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| author | Patrick Palka <ppalka@redhat.com> | 2020-05-13 16:40:10 -0400 |
|---|---|---|
| committer | Giuliano Belinassi <giuliano.belinassi@usp.br> | 2020-08-17 13:03:17 -0300 |
| commit | f7ddd68ce057008b9ddbf973d1b51c94c74110b3 (patch) | |
| tree | 5d9fe12d862c1956d3a37c670c4a4bc0d1b68641 | |
| parent | 996dc0ea9b70b2b5803c5b35caeb975888e51e76 (diff) | |
| download | gcc-f7ddd68ce057008b9ddbf973d1b51c94c74110b3.zip gcc-f7ddd68ce057008b9ddbf973d1b51c94c74110b3.tar.gz gcc-f7ddd68ce057008b9ddbf973d1b51c94c74110b3.tar.bz2 | |
c++: premature requires-expression folding [PR95020]
In the testcase below we're prematurely folding away the
requires-expression to 'true' after substituting in the function's
template arguments, but before substituting in the lambda's deduced
template arguments.
This patch removes the uses_template_parms check when deciding in
tsubst_requires_expr whether to keep around a new requires-expression.
Regardless of whether the template arguments are dependent, there still
might be more template parameters to later substitute in (as in the
below testcase) and even if not, tsubst_expr doesn't perform full
semantic processing unless !processing_template_decl, so we should still
wait until then to fold away the requires-expression.
gcc/cp/ChangeLog:
PR c++/95020
* constraint.c (tsubst_requires_expr): Produce a new
requires-expression when processing_template_decl, even if
template arguments are not dependent.
gcc/testsuite/ChangeLog:
PR c++/95020
* g++/cpp2a/concepts-lambda7.C: New test.
| -rw-r--r-- | gcc/cp/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/cp/constraint.cc | 4 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/concepts-lambda7.C | 14 |
4 files changed, 27 insertions, 3 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 145a5d5..73a6500 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,10 @@ +2020-05-13 Patrick Palka <ppalka@redhat.com> + + PR c++/95020 + * constraint.c (tsubst_requires_expr): Produce a new + requires-expression when processing_template_decl, even if + template arguments are not dependent. + 2020-05-13 Marek Polacek <polacek@redhat.com> PR c++/95066 diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc index 3a17005..eb72bfe 100644 --- a/gcc/cp/constraint.cc +++ b/gcc/cp/constraint.cc @@ -2173,9 +2173,7 @@ tsubst_requires_expr (tree t, tree args, if (reqs == error_mark_node) return boolean_false_node; - /* In certain cases, produce a new requires-expression. - Otherwise the value of the expression is true. */ - if (processing_template_decl && uses_template_parms (args)) + if (processing_template_decl) return finish_requires_expr (cp_expr_location (t), parms, reqs); return boolean_true_node; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index e2dea4d..b88e182 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-05-13 Patrick Palka <ppalka@redhat.com> + + PR c++/95020 + * g++/cpp2a/concepts-lambda7.C: New test. + 2020-05-13 Marek Polacek <polacek@redhat.com> PR c++/95066 diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-lambda7.C b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda7.C new file mode 100644 index 0000000..50746b7 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-lambda7.C @@ -0,0 +1,14 @@ +// PR c++/95020 +// { dg-do compile { target c++2a } } + +template<typename> +void foo() { + auto t = [](auto v) { + static_assert(requires { *v; }); // { dg-error "static assertion failed" } + }; + t(0); +} + +void bar() { + foo<void>(); +} |