Remove number from operator mismatch message.

pkg/front_end/lib/src/fasta/source/outline_builder.dart

 // Copyright (c) 2016, 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 fasta.outline_builder;
 
 import 'package:kernel/ast.dart' show ProcedureKind;
 
 import '../../scanner/token.dart' show Token;
 
 import '../builder/builder.dart';
 
 import '../combinator.dart' show Combinator;
 
 import '../fasta_codes.dart'
     show
         Message,
         codeExpectedBlockToSkip,
         messageOperatorWithOptionalFormals,
         messageTypedefNotFunction,
         templateDuplicatedParameterName,
         templateDuplicatedParameterNameCause,
-        templateOperatorParameterMismatch;
+        templateOperatorParameterMismatch0,
+        templateOperatorParameterMismatch1,
+        templateOperatorParameterMismatch2;
 
 import '../modifier.dart' show abstractMask, externalMask, Modifier;
 
 import '../operator.dart'
     show
         Operator,
         operatorFromString,
         operatorToString,
         operatorRequiredArgumentCount;
 
@@ skipping 341 matching lines @@
     if (Operator.subtract == nameOrOperator && formals == null) {
       nameOrOperator = Operator.unaryMinus;
     }
     String name;
     ProcedureKind kind;
     if (nameOrOperator is Operator) {
       name = operatorToString(nameOrOperator);
       kind = ProcedureKind.Operator;
       int requiredArgumentCount = operatorRequiredArgumentCount(nameOrOperator);
       if ((formals?.length ?? 0) != requiredArgumentCount) {
-        addCompileTimeError(
-            templateOperatorParameterMismatch.withArguments(
-                name, requiredArgumentCount),
-            charOffset);
+        var template;
+        switch (requiredArgumentCount) {
+          case 0:
+            template = templateOperatorParameterMismatch0;
+            break;
+
+          case 1:
+            template = templateOperatorParameterMismatch1;
+            break;
+
+          case 2:
+            template = templateOperatorParameterMismatch2;

[Johnni Winther, 2017/07/13 11:23:39]

How do you handle `operator -(a, b)` ? It shouldn't use
`templateOperatorParameterMismatch1` because it must have either 0 or 1
parameters.

[ahe, 2017/07/13 11:32:19]

Good point.

+            break;
+
+          default:
+            unhandled("$requiredArgumentCount", "operatorRequiredArgumentCount",
+                charOffset, uri);
+        }
+        addCompileTimeError(template.withArguments(name), charOffset);
       } else {
         if (formals != null) {
           for (FormalParameterBuilder formal in formals) {
             if (!formal.isRequired) {
               addCompileTimeError(
                   messageOperatorWithOptionalFormals, formal.charOffset);
             }
           }
         }
       }
@@ skipping 487 matching lines @@
   Link<Token> handleMemberName(Link<Token> identifiers) {
     if (!enableNative || identifiers.isEmpty) return identifiers;
     return removeNativeClause(identifiers, stringExpectedAfterNative);
   }
 
   @override
   void debugEvent(String name) {
     // printEvent(name);
   }
 }