diff --git a/compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala b/compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala
index eeeb3767bd34..0c701eb03d38 100644
--- a/compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala
+++ b/compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala
@@ -758,10 +758,12 @@ class ClassfileParser(
         case tpnme.MethodParametersATTR =>
           val paramCount = in.nextByte
           for i <- 0 until paramCount do
-            val name = pool.getName(in.nextChar)
+            val index = in.nextChar
             val flags = in.nextChar
-            if (flags & JAVA_ACC_SYNTHETIC) == 0 then
-              res.namedParams += (i -> name.name)
+            if index != 0 then
+              val name = pool.getName(index)
+              if (flags & JAVA_ACC_SYNTHETIC) == 0 then
+                res.namedParams += (i -> name.name)
 
         case tpnme.AnnotationDefaultATTR =>
           sym.addAnnotation(Annotation(defn.AnnotationDefaultAnnot, Nil, sym.span))