diff --git a/lib/coffee-script/lexer.js b/lib/coffee-script/lexer.js
index 2ab1e5c4..9e3224f8 100644
--- a/lib/coffee-script/lexer.js
+++ b/lib/coffee-script/lexer.js
@@ -403,11 +403,11 @@
             double: true
           }, this.formatHeregex);
           if (flags) {
-            this.token(',', ',', index, 0);
-            this.token('STRING', '"' + flags + '"', index, flags.length);
+            this.token(',', ',', index - 1, 0);
+            this.token('STRING', '"' + flags + '"', index - 1, flags.length);
           }
-          this.token(')', ')', end, 0);
-          this.token('REGEX_END', ')', end, 0);
+          this.token(')', ')', end - 1, 0);
+          this.token('REGEX_END', ')', end - 1, 0);
       }
       return end;
     };
diff --git a/src/lexer.coffee b/src/lexer.coffee
index 529caf11..dc34f53d 100644
--- a/src/lexer.coffee
+++ b/src/lexer.coffee
@@ -332,10 +332,10 @@ exports.Lexer = class Lexer
         @token 'CALL_START', '(', 0, 0
         @mergeInterpolationTokens tokens, {delimiter: '"', double: yes}, @formatHeregex
         if flags
-          @token ',', ',', index, 0
-          @token 'STRING', '"' + flags + '"', index, flags.length
-        @token ')', ')', end, 0
-        @token 'REGEX_END', ')', end, 0
+          @token ',', ',', index - 1, 0
+          @token 'STRING', '"' + flags + '"', index - 1, flags.length
+        @token ')', ')', end - 1, 0
+        @token 'REGEX_END', ')', end - 1, 0
 
     end
 
diff --git a/test/location.coffee b/test/location.coffee
index 2ffe951e..19eb3c62 100644
--- a/test/location.coffee
+++ b/test/location.coffee
@@ -564,6 +564,29 @@ test "Verify indented heredocs have the right position", ->
   eq stringToken[2].last_line, 3
   eq stringToken[2].last_column, 4
 
+test "Verify heregexes with interpolations have the right ending position", ->
+  source = '''
+    [a ///#{b}///g]
+  '''
+  [..., stringEnd, comma, flagsString, regexCallEnd, regexEnd, fnCallEnd,
+    arrayEnd, terminator] = CoffeeScript.tokens source
+
+  eq comma[0], ','
+  eq arrayEnd[0], ']'
+
+  assertColumn = (token, column) ->
+    eq token[2].first_line, 0
+    eq token[2].first_column, column
+    eq token[2].last_line, 0
+    eq token[2].last_column, column
+
+  arrayEndColumn = arrayEnd[2].first_column
+  for token in [comma, flagsString]
+    assertColumn token, arrayEndColumn - 2
+  for token in [regexCallEnd, regexEnd, fnCallEnd]
+    assertColumn token, arrayEndColumn - 1
+  assertColumn arrayEnd, arrayEndColumn
+
 test "Verify all tokens get a location", ->
   doesNotThrow ->
     tokens = CoffeeScript.tokens testScript