From 3aa5db5b1cfe56266b414633dc87ca0be6043aa5 Mon Sep 17 00:00:00 2001
From: q66 <daniel@octaforge.org>
Date: Mon, 20 Feb 2017 18:31:08 +0100
Subject: [PATCH] do not implicitly to_string as a fallback in format

---
 ostd/format.hh | 19 -------------------
 1 file changed, 19 deletions(-)

diff --git a/ostd/format.hh b/ostd/format.hh
index 04e75f6..c2001c1 100644
--- a/ostd/format.hh
+++ b/ostd/format.hh
@@ -173,17 +173,6 @@ namespace detail {
         }
     }
 
-    /* fallback test for whether a value can be converted to string */
-    template<typename T>
-    static std::true_type test_fmt_tostr(
-        decltype(ostd::to_string<T>{}(std::declval<T>())) *
-    );
-    template<typename>
-    static std::false_type test_fmt_tostr(...);
-
-    template<typename T>
-    constexpr bool fmt_tostr_test = decltype(test_fmt_tostr<T>(0))::value;
-
     /* ugly ass check for whether a type is tuple-like, like tuple itself,
      * pair, array, possibly other types added later or overridden...
      */
@@ -734,14 +723,6 @@ private:
             write_float(writer, val);
             return;
         }
-        /* stuff that can be to_string'd, worst reliable case, allocates */
-        if constexpr(detail::fmt_tostr_test<T>) {
-            if (spec() != 's') {
-                throw format_error{"custom objects need the '%s' spec"};
-            }
-            write_val(writer, false, ostd::to_string<T>{}(val));
-            return;
-        }
         /* we ran out of options, failure */
         throw format_error{"the value cannot be formatted"};
     }