[counters] Add UseCounters for 'f() = 0' syntax

src/parsing/parser-base.h

Index: src/parsing/parser-base.h
diff --git a/src/parsing/parser-base.h b/src/parsing/parser-base.h
index 6e407eef6d765e5dfc2e7012728b6019f1976955..93f1a9a70e1511c2dfacaf9624f5624de35baaec 100644
--- a/src/parsing/parser-base.h
+++ b/src/parsing/parser-base.h
@@ -4332,6 +4332,10 @@ ParserBase<Impl>::CheckAndRewriteReferenceExpression(
   if (expression->IsCall()) {
     // If it is a call, make it a runtime error for legacy web compatibility.
     // Rewrite `expr' to `expr[throw ReferenceError]'.

[Dan Ehrenberg, 2016/12/23 07:56:52]

Could you put a reference to
https://bugs.chromium.org/p/v8/issues/detail?id=4480 here?

[bakkot1, 2016/12/23 09:41:53]

Done.

+    impl()->CountUsage(
+        is_strict(language_mode())

[Dan Ehrenberg, 2016/12/23 07:56:52]

Aren't you glad we don't have strong mode?

+            ? v8::Isolate::kAssigmentExpressionLHSIsCallInStrict
+            : v8::Isolate::kAssigmentExpressionLHSIsCallInNonstrict);
     ExpressionT error = impl()->NewThrowReferenceError(message, beg_pos);
     return factory()->NewProperty(expression, error, beg_pos);
   }