When substituting into sizeof(expr), tsubst_copy_and_build elides substitution into the operand if args is NULL_TREE, and instead considers the TREE_TYPE of the operand. But here the (templated) operand is a TEMPLATE_ID_EXPR with empty TREE_TYPE, so we can't elide substitution in this case.
Contrary to the associated comment (dating back to r69130) substituting args=NULL_TREE should generally work since we do exactly that in e.g. fold_non_dependent_expr, and I don't see why the operand of sizeof would be an exception. So this patch just removes this special case. Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for trunk? Diff generated with -w to ignore noisy whitespace changes. PR c++/108563 gcc/cp/ChangeLog: * pt.cc (tsubst_copy_and_build) <case SIZEOF_EXPR>: Remove special case for empty args. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/concepts-requires35.C: New test. --- gcc/cp/pt.cc | 25 ++++++------------- .../g++.dg/cpp2a/concepts-requires35.C | 14 +++++++++++ 2 files changed, 21 insertions(+), 18 deletions(-) create mode 100644 gcc/testsuite/g++.dg/cpp2a/concepts-requires35.C diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 9f3fc1fa089..f21d28263d1 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -20652,25 +20652,14 @@ tsubst_copy_and_build (tree t, op1 = TREE_TYPE (op1); bool std_alignof = (TREE_CODE (t) == ALIGNOF_EXPR && ALIGNOF_EXPR_STD_P (t)); - if (!args) - { - /* When there are no ARGS, we are trying to evaluate a - non-dependent expression from the parser. Trying to do - the substitutions may not work. */ - if (!TYPE_P (op1)) - op1 = TREE_TYPE (op1); - } + ++cp_unevaluated_operand; + ++c_inhibit_evaluation_warnings; + if (TYPE_P (op1)) + op1 = tsubst (op1, args, complain, in_decl); else - { - ++cp_unevaluated_operand; - ++c_inhibit_evaluation_warnings; - if (TYPE_P (op1)) - op1 = tsubst (op1, args, complain, in_decl); - else - op1 = tsubst_copy_and_build (op1, args, complain, in_decl); - --cp_unevaluated_operand; - --c_inhibit_evaluation_warnings; - } + op1 = tsubst_copy_and_build (op1, args, complain, in_decl); + --cp_unevaluated_operand; + --c_inhibit_evaluation_warnings; if (TYPE_P (op1)) r = cxx_sizeof_or_alignof_type (input_location, op1, TREE_CODE (t), std_alignof, diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-requires35.C b/gcc/testsuite/g++.dg/cpp2a/concepts-requires35.C new file mode 100644 index 00000000000..2bb4b2b0b5d --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/concepts-requires35.C @@ -0,0 +1,14 @@ +// PR c++/108563 +// { dg-do compile { target c++20 } } + +template<class T> +struct foo { + static constexpr T value = 0; +}; + +template<class T> +inline constexpr T foo_v = foo<T>::value; + +static_assert(requires { sizeof(foo_v<int>); }); +static_assert(requires { requires sizeof(foo_v<int*>) == sizeof(int*); }); +static_assert(requires { requires sizeof(foo_v<char>) == sizeof(char); }); -- 2.39.1.418.g7876265d61