From 5491fdf559ec68039a218bab6bf41901611554f0 Mon Sep 17 00:00:00 2001
From: Peixin-Qiao <qiaopeixin@huawei.com>
Date: Wed, 1 Jun 2022 14:38:46 +0800
Subject: [PATCH] [flang] Add semantic check for named constant as function
 result

Similar to procedure argument, the function result cannot be one
named constant.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D126693
---
 flang/lib/Semantics/check-declarations.cpp | 4 ++++
 flang/test/Semantics/declarations01.f90    | 8 ++++++++
 2 files changed, 12 insertions(+)
 create mode 100644 flang/test/Semantics/declarations01.f90

diff --git a/flang/lib/Semantics/check-declarations.cpp b/flang/lib/Semantics/check-declarations.cpp
index 6b559545e448..805d89075e3f 100644
--- a/flang/lib/Semantics/check-declarations.cpp
+++ b/flang/lib/Semantics/check-declarations.cpp
@@ -351,6 +351,10 @@ void CheckHelper::Check(const Symbol &symbol) {
           "A dummy argument may not have the SAVE attribute"_err_en_US);
     }
   } else if (IsFunctionResult(symbol)) {
+    if (IsNamedConstant(symbol)) {
+      messages_.Say(
+          "A function result may not also be a named constant"_err_en_US);
+    }
     if (!symbol.test(Symbol::Flag::InDataStmt) /*caught elsewhere*/ &&
         IsSaved(symbol)) {
       messages_.Say(
diff --git a/flang/test/Semantics/declarations01.f90 b/flang/test/Semantics/declarations01.f90
new file mode 100644
index 000000000000..f3673a7ed0d1
--- /dev/null
+++ b/flang/test/Semantics/declarations01.f90
@@ -0,0 +1,8 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+! test named constant declarations
+
+function f1() result(x)
+  !ERROR: A function result may not also be a named constant
+  integer, parameter :: x = 1
+end
+