[flang-commits] [flang] [llvm] [flang] Enumeration Type: (PR 3/5) Intrinsics + I/O + Modules (PR #193235)

via flang-commits flang-commits at lists.llvm.org
Thu Jul 2 10:23:56 PDT 2026


https://github.com/kwyatt-ext updated https://github.com/llvm/llvm-project/pull/193235

>From f73f81cb2d0d858433973879dff869a64deb7f72 Mon Sep 17 00:00:00 2001
From: Kevin Wyatt <kwyatt at hpe.com>
Date: Thu, 16 Apr 2026 13:38:20 -0500
Subject: [PATCH 1/4] Enumeration Type Sem-3: Intrinsics + I/O + Module Files
 (PRs 6-8)

Adds enumeration type intrinsics (HUGE, NEXT, PREVIOUS, INT) with
constant folding, STAT argument support with boundary detection,
formatted I/O rejection for enumeration types, module file round-trip
support, and runtime STAT_ENUM_BOUNDARY error code.

Files from original PRs 6-8 (including PREVIOUS intrinsic from PR 7).
---
 flang-rt/include/flang-rt/runtime/stat.h    |   1 +
 flang-rt/lib/runtime/stat.cpp               |   3 +
 flang/include/flang/Runtime/magic-numbers.h |   5 +
 flang/lib/Evaluate/fold-implementation.h    |  75 ++++++-
 flang/lib/Evaluate/intrinsics.cpp           | 228 +++++++++++++++++++-
 flang/lib/Semantics/check-io.cpp            |  73 +++++++
 flang/lib/Semantics/mod-file.cpp            |  86 ++++++++
 flang/lib/Semantics/mod-file.h              |   3 +
 flang/lib/Semantics/type.cpp                |   5 +
 9 files changed, 477 insertions(+), 2 deletions(-)

diff --git a/flang-rt/include/flang-rt/runtime/stat.h b/flang-rt/include/flang-rt/runtime/stat.h
index dc372de53506a..72d45a29c71fc 100644
--- a/flang-rt/include/flang-rt/runtime/stat.h
+++ b/flang-rt/include/flang-rt/runtime/stat.h
@@ -53,6 +53,7 @@ enum Stat {
   StatMoveAllocSameAllocatable =
       FORTRAN_RUNTIME_STAT_MOVE_ALLOC_SAME_ALLOCATABLE,
   StatBadPointerDeallocation = FORTRAN_RUNTIME_STAT_BAD_POINTER_DEALLOCATION,
+  StatEnumBoundary = FORTRAN_RUNTIME_STAT_ENUM_BOUNDARY,
 
   // Dummy status for work queue continuation, declared here to perhaps
   // avoid collisions
diff --git a/flang-rt/lib/runtime/stat.cpp b/flang-rt/lib/runtime/stat.cpp
index 1d4aae2e49736..076b5b81b71d2 100644
--- a/flang-rt/lib/runtime/stat.cpp
+++ b/flang-rt/lib/runtime/stat.cpp
@@ -70,6 +70,9 @@ RT_API_ATTRS const char *StatErrorString(int stat) {
     return "DEALLOCATE of a pointer that is not the whole content of a pointer "
            "ALLOCATE";
 
+  case StatEnumBoundary:
+    return "NEXT or PREVIOUS of enumeration type at boundary";
+
   default:
     return nullptr;
   }
diff --git a/flang/include/flang/Runtime/magic-numbers.h b/flang/include/flang/Runtime/magic-numbers.h
index 6788ba098bcf9..2c15103a21bc2 100644
--- a/flang/include/flang/Runtime/magic-numbers.h
+++ b/flang/include/flang/Runtime/magic-numbers.h
@@ -73,6 +73,11 @@ Status codes for GETCWD.
 #endif
 #define FORTRAN_RUNTIME_STAT_MISSING_CWD 111
 
+#if 0
+Status code for NEXT/PREVIOUS at enumeration type boundary.
+#endif
+#define FORTRAN_RUNTIME_STAT_ENUM_BOUNDARY 112
+
 #if 0
 ieee_class_type values
 The sequence is that of F18 Clause 17.2p3, but nothing depends on that.
diff --git a/flang/lib/Evaluate/fold-implementation.h b/flang/lib/Evaluate/fold-implementation.h
index 2df2b9e5a300b..c59b0ed68289b 100644
--- a/flang/lib/Evaluate/fold-implementation.h
+++ b/flang/lib/Evaluate/fold-implementation.h
@@ -1290,7 +1290,80 @@ Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
       return Folder<T>{context}.UNPACK(std::move(funcRef));
     }
     // TODO: extends_type_of, same_type_as
-    if constexpr (!std::is_same_v<T, SomeDerived>) {
+    if constexpr (std::is_same_v<T, SomeDerived>) {
+      // Fold enumeration type intrinsics: HUGE(enum), NEXT(enum),
+      // PREVIOUS(enum)
+      if (name == "huge") {
+        // HUGE was eagerly folded — the first arg is the constant result
+        if (args.size() >= 1 && args[0]) {
+          if (auto *expr{UnwrapExpr<Expr<SomeDerived>>(args[0])}) {
+            return std::move(*expr);
+          }
+        }
+      } else if (name == "next" || name == "previous") {
+        // Don't fold if STAT is present — STAT assignment is a side effect
+        if (args.size() >= 2 && args[1]) {
+          return Expr<T>{std::move(funcRef)};
+        }
+        if (args.size() >= 1 && args[0]) {
+          if (auto *expr{UnwrapExpr<Expr<SomeDerived>>(args[0])}) {
+            if (auto type{expr->GetType()}) {
+              if (const auto *derived{GetDerivedTypeSpec(*type)}) {
+                if (derived->IsEnumerationType()) {
+                  if (const auto *scope{derived->GetScope()}) {
+                    auto ordIter{
+                        scope->find(semantics::SourceName{"__ordinal", 9})};
+                    if (ordIter != scope->end()) {
+                      const semantics::Symbol &ordSym{*ordIter->second};
+                      int count{derived->typeSymbol()
+                              .GetUltimate()
+                              .get<semantics::DerivedTypeDetails>()
+                              .enumeratorCount()};
+                      // Extract ordinal from constant value
+                      if (auto *constant{
+                              UnwrapConstantValue<SomeDerived>(*expr)}) {
+                        if (auto sc{constant->GetScalarValue()}) {
+                          if (auto ordExpr{sc->Find(ordSym)}) {
+                            if (auto ordVal{ToInt64(*ordExpr)}) {
+                              bool isNext{name == "next"};
+                              bool atBoundary{
+                                  isNext ? *ordVal >= count : *ordVal <= 1};
+                              if (atBoundary) {
+                                // At boundary without STAT — error
+                                // termination at runtime. Don't fold;
+                                // emit warning.
+                                if (isNext) {
+                                  context.messages().Say(
+                                      "NEXT() of last enumerator without STAT= causes error termination"_warn_en_US);
+                                } else {
+                                  context.messages().Say(
+                                      "PREVIOUS() of first enumerator without STAT= causes error termination"_warn_en_US);
+                                }
+                                return Expr<T>{std::move(funcRef)};
+                              }
+                              int newOrd{isNext
+                                      ? static_cast<int>(*ordVal + 1)
+                                      : static_cast<int>(*ordVal - 1)};
+                              StructureConstructor ctor{*derived};
+                              ctor.Add(ordSym,
+                                  Expr<SomeType>{Expr<SomeInteger>{
+                                      Expr<Type<TypeCategory::Integer, 4>>{
+                                          newOrd}}});
+                              return Expr<SomeDerived>{
+                                  Constant<SomeDerived>{std::move(ctor)}};
+                            }
+                          }
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    } else {
       return FoldIntrinsicFunction(context, std::move(funcRef));
     }
   }
diff --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
index bc0026746c05c..121ed9accd323 100644
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -2948,6 +2948,18 @@ class IntrinsicProcTable::Implementation {
       ActualArguments &, FoldingContext &) const;
   std::optional<SpecificCall> HandleC_Devloc(
       ActualArguments &, FoldingContext &) const;
+  std::optional<SpecificCall> HandleEnumerationHuge(
+      const semantics::DerivedTypeSpec &, ActualArguments &,
+      FoldingContext &) const;
+  std::optional<SpecificCall> HandleEnumerationNext(
+      const semantics::DerivedTypeSpec &, ActualArguments &,
+      FoldingContext &) const;
+  std::optional<SpecificCall> HandleEnumerationPrevious(
+      const semantics::DerivedTypeSpec &, ActualArguments &,
+      FoldingContext &) const;
+  std::optional<SpecificCall> HandleEnumerationInt(
+      const semantics::DerivedTypeSpec &, ActualArguments &,
+      FoldingContext &) const;
   const std::string &ResolveAlias(const std::string &name) const {
     auto iter{aliases_.find(name)};
     return iter == aliases_.end() ? name : iter->second;
@@ -2976,7 +2988,7 @@ bool IntrinsicProcTable::Implementation::IsIntrinsicFunction(
   }
   // special cases
   return name == "__builtin_c_loc" || name == "__builtin_c_devloc" ||
-      name == "null";
+      name == "null" || name == "next" || name == "previous";
 }
 bool IntrinsicProcTable::Implementation::IsIntrinsicSubroutine(
     const std::string &name0) const {
@@ -3656,6 +3668,170 @@ std::optional<SpecificCall> IntrinsicProcTable::Implementation::HandleC_Devloc(
   return std::nullopt;
 }
 
