Fix for issue 23861: CompletionSuggestion.parameterType are now populated.

pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart

Index: pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart
index e3a8f0bfc0841308d0dd7461f69d5e5c571dd00d..54529b83d0031ccf1571cada63c085915b6b730a 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/arglist_contributor.dart
@@ -262,14 +262,14 @@ class ArgListContributor extends DartCompletionContributor {
     Iterable<String> namedArgs = _namedArgs(request);
     for (ParameterElement param in parameters) {
       if (param.parameterKind == ParameterKind.NAMED) {
-        _addNamedParameterSuggestion(
-            request, namedArgs, param.name, appendComma);
+        _addNamedParameterSuggestion(request, namedArgs, param.name,
+            param.type?.displayName, appendComma);
       }
     }
   }
 
   void _addNamedParameterSuggestion(DartCompletionRequest request,
-      List<String> namedArgs, String name, bool appendComma) {
+      List<String> namedArgs, String name, String paramType, bool appendComma) {
     if (name != null && name.length > 0 && !namedArgs.contains(name)) {
       String completion = '$name: ';
       if (appendComma) {
@@ -282,7 +282,9 @@ class ArgListContributor extends DartCompletionContributor {
           completion.length,
           0,
           false,
-          false));
+          false,
+          parameterName: name,
+          parameterType: paramType));
     }
   }