On Feb 28, 2018, Jason Merrill <ja...@redhat.com> wrote:
> On Wed, Feb 28, 2018 at 7:06 AM, Alexandre Oliva <aol...@redhat.com> wrote:
>> We ICEd when returning a stmt expr that ends with an overloaded
>> function. It's ill-formed when we can't convert the function name to
>> the return type, but we should say that, not ICE.
> Hmm, what about the case where we could convert the function name to
> the return type? I think it should still be ill-formed for a
> statement-expression to have an unresolved overload as its value.
I was (not :-) thinking in those terms; I suppose one might wish ({x;})
to be equivalent to (x), but one might also wish for stmt exprs to be
self-contained, and I suppose you prefer the latter, or that there's
consensus about how the stmt expr extension should be handled in this
regard, so...
> So finish_stmt_expr_expr should check type_unknown_p.
[PR c++/84492] stmt expr ending with overload
We ICEd when returning a stmt expr that ends with an overloaded
function, because instantiate_type did not know what to do with
STMT_EXPRs. And it shouldn't have to: the expected type of a stmt
expr cannot be used to resolve its value: an unresolved overload
cannot supply the result of a stmt expr. Catch that and report the
error in the stmt expr before we have a chance to instantiate it.
Regstrapped on i686- and x86_64-linux-gnu. Ok?
for gcc/cp/ChangeLog
PR c++/84492
* semantics.c (finish_stmt_expr_expr): Reject unresolved
overloads used as stmt expr values.
for gcc/testsuite/ChangeLog
PR c++/84492
* g++.dg/pr84492.C: New.
---
gcc/cp/semantics.c | 9 ++++++++-
gcc/testsuite/g++.dg/pr84492.C | 40 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 48 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/pr84492.C
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 1ac1d23e7610..af401866b569 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -2115,7 +2115,14 @@ finish_stmt_expr_expr (tree expr, tree stmt_expr)
{
tree type = TREE_TYPE (expr);
- if (processing_template_decl)
+ if (type && type_unknown_p (type))
+ {
+ error ("a statement expression is an insufficient context"
+ " for overload resolution");
+ TREE_TYPE (stmt_expr) = error_mark_node;
+ return error_mark_node;
+ }
+ else if (processing_template_decl)
{
expr = build_stmt (input_location, EXPR_STMT, expr);
expr = add_stmt (expr);
diff --git a/gcc/testsuite/g++.dg/pr84492.C b/gcc/testsuite/g++.dg/pr84492.C
new file mode 100644
index 000000000000..1a2922096d19
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr84492.C
@@ -0,0 +1,40 @@
+// { dg-do compile }
+// { dg-options "-fpermissive" }
+
+template<int> int foo()
+{
+ return ({ foo; }); // { dg-error "insufficient context" }
+}
+
+int bar()
+{
+ return ({ foo; }); // { dg-error "insufficient context" }
+}
+
+void bar(int);
+
+typedef void (*bart)(int);
+
+bart barf()
+{
+ return ({ bar; }); // { dg-error "insufficient context" }
+}
+
+bool bark()
+{
+ return ({ barf; }); // ok, no overload
+}
+
+template <typename T>
+class C
+{
+ static int f();
+ bool g()
+ {
+ return ({ f; }); // ok, no overload
+ }
+ bool g(int)
+ {
+ return ({ g; }); // { dg-error "insufficient context" }
+ }
+};
--
Alexandre Oliva, freedom fighter http://FSFLA.org/~lxoliva/
You must be the change you wish to see in the world. -- Gandhi
Be Free! -- http://FSFLA.org/ FSF Latin America board member
Free Software Evangelist|Red Hat Brasil GNU Toolchain Engineer
