Clean up duplicate type inference code for fetching parameter types.

pkg/front_end/lib/src/fasta/type_inference/type_inferrer.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.md file.
 
 import 'package:front_end/src/base/instrumentation.dart';
 import 'package:front_end/src/fasta/errors.dart' show internalError;
 import 'package:front_end/src/fasta/kernel/kernel_shadow_ast.dart';
 import 'package:front_end/src/fasta/names.dart' show callName;
 import 'package:front_end/src/fasta/type_inference/type_inference_engine.dart';
 import 'package:front_end/src/fasta/type_inference/type_inference_listener.dart';
@@ skipping 443 matching lines @@
         return typeAsInstanceOfClass.typeArguments[0];
       }
     }
     return null;
   }
 
   /// Gets the initializer for the given [field], or `null` if there is no
   /// initializer.
   Expression getFieldInitializer(KernelField field);
 
-  DartType getNamedParameterType(FunctionType functionType, String name) {
-    return functionType.getNamedParameter(name) ?? const DynamicType();
-  }
-
-  DartType getPositionalParameterType(FunctionType functionType, int i) {
-    if (i < functionType.positionalParameters.length) {
-      return functionType.positionalParameters[i];
-    } else {
-      return const DynamicType();
-    }
-  }
-
   DartType getSetterType(Member interfaceMember, DartType receiverType) {
     if (receiverType is InterfaceType) {
       if (interfaceMember == null) return const DynamicType();
       var memberClass = interfaceMember.enclosingClass;
       DartType setterType;
       if (interfaceMember is Procedure) {
         assert(interfaceMember.kind == ProcedureKind.Setter);
         var setterParameters = interfaceMember.function.positionalParameters;
         setterType = setterParameters.length > 0
             ? setterParameters[0].type
@@ skipping 338 matching lines @@
   void _forEachArgument(
       Arguments arguments, void callback(String name, Expression expression)) {
     for (var expression in arguments.positional) {
       callback(null, expression);
     }
     for (var namedExpression in arguments.named) {
       callback(namedExpression.name, namedExpression.value);
     }
   }
 }