[ast/parsing] Pessimistically assume all top-level variables will be assigned.

src/parsing/parser.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/parsing/parser.h"
 
 #include <memory>
 
 #include "src/api.h"
 #include "src/ast/ast-expression-rewriter.h"
@@ skipping 1462 matching lines @@
 }
 
 Statement* Parser::DeclareFunction(const AstRawString* variable_name,
                                    FunctionLiteral* function, VariableMode mode,
                                    int pos, bool is_generator, bool is_async,
                                    bool is_sloppy_block_function,
                                    ZoneList<const AstRawString*>* names,
                                    bool* ok) {
   VariableProxy* proxy =
       factory()->NewVariableProxy(variable_name, NORMAL_VARIABLE);
+
+  DeclarationScope* target_scope = GetDeclarationScope();
+  MarkTopLevelVariableAsAssigned(target_scope, proxy);
+
   Declaration* declaration =
       factory()->NewFunctionDeclaration(proxy, function, scope(), pos);
   Declare(declaration, DeclarationDescriptor::NORMAL, mode, kCreatedInitialized,
           CHECK_OK);
   if (names) names->Add(variable_name, zone());
   if (is_sloppy_block_function) {
     SloppyBlockFunctionStatement* statement =
         factory()->NewSloppyBlockFunctionStatement();
-    DeclarationScope* target_scope = GetDeclarationScope();
     target_scope->DeclareSloppyBlockFunction(variable_name, scope(), statement);
     return statement;
   }
   return factory()->NewEmptyStatement(kNoSourcePosition);
 }
 
 Statement* Parser::DeclareClass(const AstRawString* variable_name,
                                 Expression* value,
                                 ZoneList<const AstRawString*>* names,
                                 int class_token_pos, int end_pos, bool* ok) {
@@ skipping 3519 matching lines @@
 
   return final_loop;
 }
 
 #undef CHECK_OK
 #undef CHECK_OK_VOID
 #undef CHECK_FAILED
 
 }  // namespace internal
 }  // namespace v8