From e3b60da8e07030b1417067295f047b25015f21f2 Mon Sep 17 00:00:00 2001 From: Marek Polacek Date: Wed, 29 Jan 2020 12:02:14 -0500 Subject: [PATCH] c++: Fix template arguments comparison with class NTTP [PR91754] Here we fail to compile the attached test, stating that the use of T in T::T() {} is "invalid use of incomplete type". It is a function definition so grokdeclarator checks that the qualifying type is complete. When we parsed the class T, finish_struct gave the class a non-null TYPE_SIZE, making it COMPLETE_TYPE_P. But then we're parsing T, a TEMPLATE_ID, in T::T() {} so try to lookup_template_class T. This failed because we couldn't find such a class: comp_template_args told us that the argument lists don't match, because one of the args was wrapped in a VIEW_CONVERT_EXPR to make it look const. It seems to me that we should see through these artificial wrappers and consider the args same. 2020-01-29 Marek Polacek PR c++/91754 - Fix template arguments comparison with class NTTP. * pt.c (class_nttp_const_wrapper_p): New. (template_args_equal): See through class_nttp_const_wrapper_p arguments. * g++.dg/cpp2a/nontype-class30.C: New test. --- gcc/cp/ChangeLog | 7 +++++++ gcc/cp/pt.c | 18 ++++++++++++++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/g++.dg/cpp2a/nontype-class30.C | 15 +++++++++++++++ 4 files changed, 45 insertions(+) create mode 100644 gcc/testsuite/g++.dg/cpp2a/nontype-class30.C diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 10ef4193125..3029714d282 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,5 +1,12 @@ 2020-01-29 Marek Polacek + PR c++/91754 - Fix template arguments comparison with class NTTP. + * pt.c (class_nttp_const_wrapper_p): New. + (template_args_equal): See through class_nttp_const_wrapper_p + arguments. + +2020-01-29 Marek Polacek + PR c++/92948 - Fix class NTTP with template arguments. * pt.c (convert_nontype_argument): Use IMPLICIT_CONV_EXPR when converting a value-dependent expression to a class type. diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index fccf4e95453..416ff63ca3c 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -8989,6 +8989,19 @@ coerce_innermost_template_parms (tree parms, return coerced_args; } +/* Returns true if T is a wrapper to make a C++20 template parameter + object const. */ + +static bool +class_nttp_const_wrapper_p (tree t) +{ + if (cxx_dialect < cxx2a) + return false; + return (TREE_CODE (t) == VIEW_CONVERT_EXPR + && CP_TYPE_CONST_P (TREE_TYPE (t)) + && TREE_CODE (TREE_OPERAND (t, 0)) == TEMPLATE_PARM_INDEX); +} + /* Returns 1 if template args OT and NT are equivalent. */ int @@ -9001,6 +9014,11 @@ template_args_equal (tree ot, tree nt, bool partial_order /* = false */) if (nt == any_targ_node || ot == any_targ_node) return true; + if (class_nttp_const_wrapper_p (nt)) + nt = TREE_OPERAND (nt, 0); + if (class_nttp_const_wrapper_p (ot)) + ot = TREE_OPERAND (ot, 0); + if (TREE_CODE (nt) == TREE_VEC) /* For member templates */ return TREE_CODE (ot) == TREE_VEC && comp_template_args (ot, nt); diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index a8db2cbfd66..e38c4da8d72 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,5 +1,10 @@ 2020-01-29 Marek Polacek + PR c++/91754 - Fix template arguments comparison with class NTTP. + * g++.dg/cpp2a/nontype-class30.C: New test. + +2020-01-29 Marek Polacek + PR c++/92948 - Fix class NTTP with template arguments. * g++.dg/cpp2a/nontype-class28.C: New test. * g++.dg/cpp2a/nontype-class29.C: New test. diff --git a/gcc/testsuite/g++.dg/cpp2a/nontype-class30.C b/gcc/testsuite/g++.dg/cpp2a/nontype-class30.C new file mode 100644 index 00000000000..b2e174c7fd3 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/nontype-class30.C @@ -0,0 +1,15 @@ +// PR c++/91754 - Fix template arguments comparison with class NTTP. +// { dg-do compile { target c++2a } } + +struct S {}; + +template +struct T { + T(); +}; + +template +T::T() {} + +S s; +T t; -- 2.11.4.GIT