From 7f7d7d552b8d6731fdfbb77a154595ddf056342e Mon Sep 17 00:00:00 2001
From: Peter Klausler <pklausler@nvidia.com>
Date: Wed, 19 Mar 2025 12:02:03 -0700
Subject: [PATCH] [flang] Use local name for structure constructor (#132047)

When reinterpreting an ambiguously parsed function reference as a
structure constructor, use the original symbol of the type in the
representation of the derived type spec of the structure constructor,
not its ultimate resolution. The distinction turns out to matter when
generating module files containing derived type constants as
initializers when the derived types' names have undergone USE
association renaming.

Fixes https://github.com/llvm/llvm-project/issues/131579.
---
 flang/lib/Semantics/expression.cpp |  2 +-
 flang/test/Semantics/bug131579.f90 | 58 ++++++++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 flang/test/Semantics/bug131579.f90

diff --git a/flang/lib/Semantics/expression.cpp b/flang/lib/Semantics/expression.cpp
index 28e29e1ed6aa..62c563e00d2e 100644
--- a/flang/lib/Semantics/expression.cpp
+++ b/flang/lib/Semantics/expression.cpp
@@ -3268,7 +3268,7 @@ MaybeExpr ExpressionAnalyzer::Analyze(const parser::FunctionReference &funcRef,
       const auto &designator{std::get<parser::ProcedureDesignator>(call.t)};
       if (const auto *name{std::get_if<parser::Name>(&designator.u)}) {
         semantics::Scope &scope{context_.FindScope(name->source)};
-        semantics::DerivedTypeSpec dtSpec{name->source, symbol.GetUltimate()};
+        semantics::DerivedTypeSpec dtSpec{name->source, symbol};
         if (!CheckIsValidForwardReference(dtSpec)) {
           return std::nullopt;
         }
diff --git a/flang/test/Semantics/bug131579.f90 b/flang/test/Semantics/bug131579.f90
new file mode 100644
index 000000000000..8a5c124612a9
--- /dev/null
+++ b/flang/test/Semantics/bug131579.f90
@@ -0,0 +1,58 @@
+! RUN: %python %S/test_modfile.py %s %flang_fc1
+MODULE M1
+    TYPE T1
+        REAL(KIND=4), DIMENSION(:, :), POINTER    :: ptr => Null()
+    END TYPE T1
+
+    TYPE O1
+        TYPE(T1), POINTER           :: d => Null()
+    END TYPE O1
+END MODULE
+
+!Expect: m1.mod
+!module m1
+!type::t1
+!real(4),pointer::ptr(:,:)=>NULL()
+!end type
+!intrinsic::null
+!type::o1
+!type(t1),pointer::d=>NULL()
+!end type
+!end
+
+MODULE M2
+    USE M1,only : &
+    o1_prv => o1
+
+    public
+    TYPE D1
+        TYPE(o1_prv), PRIVATE        :: prv = o1_prv ()
+    END TYPE D1
+END MODULE
+
+!Expect: m2.mod
+!module m2
+!use m1,only:o1_prv=>o1
+!type::d1
+!type(o1_prv),private::prv=o1_prv(d=NULL())
+!end type
+!end
+
+MODULE M3
+    USE M2 , only : d1_prv => D1
+
+    PUBLIC
+    TYPE d1_ext
+        TYPE(d1_prv), PRIVATE :: prv = d1_prv()
+    END TYPE
+END MODULE
+
+!Expect: m3.mod
+!module m3
+!use m2,only:o1_prv
+!use m2,only:d1_prv=>d1
+!private::o1_prv
+!type::d1_ext
+!type(d1_prv),private::prv=d1_prv(prv=o1_prv(d=NULL()))
+!end type
+!end