[strong] Disallow implicit conversions for add

src/runtime.js

Index: src/runtime.js
diff --git a/src/runtime.js b/src/runtime.js
index 9bb02aecb711ab6fbb932075a187905f9b72731f..7b291000e0e42badb2b3913a0465059db82ab463 100644
--- a/src/runtime.js
+++ b/src/runtime.js
@@ -160,6 +160,15 @@ function ADD(x) {
 }
 
 
+//ECMA-262, section 11.6.1, page 50.

[Dmitry Lomov (no reviews), 2015/04/30 08:43:59]

This comment does not apply anymore I guess.

[conradw, 2015/04/30 09:19:33]

Changed this and similar examples in other places.

+function ADD_STRONG(x) {
+  if (IS_NUMBER(this) && IS_NUMBER(x)) return %NumberAdd(this, x);
+  if (IS_STRING(this) && IS_STRING(x)) return %_StringAdd(this, x);
+
+  throw %MakeTypeError('strong_implicit_cast');
+}
+
+
 // Left operand (this) is already a string.
 function STRING_ADD_LEFT(y) {
   if (!IS_STRING(y)) {
@@ -175,6 +184,15 @@ function STRING_ADD_LEFT(y) {
 }
 
 
+//Left operand (this) is already a string.
+function STRING_ADD_LEFT_STRONG(y) {
+  if (IS_STRING(y)) {
+    return %_StringAdd(this, y);
+  }
+  throw %MakeTypeError('strong_implicit_cast');
+}
+
+
 // Right operand (y) is already a string.
 function STRING_ADD_RIGHT(y) {
   var x = this;
@@ -191,6 +209,15 @@ function STRING_ADD_RIGHT(y) {
 }
 
 
+//Right operand (y) is already a string.
+function STRING_ADD_RIGHT_STRONG(y) {
+  if (IS_STRING(this)) {
+    return %_StringAdd(this, y);
+  }
+  throw %MakeTypeError('strong_implicit_cast');
+}
+
+
 // ECMA-262, section 11.6.2, page 50.
 function SUB(y) {
   var x = IS_NUMBER(this) ? this : %NonNumberToNumber(this);