diff --git a/CHANGELOG.md b/CHANGELOG.md
index f7014cc7..1cee8ed1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@
 * test: Mapping test first version.
 * refactor: rename `RefuseToHandleException` to `RefuseToTransformException`.
 * perf(`CopyTransformer`): Move identity check to the beginning.
+* fix(`MainTransformer`): Fix possible bug involving an existing target.
 
 ## 0.5.10
 
diff --git a/src/MainTransformer/MainTransformer.php b/src/MainTransformer/MainTransformer.php
index de7cc6d0..e0734ebd 100644
--- a/src/MainTransformer/MainTransformer.php
+++ b/src/MainTransformer/MainTransformer.php
@@ -76,13 +76,16 @@ public function transform(
         Context $context,
         string $path = null,
     ): mixed {
-        // if targettype is not provided, guess it from target
-        // if the target is also missing then the target is mixed
+        // if target is provided, guess the type from it.
+        // if target is not provided, use the provided target type. if it is
+        // also not provided, then the target type is mixed.
 
-        if (count($targetTypes) === 0) {
-            if ($target === null) {
+        if ($target === null) {
+            if (count($targetTypes) === 0) {
                 $targetTypes = [MixedType::instance()];
-            } else {
+            }
+        } else {
+            if (count($targetTypes) === 0) {
                 $targetTypes = [$this->typeResolver->guessTypeFromVariable($target)];
             }
         }