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author | Patrick Palka <ppalka@redhat.com> | 2020-05-29 09:40:40 -0400 |
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committer | Patrick Palka <ppalka@redhat.com> | 2020-05-29 09:44:13 -0400 |
commit | 020d86db8896f088435830595640e6fc21bc64ad (patch) | |
tree | 46a81ae2adc3ed593e8ae5b548f7b9bce73ceb2e /gcc | |
parent | e069285cdf457cc85070e522380c4e25b0d2ed25 (diff) | |
download | gcc-020d86db8896f088435830595640e6fc21bc64ad.zip gcc-020d86db8896f088435830595640e6fc21bc64ad.tar.gz gcc-020d86db8896f088435830595640e6fc21bc64ad.tar.bz2 |
c++: lambdas inside constraints [PR92652]
When parsing a constraint-expression, a requires-clause or a
requires-expression, we temporarily increment processing_template_decl
so that we always obtain template trees which we could later reduce via
substitution even when not inside a template.
But incrementing processing_template_decl when we're already inside a
template has the unintended side effect of shifting up the template
parameter levels of a lambda defined inside one of these constructs,
which leads to confusion later during substitution into the lambda.
This patch fixes this issue by incrementing processing_template_decl
during parsing of these constructs only if it is 0.
Passes 'make check-c++', and also tested by building cmcstl2, does this
look OK to commit after a full bootstrap/regtest?
gcc/cp/ChangeLog:
PR c++/92652
PR c++/93698
PR c++/94128
* parser.c (cp_parser_requires_clause_expression): Temporarily
increment processing_template_decl only if it is 0.
(cp_parser_constraint_expression): Likewise.
(cp_parser_requires_expression): Likewise.
gcc/testsuite/ChangeLog:
PR c++/92652
PR c++/93698
PR c++/94128
* g++.dg/cpp2a/concepts-lambda8.C: New test.
* g++.dg/cpp2a/concepts-lambda9.C: New test.
* g++.dg/cpp2a/concepts-lambda10.C: New test.
Diffstat (limited to 'gcc')
-rw-r--r-- | gcc/cp/parser.c | 21 | ||||
-rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/concepts-lambda10.C | 7 | ||||
-rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/concepts-lambda8.C | 11 | ||||
-rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/concepts-lambda9.C | 11 |
4 files changed, 44 insertions, 6 deletions
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index 54ca875..74c40ef 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -27663,11 +27663,16 @@ static tree cp_parser_requires_clause_expression (cp_parser *parser, bool lambda_p) { processing_constraint_expression_sentinel parsing_constraint; - ++processing_template_decl; + temp_override<int> ovr (processing_template_decl); + if (!processing_template_decl) + /* Adjust processing_template_decl so that we always obtain template + trees here. We don't do the usual ++processing_template_decl + because that would skew the template parameter depth of a lambda + within if we're already inside a template. */ + processing_template_decl = 1; cp_expr expr = cp_parser_constraint_logical_or_expression (parser, lambda_p); if (check_for_bare_parameter_packs (expr)) expr = error_mark_node; - --processing_template_decl; return expr; } @@ -27684,12 +27689,14 @@ static tree cp_parser_constraint_expression (cp_parser *parser) { processing_constraint_expression_sentinel parsing_constraint; - ++processing_template_decl; + temp_override<int> ovr (processing_template_decl); + if (!processing_template_decl) + /* As in cp_parser_requires_clause_expression. */ + processing_template_decl = 1; cp_expr expr = cp_parser_binary_expression (parser, false, true, PREC_NOT_OPERATOR, NULL); if (check_for_bare_parameter_packs (expr)) expr = error_mark_node; - --processing_template_decl; expr.maybe_add_location_wrapper (); return expr; } @@ -27798,9 +27805,11 @@ cp_parser_requires_expression (cp_parser *parser) parms = NULL_TREE; /* Parse the requirement body. */ - ++processing_template_decl; + temp_override<int> ovr (processing_template_decl); + if (!processing_template_decl) + /* As in cp_parser_requires_clause_expression. */ + processing_template_decl = 1; reqs = cp_parser_requirement_body (parser); - --processing_template_decl; if (reqs == error_mark_node) return error_mark_node; } diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda10.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda10.C new file mode 100644 index 0000000..392da31 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda10.C @@ -0,0 +1,7 @@ +// PR c++/94128 +// { dg-do compile { target c++20 } } + +void test(auto param) +requires requires{ { [](auto p){return p;}(param) }; }; + +void test2() { test(1); } diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda8.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda8.C new file mode 100644 index 0000000..c1c9be6 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda8.C @@ -0,0 +1,11 @@ +// PR c++/92652 +// { dg-do compile { target concepts } } + +template < typename T > + requires ([]{return true ;}()) +void h() { } + +int main() +{ + h<int>(); +} diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda9.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda9.C new file mode 100644 index 0000000..6b81ba0 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda9.C @@ -0,0 +1,11 @@ +// PR c++/93698 +// { dg-do compile { target concepts } } + +#include <utility> + +template <int N> +concept foo = []<std::size_t... Is>(std::index_sequence<Is...>) constexpr { + return (Is + ...) > 10; +}(std::make_index_sequence<N>()); + +bool a = foo<7>; |