c++: fix ICE on FUNCTION_DECLs inside coroutines [PR115906]

When register_local_var_uses iterates a BIND_EXPRs BIND_EXPR_VARS, it
fails to account for the fact that FUNCTION_DECLs might be present, and
later passes it to DECL_HAS_VALUE_EXPR_P.  This leads to a tree check
failure in DECL_HAS_VALUE_EXPR_P:

  tree check: expected var_decl or parm_decl or result_decl, have
  function_decl in register_local_var_uses

We only care about PARM_DECL and VAR_DECL, so select only those.

PR c++/115906 - [coroutines] missing diagnostic and ICE when co_await used as default argument in function declaration

gcc/cp/ChangeLog:

	PR c++/115906
	* coroutines.cc (register_local_var_uses): Only process
	PARM_DECL and VAR_DECLs.

gcc/testsuite/ChangeLog:

	PR c++/115906
	* g++.dg/coroutines/coro-function-decl.C: New test.

(cherry picked from commit a362c9ca4ef6585e678f899705043a9aa10dd670)

diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index 200789e8910264492ab70bcc610a5358b900be59..5fe9ec422c344322365a33cdfa8869b64bba3c59 100644 (file)
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -3914,8 +3914,8 @@ register_local_var_uses (tree *stmt, int *do_subtree, void *d)
          local_var.field_idx = local_var.field_id = NULL_TREE;
 
          /* Make sure that we only present vars to the tests below.  */
-         if (TREE_CODE (lvar) == TYPE_DECL
-             || TREE_CODE (lvar) == NAMESPACE_DECL)
+         if (TREE_CODE (lvar) != PARM_DECL
+             && TREE_CODE (lvar) != VAR_DECL)
            continue;
 
          /* We don't move static vars into the frame. */

diff --git a/gcc/testsuite/g++.dg/coroutines/coro-function-decl.C b/gcc/testsuite/g++.dg/coroutines/coro-function-decl.C
new file mode 100644 (file)
index 0000000..8614056
--- /dev/null
+++ b/gcc/testsuite/g++.dg/coroutines/coro-function-decl.C
@@ -0,0 +1,19 @@
+#include <coroutine>
+
+struct task
+{
+  struct promise_type
+  {
+    std::suspend_always initial_suspend () { return {}; }
+    std::suspend_always final_suspend () noexcept { return {}; }
+    void unhandled_exception () {}
+    task get_return_object () noexcept { return {}; }
+    void return_void () {}
+  };
+};
+
+task foo ()
+{
+  void bar ();
+  co_return;
+}