diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index d0477c42afe..808e5b61b1e 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -12878,7 +12878,9 @@ do_range_for_auto_deduction (tree decl, tree range_expr)
 					    RO_UNARY_STAR,
 					    tf_warning_or_error);
 	  TREE_TYPE (decl) = do_auto_deduction (TREE_TYPE (decl),
-						iter_decl, auto_node);
+						iter_decl, auto_node,
+						tf_warning_or_error,
+						adc_variable_type);
 	}
     }
 }
diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-placeholder6.C b/gcc/testsuite/g++.dg/cpp2a/concepts-placeholder6.C
new file mode 100644
index 00000000000..fe1e3927129
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-placeholder6.C
@@ -0,0 +1,10 @@
+// PR c++/99869
+// { dg-do compile { target c++20 } }
+
+template <class T, class U> concept same_as = __is_same(T, U);
+
+template <class>
+void f() {
+  for (same_as<int> auto c : "") {} // { dg-error "constraint" }
+  for (same_as<char> auto c : "") {}
+}