On 10/15/24 12:48 AM, Patrick Palka wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk?
OK.
-- >8 -- Here we're tripping over the assert in extract_locals_r which enforces that an extra-args tree appearing inside another extra-args tree doesn't actually have extra args. This invariant no longer always holds for lambdas (which recently gained the extra-args mechanism), but it should be safe to just disable the assert for them since cp_walk_subtrees doesn't walk LAMBDA_EXPR_EXTRA_ARGS and so should be immune to the PR114303 issue for now. PR c++/117054 gcc/cp/ChangeLog: * pt.cc (extract_locals_r): Disable tree_extra_args assert for LAMBDA_EXPR. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/lambda-targ9.C: New test. --- gcc/cp/pt.cc | 7 ++++++- gcc/testsuite/g++.dg/cpp2a/lambda-targ9.C | 16 ++++++++++++++++ 2 files changed, 22 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/lambda-targ9.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index c7cbf6df26c..b90447ae6a2 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -13479,7 +13479,12 @@ extract_locals_r (tree *tp, int *walk_subtrees, void *data_) outermost tree. Nested *_EXTRA_ARGS should naturally be empty since the outermost (extra-args) tree will intercept any substitution before a nested tree can. */ - gcc_checking_assert (tree_extra_args (*tp) == NULL_TREE); + gcc_checking_assert (tree_extra_args (*tp) == NULL_TREE + /* Except a lambda nested inside an extra-args tree + can have extra args if we deferred partial + substitution into it at template parse time. But + we don't walk LAMBDA_EXPR_EXTRA_ARGS anyway. */ + || TREE_CODE (*tp) == LAMBDA_EXPR);if (TREE_CODE (*tp) == DECL_EXPR){ diff --git a/gcc/testsuite/g++.dg/cpp2a/lambda-targ9.C b/gcc/testsuite/g++.dg/cpp2a/lambda-targ9.C new file mode 100644 index 00000000000..00dd4b2406e --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/lambda-targ9.C @@ -0,0 +1,16 @@ +// PR c++/117054 +// { dg-do compile { target c++20 } } + +template<auto = [] {}> +constexpr bool a = true; + +template<typename> +void f() { + [](auto) { + if constexpr (a<>) {} + }; +} + +int main() { + f<int>(); +}
