On 11/27/24 12:29 PM, Patrick Palka wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk/14/13?
OK.
-- >8 -- Here we end up ICEing at instantiation time for the call to f<local_static> ultimately because we wrongly consider the call to be non-dependent, and so we specialize f ahead of time and then get confused when fully substituting this specialization. The call is dependent due to [temp.dep.temp]/3 and we miss that because function template-id arguments aren't coerced until overload resolution, and so the local static template argument lacks an implicit cast to reference type that value_dependent_expression_p looks for before considering dependence of the address. Other kinds of template-ids aren't affected since they're coerced ahead of time. So when considering dependence of a function template-id, we need to conservatively consider dependence of the address of each argument (if applicable). PR c++/117792 gcc/cp/ChangeLog: * pt.cc (type_dependent_expression_p): Consider the dependence of the address of each template argument of a function template-id. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/nontype7.C: New test. --- gcc/cp/pt.cc | 10 ++++++++-- gcc/testsuite/g++.dg/cpp1z/nontype7.C | 22 ++++++++++++++++++++++ 2 files changed, 30 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp1z/nontype7.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 564e368ff43..2f2ec39b083 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -28864,9 +28864,15 @@ type_dependent_expression_p (tree expression)if (TREE_CODE (expression) == TEMPLATE_ID_EXPR){ - if (any_dependent_template_arguments_p - (TREE_OPERAND (expression, 1))) + tree args = TREE_OPERAND (expression, 1); + if (any_dependent_template_arguments_p (args)) return true; + /* Arguments of a function template-id aren't necessarily coerced + yet so we must conservatively assume that the address (and not + just value) of the argument matters as per [temp.dep.temp]/3. */ + for (tree arg : tree_vec_range (args)) + if (has_value_dependent_address (arg)) + return true; expression = TREE_OPERAND (expression, 0); if (identifier_p (expression)) return true; diff --git a/gcc/testsuite/g++.dg/cpp1z/nontype7.C b/gcc/testsuite/g++.dg/cpp1z/nontype7.C new file mode 100644 index 00000000000..b03c643c987 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1z/nontype7.C @@ -0,0 +1,22 @@ +// PR c++/117792 +// { dg-do compile { target c++17 } } + +template<const int& N, class T> +void f(T) { } + +template<int, class T> +void f(...) = delete; + +template<const int& N> int v; + +template<const int& N> struct A { static const int value = 0; }; + +template<class T> +void g() { + static const int local_static = 0; + auto x = v<local_static>; // OK + auto y = A<local_static>::value; // OK + f<local_static>(0); // ICE +} + +template void g<int>();
