From 02b7995b91860d39e132638dd2f50260ca088131 Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler@nvidia.com>
Date: Fri, 21 Mar 2025 14:36:07 -0700
Subject: [PATCH] [flang] Fix missed case of symbol renaming in module file
 generation

The map of symbols requiring new local aliases for USE association
needs to use the symbols' ultimate resolutions to avoid missing
cases that can arise in convoluted codes with lots of confusing
renamings.

Fixes https://github.com/llvm/llvm-project/issues/132435.
---
 flang/lib/Evaluate/formatting.cpp  |  3 +-
 flang/lib/Semantics/mod-file.cpp   |  2 +-
 flang/test/Semantics/bug132435.f90 | 85 ++++++++++++++++++++++++++++++
 3 files changed, 88 insertions(+), 2 deletions(-)
 create mode 100644 flang/test/Semantics/bug132435.f90

diff --git a/flang/lib/Evaluate/formatting.cpp b/flang/lib/Evaluate/formatting.cpp
index c4c3998257830..6778fac9a44fd 100644
--- a/flang/lib/Evaluate/formatting.cpp
+++ b/flang/lib/Evaluate/formatting.cpp
@@ -129,7 +129,8 @@ llvm::raw_ostream &Constant<Type<TypeCategory::Character, KIND>>::AsFortran(
 llvm::raw_ostream &EmitVar(llvm::raw_ostream &o, const Symbol &symbol,
     std::optional<parser::CharBlock> name = std::nullopt) {
   const auto &renamings{symbol.owner().context().moduleFileOutputRenamings()};
-  if (auto iter{renamings.find(&symbol)}; iter != renamings.end()) {
+  if (auto iter{renamings.find(&symbol.GetUltimate())};
+      iter != renamings.end()) {
     return o << iter->second.ToString();
   } else if (name) {
     return o << name->ToString();
diff --git a/flang/lib/Semantics/mod-file.cpp b/flang/lib/Semantics/mod-file.cpp
index c3b46261228df..ee356e56e4458 100644
--- a/flang/lib/Semantics/mod-file.cpp
+++ b/flang/lib/Semantics/mod-file.cpp
@@ -348,7 +348,7 @@ void ModFileWriter::PrepareRenamings(const Scope &scope) {
     uses_ << DEREF(sMod->symbol()).name() << ",only:";
     if (rename != s->name()) {
       uses_ << rename << "=>";
-      renamings.emplace(&*s, rename);
+      renamings.emplace(&s->GetUltimate(), rename);
     }
     uses_ << s->name() << '\n';
     useExtraAttrs_ << "private::" << rename << '\n';
diff --git a/flang/test/Semantics/bug132435.f90 b/flang/test/Semantics/bug132435.f90
new file mode 100644
index 0000000000000..be8b661fcf6cc
--- /dev/null
+++ b/flang/test/Semantics/bug132435.f90
@@ -0,0 +1,85 @@
+! RUN: %python %S/test_modfile.py %s %flang_fc1
+module m1
+  type foo
+    integer :: c1 = 123
+  end type
+end
+
+module m2
+  use m1, only: foo
+  type baz
+    type(foo) :: d = foo()
+  end type
+  type bar
+    type(baz) :: e = baz()
+  end type
+end
+
+module m3
+  use m1, only: m1foo => foo
+  type foo
+    type(m1foo), private :: c2 = m1foo()
+  end type
+end
+
+module m4
+  use m2, only: m3foo => foo
+  type foo
+    type(m3foo), private :: c3 = m3foo()
+  end type
+end
+
+module m5
+  use m2, only: m2bar => bar
+  use m4, only: foo
+  type blah
+    type(m2bar) :: f = m2bar()
+  end type
+end
+
+!Expect: m1.mod
+!module m1
+!type::foo
+!integer(4)::c1=123_4
+!end type
+!end
+
+!Expect: m2.mod
+!module m2
+!use m1,only:foo
+!type::baz
+!type(foo)::d=foo(c1=123_4)
+!end type
+!type::bar
+!type(baz)::e=baz(d=foo(c1=123_4))
+!end type
+!end
+
+!Expect: m3.mod
+!module m3
+!use m1,only:m1foo=>foo
+!type::foo
+!type(m1foo),private::c2=m1foo(c1=123_4)
+!end type
+!end
+
+!Expect: m4.mod
+!module m4
+!use m2,only:m3foo=>foo
+!type::foo
+!type(m3foo),private::c3=m3foo(c1=123_4)
+!end type
+!end
+
+!Expect: m5.mod
+!module m5
+!use m2,only:m2$foo=>foo
+!use m2,only:baz
+!use m2,only:m2bar=>bar
+!use m4,only:foo
+!private::m2$foo
+!private::baz
+!type::blah
+!type(m2bar)::f=m2bar(e=baz(d=m2$foo(c1=123_4)))
+!end type
+!end