From a27d3852095a461b739da534ddc9abfb625f2e06 Mon Sep 17 00:00:00 2001
From: Tim Keith <tkeith@nvidia.com>
Date: Tue, 9 Jun 2020 14:14:01 -0700
Subject: [PATCH] [flang] Fix bug resolving type in type definition

When we encountered a type name in a derived type definition, we were
sometimes finding a component of that name rather than the type from
the enclosing scope. Fix this by introducing `NonDerivedTypeScope()` to
start the search in the right scope.

Differential Revision: https://reviews.llvm.org/D81493
---
 flang/lib/Semantics/resolve-names.cpp | 14 +++++++++-----
 flang/test/Semantics/resolve92.f90    | 26 ++++++++++++++++++++++++++
 2 files changed, 35 insertions(+), 5 deletions(-)
 create mode 100644 flang/test/Semantics/resolve92.f90

diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index 5626163144d3..218dcc07b270 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -455,6 +455,8 @@ public:
   // TODO: Will return the scope of a FORALL or implied DO loop; is this ok?
   // If not, should call FindProgramUnitContaining() instead.
   Scope &InclusiveScope();
+  // The enclosing scope, skipping derived types.
+  Scope &NonDerivedTypeScope();
 
   // Create a new scope and push it on the scope stack.
   void PushScope(Scope::Kind kind, Symbol *symbol);
@@ -1999,6 +2001,10 @@ Scope &ScopeHandler::InclusiveScope() {
   DIE("inclusive scope not found");
 }
 
+Scope &ScopeHandler::NonDerivedTypeScope() {
+  return currScope_->IsDerivedType() ? currScope_->parent() : *currScope_;
+}
+
 void ScopeHandler::PushScope(Scope::Kind kind, Symbol *symbol) {
   PushScope(currScope().MakeScope(kind, symbol));
 }
@@ -3294,9 +3300,7 @@ void DeclarationVisitor::Post(const parser::EnumDef &) {
 
 bool DeclarationVisitor::Pre(const parser::AccessSpec &x) {
   Attr attr{AccessSpecToAttr(x)};
-  const Scope &scope{
-      currScope().IsDerivedType() ? currScope().parent() : currScope()};
-  if (!scope.IsModule()) { // C817
+  if (!NonDerivedTypeScope().IsModule()) { // C817
     Say(currStmtSource().value(),
         "%s attribute may only appear in the specification part of a module"_err_en_US,
         EnumToString(attr));
@@ -4725,7 +4729,7 @@ void DeclarationVisitor::SetType(
 
 std::optional<DerivedTypeSpec> DeclarationVisitor::ResolveDerivedType(
     const parser::Name &name) {
-  Symbol *symbol{FindSymbol(name)};
+  Symbol *symbol{FindSymbol(NonDerivedTypeScope(), name)};
   if (!symbol || symbol->has<UnknownDetails>()) {
     if (allowForwardReferenceToDerivedType()) {
       if (!symbol) {
@@ -5769,7 +5773,7 @@ void ResolveNamesVisitor::HandleCall(
 void ResolveNamesVisitor::HandleProcedureName(
     Symbol::Flag flag, const parser::Name &name) {
   CHECK(flag == Symbol::Flag::Function || flag == Symbol::Flag::Subroutine);
-  auto *symbol{FindSymbol(name)};
+  auto *symbol{FindSymbol(NonDerivedTypeScope(), name)};
   if (!symbol) {
     if (context().intrinsics().IsIntrinsic(name.source.ToString())) {
       symbol =
diff --git a/flang/test/Semantics/resolve92.f90 b/flang/test/Semantics/resolve92.f90
new file mode 100644
index 000000000000..24d86c34a5d2
--- /dev/null
+++ b/flang/test/Semantics/resolve92.f90
@@ -0,0 +1,26 @@
+! RUN: %S/test_errors.sh %s %t %f18
+
+module m1
+  implicit none
+  type t
+    integer :: n
+  end type
+  type t2
+    ! t and t2 must be resolved to types in m, not components in t2
+    type(t) :: t(10) = t(1)
+    type(t) :: x = t(1)
+    integer :: t2
+    type(t2), pointer :: p
+  end type
+end
+
+module m2
+  type :: t(t)
+    integer, kind :: t
+    integer(t) :: n
+  end type
+  type :: t2(t)
+    integer, kind :: t
+    type(t(t)) :: x = t(t)(t)
+  end type
+end