+// HUGE(x) for enumeration types — returns the last enumerator
+std::optional<SpecificCall>
+IntrinsicProcTable::Implementation::HandleEnumerationHuge(
+    const semantics::DerivedTypeSpec &derived, ActualArguments &arguments,
+    FoldingContext &context) const {
+  static const char *const keywords[]{"x", nullptr};
+  if (!CheckAndRearrangeArguments(arguments, context.messages(), keywords)) {
+    return std::nullopt;
+  }
+  int count{derived.typeSymbol()
+          .GetUltimate()
+          .get<semantics::DerivedTypeDetails>()
+          .enumeratorCount()};
+  // Build a StructureConstructor with __ordinal = enumeratorCount
+  const auto *scope{derived.GetScope()};
+  if (!scope) {
+    return std::nullopt;
+  }
+  auto ordIter{scope->find(semantics::SourceName{"__ordinal", 9})};
+  if (ordIter == scope->end()) {
+    return std::nullopt;
+  }
+  const semantics::Symbol &ordSym{*ordIter->second};
+  StructureConstructor ctor{derived};
+  ctor.Add(ordSym,
+      Expr<SomeType>{
+          Expr<SomeInteger>{Expr<Type<TypeCategory::Integer, 4>>{count}}});
+  // Build FunctionResult and DummyArguments
+  DynamicType enumType{derived};
+  characteristics::DummyDataObject ddo{characteristics::TypeAndShape{enumType}};
+  ddo.intent = common::Intent::In;
+  ddo.attrs.set(characteristics::DummyDataObject::Attr::OnlyIntrinsicInquiry);
+  characteristics::Procedure::Attrs attrs;
+  attrs.set(characteristics::Procedure::Attr::Pure);
+  // Replace arguments with the constant result
+  arguments.clear();
+  arguments.emplace_back(
+      AsGenericExpr(Expr<SomeDerived>{Constant<SomeDerived>{std::move(ctor)}}));
+  return SpecificCall{
+      SpecificIntrinsic{"huge"s,
+          characteristics::Procedure{characteristics::FunctionResult{enumType},
+              characteristics::DummyArguments{
+                  characteristics::DummyArgument{"x"s, std::move(ddo)}},
+              attrs}},
+      std::move(arguments)};
+}
+
+// NEXT(a [, stat]) for enumeration types — returns the next enumerator
+std::optional<SpecificCall>
+IntrinsicProcTable::Implementation::HandleEnumerationNext(
+    const semantics::DerivedTypeSpec &derived, ActualArguments &arguments,
+    FoldingContext &context) const {
+  static const char *const keywords[]{"a", "stat", nullptr};
+  if (!CheckAndRearrangeArguments(arguments, context.messages(), keywords, 1)) {
+    return std::nullopt;
+  }
+  if (!arguments[0]) {
+    context.messages().Say("NEXT() requires argument A"_err_en_US);
+    return std::nullopt;
+  }
+  DynamicType enumerationType{derived};
+  characteristics::DummyDataObject ddoA{
+      characteristics::TypeAndShape{enumerationType}};
+  ddoA.intent = common::Intent::In;
+  DynamicType statType{
+      TypeCategory::Integer, defaults_.GetDefaultKind(TypeCategory::Integer)};
+  characteristics::DummyDataObject ddoStat{
+      characteristics::TypeAndShape{statType}};
+  ddoStat.intent = common::Intent::Out;
+  ddoStat.attrs.set(characteristics::DummyDataObject::Attr::Optional);
+  characteristics::Procedure::Attrs attrs;
+  attrs.set(characteristics::Procedure::Attr::Pure);
+  attrs.set(characteristics::Procedure::Attr::Elemental);
+  return SpecificCall{
+      SpecificIntrinsic{"next"s,
+          characteristics::Procedure{
+              characteristics::FunctionResult{enumerationType},
+              characteristics::DummyArguments{
+                  characteristics::DummyArgument{"a"s, std::move(ddoA)},
+                  characteristics::DummyArgument{"stat"s, std::move(ddoStat)}},
+              attrs}},
+      std::move(arguments)};
+}
+
+// PREVIOUS(a [, stat]) for enumeration types — returns the previous enumerator
+std::optional<SpecificCall>
+IntrinsicProcTable::Implementation::HandleEnumerationPrevious(
+    const semantics::DerivedTypeSpec &derived, ActualArguments &arguments,
+    FoldingContext &context) const {
+  static const char *const keywords[]{"a", "stat", nullptr};
+  if (!CheckAndRearrangeArguments(arguments, context.messages(), keywords, 1)) {
+    return std::nullopt;
+  }
+  if (!arguments[0]) {
+    context.messages().Say("PREVIOUS() requires argument A"_err_en_US);
+    return std::nullopt;
+  }
+  DynamicType enumerationType{derived};
+  characteristics::DummyDataObject ddoA{
+      characteristics::TypeAndShape{enumerationType}};
+  ddoA.intent = common::Intent::In;
+  DynamicType statType{
+      TypeCategory::Integer, defaults_.GetDefaultKind(TypeCategory::Integer)};
+  characteristics::DummyDataObject ddoStat{
+      characteristics::TypeAndShape{statType}};
+  ddoStat.intent = common::Intent::Out;
+  ddoStat.attrs.set(characteristics::DummyDataObject::Attr::Optional);
+  characteristics::Procedure::Attrs attrs;
+  attrs.set(characteristics::Procedure::Attr::Pure);
+  attrs.set(characteristics::Procedure::Attr::Elemental);
+  return SpecificCall{
+      SpecificIntrinsic{"previous"s,
+          characteristics::Procedure{
+              characteristics::FunctionResult{enumerationType},
+              characteristics::DummyArguments{
+                  characteristics::DummyArgument{"a"s, std::move(ddoA)},
+                  characteristics::DummyArgument{"stat"s, std::move(ddoStat)}},
+              attrs}},
+      std::move(arguments)};
+}
+
+// INT(x) for enumeration types — returns the ordinal as an integer
+std::optional<SpecificCall>
+IntrinsicProcTable::Implementation::HandleEnumerationInt(
+    const semantics::DerivedTypeSpec &derived, ActualArguments &arguments,
+    FoldingContext &context) const {
+  static const char *const keywords[]{"a", "kind", nullptr};
+  if (!CheckAndRearrangeArguments(arguments, context.messages(), keywords, 1)) {
+    return std::nullopt;
+  }
+  // Determine result kind
+  int kind{defaults_.GetDefaultKind(TypeCategory::Integer)};
+  if (arguments.size() > 1 && arguments[1]) {
+    if (const auto *kindExpr{arguments[1]->UnwrapExpr()}) {
+      if (auto kindVal{ToInt64(*kindExpr)}) {
+        kind = static_cast<int>(*kindVal);
+      }
+    }
+  }
+  DynamicType enumerationType{derived};
+  DynamicType resultType{TypeCategory::Integer, kind};
+  characteristics::DummyDataObject ddo{
+      characteristics::TypeAndShape{enumerationType}};
+  ddo.intent = common::Intent::In;
+  characteristics::Procedure::Attrs attrs;
+  attrs.set(characteristics::Procedure::Attr::Pure);
+  attrs.set(characteristics::Procedure::Attr::Elemental);
+  characteristics::DummyArguments dummies;
+  dummies.emplace_back("a"s, std::move(ddo));
+  // Always include KIND dummy — CheckAndRearrangeArguments always populates
+  // the slot even when absent
+  characteristics::DummyDataObject kindDdo{
+      characteristics::TypeAndShape{DynamicType{TypeCategory::Integer,
+          defaults_.GetDefaultKind(TypeCategory::Integer)}}};
+  kindDdo.intent = common::Intent::In;
+  auto &kindDummy{dummies.emplace_back("kind"s, std::move(kindDdo))};
+  kindDummy.SetOptional();
+  return SpecificCall{SpecificIntrinsic{"int"s,
+                          characteristics::Procedure{
+                              characteristics::FunctionResult{resultType},
+                              std::move(dummies), attrs}},
+      std::move(arguments)};
+}
+
 static bool CheckForNonPositiveValues(FoldingContext &context,
     const ActualArgument &arg, const std::string &procName,
     const std::string &argName) {
@@ -3864,6 +4040,56 @@ std::optional<SpecificCall> IntrinsicProcTable::Implementation::Probe(
         }
       }
     }
+    // Enumeration type intrinsics: HUGE, NEXT, INT
+    if (arguments.size() >= 1 && arguments[0]) {
+      if (auto type{arguments[0]->GetType()}) {
+        if (const auto *derived{GetDerivedTypeSpec(*type)}) {
+          if (derived->IsEnumerationType()) {
+            if (call.name == "huge") {
+              return HandleEnumerationHuge(*derived, arguments, context);
+            } else if (call.name == "next") {
+              return HandleEnumerationNext(*derived, arguments, context);
+            } else if (call.name == "int") {
+              return HandleEnumerationInt(*derived, arguments, context);
+            }
+          }
+        }
+      }
+    }
+    // Enumeration type intrinsics: HUGE, NEXT, INT
+    if (arguments.size() >= 1 && arguments[0]) {
+      if (auto type{arguments[0]->GetType()}) {
+        if (const auto *derived{GetDerivedTypeSpec(*type)}) {
+          if (derived->IsEnumerationType()) {
+            if (call.name == "huge") {
+              return HandleEnumerationHuge(*derived, arguments, context);
+            } else if (call.name == "next") {
+              return HandleEnumerationNext(*derived, arguments, context);
+            } else if (call.name == "int") {
+              return HandleEnumerationInt(*derived, arguments, context);
+            }
+          }
+        }
+      }
+    }
+    // Enumeration type intrinsics: HUGE, NEXT, PREVIOUS, INT
+    if (arguments.size() >= 1 && arguments[0]) {
+      if (auto type{arguments[0]->GetType()}) {
+        if (const auto *derived{GetDerivedTypeSpec(*type)}) {
+          if (derived->IsEnumerationType()) {
+            if (call.name == "huge") {
+              return HandleEnumerationHuge(*derived, arguments, context);
+            } else if (call.name == "next") {
+              return HandleEnumerationNext(*derived, arguments, context);
+            } else if (call.name == "previous") {
+              return HandleEnumerationPrevious(*derived, arguments, context);
+            } else if (call.name == "int") {
+              return HandleEnumerationInt(*derived, arguments, context);
+            }
+          }
+        }
+      }
+    }
   }
 
