Preparse functions in the scope that was created when parsing of the function was started

src/ast/scopes.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_AST_SCOPES_H_
 #define V8_AST_SCOPES_H_
 
 #include "src/base/hashmap.h"
 #include "src/globals.h"
 #include "src/objects.h"
@@ skipping 788 matching lines @@
   }
 
 #ifdef DEBUG
   void PrintParameters();
 #endif
 
   void AllocateLocals();
   void AllocateParameterLocals();
   void AllocateReceiver();
 
+  void ResetAfterPreparsing() {

[marja, 2016/09/26 12:38:27]

Why do we need this? Just by reading the code, it's unclear to me 1) is this
something that needs to be done for correctness or is it just cleaning up things
we don't need to save memory? 2) why does it clear exactly these things and not
some other things?

(Adding a comment here w/ the answer is welcome. :))

+    decls_.Clear();
+    has_rest_ = false;
+    inner_scope_ = nullptr;
+    locals_.Clear();
+    params_.Clear();
+    sloppy_block_function_map_.Clear();
+    variables_.Clear();
+  }
+
  private:
   void AllocateParameter(Variable* var, int index);
 
   // Resolve and fill in the allocation information for all variables
   // in this scopes. Must be called *after* all scopes have been
   // processed (parsed) to ensure that unresolved variables can be
   // resolved properly.
   //
   // In the case of code compiled and run using 'eval', the context
   // parameter is the context in which eval was called.  In all other
@@ skipping 58 matching lines @@
   void AllocateModuleVariables();
 
  private:
   ModuleDescriptor* module_descriptor_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_AST_SCOPES_H_