Fix references to parameters renamed with the MethodParameters table

src/org/jetbrains/java/decompiler/main/ClassWriter.java

@@ -748,12 +748,13 @@ public class ClassWriter {
 
             buffer.append(' ');
 
-            String parameterName;
+            String parameterName = methodWrapper.varproc.getVarName(new VarVersionPair(index, 0));
             if (methodParameters != null && i < methodParameters.size()) {
-              parameterName = methodParameters.get(i).myName;
+              String myName = methodParameters.get(i).myName;
+              if (myName != null) {
+                parameterName = myName;
+                methodWrapper.varproc.setVarName(new VarVersionPair(index, 0), myName);
               }
-            else {
-              parameterName = methodWrapper.varproc.getVarName(new VarVersionPair(index, 0));
             }
             buffer.append(parameterName == null ? "param" + index : parameterName); // null iff decompiled with errors