Pass through octal and binary literals as-is

See coffeescript6/discuss#45

src/lexer.coffee

@@ -191,8 +191,10 @@ exports.Lexer = class Lexer
   # Be careful not to interfere with ranges-in-progress.
   numberToken: ->
     return 0 unless match = NUMBER.exec @chunk
+
     number = match[0]
     lexedLength = number.length
+
     if /^0[BOX]/.test number
       @error "radix prefix in '#{number}' must be lowercase", offset: 1
     else if /E/.test(number) and not /^0x/.test number
@@ -202,14 +204,12 @@ exports.Lexer = class Lexer
       @error "decimal literal '#{number}' must not be prefixed with '0'", length: lexedLength
     else if /^0\d+/.test number
       @error "octal literal '#{number}' must be prefixed with '0o'", length: lexedLength
-    if octalLiteral = /^0o([0-7]+)/.exec number
-      numberValue = parseInt(octalLiteral[1], 8)
-      number = "0x#{numberValue.toString 16}"
-    else if binaryLiteral = /^0b([01]+)/.exec number
-      numberValue = parseInt(binaryLiteral[1], 2)
-      number = "0x#{numberValue.toString 16}"
-    else
+
+    numberValue = number
+
+    unless /^(0o[0-7]+)/.test(number) or /^(0b[01]+)/.test(number)
       numberValue = parseFloat(number)
+
     tag = if numberValue is Infinity then 'INFINITY' else 'NUMBER'
     @token tag, number, 0, lexedLength
     lexedLength