description:
syntax error issue in variable expression builder [0802]

build:
2.5.2.v20100203-0630

steps to reproduce:
1. new a variable with default value: birtdatetime.year()+123
2. validate in expression build
3. preview in web viewer

actual result:
no error in expression build, but exception pops up in preview

expect result:
syntax error should pop up in expression build
the ckeck pnly check the syntax error,not check the runtime error.
closed the bug