error tests and test detached rulesets without a mixin call

lib/less/tree/rule.js

@@ -30,7 +30,7 @@ tree.Rule.prototype = {
     },
     toCSS: tree.toCSS,
     eval: function (env) {
-        var strictMathBypass = false, name = this.name;    
+        var strictMathBypass = false, name = this.name, evaldValue;
         if (typeof name !== "string") {
             // expand 'primitive' name directly to get
             // things faster (~10% for benchmark.less):
@@ -43,14 +43,25 @@ tree.Rule.prototype = {
             env.strictMath = true;
         }
         try {
+            evaldValue = this.value.eval(env);
+            
+            if (!this.variable && evaldValue.type === "Ruleset") {
+                console.log(this.index);
+                throw { message: "Rulesets cannot be evaluated on a property.",
+                        index: this.index, filename: this.currentFileInfo.filename };
+            }
+
             return new(tree.Rule)(name,
-                              this.value.eval(env),
+                              evaldValue,
                               this.important,
                               this.merge,
                               this.index, this.currentFileInfo, this.inline);
         }
         catch(e) {
-            e.index = e.index || this.index;
+            if (typeof e.index !== 'number') {
+                e.index = this.index;
+                e.filename = this.currentFileInfo.filename;
+            }
             throw e;
         }
         finally {

test/css/detached-rulesets.css

@@ -42,3 +42,6 @@ html.lt-ie9 header {
   visible-one: visible;
   visible-two: visible;
 }
+.without-mixins {
+  b: 1;
+}

test/less/detached-rulesets.less

@@ -56,3 +56,10 @@ header {
   test-func: unit(90px);
   test-arithmetic: unit((9+9), px);
 });
+// without mixins
+@ruleset-2: {
+  b: 1;
+};
+.without-mixins {
+  @ruleset-2();
+}

test/less/errors/detached-ruleset-1.less

@@ -0,0 +1,6 @@
+@a: {
+  b: 1;
+};
+.a {
+  a: @a;
+}

test/less/errors/detached-ruleset-1.txt

@@ -0,0 +1,4 @@
+SyntaxError: Rulesets cannot be evaluated on a property. in {path}detached-ruleset-1.less on line 5, column 3:
+4 .a {
+5   a: @a;
+6 }

test/less/errors/detached-ruleset-2.less

@@ -0,0 +1,6 @@
+@a: {
+  b: 1;
+};
+.a {
+  a: @a();
+}

test/less/errors/detached-ruleset-2.txt

@@ -0,0 +1,4 @@
+ParseError: Unrecognised input in {path}detached-ruleset-2.less on line 5, column 3:
+4 .a {
+5   a: @a();
+6 }

test/less/errors/detached-ruleset-3.less

@@ -0,0 +1,4 @@
+@a: {
+  b: 1;
+};
+@a();

test/less/errors/detached-ruleset-3.txt

@@ -0,0 +1,4 @@
+SyntaxError: properties must be inside selector blocks, they cannot be in the root. in {path}detached-ruleset-3.less on line 2, column 3:
+1 @a: {
+2   b: 1;
+3 };

test/less/errors/detached-ruleset-4.less

@@ -0,0 +1,5 @@
+.mixin-definition(@a: {
+  b: 1;
+}) {
+  @a();
+}

test/less/errors/detached-ruleset-4.txt

@@ -0,0 +1,3 @@
+ParseError: Unrecognised input in {path}detached-ruleset-4.less on line 1, column 18:
+1 .mixin-definition(@a: {
+2   b: 1;

test/less/errors/detached-ruleset-5.less

@@ -0,0 +1,4 @@
+.mixin-definition(@b) {
+  @a();
+}
+.mixin-definition({color: red;});

test/less/errors/detached-ruleset-5.txt

@@ -0,0 +1,3 @@
+SyntaxError: variable @a is undefined in {path}detached-ruleset-5.less on line 4, column 1:
+3 }
+4 .mixin-definition({color: red;});

test/less/errors/detached-ruleset-6.less

@@ -0,0 +1,5 @@
+.a {
+  b: {
+    color: red;
+  };
+}

test/less/errors/detached-ruleset-6.txt

@@ -0,0 +1,4 @@
+ParseError: Unrecognised input in {path}detached-ruleset-6.less on line 2, column 3:
+1 .a {
+2   b: {
+3     color: red;