[flang-commits] [flang] [flang] Don't emit conversion error for max(a, b, optionalCharacter) (PR #88156)

[Peter Klausler via flang-commits]

https://github.com/klausler created https://github.com/llvm/llvm-project/pull/88156

A recent patch added an error message for whole optional dummy argument usage as optional arguments (third or later) to MAX and MIN when those names required type conversion, since that conversion only works when the optional arguments are present.  This check shouldn't care about character lengths.  Make it so.

>From 3acadd98f87210d837bf8016a1fa5b9b375d4f60 Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler at nvidia.com>
Date: Tue, 9 Apr 2024 10:08:11 -0700
Subject: [PATCH] [flang] Don't emit conversion error for max(a,b,
 optionalCharacter)

A recent patch added an error message for whole optional dummy argument
usage as optional arguments (third or later) to MAX and MIN when those
names required type conversion, since that conversion only works when
the optional arguments are present.  This check shouldn't care about
character lengths.  Make it so.
---
 flang/lib/Semantics/check-call.cpp | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/flang/lib/Semantics/check-call.cpp b/flang/lib/Semantics/check-call.cpp
index bd2f755855172a..7d73b55dac328e 100644
--- a/flang/lib/Semantics/check-call.cpp
+++ b/flang/lib/Semantics/check-call.cpp
@@ -1477,10 +1477,15 @@ static void CheckMaxMin(const characteristics::Procedure &proc,
         if (arguments[j]) {
           if (const auto *expr{arguments[j]->UnwrapExpr()};
               expr && evaluate::MayBePassedAsAbsentOptional(*expr)) {
-            if (auto thisType{expr->GetType()};
-                thisType && *thisType != typeAndShape->type()) {
-              messages.Say(arguments[j]->sourceLocation(),
-                  "An actual argument to MAX/MIN requiring data conversion may not be OPTIONAL, POINTER, or ALLOCATABLE"_err_en_US);
+            if (auto thisType{expr->GetType()}) {
+              if (thisType->category() == TypeCategory::Character &&
+                  typeAndShape->type().category() == TypeCategory::Character &&
+                  thisType->kind() == typeAndShape->type().kind()) {
+                // don't care about lengths
+              } else if (*thisType != typeAndShape->type()) {
+                messages.Say(arguments[j]->sourceLocation(),
+                    "An actual argument to MAX/MIN requiring data conversion may not be OPTIONAL, POINTER, or ALLOCATABLE"_err_en_US);
+              }
             }
           }
         }