[java decompiler] better filter for synthetic constructor parameters

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

@@ -227,7 +227,7 @@ public class ClassWriter {
       for (ClassNode inner : node.nested) {
         if (inner.type == ClassNode.CLASS_MEMBER) {
           StructClass innerCl = inner.classStruct;
-          boolean isSynthetic = (inner.access & CodeConstants.ACC_SYNTHETIC) != 0 || innerCl.isSynthetic() || inner.namelessConstructorStub;
+          boolean isSynthetic = (inner.access & CodeConstants.ACC_SYNTHETIC) != 0 || innerCl.isSynthetic();
           boolean hide = isSynthetic && DecompilerContext.getOption(IFernflowerPreferences.REMOVE_SYNTHETIC) ||
                          wrapper.getHiddenMembers().contains(innerCl.qualifiedName);
           if (hide) continue;

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

@@ -327,7 +327,6 @@ public class ClassesProcessor {
     public final Set<String> enclosingClasses = new HashSet<>();
     public ClassNode parent;
     public LambdaInformation lambdaInformation;
-    public boolean namelessConstructorStub = false;
 
     public ClassNode(String content_class_name,
                      String content_method_name,

src/org/jetbrains/java/decompiler/main/rels/NestedClassProcessor.java

@@ -61,10 +61,6 @@ public class NestedClassProcessor {
           DecompilerContext.getLogger().writeMessage(message, IFernflowerLogger.Severity.WARN);
           child.simpleName = "NamelessClass_" + (++nameless);
         }
-        child.namelessConstructorStub = !cl.hasModifier(CodeConstants.ACC_STATIC) && cl.getMethods().size() + cl.getFields().size() == 0;
-      }
-      else if (child.type == ClassNode.CLASS_ANONYMOUS && (child.access & CodeConstants.ACC_SYNTHETIC) != 0 || cl.isSynthetic()) {
-        child.namelessConstructorStub = !cl.hasModifier(CodeConstants.ACC_STATIC) && cl.getMethods().size() + cl.getFields().size() == 0;
       }
     }
 

src/org/jetbrains/java/decompiler/modules/decompiler/exps/NewExprent.java

@@ -283,11 +283,8 @@ public class NewExprent extends Exprent {
               Exprent expr = InvocationExprent.unboxIfNeeded(parameters.get(i));
               VarType leftType = constructor.getDescriptor().params[i];
 
-              if (i == parameters.size() - 1 && expr.getExprType() == VarType.VARTYPE_NULL) {
-                ClassNode node = DecompilerContext.getClassProcessor().getMapRootClasses().get(leftType.value);
-                if (node != null && node.namelessConstructorStub) {
-                  break;  // skip last parameter of synthetic constructor call
-                }
+              if (i == parameters.size() - 1 && expr.getExprType() == VarType.VARTYPE_NULL && probablySyntheticParameter(leftType.value)) {
+                break;  // skip last parameter of synthetic constructor call
               }
 
               if (!firstParam) {
@@ -360,6 +357,11 @@ public class NewExprent extends Exprent {
     return buf;
   }
 
+  private static boolean probablySyntheticParameter(String className) {
+    ClassNode node = DecompilerContext.getClassProcessor().getMapRootClasses().get(className);
+    return node != null && node.type == ClassNode.CLASS_ANONYMOUS;
+  }
+
   private static String getQualifiedNewInstance(String classname, List<Exprent> lstParams, int indent, BytecodeMappingTracer tracer) {
     ClassNode node = DecompilerContext.getClassProcessor().getMapRootClasses().get(classname);