In a SFINAE context composite_pointer_type returns error_mark_node if the given pointer types are incompatible, but the SPACESHIP_EXPR case of cp_build_binary_op wasn't prepared to handle error_mark_node, which led to an ICE (from spaceship_comp_cat) for the below testcase where we form a <=> with incompatible pointer operands.
(In a non-SFINAE context composite_pointer_type issues a permerror and returns cv void* in this case, so no ICE.) Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk/12? PR c++/107542 gcc/cp/ChangeLog: * typeck.cc (cp_build_binary_op): Handle result_type being error_mark_node in the SPACESHIP_EXPR case. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/spaceship-sfinae2.C: New test. --- gcc/cp/typeck.cc | 5 ++-- .../g++.dg/cpp2a/spaceship-sfinae2.C | 29 +++++++++++++++++++ 2 files changed, 32 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-sfinae2.C diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc index f0e7452f3a0..10b7ed020f7 100644 --- a/gcc/cp/typeck.cc +++ b/gcc/cp/typeck.cc @@ -6215,8 +6215,9 @@ cp_build_binary_op (const op_location_t &location, tree_code orig_code0 = TREE_CODE (orig_type0); tree orig_type1 = TREE_TYPE (orig_op1); tree_code orig_code1 = TREE_CODE (orig_type1); - if (!result_type) - /* Nope. */; + if (!result_type || result_type == error_mark_node) + /* Nope. */ + result_type = NULL_TREE; else if ((orig_code0 == BOOLEAN_TYPE) != (orig_code1 == BOOLEAN_TYPE)) /* "If one of the operands is of type bool and the other is not, the program is ill-formed." */ diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-sfinae2.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-sfinae2.C new file mode 100644 index 00000000000..52ff038b36f --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-sfinae2.C @@ -0,0 +1,29 @@ +// PR c++/107542 +// { dg-do compile { target c++20 } } + +#include <compare> + +template<class T, class U> +concept same_as = __is_same(T, U); + +template<class Lhs, class Rhs> +concept Ord = requires(const Lhs& lhs, const Rhs& rhs) { + { lhs <=> rhs } -> same_as<std::strong_ordering>; +}; + +static_assert(Ord<int*, int*>); // Works. +static_assert(!Ord<int*, char*>); // ICE. + +template<class T> +struct S { + T* p; +}; + +template<class T, class U> + requires(Ord<const T*, const U*>) +constexpr inline auto operator<=>(const S<T>& l, const S<U>& r) noexcept { + return l.p <=> r.p; +} + +static_assert(Ord<S<int>, S<int>>); // Works. +static_assert(!Ord<S<int>, S<char>>); // ICE. -- 2.39.0.rc0.49.g083e01275b