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
