[parsing] When failing due to variable redeclaration, point at the variable.

src/parsing/pattern-rewriter.cc

 // Copyright 2015 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/ast.h"
 #include "src/messages.h"
 #include "src/parsing/parameter-initializer-rewriter.h"
 #include "src/parsing/parser.h"
 
 namespace v8 {
@@ skipping 113 matching lines @@
 
   // Declare variable.
   // Note that we *always* must treat the initial value via a separate init
   // assignment for variables and constants because the value must be assigned
   // when the variable is encountered in the source. But the variable/constant
   // is declared (and set to 'undefined') upon entering the function within
   // which the variable or constant is declared. Only function variables have
   // an initial value in the declaration (because they are initialized upon
   // entering the function).
   const AstRawString* name = pattern->raw_name();
-  VariableProxy* proxy = factory()->NewVariableProxy(
-      name, NORMAL_VARIABLE, parser_->scanner()->location().beg_pos);
+  VariableProxy* proxy =
+      factory()->NewVariableProxy(name, NORMAL_VARIABLE, pattern->position());
   Declaration* declaration = factory()->NewVariableDeclaration(
       proxy, descriptor_->scope, descriptor_->declaration_pos);
   Variable* var = parser_->Declare(
       declaration, descriptor_->declaration_kind, descriptor_->mode,
       Variable::DefaultInitializationFlag(descriptor_->mode), ok_,
       descriptor_->hoist_scope);
   if (!*ok_) return;
   DCHECK_NOT_NULL(var);
   DCHECK(proxy->is_resolved());
   DCHECK(initializer_position_ != kNoSourcePosition);
@@ skipping 541 matching lines @@
 NOT_A_PATTERN(TryFinallyStatement)
 NOT_A_PATTERN(UnaryOperation)
 NOT_A_PATTERN(VariableDeclaration)
 NOT_A_PATTERN(WhileStatement)
 NOT_A_PATTERN(WithStatement)
 NOT_A_PATTERN(Yield)
 
 #undef NOT_A_PATTERN
 }  // namespace internal
 }  // namespace v8