A call that is the immediate operand of decltype has special semantics: no
temporary is produced, so it's OK for the return type to be e.g. incomplete.
But we were treating (e | f) the same way, which confused overload
resolution when we then tried to evaluate ... | g.
Fixed by making build_temp do what its name says, and force the C++17
temporary materialization conversion. We could also handle this by
making sure that tf_decltype is only set when appropriate, but we keep
finding more cases where we aren't getting that right yet, and the
approach of this patch is more consistent with the C++17 model.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog:
PR c++/95675
* call.c (build_temp): Wrap a CALL_EXPR in a TARGET_EXPR
if it didn't get one before.
gcc/testsuite/ChangeLog:
PR c++/95675
* g++.dg/cpp0x/decltype-call5.C: New test.
* g++.dg/cpp0x/decltype-call6.C: New test.
---
gcc/cp/call.c | 8 ++++++++
gcc/testsuite/g++.dg/cpp0x/decltype-call5.C | 7 +++++++
gcc/testsuite/g++.dg/cpp0x/decltype-call6.C | 12 ++++++++++++
3 files changed, 27 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/decltype-call5.C
create mode 100644 gcc/testsuite/g++.dg/cpp0x/decltype-call6.C
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 0ba0e19ae08..b00334d0919 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -7291,6 +7291,14 @@ build_temp (tree expr, tree type, int flags,
&& !type_has_nontrivial_copy_init (TREE_TYPE (expr)))
return get_target_expr_sfinae (expr, complain);
+ /* In decltype, we might have decided not to wrap this call in a TARGET_EXPR.
+ But it turns out to be a subexpression, so perform temporary
+ materialization now. */
+ if (TREE_CODE (expr) == CALL_EXPR
+ && CLASS_TYPE_P (type)
+ && same_type_ignoring_top_level_qualifiers_p (type, TREE_TYPE (expr)))
+ expr = build_cplus_new (type, expr, complain);
+
savew = warningcount + werrorcount, savee = errorcount;
releasing_vec args (make_tree_vector_single (expr));
expr = build_special_member_call (NULL_TREE, complete_ctor_identifier,
diff --git a/gcc/testsuite/g++.dg/cpp0x/decltype-call5.C
b/gcc/testsuite/g++.dg/cpp0x/decltype-call5.C
new file mode 100644
index 00000000000..81ef6e6f9c9
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/decltype-call5.C
@@ -0,0 +1,7 @@
+// PR c++/95675
+// { dg-do compile { target c++11 } }
+
+struct b {};
+b operator|(b, b) { return {}; }
+b e, f, g;
+using h = decltype(e | f | g);
diff --git a/gcc/testsuite/g++.dg/cpp0x/decltype-call6.C
b/gcc/testsuite/g++.dg/cpp0x/decltype-call6.C
new file mode 100644
index 00000000000..4173b607689
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/decltype-call6.C
@@ -0,0 +1,12 @@
+// PR c++/95675
+// { dg-do compile { target c++11 } }
+
+struct a {};
+template <typename> struct b;
+template <typename bq, typename br> struct b<bq(br)> {
+ decltype(bq()(br())) c;
+};
+struct e {
+ operator a();
+};
+b<e (*(e))(a)> d;
base-commit: f1b13064609a41fcaf4d1859663453bba237e277
--
2.27.0
