[flang] Avoid double finalization in Assign

First call to Assign is issuing finalization for the
LHS and its components. Avoid calling finalization for components
again when doing the component by component assignment.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D143187

Author: clementval

flang/runtime/assign.cpp

@@ -68,7 +68,8 @@ static void DoElementalDefinedAssignment(const Descriptor &to,
 // Do not perform allocatable reallocation if \p skipRealloc is true, which is
 // used for allocate statement with source specifier.
 static void Assign(Descriptor &to, const Descriptor &from,
-    Terminator &terminator, bool skipRealloc = false) {
+    Terminator &terminator, bool skipRealloc = false,
+    bool skipFinalization = false) {
   DescriptorAddendum *toAddendum{to.Addendum()};
   const typeInfo::DerivedType *toDerived{
       toAddendum ? toAddendum->derivedType() : nullptr};
@@ -184,7 +185,8 @@ static void Assign(Descriptor &to, const Descriptor &from,
     // Derived type intrinsic assignment, which is componentwise and elementwise
     // for all components, including parent components (10.2.1.2-3).
     // The target is first finalized if still necessary (7.5.6.3(1))
-    if (!wasJustAllocated && !toDerived->noFinalizationNeeded()) {
+    if (!wasJustAllocated && !toDerived->noFinalizationNeeded() &&
+        !skipFinalization) {
       Finalize(to, *toDerived);
     }
     // Copy the data components (incl. the parent) first.
@@ -205,7 +207,8 @@ static void Assign(Descriptor &to, const Descriptor &from,
             comp.CreatePointerDescriptor(toCompDesc, to, terminator, toAt);
             comp.CreatePointerDescriptor(
                 fromCompDesc, from, terminator, fromAt);
-            Assign(toCompDesc, fromCompDesc, terminator, /*skipRealloc=*/false);
+            Assign(toCompDesc, fromCompDesc, terminator, /*skipRealloc=*/false,
+                /*skipFinalization=*/true);
           }
         } else { // Component has intrinsic type; simply copy raw bytes
           std::size_t componentByteSize{comp.SizeInBytes(to)};