   // Find the specific subroutine and match the actual arguments against its
diff --git a/flang/lib/Semantics/check-io.cpp b/flang/lib/Semantics/check-io.cpp
index 5a5bee2b80e3c..f88897e362548 100644
--- a/flang/lib/Semantics/check-io.cpp
+++ b/flang/lib/Semantics/check-io.cpp
@@ -332,6 +332,21 @@ void IoChecker::Enter(const parser::InputItem &spec) {
   CheckForDefinableVariable(*var, "Input");
   if (auto expr{AnalyzeExpr(context_, *var)}) {
     auto at{var->GetSource()};
+    if (flags_.test(Flag::StarFmt)) {
+      if (auto type{expr->GetType()}; type &&
+          type->category() == TypeCategory::Derived &&
+          !type->IsUnlimitedPolymorphic()) {
+        const auto &derived{type->GetDerivedTypeSpec()};
+        if (const auto *details{
+                derived.typeSymbol().detailsIf<DerivedTypeDetails>()}) {
+          if (details->isEnumerationType()) {
+            context_.Say(at,
+                "Enumeration type may not appear in list-directed input"_err_en_US);
+            return;
+          }
+        }
+      }
+    }
     CheckForAssumedRank(UnwrapWholeSymbolDataRef(*expr), at);
     CheckForBadIoType(*expr,
         flags_.test(Flag::FmtOrNml) ? common::DefinedIo::ReadFormatted
@@ -665,6 +680,21 @@ void IoChecker::Enter(const parser::OutputItem &item) {
             "Output item must not be a procedure"_err_en_US); // C1233
       } else {
         auto at{parser::FindSourceLocation(item)};
+        if (flags_.test(Flag::StarFmt)) {
+          if (auto type{expr->GetType()}; type &&
+              type->category() == TypeCategory::Derived &&
+              !type->IsUnlimitedPolymorphic()) {
+            const auto &derived{type->GetDerivedTypeSpec()};
+            if (const auto *details{
+                    derived.typeSymbol().detailsIf<DerivedTypeDetails>()}) {
+              if (details->isEnumerationType()) {
+                context_.Say(at,
+                    "Enumeration type may not appear in list-directed output"_err_en_US);
+                return;
+              }
+            }
+          }
+        }
         CheckForAssumedRank(UnwrapWholeSymbolDataRef(*expr), at);
         CheckForBadIoType(*expr,
             flags_.test(Flag::FmtOrNml) ? common::DefinedIo::WriteFormatted
@@ -1224,6 +1254,17 @@ parser::Message *IoChecker::CheckForBadIoType(const evaluate::DynamicType &type,
         where, "I/O list item may not be unlimited polymorphic"_err_en_US);
   } else if (type.category() == TypeCategory::Derived) {
     const auto &derived{type.GetDerivedTypeSpec()};
+    if (const auto *details{
+            derived.typeSymbol().detailsIf<DerivedTypeDetails>()}) {
+      if (details->isEnumerationType()) {
+        if (which == common::DefinedIo::ReadUnformatted ||
+            which == common::DefinedIo::WriteUnformatted) {
+          return &context_.Say(where,
+              "Enumeration type may not be used in unformatted I/O"_err_en_US);
+        }
+        return nullptr; // formatted I/O is allowed
+      }
+    }
     const Scope &scope{context_.FindScope(where)};
     if (const Symbol *
         bad{FindUnsafeIoDirectComponent(which, derived, scope)}) {
@@ -1289,6 +1330,38 @@ void IoChecker::CheckNamelist(const Symbol &namelist, common::DefinedIo which,
     const auto &details{namelist.GetUltimate().get<NamelistDetails>()};
     for (const Symbol &object : details.objects()) {
       context_.CheckIndexVarRedefine(namelistLocation, object);
+      if (auto type{evaluate::DynamicType::From(object)};
+          type && type->category() == TypeCategory::Derived) {
+        const auto &derived{type->GetDerivedTypeSpec()};
+        if (const auto *dtDetails{
+                derived.typeSymbol().detailsIf<DerivedTypeDetails>()}) {
+          if (dtDetails->isEnumerationType()) {
+            context_.Say(namelistLocation,
+                "Enumeration type '%s' may not be a namelist group object"_err_en_US,
+                derived.name());
+            continue;
+          }
+        }
+        // Check direct components for enumeration types
+        if (derived.GetScope()) {
+          DirectComponentIterator directs{derived};
+          for (const Symbol &component : directs) {
+            if (auto compType{evaluate::DynamicType::From(component)};
+                compType && compType->category() == TypeCategory::Derived) {
+              const auto &compDerived{compType->GetDerivedTypeSpec()};
+              if (const auto *compDetails{compDerived.typeSymbol()
+                          .detailsIf<DerivedTypeDetails>()}) {
+                if (compDetails->isEnumerationType()) {
+                  context_.Say(namelistLocation,
+                      "Namelist group object '%s' has a direct component '%s' of enumeration type"_err_en_US,
+                      object.name(), component.name());
+                  break;
+                }
+              }
+            }
+          }
+        }
+      }
       if (auto *msg{CheckForBadIoType(object, which, namelistLocation)}) {
         evaluate::AttachDeclaration(*msg, namelist);
       } else if (which == common::DefinedIo::ReadFormatted) {
diff --git a/flang/lib/Semantics/mod-file.cpp b/flang/lib/Semantics/mod-file.cpp
index fd1b1caa7fce1..1d2c12b3303aa 100644
--- a/flang/lib/Semantics/mod-file.cpp
+++ b/flang/lib/Semantics/mod-file.cpp
@@ -10,6 +10,7 @@
 #include "resolve-names-utils.h"
 #include "resolve-names.h"
 #include "flang/Common/restorer.h"
+#include "flang/Evaluate/fold.h"
 #include "flang/Evaluate/tools.h"
 #include "flang/Parser/message.h"
 #include "flang/Parser/parsing.h"
@@ -626,6 +627,10 @@ void ModFileWriter::PutDerivedType(
     PutDECStructure(typeSymbol, scope);
     return;
   }
+  if (details.isEnumerationType()) {
+    PutEnumerationType(typeSymbol);
+    return;
+  }
   PutAttrs(decls_ << "type", typeSymbol.attrs());
   if (const DerivedTypeSpec * extends{typeSymbol.GetParentTypeSpec()}) {
     decls_ << ",extends(" << extends->name() << ')';
@@ -698,6 +703,82 @@ void ModFileWriter::PutDECStructure(
   decls_ << "end structure\n";
 }
 
+void ModFileWriter::PutEnumerationType(const Symbol &typeSymbol) {
+  auto &details{typeSymbol.get<DerivedTypeDetails>()};
+  PutAttrs(decls_ << "enumeration type", typeSymbol.attrs());
+  decls_ << "::" << typeSymbol.name() << '\n';
+  // Collect enumerator PARAMETER symbols from the enclosing scope that have
+  // this enumeration type, sorted by ordinal value. Only the first
+  // enumeratorCount PARAMETERs (by ordinal) are true enumerators created by
+  // the ENUMERATOR statement; any additional PARAMETERs of this type are
+  // user-declared and should not be included here.
+  struct EnumeratorInfo {
+    SourceName name;
+    const Symbol *sym{nullptr};
+    int ordinal{0};
+  };
+  // GetSymbols() returns symbols in source-position order. The real
+  // enumerators are created inside the ENUMERATION TYPE block and appear
+  // before any user-declared PARAMETERs of the same type. For each ordinal
+  // 1..N, take only the first PARAMETER seen (by source order) — that is
+  // the real enumerator.
+  int count{details.enumeratorCount()};
+  std::vector<EnumeratorInfo> enumerators(count); // indexed by ordinal-1
+  std::vector<bool> filled(count, false);
+  for (const auto &ref : typeSymbol.owner().GetSymbols()) {
+    if (ref->attrs().test(Attr::PARAMETER)) {
+      if (const auto *obj{ref->detailsIf<ObjectEntityDetails>()}) {
+        if (obj->type() &&
+            obj->type()->category() == DeclTypeSpec::TypeDerived &&
+            &obj->type()->derivedTypeSpec().typeSymbol() == &typeSymbol) {
+          int ordinal{0};
+          if (const auto &init{obj->init()}) {
+            // The init may be a bare StructureConstructor or a
+            // Constant<SomeDerived> (after folding). Use
+            // GetScalarConstantValue which handles both.
+            if (auto ctor{
+                    evaluate::GetScalarConstantValue<evaluate::SomeDerived>(
+                        *init)}) {
+              for (const auto &[compRef, val] : *ctor) {
+                if (auto intVal{evaluate::ToInt64(val.value())}) {
+                  ordinal = static_cast<int>(*intVal);
+                }
+              }
+            }
+          }
+          if (ordinal >= 1 && ordinal <= count && !filled[ordinal - 1]) {
+            enumerators[ordinal - 1] = {ref->name(), &*ref, ordinal};
+            filled[ordinal - 1] = true;
+            emittedEnumerators_.insert(*ref);
+          }
+        }
+      }
+    }
+  }
+  if (!enumerators.empty()) {
+    decls_ << "enumerator::";
+    bool first{true};
+    for (const auto &e : enumerators) {
+      if (!first) {
+        decls_ << ',';
+      }
+      decls_ << e.name;
+      first = false;
+    }
+    decls_ << '\n';
+  }
+  decls_ << "end enumeration type\n";
+  // Emit access overrides for individual enumerators, matching the
+  // pattern used elsewhere in mod file output (e.g., namelists, generics).
+  if (!isSubmodule_) {
+    for (const auto &e : enumerators) {
+      if (e.sym->attrs().test(Attr::PRIVATE)) {
+        decls_ << "private::" << e.name << '\n';
+      }
+    }
+  }
+}
+
 // Attributes that may be in a subprogram prefix
 static const Attrs subprogramPrefixAttrs{Attr::ELEMENTAL, Attr::IMPURE,
     Attr::MODULE, Attr::NON_RECURSIVE, Attr::PURE, Attr::SIMPLE,
@@ -1040,6 +1121,11 @@ void ModFileWriter::PutObjectEntity(
         return; // symbol was emitted on STRUCTURE statement
       }
     }
+    // Enumerator PARAMETERs are emitted as part of the ENUMERATION TYPE
+    // block — suppress standalone emission to avoid duplicates on USE.
+    if (emittedEnumerators_.find(symbol) != emittedEnumerators_.end()) {
+      return;
+    }
   }
   PutEntity(
       os, symbol, [&]() { PutType(os, DEREF(symbol.GetType())); },
diff --git a/flang/lib/Semantics/mod-file.h b/flang/lib/Semantics/mod-file.h
index 9e5724089b3c5..d4d3684f67539 100644
--- a/flang/lib/Semantics/mod-file.h
+++ b/flang/lib/Semantics/mod-file.h
@@ -52,6 +52,8 @@ class ModFileWriter {
   std::string containsBuf_;
   // Tracks nested DEC structures and fields of that type
   UnorderedSymbolSet emittedDECStructures_, emittedDECFields_;
+  // Tracks enumerator PARAMETER symbols emitted within ENUMERATION TYPE blocks
+  UnorderedSymbolSet emittedEnumerators_;
   UnorderedSymbolSet usedNonIntrinsicModules_;
 
