Dump functions on circular dependency parser error

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 2938 matching lines @@
   }
   CheckFieldsInitialized(current_class());
 
   // Empty constructor body.
   current_block_->statements->Add(new ReturnNode(ST(ctor_pos)));
   SequenceNode* statements = CloseBlock();
   return statements;
 }
 
 
+// Returns a zone allocated string.
+static char* DumpPendingFunctions(
+    Zone* zone,
+    const GrowableObjectArray& pending_functions) {
+  ASSERT(zone != NULL);
+  char* result = OS::SCreate(zone, "Pending Functions:\n");
+  for (intptr_t i = 0; i < pending_functions.Length(); i++) {
+    const Function& func =
+        Function::Handle(zone, Function::RawCast(pending_functions.At(i)));
+    const String& fname = String::Handle(zone, func.UserVisibleName());
+    result = OS::SCreate(zone, "%s%" Pd ": %s\n", result, i, fname.ToCString());

[turnidge, 2016/02/29 19:37:56]

There's kind of a quadratic thing going on here, with the copying over and over,
but this code is debug-only, so I'm fine with it.

+  }
+  return result;
+}
+
+
 void Parser::CheckRecursiveInvocation() {
   const GrowableObjectArray& pending_functions =
       GrowableObjectArray::Handle(Z, T->pending_functions());
   ASSERT(!pending_functions.IsNull());
   for (int i = 0; i < pending_functions.Length(); i++) {
     if (pending_functions.At(i) == current_function().raw()) {
       const String& fname =
           String::Handle(Z, current_function().UserVisibleName());
-      ReportError("circular dependency for function %s", fname.ToCString());
+      const char* pending_function_dump =
+          DumpPendingFunctions(Z, pending_functions);
+      ASSERT(pending_function_dump != NULL);
+      ReportError("circular dependency for function %s\n%s",
+                  fname.ToCString(),
+                  pending_function_dump);
     }
   }
   ASSERT(!unregister_pending_function_);
   pending_functions.Add(current_function(), Heap::kOld);
   unregister_pending_function_ = true;
 }
 
 
 // Parser is at the opening parenthesis of the formal parameter declaration
 // of function. Parse the formal parameters, initializers and code.
@@ skipping 11436 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