Check for a passed-in type argument vector in the prolog of generic functions.

runtime/vm/scopes.cc

Index: runtime/vm/scopes.cc
diff --git a/runtime/vm/scopes.cc b/runtime/vm/scopes.cc
index dcae0be58f60b1df800516781d758d4e506d90f6..a404f31fd5b95de77de81f3a4ccfff5a5da77364 100644
--- a/runtime/vm/scopes.cc
+++ b/runtime/vm/scopes.cc
@@ -194,6 +194,7 @@ void LocalScope::AllocateContextVariable(LocalVariable* variable,
 
 int LocalScope::AllocateVariables(int first_parameter_index,
                                   int num_parameters,
+                                  int type_args_slot,
                                   int first_frame_index,
                                   LocalScope* context_owner,
                                   bool* found_captured_variables) {
@@ -234,6 +235,12 @@ int LocalScope::AllocateVariables(int first_parameter_index,
       if (variable->is_captured()) {
         AllocateContextVariable(variable, &context_owner);
         *found_captured_variables = true;
+        if ((pos == num_parameters) && (type_args_slot == 1)) {

[Vyacheslav Egorov (Google), 2017/06/20 15:21:41]

can this instead be:

if (variable->name().raw() == Symbols::FunctionTypeArgumentsVar().raw()) {
  ASSERT(pos == num_parameters);
}

? then you don't even need to pass type_args_slot down.

[regis, 2017/06/21 04:39:04]

Good point. Thanks. I never revisited this code after it worked...

+          ASSERT(variable->name().Equals(Symbols::FunctionTypeArgumentsVar()));
+          // A captured type args variable has a slot allocated in the frame and
+          // one in the context, where it gets copied to.
+          frame_index--;
+        }
       } else {
         variable->set_index(frame_index--);
       }
@@ -243,11 +250,12 @@ int LocalScope::AllocateVariables(int first_parameter_index,
   int min_frame_index = frame_index;  // Frame index decreases with allocations.
   LocalScope* child = this->child();
   while (child != NULL) {
-    int const dummy_parameter_index = 0;    // Ignored, since no parameters.
-    int const num_parameters_in_child = 0;  // No parameters in children scopes.
+    const int dummy_parameter_index = 0;    // Ignored, since no parameters.
+    const int num_parameters_in_child = 0;  // No parameters in children scopes.
+    const int no_type_args_slot = 0;  // No type args slot in children scopes.
     int child_frame_index = child->AllocateVariables(
-        dummy_parameter_index, num_parameters_in_child, frame_index,
-        context_owner, found_captured_variables);
+        dummy_parameter_index, num_parameters_in_child, no_type_args_slot,
+        frame_index, context_owner, found_captured_variables);
     if (child_frame_index < min_frame_index) {
       min_frame_index = child_frame_index;
     }