   llvm::raw_string_ostream needs_{needsBuf_};
@@ -79,6 +81,7 @@ class ModFileWriter {
   void PutProcEntity(llvm::raw_ostream &, const Symbol &);
   void PutDerivedType(const Symbol &, const Scope * = nullptr);
   void PutDECStructure(const Symbol &, const Scope * = nullptr);
+  void PutEnumerationType(const Symbol &);
   void PutTypeParam(llvm::raw_ostream &, const Symbol &);
   void PutUserReduction(llvm::raw_ostream &, const Symbol &);
   void PutSubprogram(const Symbol &);
diff --git a/flang/lib/Semantics/type.cpp b/flang/lib/Semantics/type.cpp
index 678bae83ba68e..448a29b7c18bd 100644
--- a/flang/lib/Semantics/type.cpp
+++ b/flang/lib/Semantics/type.cpp
@@ -1007,6 +1007,11 @@ std::string DeclTypeSpec::AsFortran() const {
       return "RECORD" + derivedTypeSpec().typeSymbol().name().ToString();
     } else if (derivedTypeSpec().IsVectorType()) {
       return derivedTypeSpec().VectorTypeAsFortran();
+    } else if (derivedTypeSpec()
+                   .typeSymbol()
+                   .get<DerivedTypeDetails>()
+                   .isEnumerationType()) {
+      return "TYPE(" + derivedTypeSpec().typeSymbol().name().ToString() + ')';
     } else {
       return "TYPE(" + derivedTypeSpec().AsFortran() + ')';
     }

>From de1e25f53bd28a65ab3d34137c000d002aef6b3a Mon Sep 17 00:00:00 2001
From: Kevin Wyatt <kwyatt at hpe.com>
Date: Tue, 21 Apr 2026 09:19:46 -0500
Subject: [PATCH 2/4] Adding test cases.

---
 .../Semantics/enumeration-type-intrinsics.f90 | 153 ++++++++++++++++++
 flang/test/Semantics/enumeration-type-io.f90  |  68 ++++++++
 flang/test/Semantics/enumeration-type-mod.f90 |  84 ++++++++++
 3 files changed, 305 insertions(+)
 create mode 100644 flang/test/Semantics/enumeration-type-intrinsics.f90
 create mode 100644 flang/test/Semantics/enumeration-type-io.f90
 create mode 100644 flang/test/Semantics/enumeration-type-mod.f90

diff --git a/flang/test/Semantics/enumeration-type-intrinsics.f90 b/flang/test/Semantics/enumeration-type-intrinsics.f90
new file mode 100644
index 0000000000000..f4478903d8ddb
--- /dev/null
+++ b/flang/test/Semantics/enumeration-type-intrinsics.f90
@@ -0,0 +1,153 @@
+! RUN: %flang_fc1 -fsyntax-only -pedantic %s 2>&1 | FileCheck %s
+! Test intrinsics HUGE, NEXT, PREVIOUS, INT for enumeration types (F2023 7.6.2)
+
+module enum_intrinsics_mod
+  enumeration type :: color
+    enumerator :: red, green, blue
+  end enumeration type
+
+  enumeration type :: v_value
+    enumerator :: v_one, v_two, v_three
+    enumerator v_four
+  end enumeration type
+end module
+
+subroutine test_huge()
+  use enum_intrinsics_mod
+  type(color) :: x
+  type(v_value) :: y
+
+  ! HUGE(x) returns the last enumerator
+  x = huge(x)
+  y = huge(y)
+
+  ! HUGE in comparison — should fold to .TRUE.
+  if (huge(x) == blue) continue
+  if (huge(y) == v_four) continue
+end subroutine
+
+subroutine test_next()
+  use enum_intrinsics_mod
+  type(color) :: c, nc
+  integer :: istat
+
+  ! NEXT(a) returns the next enumerator
+  c = red
+  nc = next(c)
+
+  ! NEXT with constants
+  nc = next(red)
+  nc = next(green)
+
+  ! NEXT with STAT= argument
+  nc = next(c, stat=istat)
+  nc = next(blue, stat=istat)
+end subroutine
+
+subroutine test_previous()
+  use enum_intrinsics_mod
+  type(color) :: c, pc
+  integer :: istat
+
+  ! PREVIOUS(a) returns the previous enumerator
+  c = blue
+  pc = previous(c)
+
+  ! PREVIOUS with constants
+  pc = previous(blue)
+  pc = previous(green)
+
+  ! PREVIOUS with STAT= argument
+  pc = previous(c, stat=istat)
+  pc = previous(red, stat=istat)
+end subroutine
+
+subroutine test_int()
+  use enum_intrinsics_mod
+  integer :: i
+  integer(8) :: j
+
+  ! INT(x) returns the ordinal position
+  i = int(red)
+  i = int(green)
+  i = int(blue)
+
+  ! INT with KIND= argument
+  j = int(red, kind=8)
+  j = int(green, 8)
+end subroutine
+
+subroutine test_int_parameter()
+  use enum_intrinsics_mod
+  ! INT(x) in parameter (constant) context
+  integer, parameter :: r = int(red)
+  integer, parameter :: g = int(green)
+  integer, parameter :: b = int(blue)
+
+  ! Verify ordinals are 1-based
+  integer, parameter :: test1 = r  ! should be 1
+  integer, parameter :: test2 = g  ! should be 2
+  integer, parameter :: test3 = b  ! should be 3
+end subroutine
+
+subroutine test_huge_constant()
+  use enum_intrinsics_mod
+  ! HUGE in constant context
+  logical, parameter :: h1 = huge(red) == blue
+  logical, parameter :: h2 = huge(v_one) == v_four
+end subroutine
+
+subroutine test_next_constant()
+  use enum_intrinsics_mod
+  ! NEXT with constant folding — non-boundary cases
+  logical, parameter :: n1 = next(red) == green
+  logical, parameter :: n2 = next(green) == blue
+end subroutine
+
+subroutine test_next_boundary_with_stat()
+  use enum_intrinsics_mod
+  type(color) :: nc
+  integer :: istat
+  ! NEXT at boundary with STAT — no error, STAT gets nonzero
+  nc = next(blue, stat=istat)
+  nc = next(huge(red), stat=istat)
+end subroutine
+
+subroutine test_previous_constant()
+  use enum_intrinsics_mod
+  ! PREVIOUS with constant folding — non-boundary cases
+  logical, parameter :: p1 = previous(blue) == green
+  logical, parameter :: p2 = previous(green) == red
+end subroutine
+
+subroutine test_previous_boundary_with_stat()
+  use enum_intrinsics_mod
+  type(color) :: pc
+  integer :: istat
+  ! PREVIOUS at boundary with STAT — no error, STAT gets nonzero
+  pc = previous(red, stat=istat)
+end subroutine
+
+subroutine test_next_boundary_warning()
+  use enum_intrinsics_mod
+  type(color) :: nc
+  ! NEXT at boundary without STAT — warning
+  !CHECK: warning: NEXT() of last enumerator without STAT= causes error termination
+  nc = next(blue)
+end subroutine
+
+subroutine test_previous_boundary_warning()
+  use enum_intrinsics_mod
+  type(color) :: pc
+  ! PREVIOUS at boundary without STAT — warning
+  !CHECK: warning: PREVIOUS() of first enumerator without STAT= causes error termination
+  pc = previous(red)
+end subroutine
+
+subroutine test_huge_real_still_works()
+  ! Non-enumeration HUGE still works normally
+  real :: r
+  integer :: i
+  r = huge(r)
+  i = huge(i)
+end subroutine
diff --git a/flang/test/Semantics/enumeration-type-io.f90 b/flang/test/Semantics/enumeration-type-io.f90
new file mode 100644
index 0000000000000..2862d8d0bb9f4
--- /dev/null
+++ b/flang/test/Semantics/enumeration-type-io.f90
@@ -0,0 +1,68 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+! Test I/O constraints for enumeration types (F2023 7.6.2)
+
+module enum_io_mod
+  enumeration type :: color
+    enumerator :: red, green, blue
+  end enumeration type
+end module
+
+subroutine test_valid_io()
+  use enum_io_mod
+  type(color) :: c
+  character(10) :: fmt
+  c = red
+  fmt = '(I4)'
+  ! Valid: explicit format with I edit descriptor
+  write(*, '(I4)') c
+  ! Valid: explicit format via character variable
+  write(10, fmt) c
+  ! Valid: explicit format read
+  read(*, '(I4)') c
+end subroutine
+
+subroutine test_list_directed()
+  use enum_io_mod
+  type(color) :: c
+  c = red
+  !ERROR: Enumeration type may not appear in list-directed output
+  print *, c
+  !ERROR: Enumeration type may not appear in list-directed input
+  read *, c
+end subroutine
+
+subroutine test_unformatted()
+  use enum_io_mod
+  type(color) :: c
+  c = red
+  !ERROR: Enumeration type may not be used in unformatted I/O
+  write(10) c
+  !ERROR: Enumeration type may not be used in unformatted I/O
+  read(10) c
+end subroutine
+
+subroutine test_namelist_enum_object()
+  use enum_io_mod
+  type(color) :: c
+  namelist /nml/ c
+  !ERROR: Enumeration type 'color' may not be a namelist group object
+  write(*, nml=nml)
+end subroutine
+
+subroutine test_namelist_enum_component()
+  use enum_io_mod
+  type :: has_color
+    type(color) :: clr
+    integer :: n
+  end type
+  type(has_color) :: d
+  namelist /nml2/ d
+  !ERROR: Namelist group object 'd' has a direct component 'clr' of enumeration type
+  write(*, nml=nml2)
+end subroutine
+
+subroutine test_namelist_valid()
+  integer :: n
+  namelist /nml3/ n
+  write(*, nml=nml3)
+end subroutine
diff --git a/flang/test/Semantics/enumeration-type-mod.f90 b/flang/test/Semantics/enumeration-type-mod.f90
new file mode 100644
index 0000000000000..3c2f7c8f96289
--- /dev/null
+++ b/flang/test/Semantics/enumeration-type-mod.f90
@@ -0,0 +1,84 @@
+! RUN: %python %S/test_modfile.py %s %flang_fc1
+! Check correct modfile generation for enumeration types.
+
+! Basic enumeration type
+module m1
+  enumeration type :: color
+    enumerator :: red, green, blue
+  end enumeration type
+  type(color) :: c = green
+end
+
+!Expect: m1.mod
+!module m1
+!enumeration type::color
+!enumerator::red,green,blue
+!end enumeration type
+!type(color)::c
+!end
+
+! Private enumeration type
+module m2
+  enumeration type, private :: color
+    enumerator :: red, green, blue
+  end enumeration type
+end
+
+!Expect: m2.mod
+!module m2
+!enumeration type,private::color
+!enumerator::red,green,blue
+!end enumeration type
+!end
+
+! Multiple enumeration types
+module m3
+  enumeration type :: color
+    enumerator :: red, green, blue
+  end enumeration type
+  enumeration type :: direction
+    enumerator :: north, south, east, west
+  end enumeration type
+end
+
+!Expect: m3.mod
+!module m3
+!enumeration type::color
+!enumerator::red,green,blue
+!end enumeration type
+!enumeration type::direction
+!enumerator::north,south,east,west
+!end enumeration type
+!end
+
+! Enumeration type with variable declaration
+module m4
+  enumeration type :: color
+    enumerator :: red, green, blue
+  end enumeration type
+  type(color) :: default_color = green
+  type(color), parameter :: favorite = blue
+end
+
+!Expect: m4.mod
+!module m4
+!enumeration type::color
+!enumerator::red,green,blue
+!end enumeration type
+!type(color)::default_color
+!type(color),parameter::favorite=color(3_4)
+!end
+
+! USE and re-export
+module m5
+  use m1, only: color, red, green, blue, c
+end
+
+!Expect: m5.mod
+!module m5
+!use m1,only:color
+!use m1,only:red
+!use m1,only:green
+!use m1,only:blue
+!use m1,only:c
+!end

