PreParser: track variable declarations and parameters

src/ast/scopes.h

Index: src/ast/scopes.h
diff --git a/src/ast/scopes.h b/src/ast/scopes.h
index fa289733066386d5635780a9359cdbd13a714302..15a5f79b7aed6ecd41df076d9c18ec78ffa8a0b1 100644
--- a/src/ast/scopes.h
+++ b/src/ast/scopes.h
@@ -34,6 +34,10 @@ class VariableMap: public ZoneHashMap {
                     MaybeAssignedFlag maybe_assigned_flag = kNotAssigned,
                     bool* added = nullptr);
 
+  // Records that "name" exists but doesn't create a Variable. Useful for
+  // preparsing.
+  void DeclareName(Zone* zone, const AstRawString* name);
+
   Variable* Lookup(const AstRawString* name);
   void Remove(Variable* var);
   void Add(Zone* zone, Variable* var);
@@ -157,6 +161,8 @@ class V8_EXPORT_PRIVATE Scope : public NON_EXPORTED_BASE(ZoneObject) {
                             bool* sloppy_mode_block_scope_function_redefinition,
                             bool* ok);
 
+  void DeclareVariableName(const AstRawString* name, VariableMode mode);
+
   // Declarations list.
   ThreadedList<Declaration>* declarations() { return &decls_; }
 
@@ -526,7 +532,6 @@ class V8_EXPORT_PRIVATE Scope : public NON_EXPORTED_BASE(ZoneObject) {
   // list along the way, so full resolution cannot be done afterwards.
   // If a ParseInfo* is passed, non-free variables will be resolved.
   VariableProxy* FetchFreeVariables(DeclarationScope* max_outer_scope,
-                                    bool try_to_resolve = true,
                                     ParseInfo* info = nullptr,
                                     VariableProxy* stack = nullptr);
 
@@ -578,6 +583,7 @@ class V8_EXPORT_PRIVATE Scope : public NON_EXPORTED_BASE(ZoneObject) {
   void SetDefaults();
 
   friend class DeclarationScope;
+  friend class ScopeTestHelper;
 };
 
 class DeclarationScope : public Scope {
@@ -649,6 +655,9 @@ class DeclarationScope : public Scope {
   Variable* DeclareParameter(const AstRawString* name, VariableMode mode,
                              bool is_optional, bool is_rest, bool* is_duplicate,
                              AstValueFactory* ast_value_factory);
+  void DeclareParameterName(const AstRawString* name, bool is_optional,
+                            bool is_rest, bool* is_duplicate,
+                            AstValueFactory* ast_value_factory);
 
   // Declare an implicit global variable in this scope which must be a
   // script scope.  The variable was introduced (possibly from an inner