improve element parameter string returned by local suggestion computer

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

Index: pkg/analysis_server/lib/src/services/completion/local_computer.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/local_computer.dart b/pkg/analysis_server/lib/src/services/completion/local_computer.dart
index 3fc11ca0b02e1624b1226fa4641a32af555d187f..19e28f46065ab54e772071813f880431e0b1fe63 100644
--- a/pkg/analysis_server/lib/src/services/completion/local_computer.dart
+++ b/pkg/analysis_server/lib/src/services/completion/local_computer.dart
@@ -296,6 +296,7 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
       suggestion.element = _createElement(
           protocol.ElementKind.CLASS,
           declaration.name,
+          null,
           NO_RETURN_TYPE,
           declaration.isAbstract,
           _isDeprecated(declaration.metadata));
@@ -317,6 +318,7 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
         suggestion.element = _createElement(
             protocol.ElementKind.GETTER,
             varDecl.name,
+            '()',
             fieldDecl.fields.type,
             false,
             isDeprecated || _isDeprecated(varDecl.metadata));
@@ -340,6 +342,7 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
       suggestion.element = _createElement(
           protocol.ElementKind.FUNCTION,
           declaration.name,
+          declaration.functionExpression.parameters.toSource(),
           declaration.returnType,
           false,
           _isDeprecated(declaration.metadata));
@@ -356,6 +359,7 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
       suggestion.element = _createElement(
           protocol.ElementKind.LOCAL_VARIABLE,
           id,
+          null,
           returnType,
           false,
           false);
@@ -368,21 +372,25 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
     }
     protocol.ElementKind kind;
     CompletionSuggestionKind csKind;
+    String parameters;
     if (classMbr.isGetter) {
       kind = protocol.ElementKind.GETTER;
       csKind = CompletionSuggestionKind.GETTER;
+      parameters = '()';
     } else if (classMbr.isSetter) {
       if (excludeVoidReturn) {
         return;
       }
       kind = protocol.ElementKind.SETTER;
       csKind = CompletionSuggestionKind.SETTER;
+      parameters = '(${classMbr.returnType.toSource()} value)';
     } else {
       if (excludeVoidReturn && _isVoid(classMbr.returnType)) {
         return;
       }
       kind = protocol.ElementKind.METHOD;
       csKind = CompletionSuggestionKind.METHOD;
+      parameters = classMbr.parameters.toSource();
     }
     CompletionSuggestion suggestion =
         _addSuggestion(classMbr.name, csKind, classMbr.returnType, node);
@@ -390,6 +398,7 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
       suggestion.element = _createElement(
           kind,
           classMbr.name,
+          parameters,
           classMbr.returnType,
           classMbr.isAbstract,
           _isDeprecated(classMbr.metadata));
@@ -428,8 +437,13 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
     CompletionSuggestion suggestion =
         _addSuggestion(identifier, CompletionSuggestionKind.PARAMETER, type, null);
     if (suggestion != null) {
-      suggestion.element =
-          _createElement(protocol.ElementKind.PARAMETER, identifier, type, false, false);
+      suggestion.element = _createElement(
+          protocol.ElementKind.PARAMETER,
+          identifier,
+          null,
+          type,
+          false,
+          false);
     }
   }
 
@@ -487,6 +501,7 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
           suggestion.element = _createElement(
               protocol.ElementKind.TOP_LEVEL_VARIABLE,
               varDecl.name,
+              null,
               varList.type,
               false,
               isDeprecated || _isDeprecated(varDecl.metadata));
@@ -509,7 +524,8 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
    * Create a new protocol Element for inclusion in a completion suggestion.
    */
   protocol.Element _createElement(protocol.ElementKind kind,
-      SimpleIdentifier id, TypeName returnType, bool isAbstract, bool isDeprecated) {
+      SimpleIdentifier id, String parameters, TypeName returnType,
+      bool isAbstract, bool isDeprecated) {
     String name = id.name;
     int flags = protocol.Element.makeFlags(
         isAbstract: isAbstract,
@@ -519,6 +535,7 @@ class _LocalVisitor extends GeneralizingAstVisitor<dynamic> {
         kind,
         name,
         flags,
+        parameters: parameters,
         returnType: _nameForType(returnType));
   }