diff --git a/flang/runtime/allocatable.cpp b/flang/runtime/allocatable.cpp
--- a/flang/runtime/allocatable.cpp
+++ b/flang/runtime/allocatable.cpp
@@ -44,8 +44,9 @@
 std::int32_t RTNAME(MoveAlloc)(Descriptor &to, Descriptor &from, bool hasStat,
     const Descriptor *errMsg, const char *sourceFile, int sourceLine) {
   Terminator terminator{sourceFile, sourceLine};
-  // Should be handled by semantic analysis
-  RUNTIME_CHECK(terminator, to.type() == from.type());
+  // The types must match, unless to is unlimited polymorphic.
+  RUNTIME_CHECK(terminator,
+      to.type() == from.type() || to.type().raw() == CFI_type_other);
   RUNTIME_CHECK(terminator, to.IsAllocatable() && from.IsAllocatable());
 
   // If to and from are the same allocatable they must not be allocated