When building up *_EXTRA_ARGS for a constexpr if or pack expansion, we need
to walk into the body of a lambda to find all the local_specializations that
we need to remember, like we do in find_parameter_packs_r.
Tested x86_64-pc-linux-gnu, applying to trunk.
gcc/cp/ChangeLog:
PR c++/99201
* pt.c (class el_data): Add visited field.
(extract_local_specs): Pass it to cp_walk_tree.
(extract_locals_r): Walk into the body of a lambda.
gcc/testsuite/ChangeLog:
PR c++/99201
* g++.dg/cpp1z/constexpr-if-lambda4.C: New test.
---
gcc/cp/pt.c | 15 ++++++++++++-
.../g++.dg/cpp1z/constexpr-if-lambda4.C | 22 +++++++++++++++++++
2 files changed, 36 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp1z/constexpr-if-lambda4.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 2763aa15f1f..1d19a59dd62 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -12757,7 +12757,11 @@ tsubst_binary_right_fold (tree t, tree args,
tsubst_flags_t complain,
class el_data
{
public:
+ /* Set of variables declared within the pattern. */
hash_set<tree> internal;
+ /* Set of AST nodes that have been visited by the traversal. */
+ hash_set<tree> visited;
+ /* List of local_specializations used within the pattern. */
tree extra;
tsubst_flags_t complain;
@@ -12777,6 +12781,15 @@ extract_locals_r (tree *tp, int */*walk_subtrees*/,
void *data_)
if (TREE_CODE (*tp) == DECL_EXPR)
data.internal.add (DECL_EXPR_DECL (*tp));
+ else if (TREE_CODE (*tp) == LAMBDA_EXPR)
+ {
+ /* Since we defer implicit capture, look in the parms and body. */
+ tree fn = lambda_function (*tp);
+ cp_walk_tree (&TREE_TYPE (fn), &extract_locals_r, &data,
+ &data.visited);
+ cp_walk_tree (&DECL_SAVED_TREE (fn), &extract_locals_r, &data,
+ &data.visited);
+ }
else if (tree spec = retrieve_local_specialization (*tp))
{
if (data.internal.contains (*tp))
@@ -12833,7 +12846,7 @@ static tree
extract_local_specs (tree pattern, tsubst_flags_t complain)
{
el_data data (complain);
- cp_walk_tree_without_duplicates (&pattern, extract_locals_r, &data);
+ cp_walk_tree (&pattern, extract_locals_r, &data, &data.visited);
return data.extra;
}
diff --git a/gcc/testsuite/g++.dg/cpp1z/constexpr-if-lambda4.C
b/gcc/testsuite/g++.dg/cpp1z/constexpr-if-lambda4.C
new file mode 100644
index 00000000000..99408025629
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/constexpr-if-lambda4.C
@@ -0,0 +1,22 @@
+// PR c++/99201
+// { dg-do compile { target c++17 } }
+
+template <typename RefF>
+ auto
+ make_tester(const RefF& reffun)
+ {
+ return [=](auto in) {
+ auto&& expected = [&](const auto&... vs) {
+ if constexpr (sizeof(in) > 0)
+ return [&](int i) { return reffun(vs[i]...); }(0);
+ else
+ return [&](int i) { return reffun(vs[i]...); }(0);
+ };
+ };
+ }
+
+int main()
+{
+ make_tester([](int x) { return x; })(0);
+ return 0;
+}
base-commit: a44a753a35542f86e82e198595ce3553f6d718f6
--
2.27.0
