Tighten check disallowing use of initializing formals (fixes #26855).

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 3375 matching lines @@
     SetupDefaultsForOptionalParams(params);
     ASSERT(AbstractType::Handle(Z, func.result_type()).IsResolved());
     ASSERT(func.NumParameters() == params.parameters->length());
 
     // Check whether the function has any field initializer formal parameters,
     // which are not allowed in non-constructor functions.
     if (params.has_field_initializer) {
       for (int i = 0; i < params.parameters->length(); i++) {
         ParamDesc& param = (*params.parameters)[i];
         if (param.is_field_initializer) {
           ReportError(param.name_pos,

[hausner, 2016/07/14 09:02:45]

DBC: why does this check not cover the cases in the regression test? 

[regis, 2016/07/14 17:00:47]

There are 14 different call sites to ParseFormalParameterList in the parser.
This check only covers one call to ParseFormalParameterList on line 3377. The
cases of the regression test are parsed by other calls to 
ParseFormalParameterList. I did not want to duplicate this code everywhere and
found a common place to do the check.

Your question makes me realize that this check is actually redundant now, since
an error would be reported by the call at line 3384. I'll send you a cl removing
it. Thanks.

                       "field initializer only allowed in constructors");
         }
       }
     }
     // Populate function scope with the formal parameters.
     AddFormalParamsToScope(&params, current_block_->scope);
 
     if (I->type_checks() &&
         (FunctionLevel() > 0)) {
       // We are parsing, but not compiling, a local function.
@@ skipping 3983 matching lines @@
   ASSERT(func.parameter_types() == Object::empty_array().raw());
   ASSERT(func.parameter_names() == Object::empty_array().raw());
   func.set_parameter_types(Array::Handle(Array::New(num_parameters,
                                                     Heap::kOld)));
   func.set_parameter_names(Array::Handle(Array::New(num_parameters,
                                                     Heap::kOld)));
   for (int i = 0; i < num_parameters; i++) {
     ParamDesc& param_desc = (*params->parameters)[i];
     func.SetParameterTypeAt(i, *param_desc.type);
     func.SetParameterNameAt(i, *param_desc.name);
+    if (param_desc.is_field_initializer && !func.IsGenerativeConstructor()) {
+      // Redirecting constructors are detected later in ParseConstructor.
+      ReportError(param_desc.name_pos,
+                  "only generative constructors may have "
+                  "initializing formal parameters");
+    }
   }
 }
 
 
 // Populate local scope with the formal parameters.
 void Parser::AddFormalParamsToScope(const ParamList* params,
                                     LocalScope* scope) {
   ASSERT((params != NULL) && (params->parameters != NULL));
   ASSERT(scope != NULL);
   const int num_parameters = params->parameters->length();
@@ skipping 7260 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