Store named parameters in sorted lists instead of using maps.

lib/analyzer/ast_from_analyzer.dart

Index: lib/analyzer/ast_from_analyzer.dart
diff --git a/lib/analyzer/ast_from_analyzer.dart b/lib/analyzer/ast_from_analyzer.dart
index 7dfba0d46ba7b83f20852efd4d1715f6ceb319ce..5aebe1eb61df389a6c5f2f0f17d6bf27495f3f51 100644
--- a/lib/analyzer/ast_from_analyzer.dart
+++ b/lib/analyzer/ast_from_analyzer.dart
@@ -456,6 +456,9 @@ class TypeScope extends ReferenceScope {
           break;
       }
     }
+    if (named.isNotEmpty) {
+      named.sort();
+    }
     var returnType = element is ConstructorElement
         ? const ast.VoidType()
         : buildType(element.returnType);
@@ -557,6 +560,9 @@ class ExpressionScope extends TypeScope {
           break;
       }
     }
+    if (named.isNotEmpty) {
+      named.sort();
+    }
     return new ast.FunctionNode(buildOptionalFunctionBody(body),
         typeParameters: typeParameters,
         positionalParameters: positional,
@@ -2150,13 +2156,14 @@ class TypeAnnotationBuilder extends GeneralizingAstVisitor<ast.DartType> {
     return types.map((t) => convertType(t, boundVariables)).toList();
   }
 
-  Map<String, ast.DartType> convertTypeMap(
+  List<ast.NamedType> convertTypeMap(
       Map<String, DartType> types, List<TypeParameterElement> boundVariables) {
-    if (types.isEmpty) return const <String, ast.DartType>{};
-    var result = <String, ast.DartType>{};
+    if (types.isEmpty) return const <ast.NamedType>[];
+    List<ast.NamedType> result = <ast.NamedType>[];
     types.forEach((name, type) {
-      result[name] = convertType(type, boundVariables);
+      result.add(new ast.NamedType(name, convertType(type, boundVariables)));
     });
+    result.sort();
     return result;
   }