Don't include parameter names in types, don't use Unicode arrow.

pkg/front_end/testcases/inference/downwards_inference_on_generic_function_expressions.dart

 // Copyright (c) 2017, 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.
 
 /*@testedFeatures=inference*/
 library test;
 
 void main() {
   {
     String f<S>(int x) => null;
-    var /*@type=f(int x) → String*/ v = f;
+    var /*@type=f(int) -> String*/ v = f;
     v = /*@returnType=String*/ <T>(int x) => null;
     v = /*@returnType=String*/ <T>(int x) => "hello";
     v = /*error:INVALID_ASSIGNMENT*/ /*@returnType=String*/ <T>(String x) =>
         "hello";
     v = /*error:INVALID_ASSIGNMENT*/ /*@returnType=int*/ <T>(int x) => 3;
     v = /*@returnType=String*/ <T>(int x) {
       return /*error:RETURN_OF_INVALID_TYPE*/ 3;
     };
   }
   {
     String f<S>(int x) => null;
-    var /*@type=f(int x) → String*/ v = f;
+    var /*@type=f(int) -> String*/ v = f;
     v = /*@returnType=String*/ <T>(/*@type=int*/ x) => null;
     v = /*@returnType=String*/ <T>(/*@type=int*/ x) => "hello";
     v = /*info:INFERRED_TYPE_CLOSURE, error:INVALID_ASSIGNMENT*/ /*@returnType=int*/ <
             T>(/*@type=int*/ x) =>
         3;
     v = /*@returnType=String*/ <T>(/*@type=int*/ x) {
       return /*error:RETURN_OF_INVALID_TYPE*/ 3;
     };
     v = /*@returnType=String*/ <T>(/*@type=int*/ x) {
       return /*error:RETURN_OF_INVALID_TYPE*/ x;
     };
   }
   {
     List<String> f<S>(int x) => null;
-    var /*@type=f(int x) → List<String>*/ v = f;
+    var /*@type=f(int) -> List<String>*/ v = f;
     v = /*@returnType=List<String>*/ <T>(int x) => null;
     v = /*@returnType=List<String>*/ <T>(int x) => /*@typeArgs=String*/ [
           "hello"
         ];
     v = /*error:INVALID_ASSIGNMENT*/ /*@returnType=List<String>*/ <
         T>(String x) => /*@typeArgs=String*/ ["hello"];
     v = /*@returnType=List<String>*/ <T>(int x) => /*@typeArgs=String*/ [
           /*error:LIST_ELEMENT_TYPE_NOT_ASSIGNABLE*/ 3
         ];
     v = /*@returnType=List<String>*/ <T>(int x) {
       return /*@typeArgs=String*/ [
         /*error:LIST_ELEMENT_TYPE_NOT_ASSIGNABLE*/ 3
       ];
     };
   }
   {
     int int2int<S>(int x) => null;
     String int2String<T>(int x) => null;
     String string2String<T>(String x) => null;
-    var /*@type=int2int(int x) → int*/ x = int2int;
+    var /*@type=int2int(int) -> int*/ x = int2int;
     x = /*@returnType=int*/ <T>(/*@type=int*/ x) => x;
     x = /*@returnType=int*/ <T>(/*@type=int*/ x) => x + 1;
-    var /*@type=int2String(int x) → String*/ y = int2String;
+    var /*@type=int2String(int) -> String*/ y = int2String;
     y = /*info:INFERRED_TYPE_CLOSURE, error:INVALID_ASSIGNMENT*/ /*@returnType=int*/ <
             T>(/*@type=int*/ x) =>
         x;
     y = /*@returnType=String*/ <
         T>(/*@type=int*/ x) => /*info:DYNAMIC_INVOKE, info:DYNAMIC_CAST*/ x.substring(3);
-    var /*@type=string2String(String x) → String*/ z = string2String;
+    var /*@type=string2String(String) -> String*/ z = string2String;
     z = /*@returnType=String*/ <T>(/*@type=String*/ x) => x.substring(3);
   }
 }