From 29bb9224fcd5aaf7a126f49d2004858a9ba620d5 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Wed, 2 Jan 2019 22:20:45 +0000 Subject: [PATCH] PR c++/88631 - CTAD failing for value-initialization. * typeck2.c (build_functional_cast): Try deducing the template arguments even if there are no arguments to deduce from. * g++.dg/cpp1z/class-deduction59.C: New test. From-SVN: r267533 --- gcc/cp/ChangeLog | 4 ++++ gcc/cp/typeck2.c | 15 ++++++++++++--- gcc/testsuite/ChangeLog | 3 +++ gcc/testsuite/g++.dg/cpp1z/class-deduction59.C | 12 ++++++++++++ 4 files changed, 31 insertions(+), 3 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp1z/class-deduction59.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index fa03419c53e..1ac5832d455 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -4,6 +4,10 @@ * call.c (convert_for_arg_passing): Only give warnings with tf_warning. * typeck.c (convert_for_assignment): Likewise. + PR c++/88631 - CTAD failing for value-initialization. + * typeck2.c (build_functional_cast): Try deducing the template + arguments even if there are no arguments to deduce from. + 2019-01-01 Jakub Jelinek Update copyright years. diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c index 5dec117fb9e..03b24a94ede 100644 --- a/gcc/cp/typeck2.c +++ b/gcc/cp/typeck2.c @@ -2147,9 +2147,18 @@ build_functional_cast (tree exp, tree parms, tsubst_flags_t complain) } else if (!parms) { - if (complain & tf_error) - error ("cannot deduce template arguments for %qT from ()", anode); - return error_mark_node; + /* Even if there are no parameters, we might be able to deduce from + default template arguments. Pass TF_NONE so that we don't + generate redundant diagnostics. */ + type = do_auto_deduction (type, parms, anode, tf_none, + adc_variable_type); + if (type == error_mark_node) + { + if (complain & tf_error) + error ("cannot deduce template arguments for %qT from ()", + anode); + return error_mark_node; + } } else type = do_auto_deduction (type, parms, anode, complain, diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index d2a214b3a1c..b4cf17811ab 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -3,6 +3,9 @@ PR c++/88612 - ICE with -Waddress-of-packed-member. * g++.dg/warn/Waddress-of-packed-member1.C: New test. + PR c++/88631 - CTAD failing for value-initialization. + * g++.dg/cpp1z/class-deduction59.C: New test. + 2019-01-02 Martin Sebor Jeff Law diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction59.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction59.C new file mode 100644 index 00000000000..129d723d07c --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction59.C @@ -0,0 +1,12 @@ +// PR c++/88631 +// { dg-do compile { target c++17 } } + +template +class A { }; + +int main() +{ + auto x = A(); + auto x2 = A{}; + A y; +} -- 2.30.2