From d4537819f10404d2a0e1a8b4098981b0e0491bf5 Mon Sep 17 00:00:00 2001
From: "M.Schmidt" <markus262@web.de>
Date: Fri, 22 Dec 2023 14:32:53 +0100
Subject: [PATCH] fix merging outputLocals when they are the same Local

---
 .../sootup/java/bytecode/frontend/OperandMerging.java     | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/sootup.java.bytecode/src/main/java/sootup/java/bytecode/frontend/OperandMerging.java b/sootup.java.bytecode/src/main/java/sootup/java/bytecode/frontend/OperandMerging.java
index 1fe7d43446c..b1f4e233192 100644
--- a/sootup.java.bytecode/src/main/java/sootup/java/bytecode/frontend/OperandMerging.java
+++ b/sootup.java.bytecode/src/main/java/sootup/java/bytecode/frontend/OperandMerging.java
@@ -68,11 +68,11 @@ final class OperandMerging {
   void mergeOutput(@Nonnull Operand outputOperand) {
     if (output == null) {
       output = outputOperand;
-    } else {
-      if (output.stackLocal != null) {
-        assert outputOperand.stackLocal == null;
-        outputOperand.changeStackLocal(output.stackLocal);
+    } else if (output.stackLocal != null) {
+      if (output.stackLocal != outputOperand.stackLocal && outputOperand.stackLocal != null) {
+        throw new IllegalStateException("Incompatible StackLocals. There already exists more than one StackLocal (" + outputOperand.stackLocal + " != " + output.stackLocal+").");
       }
+      outputOperand.changeStackLocal(output.stackLocal);
     }
   }