diff --git a/lib/less/parser.js b/lib/less/parser.js
index d3c6ce66..3775b8fb 100644
--- a/lib/less/parser.js
+++ b/lib/less/parser.js
@@ -1066,7 +1066,8 @@ less.Parser = function Parser(env) {
                     }
 
                     option = option && option[1];
-
+                    if (!elements)
+                        error("Missing target selector for :extend().");
                     extend = new(tree.Extend)(new(tree.Selector)(elements), option, index);
                     if (extendList) { extendList.push(extend); } else { extendList = [ extend ]; }
 
diff --git a/test/sourcemaps/basic.json b/test/sourcemaps/basic.json
index ab73305d..24d5ce21 100644
--- a/test/sourcemaps/basic.json
+++ b/test/sourcemaps/basic.json
@@ -1 +1 @@
-{"version":3,"file":"sourcemaps/basic.css","sources":["testweb/sourcemaps/imported.css","testweb/sourcemaps/basic.less"],"names":[],"mappings":"AAAA;AACA;AACA;AACA;AACA;AACA;AACA;ACAA;EACE,YAAA;EAJA,UAAA;EAWA,iBAAA;EALA,WAAA;EACA,mBAAA;;AAJF,EASE;AATF,EASM;EACF,gBAAA;;AACA,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFA;AAEF,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFA;EAGA,UAAA;;AALN;AAAI;AAUJ;EATE,iBAAA;;AADF,EAEE;AAFE,EAEF;AAFF,EAEM;AAFF,EAEE;AAQN,OARE;AAQF,OARM;EACF,gBAAA;;AACA,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFA;AAEF,EAFF,GAEI,KAFA;AAEF,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFA;AAEF,EAFF,GAEI,KAFA;AAEF,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFA;AAEF,EAFE,GAEA,KAFA;AAEF,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFA;AAEF,EAFE,GAEA,KAFA;AAQN,OARE,GAQF,UARE;AAQF,OARE,GAEI,KAFJ;AAQF,OARE,GAQF,UARM;AAQN,OARE,GAEI,KAFA;AAEF,EAFF,GAQF,UARE;AAEE,EAFF,GAQF,UARM;AAQN,OARM,GAQN,UARE;AAQF,OARM,GAEA,KAFJ;AAQF,OARM,GAQN,UARM;AAQN,OARM,GAEA,KAFA;AAEF,EAFE,GAQN,UARE;AAEE,EAFE,GAQN,UARM;EAGA,UAAA;;AAKN;EACE,WAAA"}
\ No newline at end of file
+{"version":3,"sources":["testweb/sourcemaps/imported.css","testweb/sourcemaps/basic.less"],"names":[],"mappings":"AAAA;AACA;AACA;AACA;AACA;AACA;AACA;ACAA;EACE,YAAA;EAJA,UAAA;EAWA,iBAAA;EALA,WAAA;EACA,mBAAA;;AAJF,EASE;AATF,EASM;EACF,gBAAA;;AACA,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFA;AAEF,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFA;EAGA,UAAA;;AALN;AAAI;AAUJ;EATE,iBAAA;;AADF,EAEE;AAFE,EAEF;AAFF,EAEM;AAFF,EAEE;AAQN,OARE;AAQF,OARM;EACF,gBAAA;;AACA,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFA;AAEF,EAFF,GAEI,KAFA;AAEF,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFJ;AAEE,EAFF,GAEI,KAFA;AAEF,EAFF,GAEI,KAFA;AAEF,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFA;AAEF,EAFE,GAEA,KAFA;AAEF,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFJ;AAEE,EAFE,GAEA,KAFA;AAEF,EAFE,GAEA,KAFA;AAQN,OARE,GAQF,UARE;AAQF,OARE,GAEI,KAFJ;AAQF,OARE,GAQF,UARM;AAQN,OARE,GAEI,KAFA;AAEF,EAFF,GAQF,UARE;AAEE,EAFF,GAQF,UARM;AAQN,OARM,GAQN,UARE;AAQF,OARM,GAEA,KAFJ;AAQF,OARM,GAQN,UARM;AAQN,OARM,GAEA,KAFA;AAEF,EAFE,GAQN,UARE;AAEE,EAFE,GAQN,UARM;EAGA,UAAA;;AAKN;EACE,WAAA","file":"sourcemaps/basic.css"}
\ No newline at end of file