Fix mirrors to keep typedef as scope class of function types (fixes #26187).

runtime/vm/parser.cc

 // Copyright (c) 2012, 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.
 
 #include "vm/parser.h"
 #include "vm/flags.h"
 
 #ifndef DART_PRECOMPILED_RUNTIME
 
 #include "lib/invocation_mirror.h"
@@ skipping 5044 matching lines @@
   // Parse the formal parameters of the function type.
   CheckToken(Token::kLPAREN, "formal parameter list expected");
   ParamList func_params;
 
   // Add implicit closure object parameter.
   func_params.AddFinalParameter(
       TokenPos(),
       &Symbols::ClosureParameter(),
       &Object::dynamic_type());
 
+  // Mark the current class as a typedef class (by setting its signature
+  // function field to a non-null function) before parsing its formal parameters
+  // so that parsed function types are aware that their owner class is a
+  // typedef class.
+  Function& signature_function =
+      Function::Handle(Z, Function::NewSignatureFunction(function_type_alias,
+                                                         alias_name_pos));
+  // Set the signature function in the function type alias class.
+  function_type_alias.set_signature_function(signature_function);
+
   const bool no_explicit_default_values = false;
   ParseFormalParameterList(no_explicit_default_values, false, &func_params);
   ExpectSemicolon();
-  Function& signature_function =
-      Function::Handle(Z, Function::NewSignatureFunction(function_type_alias,
-                                                         alias_name_pos));
   signature_function.set_result_type(result_type);
   AddFormalParamsToFunction(&func_params, signature_function);
 
-  // Set the signature function in the function type alias class.
-  function_type_alias.set_signature_function(signature_function);
-
   if (FLAG_trace_parser) {
     OS::Print("TopLevel parsing function type alias '%s'\n",
               String::Handle(Z, signature_function.Signature()).ToCString());
   }
   // The alias should not be marked as finalized yet, since it needs to be
   // checked in the class finalizer for illegal self references.
   ASSERT(!function_type_alias.is_finalized());
   pending_classes.Add(function_type_alias, Heap::kOld);
   if (FLAG_enable_mirrors && metadata_pos.IsReal()) {
     library_.AddClassMetadata(function_type_alias,
@@ skipping 9394 matching lines @@
     const ArgumentListNode& function_args,
     const LocalVariable* temp_for_last_arg,
     bool is_super_invocation) {
   UNREACHABLE();
   return NULL;
 }
 
 }  // namespace dart
 
 #endif  // DART_PRECOMPILED_RUNTIME