Ensure that sorting of variables is stable. (gopherjs#681)

nmiyake · dmitshur · commit 95deb33d587c · 2017-08-23T11:17:20.000-04:00
If names are equal, sort ties by position. Fixes gopherjs#679.
diff --git a/compiler/utils.go b/compiler/utils.go
@@ -369,7 +369,12 @@ func (c *funcContext) handleEscapingVars(n ast.Node) {
 
 	var names []string
 	objs := analysis.EscapingObjects(n, c.p.Info.Info)
-	sort.Sort(varsByName(objs))
+	sort.Slice(objs, func(i, j int) bool {
+		if objs[i].Name() == objs[j].Name() {
+			return objs[i].Pos() < objs[j].Pos()
+		}
+		return objs[i].Name() < objs[j].Name()
+	})
 	for _, obj := range objs {
 		names = append(names, c.objectName(obj))
 		c.p.escapingVars[obj] = true
@@ -638,17 +643,3 @@ func endsWithReturn(stmts []ast.Stmt) bool {
 func encodeIdent(name string) string {
 	return strings.Replace(url.QueryEscape(name), "%", "$", -1)
 }
-
-type varsByName []*types.Var
-
-func (s varsByName) Len() int {
-	return len(s)
-}
-
-func (s varsByName) Swap(i, j int) {
-	s[i], s[j] = s[j], s[i]
-}
-
-func (s varsByName) Less(i, j int) bool {
-	return s[i].Name() < s[j].Name()
-}
