langtools/src/share/classes/com/sun/tools/javac/code/Symbol.java

@@ -1210,29 +1210,50 @@
         }
 
         public List<VarSymbol> params() {
             owner.complete();
             if (params == null) {
-                List<Name> names = savedParameterNames;
+                List<Name> paramNames = savedParameterNames;
                 savedParameterNames = null;
-                if (names == null) {
-                    names = List.nil();
-                    int i = 0;
-                    for (Type t : type.getParameterTypes())
-                        names = names.prepend(name.table.fromString("arg" + i++));
-                    names = names.reverse();
-                }
+                if (paramNames == null || paramNames.size() != type.getParameterTypes().size())
+                    paramNames = List.nil();
                 ListBuffer<VarSymbol> buf = new ListBuffer<VarSymbol>();
+                List<Name> remaining = paramNames;
+                // assert: remaining and paramNames are both empty or both
+                // have same cardinality as type.getParameterTypes()
+                int i = 0;
                 for (Type t : type.getParameterTypes()) {
-                    buf.append(new VarSymbol(PARAMETER, names.head, t, this));
-                    names = names.tail;
+                    Name paramName;
+                    if (remaining.isEmpty()) {
+                        // no names for any parameters available
+                        paramName = createArgName(i, paramNames);
+                    } else {
+                        paramName = remaining.head;
+                        remaining = remaining.tail;
+                        if (paramName.isEmpty()) {
+                            // no name for this specific parameter
+                            paramName = createArgName(i, paramNames);
+                        }
+                    }
+                    buf.append(new VarSymbol(PARAMETER, paramName, t, this));
+                    i++;
                 }
                 params = buf.toList();
             }
             return params;
         }
 
+        private Name createArgName(int index, List<Name> exclude) {
+            String prefix = "arg";
+            while (true) {
+                Name argName = name.table.fromString(prefix + index);
+                if (!exclude.contains(argName))
+                    return argName;
+                prefix += "$";
+            }
+        }
+
         public Symbol asMemberOf(Type site, Types types) {
             return new MethodSymbol(flags_field, name, types.memberType(site, this), owner);
         }
 
         public ElementKind getKind() {