From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Wed, 22 Mar 2023 23:07:51 +0000 (-0600)
Subject: Fix a couple of C++20 concepts in parallel.h.
X-Git-Tag: v9.5.0-rc1~430^2
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=96e557fe09c3254708fbc5915e8459a18e164d6e;p=dealii.git

Fix a couple of C++20 concepts in parallel.h.
---

diff --git a/include/deal.II/base/parallel.h b/include/deal.II/base/parallel.h
index 4da420b7eb..6ac43510e3 100644
--- a/include/deal.II/base/parallel.h
+++ b/include/deal.II/base/parallel.h
@@ -134,9 +134,11 @@ namespace parallel
    */
   template <typename InputIterator, typename OutputIterator, typename Function>
   DEAL_II_CXX20_REQUIRES(
-    (std::invocable<Function, InputIterator> &&
-     std::assignable_from<decltype(*std::declval<OutputIterator>()),
-                          std::invoke_result_t<Function, InputIterator>>))
+    (std::invocable<Function, decltype(*std::declval<InputIterator>())> &&
+     std::assignable_from<
+       decltype(*std::declval<OutputIterator>()),
+       std::invoke_result_t<Function,
+                            decltype(*std::declval<InputIterator>())>>))
   void transform(const InputIterator &begin_in,
                  const InputIterator &end_in,
                  OutputIterator       out,
@@ -196,10 +198,14 @@ namespace parallel
             typename OutputIterator,
             typename Function>
   DEAL_II_CXX20_REQUIRES(
-    (std::invocable<Function, InputIterator1, InputIterator2> &&
+    (std::invocable<Function,
+                    decltype(*std::declval<InputIterator1>()),
+                    decltype(*std::declval<InputIterator2>())> &&
      std::assignable_from<
        decltype(*std::declval<OutputIterator>()),
-       std::invoke_result_t<Function, InputIterator1, InputIterator2>>))
+       std::invoke_result_t<Function,
+                            decltype(*std::declval<InputIterator1>()),
+                            decltype(*std::declval<InputIterator2>())>>))
   void transform(const InputIterator1 &begin_in1,
                  const InputIterator1 &end_in1,
                  InputIterator2        in2,
@@ -262,12 +268,16 @@ namespace parallel
             typename OutputIterator,
             typename Function>
   DEAL_II_CXX20_REQUIRES(
-    (std::invocable<Function, InputIterator1, InputIterator2, InputIterator3> &&
-     std::assignable_from<decltype(*std::declval<OutputIterator>()),
-                          std::invoke_result_t<Function,
-                                               InputIterator1,
-                                               InputIterator2,
-                                               InputIterator3>>))
+    (std::invocable<Function,
+                    decltype(*std::declval<InputIterator1>()),
+                    decltype(*std::declval<InputIterator2>()),
+                    decltype(*std::declval<InputIterator3>())> &&
+     std::assignable_from<
+       decltype(*std::declval<OutputIterator>()),
+       std::invoke_result_t<Function,
+                            decltype(*std::declval<InputIterator1>()),
+                            decltype(*std::declval<InputIterator2>()),
+                            decltype(*std::declval<InputIterator3>())>>))
   void transform(const InputIterator1 &begin_in1,
                  const InputIterator1 &end_in1,
                  InputIterator2        in2,