[flang-commits] [PATCH] D117158: [flang] Allow pointers to non-sequence types in sequence types

[Peter Klausler via Phabricator via flang-commits]

klausler created this revision.
klausler added a reviewer: PeteSteinfeld.
klausler added a project: Flang.
Herald added a subscriber: jdoerfert.
klausler requested review of this revision.

Derived types with SEQUENCE must have data components of sequence
types; but this rule is relaxed as common an extension in the case of
pointer components, whose targets' types are not really relevant
to the implementation requirements of sequence types.


https://reviews.llvm.org/D117158

Files:
  flang/docs/Extensions.md
  flang/include/flang/Common/Fortran-features.h
  flang/lib/Semantics/resolve-names.cpp
  flang/test/Semantics/resolve31.f90


Index: flang/test/Semantics/resolve31.f90
===================================================================
--- flang/test/Semantics/resolve31.f90
+++ flang/test/Semantics/resolve31.f90
@@ -83,6 +83,8 @@
     class(*), allocatable :: typeStarField
     !ERROR: A sequence type data component must either be of an intrinsic type or a derived sequence type
     type(plainType) :: testField1
+    !Pointers are ok as an extension
+    type(plainType), pointer :: testField1p
     type(sequenceType) :: testField2
     procedure(real), pointer, nopass :: procField
   end type testType
Index: flang/lib/Semantics/resolve-names.cpp
===================================================================
--- flang/lib/Semantics/resolve-names.cpp
+++ flang/lib/Semantics/resolve-names.cpp
@@ -4280,6 +4280,20 @@
       GetAttrs().HasAny({Attr::POINTER, Attr::ALLOCATABLE}));
   Walk(std::get<parser::DeclarationTypeSpec>(x.t));
   set_allowForwardReferenceToDerivedType(false);
+  if (derivedTypeInfo_.sequence) { // C740
+    if (const auto *declType{GetDeclTypeSpec()}) {
+      if (!declType->AsIntrinsic() && !declType->IsSequenceType()) {
+        if (GetAttrs().test(Attr::POINTER) &&
+            context().IsEnabled(common::LanguageFeature::PointerInSeqType)) {
+          if (context().ShouldWarn(common::LanguageFeature::PointerInSeqType)) {
+            Say("A sequence type data component that is a pointer to a non-sequence type is not standard"_en_US);
+          }
+        } else {
+          Say("A sequence type data component must either be of an intrinsic type or a derived sequence type"_err_en_US);
+        }
+      }
+    }
+  }
   Walk(std::get<std::list<parser::ComponentDecl>>(x.t));
   return false;
 }
Index: flang/include/flang/Common/Fortran-features.h
===================================================================
--- flang/include/flang/Common/Fortran-features.h
+++ flang/include/flang/Common/Fortran-features.h
@@ -31,7 +31,7 @@
     OldLabelDoEndStatements, LogicalIntegerAssignment, EmptySourceFile,
     ProgramReturn, ImplicitNoneTypeNever, ImplicitNoneTypeAlways,
     ForwardRefDummyImplicitNone, OpenAccessAppend, BOZAsDefaultInteger,
-    DistinguishableSpecifics, DefaultSave)
+    DistinguishableSpecifics, DefaultSave, PointerInSeqType)
 
 using LanguageFeatures = EnumSet<LanguageFeature, LanguageFeature_enumSize>;
 
Index: flang/docs/Extensions.md
===================================================================
--- flang/docs/Extensions.md
+++ flang/docs/Extensions.md
@@ -190,6 +190,10 @@
   exactly one is unlimited polymorphic).
 * External unit 0 is predefined and connected to the standard error output,
   and defined as `ERROR_UNIT` in the intrinsic `ISO_FORTRAN_ENV` module.
+* A `POINTER` component's type need not be a sequence type when
+  the component appears in a derived type with `SEQUENCE`.
+  (This case should probably be an exception to constraint C740 in
+  the standard.)
 
 ### Extensions supported when enabled by options
 


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