Fixed #1426

Signed-off-by: Vishal Rana <vr@labstack.com>

.travis.yml

@@ -1,10 +1,8 @@
 language: go
 go:
-  - 1.11.x
   - 1.12.x
+  - 1.13.x
   - tip
-env:
-  - GO111MODULE=on
 install:
   - go get -v golang.org/x/lint/golint
 script:

echo.go

@@ -354,10 +354,14 @@ func (e *Echo) DefaultHTTPErrorHandler(err error, c Context) {
 			Message: http.StatusText(http.StatusInternalServerError),
 		}
 	}
+
+	// Issue #1426
+	code := he.Code
+	message := he.Message
 	if e.Debug {
-		he.Message = err.Error()
-	} else if m, ok := he.Message.(string); ok {
-		he.Message = Map{"message": m}
+		message = err.Error()
+	} else if m, ok := message.(string); ok {
+		message = Map{"message": m}
 	}
 
 	// Send response
@@ -365,7 +369,7 @@ func (e *Echo) DefaultHTTPErrorHandler(err error, c Context) {
 		if c.Request().Method == http.MethodHead { // Issue #608
 			err = c.NoContent(he.Code)
 		} else {
-			err = c.JSON(he.Code, he.Message)
+			err = c.JSON(code, message)
 		}
 		if err != nil {
 			e.Logger.Error(err)