On Thu, Jun 11, 2020 at 06:15:26PM -0400, Jason Merrill via Gcc-patches wrote:
> On 6/11/20 5:28 PM, Marek Polacek wrote:
> > On Thu, Jun 11, 2020 at 03:51:29PM -0400, Jason Merrill wrote:
> > > On 6/9/20 2:17 PM, Marek Polacek wrote:
> > > > Another part of 95369 is that we accept designated initializers with
> > > > non-aggregate types. That seems to be wrong since they're part of
> > > > aggregate initialization. clang/icc also reject it.
> > > >
> > > > (Un)fortunately there are multiple contexts where we can use designated
> > > > initializers: function-like casts, member list initializers, NTTP, etc.
> > > > So I've adjusted multiple places in the compiler in order to to detect
> > > > this case and to provide a nice diagnostic, instead of an ugly raft of
> > > > errors.
> > >
> > > Would it work to handle this only in add_list_candidates?
> >
> > 'fraid not -- we don't call add_list_candidates at all when compiling
> > desig16.C.
>
> Hmm, why not? What is turning the CONSTRUCTOR into an argument vec?
Nevermind, I must've glossed over a local patch. This better patch
implements your suggestion. I still changed implicit_conversion_error
to give a better diagnostic but that should be fine. Thanks,
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Another part of 95369 is that we accept designated initializers with
non-aggregate types. That seems to be wrong since they're part of
aggregate initialization. clang/icc also reject it.
There are multiple contexts where we can use designated initializers:
function-like casts, member list initializers, NTTP, etc. I've adjusted
add_list_candidates and implicit_conversion_error in order to to detect
this case.
gcc/cp/ChangeLog:
PR c++/95369
* call.c (add_list_candidates): Return if a designated initializer
is used with a non-aggregate.
(implicit_conversion_error): Give an error for the case above.
gcc/testsuite/ChangeLog:
PR c++/95369
* g++.dg/cpp2a/desig11.C: Adjust dg-error.
* g++.dg/cpp2a/desig16.C: New test.
---
gcc/cp/call.c | 13 +++++++++++++
gcc/testsuite/g++.dg/cpp2a/desig11.C | 2 +-
gcc/testsuite/g++.dg/cpp2a/desig16.C | 28 ++++++++++++++++++++++++++++
3 files changed, 42 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/desig16.C
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index b99959f76f9..1a54e9f4440 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -3952,6 +3952,14 @@ add_list_candidates (tree fns, tree first_arg,
if (any_strictly_viable (*candidates))
return;
}
+ else if (CONSTRUCTOR_IS_DESIGNATED_INIT (init_list)
+ && !CP_AGGREGATE_TYPE_P (totype))
+ {
+ if (complain & tf_error)
+ error ("designated initializers cannot be used with a "
+ "non-aggregate type %qT", totype);
+ return;
+ }
/* Expand the CONSTRUCTOR into a new argument vec. */
vec<tree, va_gc> *new_args;
@@ -4301,6 +4309,11 @@ implicit_conversion_error (location_t loc, tree type,
tree expr)
instantiate_type (type, expr, complain);
else if (invalid_nonstatic_memfn_p (loc, expr, complain))
/* We gave an error. */;
+ else if (BRACE_ENCLOSED_INITIALIZER_P (expr)
+ && CONSTRUCTOR_IS_DESIGNATED_INIT (expr)
+ && !CP_AGGREGATE_TYPE_P (type))
+ error_at (loc, "designated initializers cannot be used with a "
+ "non-aggregate type %qT", type);
else
{
range_label_for_type_mismatch label (TREE_TYPE (expr), type);
diff --git a/gcc/testsuite/g++.dg/cpp2a/desig11.C
b/gcc/testsuite/g++.dg/cpp2a/desig11.C
index d6895a7be56..a189fff2059 100644
--- a/gcc/testsuite/g++.dg/cpp2a/desig11.C
+++ b/gcc/testsuite/g++.dg/cpp2a/desig11.C
@@ -11,4 +11,4 @@ int bar (_Complex int); // { dg-message
"initializing argument 1 of" }
int y = bar ({.real = 0, .imag = 1}); // { dg-error "cannot convert" }
int baz (std::initializer_list<int>);
-int z = baz ({.one = 1, .two = 2, .three = 3}); // { dg-error "could
not convert" }
+int z = baz ({.one = 1, .two = 2, .three = 3}); // { dg-error
"designated initializers" }
diff --git a/gcc/testsuite/g++.dg/cpp2a/desig16.C
b/gcc/testsuite/g++.dg/cpp2a/desig16.C
new file mode 100644
index 00000000000..3edb68d24a4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/desig16.C
@@ -0,0 +1,28 @@
+// PR c++/95369
+// { dg-do compile { target c++20 } }
+
+struct S {
+ unsigned a;
+ unsigned b;
+ constexpr S(unsigned _a, unsigned _b) noexcept: a{_a}, b{_b} { }
+};
+
+template<S s> struct X { };
+void g(S);
+
+struct Z {
+ S s;
+ Z() : s{.a = 1, .b = 2} { } // { dg-error "designated initializers|no
matching function" }
+};
+
+S
+f()
+{
+ X<{.a = 1, .b = 2}> x; // { dg-error "designated initializers" }
+ S s{ .a = 1, .b = 2 }; // { dg-error "designated initializers|no matching
function" }
+ S s2 = { .a = 1, .b = 2 }; // { dg-error "designated initializers" }
+ S s3 = S{ .a = 1, .b = 2 }; // { dg-error "designated initializers|no
matching function" }
+ g({.a = 1, .b = 2}); // { dg-error "designated initializers" }
+ g(S{.a = 1, .b = 2}); // { dg-error "designated initializers|no matching
function" }
+ return {.a = 1, .b = 2}; // { dg-error "designated initializers" }
+}
base-commit: c7bac01ab41f019a66bc07fc704752f436707eb8
--
Marek Polacek • Red Hat, Inc. • 300 A St, Boston, MA
