[strong] no sloppy equality

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index b4da5326d661379e389b12f13abc3b4337196642..e60ab92586e0a5f4aa2002397492d1d171769e2a 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -161,6 +161,7 @@ var kMessages = {
   strict_cannot_assign:          ["Cannot assign to read only '", "%0", "' in strict mode"],
   strict_poison_pill:            ["'caller', 'callee', and 'arguments' properties may not be accessed on strict mode functions or the arguments objects for calls to them"],
   strict_caller:                 ["Illegal access to a strict mode caller function."],
+  strong_equal:                  ["Please don't use '==' or '!=' in strong mode, use '===' or '!==' instead"],

[marja, 2015/02/12 09:59:37]

I find this error message strangely polite :) How about:

'==' and '!=' not allowed in strong mode

[rossberg, 2015/02/12 14:47:16]

Totally intentional, I thought people should think good of strong mode instead
of feeling harassed. :)

The "please" might be over the top, but at least I'd like strong mode errors to
point out the recommended alternative to using the forbidden feature.

   malformed_arrow_function_parameter_list: ["Malformed arrow function parameter list"],
   generator_poison_pill:         ["'caller' and 'arguments' properties may not be accessed on generator functions."],
   cant_prevent_ext_external_array_elements: ["Cannot prevent extension of an object with external array elements"],