Fixes #1280, regex and compound division mixup.

lib/lexer.js

@@ -617,7 +617,7 @@
   MULTI_DENT = /^(?:\n[^\n\S]*)+/;
   SIMPLESTR = /^'[^\\']*(?:\\.[^\\']*)*'/;
   JSTOKEN = /^`[^\\`]*(?:\\.[^\\`]*)*`/;
-  REGEX = /^\/(?!\s)[^[\/\n\\]*(?:(?:\\[\s\S]|\[[^\]\n\\]*(?:\\[\s\S][^\]\n\\]*)*])[^[\/\n\\]*)*\/[imgy]{0,4}(?!\w)/;
+  REGEX = /^\/(?![\s=])[^[\/\n\\]*(?:(?:\\[\s\S]|\[[^\]\n\\]*(?:\\[\s\S][^\]\n\\]*)*])[^[\/\n\\]*)*\/[imgy]{0,4}(?!\w)/;
   HEREGEX = /^\/{3}([\s\S]+?)\/{3}([imgy]{0,4})(?!\w)/;
   HEREGEX_OMIT = /\s+(?:#.*)?/g;
   MULTILINER = /\n/g;

src/lexer.coffee

@@ -575,7 +575,7 @@ JSTOKEN    = /^`[^\\`]*(?:\\.[^\\`]*)*`/
 
 # Regex-matching-regexes.
 REGEX = /// ^
-  / (?! \s )       # disallow leading whitespace
+  / (?! [\s=] )       # disallow leading whitespace or equals signs
   [^ [ / \n \\ ]*  # every other thing
   (?:
     (?: \\[\s\S]   # anything escaped

test/regular_expression_literals.coffee

@@ -20,6 +20,10 @@ test "division is not confused for a regular expression", ->
   g = 1
   eq 2, a / b/g
 
+  a = 10
+  b = a /= 4 / 2
+  eq a, 5
+
   obj = method: -> 2
   two = 2
   eq 2, (obj.method()/two + obj.method()/two)