>From c67715f9025e2abc41aff264d73f180b712dcf73 Mon Sep 17 00:00:00 2001
From: Kevin Wyatt <kwyatt at hpe.com>
Date: Tue, 30 Jun 2026 16:09:01 -0500
Subject: [PATCH 3/4] Gated NEXT/PREVIOUS lowering with a temporary error.

Fixed INT to utilize the same KIND conversion logic as the normal INT.
---
 flang/lib/Evaluate/fold-implementation.h      | 14 ++--
 flang/lib/Evaluate/intrinsics.cpp             | 79 +++++++++++--------
 .../Semantics/enumeration-type-intrinsics.f90 | 29 ++++---
 flang/test/Semantics/enumeration-type-io.f90  |  3 +-
 flang/test/Semantics/enumeration-type-mod.f90 |  2 +-
 5 files changed, 75 insertions(+), 52 deletions(-)

diff --git a/flang/lib/Evaluate/fold-implementation.h b/flang/lib/Evaluate/fold-implementation.h
index c59b0ed68289b..821f76c950840 100644
--- a/flang/lib/Evaluate/fold-implementation.h
+++ b/flang/lib/Evaluate/fold-implementation.h
@@ -1311,8 +1311,11 @@ Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
               if (const auto *derived{GetDerivedTypeSpec(*type)}) {
                 if (derived->IsEnumerationType()) {
                   if (const auto *scope{derived->GetScope()}) {
-                    auto ordIter{
-                        scope->find(semantics::SourceName{"__ordinal", 9})};
+                    auto ordIter{scope->find(semantics::SourceName{
+                        semantics::DerivedTypeDetails::ordinalComponentName,
+                        sizeof(semantics::DerivedTypeDetails::
+                            ordinalComponentName) -
+                            1})};
                     if (ordIter != scope->end()) {
                       const semantics::Symbol &ordSym{*ordIter->second};
                       int count{derived->typeSymbol()
@@ -1334,10 +1337,10 @@ Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
                                 // emit warning.
                                 if (isNext) {
                                   context.messages().Say(
-                                      "NEXT() of last enumerator without STAT= causes error termination"_warn_en_US);
+                                      "NEXT() of last enumerator without STAT= causes error termination"_err_en_US);
                                 } else {
                                   context.messages().Say(
-                                      "PREVIOUS() of first enumerator without STAT= causes error termination"_warn_en_US);
+                                      "PREVIOUS() of first enumerator without STAT= causes error termination"_err_en_US);
                                 }
                                 return Expr<T>{std::move(funcRef)};
                               }
@@ -1347,8 +1350,7 @@ Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
                               StructureConstructor ctor{*derived};
                               ctor.Add(ordSym,
                                   Expr<SomeType>{Expr<SomeInteger>{
-                                      Expr<Type<TypeCategory::Integer, 4>>{
-                                          newOrd}}});
+                                      Expr<CInteger>{newOrd}}});
                               return Expr<SomeDerived>{
                                   Constant<SomeDerived>{std::move(ctor)}};
                             }
diff --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
index 121ed9accd323..0b1e3e0a19140 100644
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -3728,6 +3728,20 @@ IntrinsicProcTable::Implementation::HandleEnumerationNext(
     context.messages().Say("NEXT() requires argument A"_err_en_US);
     return std::nullopt;
   }
+  // TEMPORARY: Reject STAT= until lowering handler lands in PR 4/5
+  if (arguments.size() > 1 && arguments[1]) {
+    context.messages().Say(arguments[1]->sourceLocation(),
+        "NEXT() with STAT= is not yet supported"_err_en_US);
+    return std::nullopt;
+  }
+  // TEMPORARY: Reject non-constant argument until lowering handler in PR 4/5
+  if (const auto *expr{arguments[0]->UnwrapExpr()}) {
+    if (!IsConstantExpr(*expr)) {
+      context.messages().Say(arguments[0]->sourceLocation(),
+          "NEXT() with a non-constant argument is not yet supported"_err_en_US);
+      return std::nullopt;
+    }
+  }
   DynamicType enumerationType{derived};
   characteristics::DummyDataObject ddoA{
       characteristics::TypeAndShape{enumerationType}};
@@ -3765,6 +3779,20 @@ IntrinsicProcTable::Implementation::HandleEnumerationPrevious(
     context.messages().Say("PREVIOUS() requires argument A"_err_en_US);
     return std::nullopt;
   }
+  // TEMPORARY: Reject STAT= until lowering handler lands in PR 4/5
+  if (arguments.size() > 1 && arguments[1]) {
+    context.messages().Say(arguments[1]->sourceLocation(),
+        "PREVIOUS() with STAT= is not yet supported"_err_en_US);
+    return std::nullopt;
+  }
+  // TEMPORARY: Reject non-constant argument until lowering handler in PR 4/5
+  if (const auto *expr{arguments[0]->UnwrapExpr()}) {
+    if (!IsConstantExpr(*expr)) {
+      context.messages().Say(arguments[0]->sourceLocation(),
+          "PREVIOUS() with a non-constant argument is not yet supported"_err_en_US);
+      return std::nullopt;
+    }
+  }
   DynamicType enumerationType{derived};
   characteristics::DummyDataObject ddoA{
       characteristics::TypeAndShape{enumerationType}};
@@ -3798,12 +3826,24 @@ IntrinsicProcTable::Implementation::HandleEnumerationInt(
   if (!CheckAndRearrangeArguments(arguments, context.messages(), keywords, 1)) {
     return std::nullopt;
   }
-  // Determine result kind
+  // Determine result kind using the same validation as the ordinary INT
+  // intrinsic (fold, check IsTypeEnabled, emit the same diagnostic on failure).
   int kind{defaults_.GetDefaultKind(TypeCategory::Integer)};
   if (arguments.size() > 1 && arguments[1]) {
     if (const auto *kindExpr{arguments[1]->UnwrapExpr()}) {
-      if (auto kindVal{ToInt64(*kindExpr)}) {
-        kind = static_cast<int>(*kindVal);
+      bool kindOk{false};
+      if (auto kindVal{ToInt64(Fold(context, common::Clone(*kindExpr)))}) {
+        if (context.targetCharacteristics().IsTypeEnabled(
+                TypeCategory::Integer, *kindVal)) {
+          kind = static_cast<int>(*kindVal);
+          kindOk = true;
+        }
+      }
+      if (!kindOk) {
+        context.messages().Say(arguments[1]->sourceLocation(),
+            "'kind=' argument must be a constant scalar integer whose value is "
+            "a supported kind for the intrinsic result type"_err_en_US);
+        // fall through with default kind for error recovery
       }
     }
   }
@@ -4040,38 +4080,7 @@ std::optional<SpecificCall> IntrinsicProcTable::Implementation::Probe(
         }
       }
     }
-    // Enumeration type intrinsics: HUGE, NEXT, INT
-    if (arguments.size() >= 1 && arguments[0]) {
-      if (auto type{arguments[0]->GetType()}) {
-        if (const auto *derived{GetDerivedTypeSpec(*type)}) {
-          if (derived->IsEnumerationType()) {
-            if (call.name == "huge") {
-              return HandleEnumerationHuge(*derived, arguments, context);
-            } else if (call.name == "next") {
-              return HandleEnumerationNext(*derived, arguments, context);
-            } else if (call.name == "int") {
-              return HandleEnumerationInt(*derived, arguments, context);
-            }
-          }
-        }
-      }
-    }
-    // Enumeration type intrinsics: HUGE, NEXT, INT
-    if (arguments.size() >= 1 && arguments[0]) {
-      if (auto type{arguments[0]->GetType()}) {
-        if (const auto *derived{GetDerivedTypeSpec(*type)}) {
-          if (derived->IsEnumerationType()) {
-            if (call.name == "huge") {
-              return HandleEnumerationHuge(*derived, arguments, context);
-            } else if (call.name == "next") {
-              return HandleEnumerationNext(*derived, arguments, context);
-            } else if (call.name == "int") {
-              return HandleEnumerationInt(*derived, arguments, context);
-            }
-          }
-        }
-      }
-    }
+
     // Enumeration type intrinsics: HUGE, NEXT, PREVIOUS, INT
     if (arguments.size() >= 1 && arguments[0]) {
       if (auto type{arguments[0]->GetType()}) {
diff --git a/flang/test/Semantics/enumeration-type-intrinsics.f90 b/flang/test/Semantics/enumeration-type-intrinsics.f90
index f4478903d8ddb..fa9b1aae79c13 100644
--- a/flang/test/Semantics/enumeration-type-intrinsics.f90
+++ b/flang/test/Semantics/enumeration-type-intrinsics.f90
@@ -1,5 +1,7 @@
-! RUN: %flang_fc1 -fsyntax-only -pedantic %s 2>&1 | FileCheck %s
+! RUN: not %flang_fc1 -fsyntax-only -fenumeration-type -pedantic %s 2>&1 | FileCheck %s
 ! Test intrinsics HUGE, NEXT, PREVIOUS, INT for enumeration types (F2023 7.6.2)
+! NOTE: This test will start failing when the whole PR stack is merged.  It will
+!       need to have expected results changed and the "not" above removed.
 
