Named parameters of generic functions should have names.

pkg/analyzer/lib/src/dart/element/element.dart

Index: pkg/analyzer/lib/src/dart/element/element.dart
diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index cbf2bfc4433fb89868694740f044f409feacb908..7d9e91e664783b3838dfe5694611f90f2a38f859 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -7600,6 +7600,7 @@ class ParameterElementImpl extends VariableElementImpl
     if (offset == 0 && _unlinkedParam != null) {
       if (isSynthetic ||
           (_unlinkedParam.name.isEmpty &&
+              _unlinkedParam.kind != UnlinkedParamKind.named &&
               enclosingElement is GenericFunctionTypeElement)) {
         return -1;
       }