On 9/10/25 2:13 PM, Nathaniel Shead wrote:
Bootstrapped and regtested on x86_64-pc-linux-gnu, OK for trunk?
OK.
-- >8 -- A static member template doesn't always have a DECL_INITIAL, as in the below testcase, and so checking its TREE_CODE performs a null-pointer dereference. I don't think we need to specially detect this case as traits we care about are unlikely to be members, so this just adds the missing null check. PR c++/121859 gcc/cp/ChangeLog: * constraint.cc (maybe_diagnose_standard_trait): Check if expr is non-null. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-traits5.C: New test. Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com> --- gcc/cp/constraint.cc | 2 +- gcc/testsuite/g++.dg/cpp2a/concepts-traits5.C | 14 ++++++++++++++ 2 files changed, 15 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-traits5.C diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc index 4b20b791e5d..309ebc81324 100644 --- a/gcc/cp/constraint.cc +++ b/gcc/cp/constraint.cc @@ -3360,7 +3360,7 @@ maybe_diagnose_standard_trait (location_t loc, tree expr) } }- if (TREE_CODE (expr) == TRAIT_EXPR)+ if (expr && TREE_CODE (expr) == TRAIT_EXPR) { diagnose_trait_expr (loc, expr, args); return true; diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-traits5.C b/gcc/testsuite/g++.dg/cpp2a/concepts-traits5.C new file mode 100644 index 00000000000..de99dcd13c8 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-traits5.C @@ -0,0 +1,14 @@ +// PR c++/121859 +// { dg-do compile { target c++20 } } + +template <typename T> +struct S { + template <typename U> + static constexpr bool foo = sizeof(T) == sizeof(U); +}; + +template <typename U> void bar(U x) requires S<char>::foo<U> {} + +int main() { + bar(double{}); // { dg-error "no matching function" } +}