 module enum_intrinsics_mod
   enumeration type :: color
@@ -33,14 +35,17 @@ subroutine test_next()
 
   ! NEXT(a) returns the next enumerator
   c = red
+  !CHECK: error: NEXT() with a non-constant argument is not yet supported
   nc = next(c)
 
   ! NEXT with constants
   nc = next(red)
   nc = next(green)
 
-  ! NEXT with STAT= argument
+  ! NEXT with STAT= argument (temporarily unsupported)
+  !CHECK: error: NEXT() with STAT= is not yet supported
   nc = next(c, stat=istat)
+  !CHECK: error: NEXT() with STAT= is not yet supported
   nc = next(blue, stat=istat)
 end subroutine
 
@@ -51,14 +56,17 @@ subroutine test_previous()
 
   ! PREVIOUS(a) returns the previous enumerator
   c = blue
+  !CHECK: error: PREVIOUS() with a non-constant argument is not yet supported
   pc = previous(c)
 
   ! PREVIOUS with constants
   pc = previous(blue)
   pc = previous(green)
 
-  ! PREVIOUS with STAT= argument
+  ! PREVIOUS with STAT= argument (temporarily unsupported)
+  !CHECK: error: PREVIOUS() with STAT= is not yet supported
   pc = previous(c, stat=istat)
+  !CHECK: error: PREVIOUS() with STAT= is not yet supported
   pc = previous(red, stat=istat)
 end subroutine
 
@@ -108,8 +116,10 @@ subroutine test_next_boundary_with_stat()
   use enum_intrinsics_mod
   type(color) :: nc
   integer :: istat
-  ! NEXT at boundary with STAT — no error, STAT gets nonzero
+  ! NEXT at boundary with STAT — TEMPORARILY rejected until lowering lands in PR 4/5
+  !CHECK: error: NEXT() with STAT= is not yet supported
   nc = next(blue, stat=istat)
+  !CHECK: error: NEXT() with STAT= is not yet supported
   nc = next(huge(red), stat=istat)
 end subroutine
 
@@ -124,23 +134,24 @@ subroutine test_previous_boundary_with_stat()
   use enum_intrinsics_mod
   type(color) :: pc
   integer :: istat
-  ! PREVIOUS at boundary with STAT — no error, STAT gets nonzero
+  ! PREVIOUS at boundary with STAT — TEMPORARILY rejected until lowering lands in PR 4/5
+  !CHECK: error: PREVIOUS() with STAT= is not yet supported
   pc = previous(red, stat=istat)
 end subroutine
 
 subroutine test_next_boundary_warning()
   use enum_intrinsics_mod
   type(color) :: nc
-  ! NEXT at boundary without STAT — warning
-  !CHECK: warning: NEXT() of last enumerator without STAT= causes error termination
+  ! NEXT at boundary without STAT — error
+  !CHECK: error: NEXT() of last enumerator without STAT= causes error termination
   nc = next(blue)
 end subroutine
 
 subroutine test_previous_boundary_warning()
   use enum_intrinsics_mod
   type(color) :: pc
-  ! PREVIOUS at boundary without STAT — warning
-  !CHECK: warning: PREVIOUS() of first enumerator without STAT= causes error termination
+  ! PREVIOUS at boundary without STAT — error
+  !CHECK: error: PREVIOUS() of first enumerator without STAT= causes error termination
   pc = previous(red)
 end subroutine
 
diff --git a/flang/test/Semantics/enumeration-type-io.f90 b/flang/test/Semantics/enumeration-type-io.f90
index 2862d8d0bb9f4..93d651cb1bb88 100644
--- a/flang/test/Semantics/enumeration-type-io.f90
+++ b/flang/test/Semantics/enumeration-type-io.f90
@@ -1,7 +1,8 @@
-! RUN: %python %S/test_errors.py %s %flang_fc1
+! RUN: %python %S/test_errors.py %s %flang_fc1 -fenumeration-type
 ! Test I/O constraints for enumeration types (F2023 7.6.2)
 
 module enum_io_mod
+  !WARNING: ENUMERATION TYPE support is incomplete and should be enabled only for testing
   enumeration type :: color
     enumerator :: red, green, blue
   end enumeration type
diff --git a/flang/test/Semantics/enumeration-type-mod.f90 b/flang/test/Semantics/enumeration-type-mod.f90
index 3c2f7c8f96289..17abf8a60c43c 100644
--- a/flang/test/Semantics/enumeration-type-mod.f90
+++ b/flang/test/Semantics/enumeration-type-mod.f90
@@ -1,4 +1,4 @@
-! RUN: %python %S/test_modfile.py %s %flang_fc1
+! RUN: %python %S/test_modfile.py %s %flang_fc1 -fenumeration-type
 ! Check correct modfile generation for enumeration types.
 
 ! Basic enumeration type

>From eefbbc918316d6d565b82100062abbd7efe0e0a4 Mon Sep 17 00:00:00 2001
From: Kevin Wyatt <kwyatt at hpe.com>
Date: Thu, 2 Jul 2026 12:22:12 -0500
Subject: [PATCH 4/4] Incorporated the following fixes:

- Fold enum INT/NEXT/PREVIOUS over constant array arguments elementwise
- Enumeration Type inlines HUGE/INT/NEXT/PREVIOUS now look at argument by keyword.
- Gated and report an error on NEXT/PREVIOUS intrinsic use.
---
 flang/lib/Evaluate/fold-implementation.h      | 73 +++++++++++++++----
 flang/lib/Evaluate/fold-integer.cpp           | 26 +++++++
 flang/lib/Evaluate/intrinsics.cpp             | 68 +++++++++++++----
 flang/lib/Semantics/resolve-names.cpp         | 12 +++
 ...enumeration-type-intrinsics-array-fold.f90 | 29 ++++++++
 .../enumeration-type-intrinsics-gating.f90    | 14 ++++
 .../enumeration-type-intrinsics-keyword.f90   | 45 ++++++++++++
 .../enumeration-type-intrinsics-nonenum.f90   | 16 ++++
 .../Semantics/enumeration-type-intrinsics.f90 | 27 +++++++
 9 files changed, 281 insertions(+), 29 deletions(-)
 create mode 100644 flang/test/Semantics/enumeration-type-intrinsics-array-fold.f90
 create mode 100644 flang/test/Semantics/enumeration-type-intrinsics-gating.f90
 create mode 100644 flang/test/Semantics/enumeration-type-intrinsics-keyword.f90
 create mode 100644 flang/test/Semantics/enumeration-type-intrinsics-nonenum.f90

