diff options
| -rw-r--r-- | gcc/cp/pt.cc | 5 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/cpp2a/class-deduction-alias24.C | 16 |
2 files changed, 21 insertions, 0 deletions
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 538ff22..39c0ee6 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -15920,6 +15920,11 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain, if (TYPE_USER_ALIGN (TREE_TYPE (t))) TREE_TYPE (r) = build_aligned_type (TREE_TYPE (r), TYPE_ALIGN (TREE_TYPE (t))); + + /* Preserve structural-ness of a partially instantiated typedef. */ + if (TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (t)) + && dependent_type_p (TREE_TYPE (r))) + SET_TYPE_STRUCTURAL_EQUALITY (TREE_TYPE (r)); } layout_decl (r, 0); diff --git a/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias24.C b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias24.C new file mode 100644 index 0000000..cceddac --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp2a/class-deduction-alias24.C @@ -0,0 +1,16 @@ +// PR c++/119379 +// { dg-do compile { target c++20 } } + +template<class T, class U> +struct pair { + pair(T, U); +}; + +template<class T> +struct S { + template<class U> requires true + using P = pair<T, U>; +}; + +using type = decltype(S<int>::P(1, 2)); +using type = S<int>::P<int>; |