Improve error messages for unexpected regexes

lib/coffee-script/lexer.js

@@ -279,7 +279,7 @@
     };
 
     Lexer.prototype.regexToken = function() {
-      var closed, end, flags, index, match, prev, re, ref2, ref3, regex, rparen, tokens;
+      var closed, end, errorToken, flags, index, match, prev, re, ref2, ref3, regex, rparen, tokens;
       switch (false) {
         case !(match = REGEX_ILLEGAL.exec(this.chunk)):
           this.error("regular expressions cannot begin with " + match[2], match.index + match[1].length);
@@ -309,6 +309,7 @@
       }
       flags = REGEX_FLAGS.exec(this.chunk.slice(index))[0];
       end = index + flags.length;
+      errorToken = this.makeToken('REGEX', this.chunk.slice(0, end), 0, end);
       switch (false) {
         case !!VALID_FLAGS.test(flags):
           this.error("invalid regular expression flags " + flags, index);
@@ -318,11 +319,11 @@
           break;
         case tokens.length !== 1:
           re = this.formatHeregex(tokens[0][1]).replace(/\//g, '\\/');
-          this.token('REGEX', "/" + (re || '(?:)') + "/" + flags);
+          this.token('REGEX', "/" + (re || '(?:)') + "/" + flags, 0, end, errorToken);
           break;
         default:
           this.token('IDENTIFIER', 'RegExp', 0, 0);
-          this.token('CALL_START', '(', 0, 0);
+          this.token('CALL_START', '(', 0, 0, errorToken);
           this.mergeInterpolationTokens(tokens, '"', (function(_this) {
             return function(value) {
               return _this.formatHeregex(value).replace(/\\/g, '\\\\');

src/lexer.coffee

@@ -272,6 +272,7 @@ exports.Lexer = class Lexer
 
     [flags] = REGEX_FLAGS.exec @chunk[index..]
     end = index + flags.length
+    errorToken = @makeToken 'REGEX', @chunk[...end], 0, end
     switch
       when not VALID_FLAGS.test flags
         @error "invalid regular expression flags #{flags}", index
@@ -279,10 +280,10 @@ exports.Lexer = class Lexer
         @token 'REGEX', "#{regex}#{flags}"
       when tokens.length is 1
         re = @formatHeregex(tokens[0][1]).replace(/\//g, '\\/')
-        @token 'REGEX', "/#{ re or '(?:)' }/#{flags}"
+        @token 'REGEX', "/#{ re or '(?:)' }/#{flags}", 0, end, errorToken
       else
         @token 'IDENTIFIER', 'RegExp', 0, 0
-        @token 'CALL_START', '(', 0, 0
+        @token 'CALL_START', '(', 0, 0, errorToken
         @mergeInterpolationTokens tokens, '"', (value) =>
           @formatHeregex(value).replace(/\\/g, '\\\\')
         if flags

test/error_messages.coffee

@@ -125,6 +125,22 @@ test "#1096: unexpected generated tokens", ->
     for i in [1]:
                 ^
   '''
+  # Unexpected regex
+  assertErrorFormat '{/a/i: val}', '''
+    [stdin]:1:2: error: unexpected /a/i
+    {/a/i: val}
+     ^^^^
+  '''
+  assertErrorFormat '{///a///i: val}', '''
+    [stdin]:1:2: error: unexpected ///a///i
+    {///a///i: val}
+     ^^^^^^^^
+  '''
+  assertErrorFormat '{///#{a}///i: val}', '''
+    [stdin]:1:2: error: unexpected ///#{a}///i
+    {///#{a}///i: val}
+     ^^^^^^^^^^^
+  '''
 
 test "#1316: unexpected end of interpolation", ->
   assertErrorFormat '''

test/location.coffee

@@ -446,7 +446,7 @@ test "#3621: Multiline regex and manual `Regex` call with interpolation should
     tokenB = tokensB[i]
     eq tokenA[0], tokenB[0]
     eq tokenA[1], tokenB[1]
-    eq tokenA.origin?[1], tokenB.origin?[1]
+    eq tokenA.origin?[1], tokenB.origin?[1] unless tokenA[0] is 'CALL_START'
     eq tokenA.stringEnd, tokenB.stringEnd
 
 test "Verify all tokens get a location", ->