[strong] Disallow implicit conversions for binary arithmetic operations

src/ic/ic-state.h

Index: src/ic/ic-state.h
diff --git a/src/ic/ic-state.h b/src/ic/ic-state.h
index d3fdbe0dfbee75dd9d55286fdc297897bb424c3c..6863c6e7b91281192d247d1c3d3e4eebdfbd3420 100644
--- a/src/ic/ic-state.h
+++ b/src/ic/ic-state.h
@@ -57,9 +57,9 @@ std::ostream& operator<<(std::ostream& os, const CallICState& s);
 class BinaryOpICState final BASE_EMBEDDED {
  public:
   BinaryOpICState(Isolate* isolate, ExtraICState extra_ic_state);
-
-  BinaryOpICState(Isolate* isolate, Token::Value op)
+  BinaryOpICState(Isolate* isolate, Token::Value op, LanguageMode language_mode)
       : op_(op),
+        language_mode_(language_mode),
         left_kind_(NONE),
         right_kind_(NONE),
         result_kind_(NONE),
@@ -106,6 +106,10 @@ class BinaryOpICState final BASE_EMBEDDED {
     return Max(left_kind_, right_kind_) == GENERIC;
   }
 
+  LanguageMode language_mode() const {
+    return language_mode_;
+  }
+
   // Returns true if the IC should enable the inline smi code (i.e. if either
   // parameter may be a smi).
   bool UseInlinedSmiCode() const {
@@ -147,10 +151,12 @@ class BinaryOpICState final BASE_EMBEDDED {
   // When fixed right arg is set, we don't need to store the right kind.
   // Thus the two fields can overlap.
   class HasFixedRightArgField : public BitField<bool, 10, 1> {};
-  class FixedRightArgValueField : public BitField<int, 11, 4> {};
-  class RightKindField : public BitField<Kind, 11, 3> {};
+  class LanguageModeField : public BitField<LanguageMode, 11, 2> {};
+  class FixedRightArgValueField : public BitField<int, 13, 4> {};
+  class RightKindField : public BitField<Kind, 13, 3> {};
 
   Token::Value op_;
+  LanguageMode language_mode_;
   Kind left_kind_;
   Kind right_kind_;
   Kind result_kind_;