diff --git a/flang/lib/Evaluate/fold-implementation.h b/flang/lib/Evaluate/fold-implementation.h
index 821f76c950840..74848c94c7d62 100644
--- a/flang/lib/Evaluate/fold-implementation.h
+++ b/flang/lib/Evaluate/fold-implementation.h
@@ -1314,7 +1314,7 @@ Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
                     auto ordIter{scope->find(semantics::SourceName{
                         semantics::DerivedTypeDetails::ordinalComponentName,
                         sizeof(semantics::DerivedTypeDetails::
-                            ordinalComponentName) -
+                                ordinalComponentName) -
                             1})};
                     if (ordIter != scope->end()) {
                       const semantics::Symbol &ordSym{*ordIter->second};
@@ -1325,24 +1325,21 @@ Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
                       // Extract ordinal from constant value
                       if (auto *constant{
                               UnwrapConstantValue<SomeDerived>(*expr)}) {
+                        const bool isNext{name == "next"};
+                        // Boundary without STAT= is runtime error
+                        // termination; diagnose and leave the reference
+                        // unfolded (matches the scalar behavior).
+                        auto boundaryBail{[&]() -> Expr<T> {
+                          context.messages().Say(isNext
+                                  ? "NEXT() of last enumerator without STAT= causes error termination"_err_en_US
+                                  : "PREVIOUS() of first enumerator without STAT= causes error termination"_err_en_US);
+                          return Expr<T>{std::move(funcRef)};
+                        }};
                         if (auto sc{constant->GetScalarValue()}) {
                           if (auto ordExpr{sc->Find(ordSym)}) {
                             if (auto ordVal{ToInt64(*ordExpr)}) {
-                              bool isNext{name == "next"};
-                              bool atBoundary{
-                                  isNext ? *ordVal >= count : *ordVal <= 1};
-                              if (atBoundary) {
-                                // At boundary without STAT — error
-                                // termination at runtime. Don't fold;
-                                // emit warning.
-                                if (isNext) {
-                                  context.messages().Say(
-                                      "NEXT() of last enumerator without STAT= causes error termination"_err_en_US);
-                                } else {
-                                  context.messages().Say(
-                                      "PREVIOUS() of first enumerator without STAT= causes error termination"_err_en_US);
-                                }
-                                return Expr<T>{std::move(funcRef)};
+                              if (isNext ? *ordVal >= count : *ordVal <= 1) {
+                                return boundaryBail();
                               }
                               int newOrd{isNext
                                       ? static_cast<int>(*ordVal + 1)
@@ -1355,6 +1352,50 @@ Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
                                   Constant<SomeDerived>{std::move(ctor)}};
                             }
                           }
+                        } else if (constant->Rank() > 0) {
+                          // Array constant: NEXT/PREVIOUS are elemental, so
+                          // fold elementwise into a constant array of
+                          // enumerators.  STAT= is absent here (the
+                          // STAT-present case bails out above), so there is
+                          // no side effect to preserve.
+                          //
+                          // NOTE (enum-lowering / next PR): the runtime
+                          // counterpart of this array case is not yet
+                          // implemented.  genEnumerationNext/Previous in
+                          // flang/lib/Lower/ConvertExprToHLFIR.cpp call
+                          // hlfir::loadTrivialScalar and emit scalar arith,
+                          // so they only accept scalar arguments.  When a
+                          // non-constant array argument reaches lowering,
+                          // those emitters must be wrapped in an
+                          // hlfir.elemental region (one scalar min/max plus a
+                          // per-element boundary test, per element), and STAT
+                          // handling must reduce the per-element boundary
+                          // flags (any-boundary -> STAT/abort).  This
+                          // elementwise fold is the compile-time mirror of
+                          // that loop.  Until the lowering lands, only
+                          // constant array arguments fold here; the sem-3
+                          // handler's temporary "non-constant argument is not
+                          // yet supported" guard still rejects runtime arrays.
+                          std::vector<StructureConstructor> elements;
+                          elements.reserve(constant->values().size());
+                          for (const StructureConstructorValues &scv :
+                              constant->values()) {
+                            auto ordVal{
+                                ToInt64(scv.find(ordSym)->second.value())};
+                            if (isNext ? *ordVal >= count : *ordVal <= 1) {
+                              return boundaryBail();
+                            }
+                            int newOrd{isNext ? static_cast<int>(*ordVal + 1)
+                                              : static_cast<int>(*ordVal - 1)};
+                            StructureConstructor ctor{*derived};
+                            ctor.Add(ordSym,
+                                Expr<SomeType>{
+                                    Expr<SomeInteger>{Expr<CInteger>{newOrd}}});
+                            elements.emplace_back(std::move(ctor));
+                          }
+                          return Expr<SomeDerived>{Constant<SomeDerived>{
+                              *derived, std::move(elements),
+                              ConstantSubscripts{constant->shape()}}};
                         }
                       }
                     }
diff --git a/flang/lib/Evaluate/fold-integer.cpp b/flang/lib/Evaluate/fold-integer.cpp
index 6619453148dba..2b607c67ec699 100644
--- a/flang/lib/Evaluate/fold-integer.cpp
+++ b/flang/lib/Evaluate/fold-integer.cpp
@@ -766,10 +766,36 @@ std::optional<Expr<T>> FoldIntrinsicFunctionCommon(
         if (auto type{derivedExpr->GetType()}) {
           if (const auto *derived{GetDerivedTypeSpec(*type)}) {
             if (derived->IsEnumerationType()) {
+              // Scalar: fold to the single ordinal.
               if (auto ordExpr{GetEnumerationOrdinal(*derivedExpr)}) {
                 if (auto ordVal{ToInt64(*ordExpr)}) {
                   return Expr<T>{Constant<T>{Scalar<T>{*ordVal}}};
                 }
+              } else if (const auto *constant{
+                             UnwrapConstantValue<SomeDerived>(*derivedExpr)};
+                  constant && constant->Rank() > 0) {
+                // Array constant: fold elementwise into a constant array of
+                // ordinals.  Reaching here means the whole constructor already
+                // folded to a constant, so every element's __ordinal is a
+                // constant integer.
+                if (const auto *scope{derived->GetScope()}) {
+                  auto ordIter{scope->find(semantics::SourceName{
+                      semantics::DerivedTypeDetails::ordinalComponentName,
+                      sizeof(
+                          semantics::DerivedTypeDetails::ordinalComponentName) -
+                          1})};
+                  if (ordIter != scope->end()) {
+                    const semantics::Symbol &ordSym{*ordIter->second};
+                    std::vector<Scalar<T>> elements;
+                    for (const StructureConstructorValues &scv :
+                        constant->values()) {
+                      elements.emplace_back(
+                          *ToInt64(scv.find(ordSym)->second.value()));
+                    }
+                    return Expr<T>{Constant<T>{std::move(elements),
+                        ConstantSubscripts{constant->shape()}}};
+                  }
+                }
               }
               // Non-constant enumeration argument — leave unfolded
               return Expr<T>{std::move(funcRef)};
diff --git a/flang/lib/Evaluate/intrinsics.cpp b/flang/lib/Evaluate/intrinsics.cpp
index 0b1e3e0a19140..c0090076de9a0 100644
--- a/flang/lib/Evaluate/intrinsics.cpp
+++ b/flang/lib/Evaluate/intrinsics.cpp
@@ -3100,6 +3100,31 @@ bool CheckAndRearrangeArguments(ActualArguments &arguments,
   return !anyMissing;
 }
 
+// Locates the actual argument that binds to the first dummy argument of an
+// intrinsic, honoring keyword syntax.  The enumeration-type inline handlers
+// (HUGE/INT/NEXT/PREVIOUS) must decide whether the enum path applies before
+// the actual arguments have been rearranged into dummy order, so they cannot
+// simply inspect arguments[0].  The first dummy is bound either by an explicit
+// keyword (e.g. INT(KIND=8, A=RED)) or, absent that keyword, by the first
+// positional argument.  Returns nullptr if no such argument is present.
+static const ActualArgument *FindFirstDummyArgument(
+    const ActualArguments &arguments, const char *firstDummyKeyword) {
+  const ActualArgument *firstPositional{nullptr};
+  for (const std::optional<ActualArgument> &arg : arguments) {
+    if (!arg) {
+      continue;
+    }
+    if (arg->keyword()) {
+      if (*arg->keyword() == firstDummyKeyword) {
+        return &*arg;
+      }
+    } else if (!firstPositional) {
+      firstPositional = &*arg;
+    }
+  }
+  return firstPositional;
+}
+
 // The NULL() intrinsic is a special case.
 SpecificCall IntrinsicProcTable::Implementation::HandleNull(
     ActualArguments &arguments, FoldingContext &context) const {
@@ -4081,19 +4106,36 @@ std::optional<SpecificCall> IntrinsicProcTable::Implementation::Probe(
       }
     }
 
