[flang] Fix crash in fuzzer-generated error test.

[klausler]

Fixes #121973.

[llvmbot]

@llvm/pr-subscribers-flang-semantics

Author: Peter Klausler (klausler)

Changes

Fixes #121973.

---

Full diff: https://github.com/llvm/llvm-project/pull/122199.diff

2 Files Affected:

• (modified) flang/lib/Semantics/resolve-names.cpp (+3)
• (added) flang/test/Semantics/bug121973.f90 (+9)

diff --git a/flang/lib/Semantics/resolve-names.cpp b/flang/lib/Semantics/resolve-names.cpp
index 724f1b28078356..09355675ff5d55 100644
--- a/flang/lib/Semantics/resolve-names.cpp
+++ b/flang/lib/Semantics/resolve-names.cpp
@@ -8213,6 +8213,9 @@ bool DeclarationVisitor::CheckForHostAssociatedImplicit(
 }
 
 bool DeclarationVisitor::IsUplevelReference(const Symbol &symbol) {
+  if (symbol.owner().IsTopLevel()) {
+    return false;
+  }
   const Scope &symbolUnit{GetProgramUnitContaining(symbol)};
   if (symbolUnit == GetProgramUnitContaining(currScope())) {
     return false;
diff --git a/flang/test/Semantics/bug121973.f90 b/flang/test/Semantics/bug121973.f90
new file mode 100644
index 00000000000000..0ae04c808e416b
--- /dev/null
+++ b/flang/test/Semantics/bug121973.f90
@@ -0,0 +1,9 @@
+! RUN: %python %S/test_errors.py %s %flang_fc1
+subroutine s()
+  real(8) :: a
+  !ERROR: COMPLEX(KIND=128) is not a supported type
+  complex(128) :: x
+  a(i)=a + ((i)+1) + 3.14
+  !ERROR: 'a' has not been declared as an array or pointer-valued function
+  a()=z(a * a + n-1 - x) + i((/0,0,0,0,0,0,0,0,0,0/)) + 8
+end