Index: flang/lib/Semantics/resolve-names.cpp
===================================================================
--- flang/lib/Semantics/resolve-names.cpp
+++ flang/lib/Semantics/resolve-names.cpp
@@ -5188,7 +5188,6 @@
   CHECK(scope.symbol());
   CHECK(scope.symbol()->scope() == &scope);
   auto &details{scope.symbol()->get<DerivedTypeDetails>()};
-  details.set_isForwardReferenced(false);
   std::set<SourceName> paramNames;
   for (auto &paramName : std::get<std::list<parser::Name>>(stmt.statement.t)) {
     details.add_paramName(paramName.source);
@@ -5240,6 +5239,7 @@
   }
   Walk(std::get<std::optional<parser::TypeBoundProcedurePart>>(x.t));
   Walk(std::get<parser::Statement<parser::EndTypeStmt>>(x.t));
+  details.set_isForwardReferenced(false);
   derivedTypeInfo_ = {};
   PopScope();
   return false;
@@ -5255,7 +5255,13 @@
   auto *extendsName{derivedTypeInfo_.extends};
   std::optional<DerivedTypeSpec> extendsType{
       ResolveExtendsType(name, extendsName)};
-  auto &symbol{MakeSymbol(name, GetAttrs(), DerivedTypeDetails{})};
+  DerivedTypeDetails derivedTypeDetails;
+  if (Symbol *typeSymbol{FindInScope(currScope(), name)}; typeSymbol &&
+      typeSymbol->has<DerivedTypeDetails>() &&
+      typeSymbol->get<DerivedTypeDetails>().isForwardReferenced()) {
+    derivedTypeDetails.set_isForwardReferenced(true);
+  }
+  auto &symbol{MakeSymbol(name, GetAttrs(), std::move(derivedTypeDetails))};
   symbol.ReplaceName(name.source);
   derivedTypeInfo_.type = &symbol;
   PushScope(Scope::Kind::DerivedType, &symbol);
Index: flang/test/Semantics/typeinfo05.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/typeinfo05.f90
@@ -0,0 +1,16 @@
+!RUN: bbc --dump-symbols %s | FileCheck %s
+!RUN: %flang_fc1 -fdebug-dump-symbols %s | FileCheck %s
+! Ensure that cycles via POINTERs do not instantiate incomplete derived
+! types that would lead to types whose sizeinbytes=0
+program main
+  implicit none
+  type t1
+    type(t2), pointer :: b
+  end type t1
+!CHECK: .dt.t1, SAVE, TARGET (CompilerCreated, ReadOnly): ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t1,sizeinbytes=40_8,uninstantiated=NULL(),kindparameter=NULL(),lenparameterkind=NULL(),component=.c.t1,procptr=NULL(),special=NULL(),specialbitset=0_4,hasparent=0_1,noinitializationneeded=0_1,nodestructionneeded=1_1,nofinalizationneeded=1_1)
+  type :: t2
+    type(t1) :: a
+  end type t2
+! CHECK: .dt.t2, SAVE, TARGET (CompilerCreated, ReadOnly): ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t2,sizeinbytes=40_8,uninstantiated=NULL(),kindparameter=NULL(),lenparameterkind=NULL(),component=.c.t2,procptr=NULL(),special=NULL(),specialbitset=0_4,hasparent=0_1,noinitializationneeded=0_1,nodestructionneeded=1_1,nofinalizationneeded=1_1)
+end program main
+
Index: flang/test/Semantics/typeinfo06.f90
===================================================================
--- /dev/null
+++ flang/test/Semantics/typeinfo06.f90
@@ -0,0 +1,16 @@
+!RUN: bbc --dump-symbols %s | FileCheck %s
+!RUN: %flang_fc1 -fdebug-dump-symbols %s | FileCheck %s
+! Ensure that cycles via ALLOCATABLEs do not instantiate incomplete derived
+! types that would lead to types whose sizeinbytes=0
+program main
+  implicit none
+  type t1
+    type(t2), allocatable :: b
+  end type t1
+!CHECK: .dt.t1, SAVE, TARGET (CompilerCreated, ReadOnly): ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t1,sizeinbytes=40_8,uninstantiated=NULL(),kindparameter=NULL(),lenparameterkind=NULL(),component=.c.t1,procptr=NULL(),special=NULL(),specialbitset=0_4,hasparent=0_1,noinitializationneeded=0_1,nodestructionneeded=0_1,nofinalizationneeded=1_1)
+  type :: t2
+    type(t1) :: a
+  end type t2
+! CHECK: .dt.t2, SAVE, TARGET (CompilerCreated, ReadOnly): ObjectEntity type: TYPE(derivedtype) init:derivedtype(binding=NULL(),name=.n.t2,sizeinbytes=40_8,uninstantiated=NULL(),kindparameter=NULL(),lenparameterkind=NULL(),component=.c.t2,procptr=NULL(),special=NULL(),specialbitset=0_4,hasparent=0_1,noinitializationneeded=0_1,nodestructionneeded=0_1,nofinalizationneeded=1_1)
+end program main
+