diff --git a/expr.go b/expr.go
index 22982ba..cb4e050 100644
--- a/expr.go
+++ b/expr.go
@@ -33,7 +33,7 @@ func parseExpr(expr string) (*Expr, error) {
 	s := expr
 	_, err := p.parseExprNode(&s, e)
 	if err != nil {
-		return nil, fmt.Errorf("%q (syntax error): %s", expr, err.Error())
+		return nil, err
 	}
 	sortPriority(e.RightOperand())
 	err = p.checkSyntax()
@@ -146,9 +146,8 @@ func (p *Expr) parseExprNode(expr *string, e ExprNode) (ExprNode, error) {
 		}
 	}
 	if operand == nil {
-		return nil, fmt.Errorf("parsing pos: %q", *expr)
+		return nil, fmt.Errorf("syntax error: %q", *expr)
 	}
-
 	trimLeftSpace(expr)
 	operator := p.parseOperator(expr)
 	if operator == nil {
diff --git a/tagexpr.go b/tagexpr.go
index b1ab939..66c9639 100644
--- a/tagexpr.go
+++ b/tagexpr.go
@@ -52,6 +52,7 @@ type structVM struct {
 	exprs                      map[string]*Expr
 	exprSelectorList           []string
 	ifaceTagExprGetters        []func(unsafe.Pointer, string, func(*TagExpr, error) error) error
+	err                        error
 }
 
 // fieldVM tag expression set of struct field
@@ -141,6 +142,9 @@ func (vm *VM) Run(structPtrOrReflectValue interface{}) (*TagExpr, error) {
 		}
 		vm.rw.Unlock()
 	}
+	if s.err != nil {
+		return nil, s.err
+	}
 	return s.newTagExpr(ptr, ""), nil
 }
 
@@ -258,6 +262,9 @@ func (vm *VM) subRun(path string, t reflect.Type, tid uintptr, ptr unsafe.Pointe
 		}
 		vm.rw.Unlock()
 	}
+	if s.err != nil {
+		return nil, s.err
+	}
 	return s.newTagExpr(ptr, path), nil
 }
 
@@ -269,7 +276,7 @@ func (vm *VM) registerStructLocked(structType reflect.Type) (*structVM, error) {
 	tid := ameda.RuntimeTypeID(structType)
 	s, had := vm.structJar[tid]
 	if had {
-		return s, nil
+		return s, s.err
 	}
 	s = vm.newStructVM()
 	s.name = structType.String()
@@ -281,6 +288,7 @@ func (vm *VM) registerStructLocked(structType reflect.Type) (*structVM, error) {
 		structField = structType.Field(i)
 		field, err := s.newFieldVM(structField)
 		if err != nil {
+			s.err = err
 			return nil, err
 		}
 		switch field.elemKind {
@@ -290,6 +298,7 @@ func (vm *VM) registerStructLocked(structType reflect.Type) (*structVM, error) {
 			case reflect.Struct:
 				sub, err = vm.registerStructLocked(field.structField.Type)
 				if err != nil {
+					s.err = err
 					return nil, err
 				}
 				s.mergeSubStructVM(field, sub)
@@ -307,6 +316,7 @@ func (vm *VM) registerStructLocked(structType reflect.Type) (*structVM, error) {
 		case reflect.Array, reflect.Slice, reflect.Map:
 			err = vm.registerIndirectStructLocked(field)
 			if err != nil {
+				s.err = err
 				return nil, err
 			}
 		}
diff --git a/tagparser.go b/tagparser.go
index 66d098b..864d85a 100644
--- a/tagparser.go
+++ b/tagparser.go
@@ -60,10 +60,10 @@ func parseTag(tag string) (map[string]string, error) {
 		}
 		key, val := splitExpr(one)
 		if val == "" {
-			return nil, fmt.Errorf("%q (syntax error): expression string can not be empty", tag)
+			return nil, fmt.Errorf("syntax error: %q expression string can not be empty", tag)
 		}
 		if _, ok := kvs[key]; ok {
-			return nil, fmt.Errorf("%q (syntax error): duplicate expression name %q", tag, key)
+			return nil, fmt.Errorf("syntax error: %q duplicate expression name %q", tag, key)
 		}
 		kvs[key] = val
 	}
@@ -121,7 +121,7 @@ func readOneExpr(tag *string) (string, error) {
 			patch++
 		}
 	}
-	return "", fmt.Errorf("%q (syntax error): unclosed single quote \"'\"", s)
+	return "", fmt.Errorf("syntax error: %q unclosed single quote \"'\"", s)
 }
 
 func trimLeftSpace(p *string) *string {
diff --git a/validator/validator_test.go b/validator/validator_test.go
index d186835..c941537 100644
--- a/validator/validator_test.go
+++ b/validator/validator_test.go
@@ -290,3 +290,12 @@ func TestIssue30(t *testing.T) {
 	assert.EqualError(t, vd.Validate(&TStruct{TOk: "1"}), "invalid parameter: TOk")
 	// assert.NoError(t, vd.Validate(&TStruct{TOk: "1", TFail: "1"}))
 }
+
+func TestIssue31(t *testing.T) {
+	type TStruct struct {
+		A []int32 `vd:"$ == nil || ($ != nil && range($, in(#v, 1, 2, 3))"`
+	}
+	assert.EqualError(t, vd.Validate(&TStruct{A: []int32{1}}), "syntax error: \"($ != nil && range($, in(#v, 1, 2, 3))\"")
+	assert.EqualError(t, vd.Validate(&TStruct{A: []int32{1}}), "syntax error: \"($ != nil && range($, in(#v, 1, 2, 3))\"")
+	assert.EqualError(t, vd.Validate(&TStruct{A: []int32{1}}), "syntax error: \"($ != nil && range($, in(#v, 1, 2, 3))\"")
+}