From 9cf3c638ecdf3cb749977e44546bf98a686dc459 Mon Sep 17 00:00:00 2001
From: peter klausler <pklausler@nvidia.com>
Date: Tue, 3 Dec 2019 10:21:37 -0800
Subject: [PATCH] [flang] Fix forward ref to derived type when symbol exists

Fix some comments

Original-commit: flang-compiler/f18@3274ed95459865057a2e77966863e6b01b5f6d35
Reviewed-on: https://github.com/flang-compiler/f18/pull/852
---
 flang/lib/evaluate/intrinsics.cc     |  6 +++---
 flang/lib/semantics/resolve-names.cc | 14 ++++++-------
 flang/test/semantics/symbol17.f90    | 31 ++++++++++++++++++++++++++++
 3 files changed, 41 insertions(+), 10 deletions(-)

diff --git a/flang/lib/evaluate/intrinsics.cc b/flang/lib/evaluate/intrinsics.cc
index 844fffa3a471..f513b2c014f6 100644
--- a/flang/lib/evaluate/intrinsics.cc
+++ b/flang/lib/evaluate/intrinsics.cc
@@ -708,8 +708,8 @@ static const IntrinsicInterface genericIntrinsicFunction[]{
 // TODO: Non-standard intrinsic functions
 //  AND, OR, XOR, LSHIFT, RSHIFT, SHIFT, ZEXT, IZEXT,
 //  COSD, SIND, TAND, ACOSD, ASIND, ATAND, ATAN2D, COMPL,
-//  DCMPLX, EQV, NEQV, INT8, JINT, JNINT, KNINT,
-//  QCMPLX, DREAL, DFLOAT, QEXT, QFLOAT, QREAL, DNUM,
+//  EQV, NEQV, INT8, JINT, JNINT, KNINT,
+//  QCMPLX, DFLOAT, QEXT, QFLOAT, QREAL, DNUM,
 //  INUM, JNUM, KNUM, QNUM, RNUM, RAN, RANF, ILEN, SIZEOF,
 //  MCLOCK, SECNDS, COTAN, IBCHNG, ISHA, ISHC, ISHL, IXOR
 //  IARG, IARGC, NARGS, NUMARG, BADDRESS, IADDR, CACHESIZE,
@@ -740,7 +740,7 @@ struct SpecificIntrinsicInterface : public IntrinsicInterface {
   //  e.g. IABS(INT(i), INT(j)) not equiv to INT(ABS(i, j)).
   // This is allowed for restricted min/max specific functions because
   // the expected behavior is clear from their definitions. A warning is though
-  // always emitted because other compilers behavior is not ubiquitous here.
+  // always emitted because other compilers' behavior is not ubiquitous here.
   bool useGenericAndForceResultType{false};
 };
 
diff --git a/flang/lib/semantics/resolve-names.cc b/flang/lib/semantics/resolve-names.cc
index 4e6bbe9d6ff6..b8eb6a8b6291 100644
--- a/flang/lib/semantics/resolve-names.cc
+++ b/flang/lib/semantics/resolve-names.cc
@@ -4429,15 +4429,16 @@ void DeclarationVisitor::SetType(
 
 std::optional<DerivedTypeSpec> DeclarationVisitor::ResolveDerivedType(
     const parser::Name &name) {
-  const Symbol *symbol{FindSymbol(name)};
-  if (!symbol) {
+  Symbol *symbol{FindSymbol(name)};
+  if (!symbol || symbol->has<UnknownDetails>()) {
     if (allowForwardReferenceToDerivedType()) {
-      Symbol &forward{MakeSymbol(InclusiveScope(), name.source, Attrs{})};
+      if (!symbol) {
+        symbol = &MakeSymbol(InclusiveScope(), name.source, Attrs{});
+        Resolve(name, *symbol);
+      };
       DerivedTypeDetails details;
       details.set_isForwardReferenced();
-      forward.set_details(std::move(details));
-      Resolve(name, forward);
-      symbol = &forward;
+      symbol->set_details(std::move(details));
     } else {
       Say(name, "Derived type '%s' not found"_err_en_US);
       return std::nullopt;
@@ -6221,5 +6222,4 @@ bool ResolveNames(SemanticsContext &context, const parser::Program &program) {
   ResolveNamesVisitor{context}.Walk(program);
   return !context.AnyFatalError();
 }
-
 }
diff --git a/flang/test/semantics/symbol17.f90 b/flang/test/semantics/symbol17.f90
index 1ee8e4d49fc9..7b6ee08c4e8e 100644
--- a/flang/test/semantics/symbol17.f90
+++ b/flang/test/semantics/symbol17.f90
@@ -120,3 +120,34 @@ subroutine s2 (q1)
  !DEF: /s2/DerivedType2/n ObjectEntity INTEGER(4)
  q1%n = 1
 end subroutine
+!DEF: /m1 Module
+module m1
+ !DEF: /m1/forward PRIVATE DerivedType
+  private :: forward
+ !DEF: /m1/base PUBLIC DerivedType
+  type :: base
+  !REF: /m1/forward
+  !DEF: /m1/base/p POINTER ObjectEntity CLASS(forward)
+    class(forward), pointer :: p
+  end type
+ !REF: /m1/base
+ !REF: /m1/forward
+  type, extends(base) :: forward
+  !DEF: /m1/forward/n ObjectEntity INTEGER(4)
+    integer :: n
+  end type
+ contains
+ !DEF: /m1/test PUBLIC (Subroutine) Subprogram
+  subroutine test
+  !REF: /m1/forward
+  !DEF: /m1/test/object TARGET ObjectEntity TYPE(forward)
+    type(forward), target :: object
+  !REF: /m1/test/object
+  !REF: /m1/base/p
+    object%p => object
+  !REF: /m1/test/object
+  !REF: /m1/base/p
+  !REF: /m1/forward/n
+    object%p%n = 666
+  end subroutine
+end module