diff --git a/lib/ace/mode/lean_highlight_rules.js b/lib/ace/mode/lean_highlight_rules.js
index 44eb8d50..48241c0e 100644
--- a/lib/ace/mode/lean_highlight_rules.js
+++ b/lib/ace/mode/lean_highlight_rules.js
@@ -108,13 +108,6 @@ var leanHighlightRules = function() {
                 token : "string", // multi line string start
                 regex : '["].*\\\\$',
                 next : "qqstring"
-            }, {
-                token : "string", // single line
-                regex : "['](?:(?:\\\\.)|(?:[^'\\\\]))*?[']"
-            }, {
-                token : "string", // multi line string start
-                regex : "['].*\\\\$",
-                next : "qstring"
             }, {
                 token : "constant.numeric", // hex
                 regex : "0[xX][0-9a-fA-F]+(L|l|UL|ul|u|U|F|f|ll|LL|ull|ULL)?\\b"
@@ -155,8 +148,6 @@ var leanHighlightRules = function() {
                       {defaultToken: "comment"} ],
         "qqstring" : [ {token : "string", regex : '(?:(?:\\\\.)|(?:[^"\\\\]))*?"', next : "start" },
                        {defaultToken: "qqstring"} ],
-        "qstring" : [ {token : "string", regex : "(?:(?:\\\\.)|(?:[^'\\\\]))*?'", next : "start" },
-                      {defaultToken: "qstring"} ],
         "directive" : [
             {
                 token : "constant.other.multiline",