-    // Enumeration type intrinsics: HUGE, NEXT, PREVIOUS, INT
-    if (arguments.size() >= 1 && arguments[0]) {
-      if (auto type{arguments[0]->GetType()}) {
-        if (const auto *derived{GetDerivedTypeSpec(*type)}) {
-          if (derived->IsEnumerationType()) {
-            if (call.name == "huge") {
-              return HandleEnumerationHuge(*derived, arguments, context);
-            } else if (call.name == "next") {
-              return HandleEnumerationNext(*derived, arguments, context);
-            } else if (call.name == "previous") {
-              return HandleEnumerationPrevious(*derived, arguments, context);
-            } else if (call.name == "int") {
-              return HandleEnumerationInt(*derived, arguments, context);
+    // NEXT/PREVIOUS are enumeration-type-only intrinsics.
+    if (call.name == "next" || call.name == "previous") {
+      const semantics::DerivedTypeSpec *derived{nullptr};
+      if (const ActualArgument *arg{FindFirstDummyArgument(arguments, "a")}) {
+        if (auto type{arg->GetType()}) {
+          derived = GetDerivedTypeSpec(*type);
+        }
+      }
+      if (derived && derived->IsEnumerationType()) {
+        return call.name == "next"
+            ? HandleEnumerationNext(*derived, arguments, context)
+            : HandleEnumerationPrevious(*derived, arguments, context);
+      }
+      context.messages().Say(
+          "Argument of %s() must be of enumeration type"_err_en_US,
+          parser::ToUpperCaseLetters(call.name));
+      return std::nullopt;
+    }
+
+    // HUGE/INT are ordinary intrinsics that also accept enumeration types.
+    if (call.name == "huge" || call.name == "int") {
+      const char *firstDummyKeyword{call.name == "huge" ? "x" : "a"};
+      if (const ActualArgument *arg{
+              FindFirstDummyArgument(arguments, firstDummyKeyword)}) {
+        if (auto type{arg->GetType()}) {
+          if (const auto *derived{GetDerivedTypeSpec(*type)}) {
+            if (derived->IsEnumerationType()) {
+              return call.name == "huge"
+                  ? HandleEnumerationHuge(*derived, arguments, context)
+                  : HandleEnumerationInt(*derived, arguments, context);
             }
           }
         }
diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index fdfbf3cafd895..510b8b575a119 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -172,6 +172,18 @@ class BaseVisitor {
   }
   bool IsIntrinsic(
       const SourceName &name, std::optional<Symbol::Flag> flag) const {
+    // TEMPORARY (enumeration-type feature gating): NEXT and PREVIOUS are only
+    // recognized as intrinsic names when the enumeration-type feature is
+    // enabled, so that pre-F2023 programs may still use those names for
+    // implicit external procedures.  This gating is removed once the
+    // enumeration-type feature is fully implemented.
+    if (!context_->languageFeatures().IsEnabled(
+            common::LanguageFeature::EnumerationType)) {
+      const std::string nameStr{name.ToString()};
+      if (nameStr == "next" || nameStr == "previous") {
+        return false;
+      }
+    }
     if (!flag) {
       return context_->intrinsics().IsIntrinsic(name.ToString());
     } else if (flag == Symbol::Flag::Function) {
diff --git a/flang/test/Semantics/enumeration-type-intrinsics-array-fold.f90 b/flang/test/Semantics/enumeration-type-intrinsics-array-fold.f90
new file mode 100644
index 0000000000000..d7af7199aa4ba
--- /dev/null
+++ b/flang/test/Semantics/enumeration-type-intrinsics-array-fold.f90
@@ -0,0 +1,29 @@
+! RUN: %flang_fc1 -fdebug-dump-symbols -fenumeration-type %s 2>&1 | FileCheck %s
+! Regression test: the enumeration-type intrinsics INT/NEXT/PREVIOUS are
+! elemental, so a constant array argument must fold elementwise in a constant
+! context.  Previously the enum fold path extracted only a scalar ordinal, so an
+! array-valued call was left unfolded and a named constant reported "cannot be
+! computed as a constant value".  Ordinals are 1-based, so
+! [red, green, blue] -> [1, 2, 3].
+
+module enum_array_fold_mod
+  enumeration type :: color
+    enumerator :: red, green, blue
+  end enumeration type
+
+  ! Default-kind INT() over an array constructor folds to INTEGER(4) [1,2,3].
+  integer, parameter :: a(3) = int([red, green, blue])
+  !CHECK: a, PARAMETER, PUBLIC size={{[0-9]+}} offset={{[0-9]+}}: ObjectEntity type: INTEGER(4) shape: 1_8:3_8 init:[INTEGER(4)::1_4,2_4,3_4]
+
+  ! KIND= is honored: folds to INTEGER(8) with the reversed order [3,2,1].
+  integer(8), parameter :: b(3) = int([blue, green, red], kind=8)
+  !CHECK: b, PARAMETER, PUBLIC size={{[0-9]+}} offset={{[0-9]+}}: ObjectEntity type: INTEGER(8) shape: 1_8:3_8 init:[INTEGER(8)::3_8,2_8,1_8]
+
+  ! NEXT() over a (non-boundary) constant array folds to [green, blue].
+  type(color), parameter :: cn(2) = next([red, green])
+  !CHECK: cn, PARAMETER, PUBLIC size={{[0-9]+}} offset={{[0-9]+}}: ObjectEntity type: TYPE(color) shape: 1_8:2_8 init:[color::color(2_4),color(3_4)]
+
+  ! PREVIOUS() over a (non-boundary) constant array folds to [red, green].
+  type(color), parameter :: cp(2) = previous([green, blue])
+  !CHECK: cp, PARAMETER, PUBLIC size={{[0-9]+}} offset={{[0-9]+}}: ObjectEntity type: TYPE(color) shape: 1_8:2_8 init:[color::color(1_4),color(2_4)]
+end module
diff --git a/flang/test/Semantics/enumeration-type-intrinsics-gating.f90 b/flang/test/Semantics/enumeration-type-intrinsics-gating.f90
new file mode 100644
index 0000000000000..11fda942208c5
--- /dev/null
+++ b/flang/test/Semantics/enumeration-type-intrinsics-gating.f90
@@ -0,0 +1,14 @@
+! RUN: %flang_fc1 -fsyntax-only %s
+! Without -fenumeration-type, NEXT and PREVIOUS are not reserved intrinsic
+! names, so a pre-F2023 program may use them as implicit external procedures.
+! This exercises the enumeration-type feature gating in resolve-names.cpp and
+! verifies the reference no longer triggers an internal compiler error.
+! NOTE: This gating is TEMPORARY and is removed once the enumeration-type
+!       feature is fully implemented.
+
+program p
+  integer :: i
+  real :: r
+  i = next(5)
+  r = previous(3)
+end program
diff --git a/flang/test/Semantics/enumeration-type-intrinsics-keyword.f90 b/flang/test/Semantics/enumeration-type-intrinsics-keyword.f90
new file mode 100644
index 0000000000000..85e70baf9ca0e
--- /dev/null
+++ b/flang/test/Semantics/enumeration-type-intrinsics-keyword.f90
@@ -0,0 +1,45 @@
+! RUN: %flang_fc1 -fsyntax-only -fenumeration-type %s
+! Verify keyword-order argument binding for enumeration-type intrinsics.
+! INT(KIND=..., A=...) must recognize the enumeration argument even when it is
+! not the first positional actual.  This is a regression test: previously the
+! enum dispatch inspected only the first positional argument, so a keyword call
+! that placed KIND= before A= reported "Actual argument for 'a=' has bad type".
+! A clean compile (exit 0) confirms the enum path is taken for the keyword form.
+
+module enum_keyword_mod
+  enumeration type :: color
+    enumerator :: red, green, blue
+  end enumeration type
+end module
+
+subroutine test_int_keyword_order()
+  use enum_keyword_mod
+  integer :: i
+  integer(8) :: j
+
+  ! Enum argument bound by keyword A=, KIND= appears first.
+  j = int(kind=8, a=red)
+  i = int(a=green, kind=4)
+  j = int(a=blue, kind=8)
+
+  ! Positional forms continue to work.
+  i = int(red)
+  j = int(green, 8)
+end subroutine
+
+subroutine test_huge_keyword()
+  use enum_keyword_mod
+  type(color) :: x
+
+  ! HUGE bound by keyword X=.
+  x = huge(x=x)
+end subroutine
+
+subroutine test_next_previous_keyword()
+  use enum_keyword_mod
+  type(color) :: c
+
+  ! Enum argument bound by keyword A= (first and only dummy).
+  c = next(a=red)
+  c = previous(a=blue)
+end subroutine
diff --git a/flang/test/Semantics/enumeration-type-intrinsics-nonenum.f90 b/flang/test/Semantics/enumeration-type-intrinsics-nonenum.f90
new file mode 100644
index 0000000000000..37a04c6f0fffb
--- /dev/null
+++ b/flang/test/Semantics/enumeration-type-intrinsics-nonenum.f90
@@ -0,0 +1,16 @@
+! RUN: not %flang_fc1 -fsyntax-only -fenumeration-type %s 2>&1 | FileCheck %s
+! With the enumeration-type feature enabled, NEXT and PREVIOUS require an
+! argument of enumeration type.  A non-enumeration argument must produce a
+! proper diagnostic rather than an internal compiler error.
+
+subroutine test_next_nonenum()
+  integer :: i, j
+  !CHECK: error: Argument of NEXT() must be of enumeration type
+  i = next(j)
+end subroutine
+
+subroutine test_previous_nonenum()
+  integer :: i, j
+  !CHECK: error: Argument of PREVIOUS() must be of enumeration type
+  i = previous(j)
+end subroutine
diff --git a/flang/test/Semantics/enumeration-type-intrinsics.f90 b/flang/test/Semantics/enumeration-type-intrinsics.f90
index fa9b1aae79c13..0609b16f35bfe 100644
--- a/flang/test/Semantics/enumeration-type-intrinsics.f90
+++ b/flang/test/Semantics/enumeration-type-intrinsics.f90
@@ -155,6 +155,18 @@ subroutine test_previous_boundary_warning()
   pc = previous(red)
 end subroutine
 
+subroutine test_next_previous_array_boundary()
+  use enum_intrinsics_mod
+  type(color) :: nc(2), pc(2)
+  ! NEXT/PREVIOUS are elemental: a constant array with any element at the
+  ! boundary is error termination without STAT=, so the whole reference is
+  ! diagnosed and left unfolded (same as the scalar boundary case).
+  !CHECK: error: NEXT() of last enumerator without STAT= causes error termination
+  nc = next([green, blue])
+  !CHECK: error: PREVIOUS() of first enumerator without STAT= causes error termination
+  pc = previous([red, green])
+end subroutine
+
 subroutine test_huge_real_still_works()
   ! Non-enumeration HUGE still works normally
   real :: r
@@ -162,3 +174,18 @@ subroutine test_huge_real_still_works()
   r = huge(r)
   i = huge(i)
 end subroutine
+
+! NOTE: This test will need to be modified after completion of the feature.
+subroutine test_next_previous_keyword_order()
+  use enum_intrinsics_mod
+  type(color) :: nc
+  integer :: istat
+  ! The enum argument passed by keyword AFTER a non-enum keyword (STAT=) must
+  ! still be recognized as the enumeration call.  Reaching the STAT handler
+  ! (rather than the "must be of enumeration type" diagnostic) proves the
+  ! keyword-order dispatch works.
+  !CHECK: error: NEXT() with STAT= is not yet supported
+  nc = next(stat=istat, a=red)
+  !CHECK: error: PREVIOUS() with STAT= is not yet supported
+  nc = previous(stat=istat, a=blue)
+end subroutine



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