Intellij无法识别Scala List运算符

Question

Here is the intellij warning :

When overing "::" Intellij display this message : Cannot resolve symbol ::

I have scala + sbt plugins correctly installed.

How can i fix this error ?

Answer 1

Your code is incorrect : :: is a method on List , not on Integer . Your last element must be an instance of List .

Either of those will work :

val otherList = 3::2::List(3)

or

val otherList = 3::2::3::Nil

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Note that :: is called on List and not the Integer because it is right-associative.

From the Scala Specification ( Infix Operations , 6.12.3) :

The associativity of an operator is determined by the operator's last character. Operators ending in a colon ':' are right-associative. All other operators are left-associative.