c++: double non-dep folding from finish_compound_literal [PR104565]

In finish_compound_literal, we perform non-dependent expr folding before
the call to check_narrowing ever since r9-5973.  But ever since r10-7096,
check_narrowing also performs non-dependent expr folding of its own.
This double folding means tsubst will see non-templated trees during the
second folding, which causes a spurious error in the below testcase.

This patch removes the former folding operation; it seems obviated by
the latter one.

	PR c++/104565

gcc/cp/ChangeLog:

	* semantics.c (finish_compound_literal): Don't perform
	non-dependent expr folding before calling check_narrowing.

gcc/testsuite/ChangeLog:

	* g++.dg/template/non-dependent22.C: New test.

(cherry picked from commit 6bbd8afee0036c274f5ebb5b48d6fdc2091bd046)

diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 7069e196d162779c53af86b3a759fab17f1656d7..d447ce8017457de399431596bb21c75f5d30a19a 100644 (file)
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -3109,13 +3109,9 @@ finish_compound_literal (tree type, tree compound_literal,
     return error_mark_node;
   compound_literal = reshape_init (type, compound_literal, complain);
   if (SCALAR_TYPE_P (type)
-      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal))
-    {
-      tree t = instantiate_non_dependent_expr_sfinae (compound_literal,
-                                                     complain);
-      if (!check_narrowing (type, t, complain))
-       return error_mark_node;
-    }
+      && !BRACE_ENCLOSED_INITIALIZER_P (compound_literal)
+      && !check_narrowing (type, compound_literal, complain))
+    return error_mark_node;
   if (TREE_CODE (type) == ARRAY_TYPE
       && TYPE_DOMAIN (type) == NULL_TREE)
     {

diff --git a/gcc/testsuite/g++.dg/template/non-dependent22.C b/gcc/testsuite/g++.dg/template/non-dependent22.C
new file mode 100644 (file)
index 0000000..83a6a13
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/non-dependent22.C
@@ -0,0 +1,12 @@
+// PR c++/104565
+// { dg-do compile { target c++11 } }
+
+struct apa {
+  constexpr int n() const { return 3; }
+};
+
+template<class>
+int f() {
+  apa foo;
+  return int{foo.n()};  // no matching function for call to 'apa::n(apa*)'
+}