This doesn't really work but it's a start.

src/main/java/info/sigterm/deob/attributes/code/instruction/types/PushConstantInstruction.java

@@ -5,4 +5,6 @@ import info.sigterm.deob.pool.PoolEntry;
 public interface PushConstantInstruction
 {
 	public PoolEntry getConstant();
+	
+	public void setConstant(PoolEntry entry);
 }

src/main/java/info/sigterm/deob/attributes/code/instructions/LDC.java

@@ -63,4 +63,10 @@ public class LDC extends Instruction implements PushConstantInstruction
 	{
 		return value;
 	}
+	
+	@Override
+	public void setConstant(PoolEntry entry)
+	{
+		value = entry;
+	}
 }

src/main/java/info/sigterm/deob/attributes/code/instructions/LDC2_W.java

@@ -53,4 +53,10 @@ public class LDC2_W extends Instruction implements PushConstantInstruction
 	{
 		return value;
 	}
+	
+	@Override
+	public void setConstant(PoolEntry entry)
+	{
+		value = entry;
+	}
 }

src/main/java/info/sigterm/deob/attributes/code/instructions/LDC_W.java

@@ -68,4 +68,10 @@ public class LDC_W extends Instruction implements PushConstantInstruction
 	{
 		return value;
 	}
+
+	@Override
+	public void setConstant(PoolEntry entry)
+	{
+		value = entry;
+	}
 }