.
* call.c (reference_binding): Don't modify EXPR. Set
need_temporary_p on the ck_user conversion for a temporary.
(convert_like_real): Check it.
---
gcc/cp/call.c | 11 +++++++---
.../g++.dg/cpp0x/initlist-explicit2.C | 20 +++++++++++++++++++
gcc/cp/ChangeLog | 7 +++++++
3 files changed, 35 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/initlist-explicit2.C
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 499894b353f..16c3706cc5c 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -94,7 +94,7 @@ struct conversion {
BOOL_BITFIELD bad_p : 1;
/* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
temporary should be created to hold the result of the
- conversion. If KIND is ck_ambig, true if the context is
+ conversion. If KIND is ck_ambig or ck_user, true means force
copy-initialization. */
BOOL_BITFIELD need_temporary_p : 1;
/* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
@@ -1560,6 +1560,7 @@ reference_binding (tree rto, tree rfrom, tree expr, bool c_cast_p, int flags,
from = TREE_TYPE (expr);
}
+ bool copy_list_init = false;
if (expr && BRACE_ENCLOSED_INITIALIZER_P (expr))
{
maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);
@@ -1582,7 +1583,7 @@ reference_binding (tree rto, tree rfrom, tree expr, bool c_cast_p, int flags,
/* Otherwise, if T is a reference type, a prvalue temporary of the type
referenced by T is copy-list-initialized, and the reference is bound
to that temporary. */
- CONSTRUCTOR_IS_DIRECT_INIT (expr) = false;
+ copy_list_init = true;
skip:;
}
@@ -1770,6 +1771,10 @@ reference_binding (tree rto, tree rfrom, tree expr, bool c_cast_p, int flags,
if (conv->user_conv_p)
{
+ if (copy_list_init)
+ /* Remember this was copy-list-initialization. */
+ conv->need_temporary_p = true;
+
/* If initializing the temporary used a conversion function,
recalculate the second conversion sequence. */
for (conversion *t = conv; t; t = next_conversion (t))
@@ -6941,7 +6946,7 @@ convert_like_real (conversion *convs, tree expr, tree fn, int argnum,
if (DECL_NONCONVERTING_P (convfn) && DECL_CONSTRUCTOR_P (convfn)
&& BRACE_ENCLOSED_INITIALIZER_P (expr)
/* Unless this is for direct-list-initialization. */
- && !CONSTRUCTOR_IS_DIRECT_INIT (expr)
+ && (!CONSTRUCTOR_IS_DIRECT_INIT (expr) || convs->need_temporary_p)
/* And in C++98 a default constructor can't be explicit. */
&& cxx_dialect >= cxx11)
{
diff --git a/gcc/testsuite/g++.dg/cpp0x/initlist-explicit2.C b/gcc/testsuite/g++.dg/cpp0x/initlist-explicit2.C
new file mode 100644
index 00000000000..26a63bf2aa7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/initlist-explicit2.C
@@ -0,0 +1,20 @@
+// PR c++/88875
+// { dg-do compile { target c++11 } }
+
+#include <initializer_list>
+
+struct X {
+ X();
+ explicit X(const std::initializer_list<int>& init);
+};
+
+struct Y
+{
+ X x { 1, 2 }; // error
+
+ Y (int)
+ : x {1, 2} // ok
+ {
+ }
+
+};
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index d224b72c0bb..4292930daf3 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2019-01-18 Jason Merrill <jason@redhat.com>
+
+ PR c++/88875 - error with explicit list constructor.
+ * call.c (reference_binding): Don't modify EXPR. Set
+ need_temporary_p on the ck_user conversion for a temporary.
+ (convert_like_real): Check it.
+
2019-01-18 H.J. Lu <hongjiu.lu@intel.com>
PR c/51628
base-commit: 31975c5ea11cee1a66a59e6d941db4c6b3cc602c
--
2.20.1
reply other threads:[~2019-01-18 20:35 UTC|newest]
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