From e5d72c840a226fdbab65912f97d42a1dbdaf6ed2 Mon Sep 17 00:00:00 2001 From: Patrick Palka Date: Sat, 19 Sep 2020 11:02:46 -0400 Subject: [PATCH] c++: Fix self-mapping in map_arguments [PR96531, PR97103] With r10-8077 we stopped passing the argified current_template_parms to normalize_constraint_expression from finish_nested_requirement, and instead made map_arguments perform a self-mapping of parameters when args is NULL. But we're currently not handling parameter packs and BOUND_TEMPLATE_TEMPLATE_PARMs properly during this self-mapping, which leads to ICEs later during satisfaction. To properly handle self-mapping of a parameter pack, this patch extends template_parm_to_arg to handle TEMPLATE_PARM_P nodes, and makes map_arguments use it. (This change revealed that the call to template_parm_to_arg in convert_generic_types_to_packs was a no-op because the argument 't' is never a TREE_LIST, so this patch additionally removes this call.) As for bound ttps, map_arguments before r10-8077 would map a BOUND_TEMPLATE_TEMPLATE_PARM not to itself but to its underlying TEMPLATE_TEMPLATE_PARM. We could restore this behavior in map_arguments, but since a bound ttp is not really a template parameter it seems better to make keep_template_parm not give us a bound ttp in the first place. So this patch makes keep_template_parm return the underlying ttp when it sees a bound ttp. gcc/cp/ChangeLog: PR c++/96531 PR c++/97103 * constraint.cc (map_arguments): Call template_parm_to_arg in the self-mapping case. (finish_shorthand_constraint): No need to build a TREE_LIST before calling template_parm_to_arg. * pt.c (template_parm_to_arg): Rewrite to handle TEMPLATE_PARM_P nodes as well as DECL_TEMPLATE_PARM_P nodes, and to make the overlying TREE_LIST node optional. (keep_template_parm): Don't record a BOUND_TEMPLATE_TEMPLATE_PARM, instead record its corresponding TEMPLATE_TEMPLATE_PARM. (convert_generic_types_to_packs): Don't call template_parm_to_arg. gcc/testsuite/ChangeLog: PR c++/96531 PR c++/97103 * g++.dg/cpp2a/concepts-ttp2.C: New test. * g++.dg/cpp2a/concepts-variadic1.C: New test. --- gcc/cp/constraint.cc | 4 +- gcc/cp/pt.c | 43 ++++++++++++------- gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C | 11 +++++ .../g++.dg/cpp2a/concepts-variadic1.C | 28 ++++++++++++ 4 files changed, 68 insertions(+), 18 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc index 8137df59e37..d49957a6c4a 100644 --- a/gcc/cp/constraint.cc +++ b/gcc/cp/constraint.cc @@ -554,7 +554,7 @@ map_arguments (tree parms, tree args) TREE_PURPOSE (p) = TMPL_ARG (args, level, index); } else - TREE_PURPOSE (p) = TREE_VALUE (p); + TREE_PURPOSE (p) = template_parm_to_arg (p); return parms; } @@ -1492,7 +1492,7 @@ finish_shorthand_constraint (tree decl, tree constr) /* Get the argument and overload used for the requirement and adjust it if we're going to expand later. */ - tree arg = template_parm_to_arg (build_tree_list (NULL_TREE, decl)); + tree arg = template_parm_to_arg (decl); if (apply_to_each_p && declared_pack_p) arg = PACK_EXPANSION_PATTERN (TREE_VEC_ELT (ARGUMENT_PACK_ARGS (arg), 0)); diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c index cfe5ff4a94f..fe45de8d796 100644 --- a/gcc/cp/pt.c +++ b/gcc/cp/pt.c @@ -4704,29 +4704,37 @@ end_template_decl (void) current_template_parms = TREE_CHAIN (current_template_parms); } -/* Takes a TREE_LIST representing a template parameter and convert it - into an argument suitable to be passed to the type substitution - functions. Note that If the TREE_LIST contains an error_mark - node, the returned argument is error_mark_node. */ +/* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST + thereof, and converts it into an argument suitable to be passed to + the type substitution functions. Note that if the TREE_LIST contains + an error_mark node, the returned argument is error_mark_node. */ tree template_parm_to_arg (tree t) { + if (!t) + return NULL_TREE; - if (t == NULL_TREE - || TREE_CODE (t) != TREE_LIST) - return t; + if (TREE_CODE (t) == TREE_LIST) + t = TREE_VALUE (t); - if (error_operand_p (TREE_VALUE (t))) + if (error_operand_p (t)) return error_mark_node; - t = TREE_VALUE (t); - - if (TREE_CODE (t) == TYPE_DECL - || TREE_CODE (t) == TEMPLATE_DECL) + if (DECL_P (t) && DECL_TEMPLATE_PARM_P (t)) { - t = TREE_TYPE (t); + if (TREE_CODE (t) == TYPE_DECL + || TREE_CODE (t) == TEMPLATE_DECL) + t = TREE_TYPE (t); + else + t = DECL_INITIAL (t); + } + gcc_assert (TEMPLATE_PARM_P (t)); + + if (TREE_CODE (t) == TEMPLATE_TYPE_PARM + || TREE_CODE (t) == TEMPLATE_TEMPLATE_PARM) + { if (TEMPLATE_TYPE_PARAMETER_PACK (t)) { /* Turn this argument into a TYPE_ARGUMENT_PACK @@ -4743,8 +4751,6 @@ template_parm_to_arg (tree t) } else { - t = DECL_INITIAL (t); - if (TEMPLATE_PARM_PARAMETER_PACK (t)) { /* Turn this argument into a NONTYPE_ARGUMENT_PACK @@ -10539,6 +10545,11 @@ keep_template_parm (tree t, void* data) if (level > ftpi->max_depth) return 0; + if (TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM) + /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the + BOUND_TEMPLATE_TEMPLATE_PARM itself. */ + t = TREE_TYPE (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (t)); + /* Arguments like const T yield parameters like const T. This means that a template-id like X would yield two distinct parameters: T and const T. Adjust types to their unqualified versions. */ @@ -29448,7 +29459,7 @@ convert_generic_types_to_packs (tree parm, int start_idx, int end_idx) if (tree constr = TEMPLATE_PARM_CONSTRAINTS (node)) { tree id = unpack_concept_check (constr); - TREE_VEC_ELT (TREE_OPERAND (id, 1), 0) = template_parm_to_arg (t); + TREE_VEC_ELT (TREE_OPERAND (id, 1), 0) = t; tree fold = finish_left_unary_fold_expr (constr, TRUTH_ANDIF_EXPR); TEMPLATE_PARM_CONSTRAINTS (node) = fold; diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C b/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C new file mode 100644 index 00000000000..7f4883754dd --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-ttp2.C @@ -0,0 +1,11 @@ +// PR c++/97103 +// { dg-do compile { target c++20 } } + +template +class quantity {}; + +template typename Q> +inline constexpr bool valid_template_arguments = requires { + requires requires { typename Q; }; +}; +static_assert(valid_template_arguments); diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C b/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C new file mode 100644 index 00000000000..deab028ca3c --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-variadic1.C @@ -0,0 +1,28 @@ +// PR c++/96531 +// { dg-do compile { target c++20 } } + +template +concept is_bool = __is_same(bool, T); + +template +concept C = requires { + requires (is_bool || ...); +}; + +template +concept D = requires { + requires (Bs || ...); +}; + +template +requires C +void bar() {} + +template +requires D +void baz() {} + +int main() { + bar(); + baz(); +}