From b36b249ac4ecfc59e7c0d8a555ed6b070a7433d7 Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler@nvidia.com>
Date: Thu, 19 Dec 2024 09:24:48 -0800
Subject: [PATCH] [flang] Silence inappropriate error message

A recent patch added better compatibility checking for actual
procedure arguments, but it has led to a few failures in the Fujitsu
Fortran test suite in cases of NULL() actual arguments being
associated with dummy procedure pointers.  As is the case with
dummy data pointers, these must always be accepted.

Fixes Fujitsu Fortran test cases 0249_0023 through 0028 and
0387_0047.
---
 flang/lib/Semantics/expression.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index c2eb17c1ac8e5..4a986cb51b1b1 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -2536,6 +2536,15 @@ static bool CheckCompatibleArgument(bool isElemental,
             return false;
           },
           [&](const characteristics::DummyProcedure &dummy) {
+            if ((dummy.attrs.test(
+                     characteristics::DummyProcedure::Attr::Optional) ||
+                    dummy.attrs.test(
+                        characteristics::DummyProcedure::Attr::Pointer)) &&
+                IsBareNullPointer(expr)) {
+              // NULL() is compatible with any dummy pointer
+              // or optional dummy procedure.
+              return true;
+            }
             if (!expr || !IsProcedurePointerTarget(*expr)) {
               return false;
             }