Properly handle implicit closure function when a generic function.

runtime/vm/object.cc

Index: runtime/vm/object.cc
diff --git a/runtime/vm/object.cc b/runtime/vm/object.cc
index 08821a27c542653e4afa6d19076ed8b2754b7551..28b4dbee71ec0f81088e2fe66f1415791c8db73e 100644
--- a/runtime/vm/object.cc
+++ b/runtime/vm/object.cc
@@ -5616,6 +5616,11 @@ void Function::set_parent_function(const Function& value) const {
 
 
 bool Function::HasGenericParent() const {
+  if (IsImplicitClosureFunction()) {
+    // The parent function of an implicit closure function is not the enclosing
+    // function we are asking about here.
+    return false;
+  }
   Function& parent = Function::Handle(parent_function());
   while (!parent.IsNull()) {
     if (parent.IsGeneric()) {
@@ -6014,6 +6019,9 @@ intptr_t Function::NumTypeParameters(Thread* thread) const {
 
 
 intptr_t Function::NumParentTypeParameters() const {
+  if (IsImplicitClosureFunction()) {
+    return 0;
+  }
   Thread* thread = Thread::Current();
   Function& parent = Function::Handle(parent_function());
   intptr_t num_parent_type_params = 0;
@@ -6052,6 +6060,11 @@ RawTypeParameter* Function::LookupTypeParameter(
         }
       }
     }
+    if (function.IsImplicitClosureFunction()) {
+      // The parent function is not the enclosing function, but the closurized
+      // function with identical type parameters.
+      break;
+    }
     function ^= function.parent_function();
     if (function_level != NULL) {
       (*function_level)--;
@@ -6343,11 +6356,14 @@ enum QualifiedFunctionLibKind {
 
 
 static intptr_t ConstructFunctionFullyQualifiedCString(
-    const Function& function,
+    const Function& fun,
     char** chars,
     intptr_t reserve_len,
     bool with_lib,
     QualifiedFunctionLibKind lib_kind) {
+  // Hide implicit closure functions.
+  const Function& function = Function::Handle(

[rmacnak, 2017/04/25 19:21:42]

I think this output is only used for debug printing in the VM. Can we keep the
current format or some other identifying mark in the string? It's helpful to
distinguish the implicit closure function.

[regis, 2017/04/25 19:57:26]

OK, I removed the change.

+      fun.IsImplicitClosureFunction() ? fun.parent_function() : fun.raw());
   const char* name = String::Handle(function.name()).ToCString();
   const char* function_format = (reserve_len == 0) ? "%s" : "%s_";
   reserve_len += OS::SNPrint(NULL, 0, function_format, name);