Preparse lazy function parameters

src/ast/scopes.cc

 // 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.
 
 #include "src/ast/scopes.h"
 
 #include <set>
 
 #include "src/accessors.h"
 #include "src/ast/ast.h"
@@ skipping 1234 matching lines @@
     non_locals = StringSet::Add(non_locals, proxy->name());
   }
   return non_locals;
 }
 
 void DeclarationScope::ResetAfterPreparsing(AstValueFactory* ast_value_factory,
                                             bool aborted) {
   DCHECK(is_function_scope());
 
   // Reset all non-trivial members.
+  params_.Clear();
   decls_.Clear();
   locals_.Clear();
   sloppy_block_function_map_.Clear();
   variables_.Clear();
   // Make sure we won't walk the scope tree from here on.
   inner_scope_ = nullptr;
   unresolved_ = nullptr;
 
-  // TODO(verwaest): We should properly preparse the parameters (no declarations
-  // should be created), and reparse on abort.
-  if (aborted) {
-    if (!IsArrowFunction(function_kind_)) {
-      DeclareDefaultFunctionVariables(ast_value_factory);
-    }
-    // Recreate declarations for parameters.
-    for (int i = 0; i < params_.length(); i++) {
-      Variable* var = params_[i];
-      if (var->mode() == TEMPORARY) {
-        // TODO(verwaest): Remove and unfriend DeclarationScope from Variable.
-        *var->next() = nullptr;
-        locals_.Add(var);
-      } else if (variables_.Lookup(var->raw_name()) == nullptr) {
-        // TODO(verwaest): Remove and unfriend DeclarationScope from Variable.
-        *var->next() = nullptr;
-        variables_.Add(zone(), var);
-        locals_.Add(var);
-      }
-    }
-  } else {
-    params_.Rewind(0);
+  if (aborted && !IsArrowFunction(function_kind_)) {
+    DeclareDefaultFunctionVariables(ast_value_factory);
   }
 
 #ifdef DEBUG
   needs_migration_ = false;
 #endif
 
   is_lazily_parsed_ = !aborted;
 }
 
 void DeclarationScope::AnalyzePartially(AstNodeFactory* ast_node_factory) {
@@ skipping 741 matching lines @@
   Variable* function =
       is_function_scope() ? AsDeclarationScope()->function_var() : nullptr;
   bool is_function_var_in_context =
       function != nullptr && function->IsContextSlot();
   return num_heap_slots() - Context::MIN_CONTEXT_SLOTS -
          (is_function_var_in_context ? 1 : 0);
 }
 
 }  // namespace internal
 }  // namespace v8