diff --git a/flang/lib/Evaluate/fold-implementation.h b/flang/lib/Evaluate/fold-implementation.h
--- a/flang/lib/Evaluate/fold-implementation.h
+++ b/flang/lib/Evaluate/fold-implementation.h
@@ -1349,6 +1349,7 @@
 template <typename RESULT, typename OPERAND>
 std::optional<Expr<RESULT>> MapOperation(FoldingContext &context,
     std::function<Expr<RESULT>(Expr<OPERAND> &&)> &&f, const Shape &shape,
+    [[maybe_unused]] std::optional<Expr<SubscriptInteger>> &&length,
     Expr<OPERAND> &&values) {
   ArrayConstructor<RESULT> result{values};
   if constexpr (common::HasMember<OPERAND, AllIntrinsicCategoryTypes>) {
@@ -1369,6 +1370,11 @@
       result.Push(Fold(context, f(std::move(scalar))));
     }
   }
+  if constexpr (RESULT::category == TypeCategory::Character) {
+    if (length) {
+      result.set_LEN(std::move(*length));
+    }
+  }
   return FromArrayConstructor(context, std::move(result), shape);
 }
 
@@ -1506,9 +1512,9 @@
   return FromArrayConstructor(context, std::move(result), shape);
 }
 
-template <typename DERIVED, typename RESULT, typename LEFT, typename RIGHT>
+template <typename DERIVED, typename RESULT, typename... OPD>
 std::optional<Expr<SubscriptInteger>> ComputeResultLength(
-    Operation<DERIVED, RESULT, LEFT, RIGHT> &operation) {
+    Operation<DERIVED, RESULT, OPD...> &operation) {
   if constexpr (RESULT::category == TypeCategory::Character) {
     return Expr<RESULT>{operation.derived()}.LEN();
   }
@@ -1529,7 +1535,8 @@
   if (expr.Rank() > 0) {
     if (std::optional<Shape> shape{GetShape(context, expr)}) {
       if (auto values{AsFlatArrayConstructor(expr)}) {
-        return MapOperation(context, std::move(f), *shape, std::move(*values));
+        return MapOperation(context, std::move(f), *shape,
+            ComputeResultLength(operation), std::move(*values));
       }
     }
   }
diff --git a/flang/test/Evaluate/folding31.f90 b/flang/test/Evaluate/folding31.f90
new file mode 100644
--- /dev/null
+++ b/flang/test/Evaluate/folding31.f90
@@ -0,0 +1,6 @@
+! RUN: %python %S/test_folding.py %s %flang_fc1
+! Test folding of character array conversion.
+module m
+  character(*,4), parameter :: str4arr(1) = ['a']
+  logical, parameter :: test = str4arr(1) == 4_'a'
+end