Store named parameters in sorted lists instead of using maps.

lib/text/ast_to_text.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 kernel.ast_to_text;
 
 import '../ast.dart';
 import '../import_table.dart';
 import '../type_propagation/type_propagation.dart';
 
 class Namer<T> {
@@ skipping 1373 matching lines @@
       }
       writeSymbol('[');
       writeList(positional.skip(node.requiredParameterCount), writeType);
       writeSymbol(']');
     }
     if (node.namedParameters.isNotEmpty) {
       if (node.positionalParameters.isNotEmpty) {
         writeComma();
       }
       writeSymbol('{');
-      writeList(node.namedParameters.keys, (name) {
-        writeType(node.namedParameters[name]);
-        writeWord(name);
-      });
+      writeList(node.namedParameters, visitNamedType);
       writeSymbol('}');
     }
     writeSymbol(')');
     writeSpaced('→');
     writeType(node.returnType);
   }
 
+  visitNamedType(NamedType node) {
+    writeWord(node.name);
+    writeSymbol(':');
+    writeSpace();
+    writeType(node.type);
+  }
+
   visitTypeParameterType(TypeParameterType node) {
     writeTypeParameterReference(node.parameter);
   }
 
   visitTypeParameter(TypeParameter node) {
     writeWord(getTypeParameterName(node));
     writeSpaced('extends');
     writeType(node.bound);
   }
 
@@ skipping 110 matching lines @@
   }
   throw 'illegal ProcedureKind: $kind';
 }
 
 class ExpressionPrinter {
   final Printer writeer;
   final int minimumPrecedence;
 
   ExpressionPrinter(this.writeer, this.minimumPrecedence);
 }