From 1d3bcf99bd0698fb5ebf5fccc24cebf2596dce0a Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler@nvidia.com>
Date: Thu, 12 Sep 2024 09:10:58 -0700
Subject: [PATCH] [flang] Better error recovery for REAL(x, [KIND=]bad)
 (#108222)

There's two entries in the intrinsic table for REAL; the first handles
the REAL(z) case of a COMPLEX argument, and the second handles the data
type/kind conversion case.

In the case of REAL(x,bad) with a bad or unsupported kind of REAL,
neither table entry was matching. In the event of an unrecognized
intrinsic function, the compiler emits the first error message that
resulted, which was confusing here because it was a complaint about
having too many arguments.

Reversing the order of the intrinsic table entries would fix the error
message, but would also have broken REAL(z) with a complex argument,
since it would then be treated as REAL(z,KIND=KIND(0.)) rather than
REAL(z,KIND=KIND(z)).

The fix is to let the second entry "hit" with improved error recovery.
---
 flang/lib/Evaluate/intrinsics.cpp | 4 +++-
 flang/test/Semantics/kinds06.f90  | 4 ++++
 2 files changed, 7 insertions(+), 1 deletion(-)
 create mode 100644 flang/test/Semantics/kinds06.f90

diff --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
index 876c2aed4ffd..166dae93178c 100644
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -2264,7 +2264,7 @@ std::optional<SpecificCall> IntrinsicInterface::Match(
         messages.Say("'kind=' argument must be a constant scalar integer "
                      "whose value is a supported kind for the "
                      "intrinsic result type"_err_en_US);
-        return std::nullopt;
+        // use default kind below for error recovery
       } else if (kindDummyArg->flags.test(ArgFlag::defaultsToSameKind)) {
         CHECK(sameArg);
         resultType = *sameArg->GetType();
@@ -2274,6 +2274,8 @@ std::optional<SpecificCall> IntrinsicInterface::Match(
             DynamicType{TypeCategory::Integer, defaults.sizeIntegerKind()};
       } else {
         CHECK(kindDummyArg->flags.test(ArgFlag::defaultsToDefaultForResult));
+      }
+      if (!resultType) {
         int kind{defaults.GetDefaultKind(*category)};
         if (*category == TypeCategory::Character) { // ACHAR & CHAR
           resultType = DynamicType{kind, 1};
diff --git a/flang/test/Semantics/kinds06.f90 b/flang/test/Semantics/kinds06.f90
new file mode 100644
index 000000000000..f5b488ebc714
--- /dev/null
+++ b/flang/test/Semantics/kinds06.f90
@@ -0,0 +1,4 @@
+!RUN: %python %S/test_errors.py %s %flang_fc1
+!ERROR: 'kind=' argument must be a constant scalar integer whose value is a supported kind for the intrinsic result type
+print *, real(1.,666)
+end