[parser] Better error msg for destructuring non iterable

This patch updates the error positition and the error msg.

Previously,

  → ./out.gn/x64.release/d8 test.js
  test.js:1: TypeError: undefined is not a function
  var [a] = {};
  ^
  TypeError: undefined is not a function
      at test.js:1:1


With this patch,

  → ./out.gn/x64.release/d8 test.js
  test.js:1: TypeError: [Symbol.iterator] is not a function
  var [a] = {};
            ^
  TypeError: [Symbol.iterator] is not a function
      at test.js:1:11

Bug: v8:5532
Change-Id: Ib066e8ec8a53fdf06cce491bde4b1d0c6d564cbc
Reviewed-on: https://chromium-review.googlesource.com/539024Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Commit-Queue: Sathya Gunasekaran <gsathya@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46015}

src/interpreter/bytecode-generator.cc

@@ -3420,6 +3420,7 @@ void BytecodeGenerator::VisitImportCallExpression(ImportCallExpression* expr) {
 }
 
 void BytecodeGenerator::VisitGetIterator(GetIterator* expr) {
+  builder()->SetExpressionPosition(expr);
   FeedbackSlot load_slot = expr->IteratorPropertyFeedbackSlot();
   FeedbackSlot call_slot = expr->IteratorCallFeedbackSlot();
 

src/parsing/pattern-rewriter.cc

@@ -435,9 +435,9 @@ void Parser::PatternRewriter::VisitArrayLiteral(ArrayLiteral* node,
   DCHECK(block_->ignore_completion_value());
 
   auto temp = *temp_var = CreateTempVar(current_value_);
-  auto iterator = CreateTempVar(
-      factory()->NewGetIterator(factory()->NewVariableProxy(temp),
-                                IteratorType::kNormal, kNoSourcePosition));
+  auto iterator = CreateTempVar(factory()->NewGetIterator(
+      factory()->NewVariableProxy(temp), IteratorType::kNormal,
+      current_value_->position()));
   auto done =
       CreateTempVar(factory()->NewBooleanLiteral(false, kNoSourcePosition));
   auto result = CreateTempVar();

test/message/destructuring-array-non-iterable-number.js

+// Copyright 2017 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.
+
+var [a] = 1;

test/message/destructuring-array-non-iterable-number.out

+*%(basename)s:5: TypeError: [Symbol.iterator] is not a function
+var [a] = 1;
+          ^
+TypeError: [Symbol.iterator] is not a function
+    at *%(basename)s:5:11

test/message/destructuring-array-non-iterable-object.js

+// Copyright 2017 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.
+
+var x = {};
+var [a] = x;

test/message/destructuring-array-non-iterable-object.out

+*%(basename)s:6: TypeError: [Symbol.iterator] is not a function
+var [a] = x;
+          ^
+TypeError: [Symbol.iterator] is not a function
+    at *%(basename)s:6:11

test/message/get-iterator-return-non-receiver.js

+// Copyright 2017 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.
+
+Array.prototype[Symbol.iterator] = function() { return 1; }
+var [a] = [1];

test/message/get-iterator-return-non-receiver.out

+*%(basename)s:6: TypeError: Result of the Symbol.iterator method is not an object
+var [a] = [1];
+          ^
+TypeError: Result of the Symbol.iterator method is not an object
+    at *%(basename)s:6:11
\ No newline at end of file