Split error code to ease future improvements

pkg/analyzer/lib/src/generated/resolver.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library analyzer.src.generated.resolver;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_resolution_map.dart';
@@ skipping 7139 matching lines @@
     if (positionalArgumentCount < requiredParameterCount && noBlankArguments) {
       ErrorCode errorCode = (reportAsError
           ? CompileTimeErrorCode.NOT_ENOUGH_REQUIRED_ARGUMENTS
           : StaticWarningCode.NOT_ENOUGH_REQUIRED_ARGUMENTS);
       if (onError != null) {
         onError(errorCode, argumentList,
             [requiredParameterCount, positionalArgumentCount]);
       }
     } else if (positionalArgumentCount > unnamedParameterCount &&
         noBlankArguments) {
-      ErrorCode errorCode = (reportAsError
-          ? CompileTimeErrorCode.EXTRA_POSITIONAL_ARGUMENTS
-          : StaticWarningCode.EXTRA_POSITIONAL_ARGUMENTS);
+      ErrorCode errorCode;
+      int namedParameterCount = namedParameters?.length ?? 0;
+      int namedArgumentCount = usedNames?.length ?? 0;
+      if (namedParameterCount > namedArgumentCount) {
+        errorCode = (reportAsError
+            ? CompileTimeErrorCode.EXTRA_POSITIONAL_ARGUMENTS_COULD_BE_NAMED
+            : StaticWarningCode.EXTRA_POSITIONAL_ARGUMENTS_COULD_BE_NAMED);
+      } else {
+        errorCode = (reportAsError
+            ? CompileTimeErrorCode.EXTRA_POSITIONAL_ARGUMENTS
+            : StaticWarningCode.EXTRA_POSITIONAL_ARGUMENTS);
+      }
       if (onError != null) {
         onError(errorCode, argumentList,
             [unnamedParameterCount, positionalArgumentCount]);
       }
     }
     return resolvedParameters;
   }
 }
 
 /**
@@ skipping 3741 matching lines @@
       return null;
     }
     if (identical(node.staticElement, variable)) {
       if (node.inSetterContext()) {
         result = true;
       }
     }
     return null;
   }
 }