fixes false positive in unconditional-recursion

rule/unconditional-recursion.go

@@ -61,8 +61,10 @@ func (w lintUnconditionalRecursionRule) Visit(node ast.Node) ast.Visitor {
 	case *ast.FuncDecl:
 		var rec *ast.Ident
 		switch {
-		case n.Recv == nil || n.Recv.NumFields() < 1 || len(n.Recv.List[0].Names) < 1:
+		case n.Recv == nil:
 			rec = nil
+		case n.Recv.NumFields() < 1 || len(n.Recv.List[0].Names) < 1:
+			rec = &ast.Ident{Name: "_"}
 		default:
 			rec = n.Recv.List[0].Names[0]
 		}

testdata/unconditional-recursion.go

@@ -178,3 +178,12 @@ func urn17(ch chan int) {
 	}
 	urn17(ch) // MATCH /unconditional recursive call/
 }
+
+// Tests for #596
+func (*fooType) BarFunc() {
+	BarFunc()
+}
+
+func (_ *fooType) BazFunc() {
+	BazFunc()
+}