PR c++/88795 reports an ICE building a function_type for a deduction guide
when the substitution into the function signature fails, due to an
error_mark_node being returned from tsubst_arg_types but not being checked
for. This error_mark_node gets used as the TYPE_ARG_TYPES, leading to
ICEs in various places that assume this is a TREE_LIST.
This patch checks the result of tsubst_arg_types and propagates the failure
if it returns error_mark_node. It also adds an assertion to
build_function_type, to fail faster if passed in error_mark_node.
Successfully bootstrapped & regrtested on x86_64-pc-linux-gnu.
OK for trunk?
gcc/cp/ChangeLog:
PR c++/88795
* pt.c (build_deduction_guide): Bail out if tsubst_arg_types
fails.
gcc/testsuite/ChangeLog:
PR c++/88795
* g++.dg/template/pr88795.C: New test.
gcc/ChangeLog:
PR c++/88795
* tree.c (build_function_type): Assert that arg_types is not
error_mark_node.
---
gcc/cp/pt.c | 2 ++
gcc/testsuite/g++.dg/template/pr88795.C | 23 +++++++++++++++++++++++
gcc/tree.c | 2 ++
3 files changed, 27 insertions(+)
create mode 100644 gcc/testsuite/g++.dg/template/pr88795.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 9473241..ba3b112 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -26909,6 +26909,8 @@ build_deduction_guide (tree ctor, tree outer_args,
tsubst_flags_t complain)
targs = template_parms_to_args (tparms);
fparms = tsubst_arg_types (fparms, tsubst_args, NULL_TREE,
complain, ctor);
+ if (fparms == error_mark_node)
+ ok = false;
fargs = tsubst (fargs, tsubst_args, complain, ctor);
if (ci)
ci = tsubst_constraint_info (ci, tsubst_args, complain, ctor);
diff --git a/gcc/testsuite/g++.dg/template/pr88795.C
b/gcc/testsuite/g++.dg/template/pr88795.C
new file mode 100644
index 0000000..918aa6d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/pr88795.C
@@ -0,0 +1,23 @@
+// { dg-do compile { target c++17 } }
+
+template<class, int>
+struct Array {};
+
+template<class T, int size_>
+struct Foo {
+ static constexpr int size() {
+ return size_;
+ }
+
+ template<class U>
+ Foo(U, Array<T, size()>) {}
+};
+
+template<class T, int size, class U>
+Foo(U, Array<T, size>) -> Foo<T, size>;
+
+int main() {
+ Array<int, 2> arr{};
+
+ Foo foo{2.0, arr};
+}
diff --git a/gcc/tree.c b/gcc/tree.c
index 2c0a09d..850fc61 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -8455,6 +8455,8 @@ build_function_type (tree value_type, tree arg_types)
bool any_structural_p, any_noncanonical_p;
tree canon_argtypes;
+ gcc_assert (arg_types != error_mark_node);
+
if (TREE_CODE (value_type) == FUNCTION_TYPE)
{
error ("function return type cannot be function");
--
1.8.5.3
