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DisableSyntax

This rule reports errors when a "disallowed" syntax is used. This is a syntactic rule, which means it does not require compilation to run unlike the Disable rule.

Example:

MyCode.scala:10: error: [DisableSyntax.throw] exceptions should be avoided,
                        consider encoding the error in the return type instead
  throw new IllegalArgumentException
  ^^^^^

Configuration

By default, this rule does not disable any particular syntax, every setting is opt-in.

Name	Type	Description
noVars	Boolean	Report error for usage of vars.
noThrows	Boolean	Report error for throwing exceptions.
noNulls	Boolean	Report error for usage of null.
noReturns	Boolean	Report error for usage of return.
noWhileLoops	Boolean	Report error for usage of while loops.
noAsInstanceOf	Boolean	Report error for usage of asInstanceOf[T] casts.
noIsInstanceOf	Boolean	Report error for usage of isInstanceOf[T] checks.
noXml	Boolean	Report error on xml literals.
noDefaultArgs	Boolean	Report error on method parameters with default arguments.
noFinalVal	Boolean	Report error on `final` modifier for val definitions, see [motivation](https://github.com/sbt/zinc/issues/227)
noFinalize	Boolean	Reports error when finalize is overridden.
noValPatterns	Boolean	Report error when pattern matching in val assignment with non-tuple patterns.
noUniversalEquality	Boolean	Report error on `==` (universal equality)
noUniversalEqualityMessage	String	Reporter message for noUniversalEquality
regex	List[Regex]	Report error if the text contents of a source file matches a given regex.

Defaults

DisableSyntax.noVars = false
DisableSyntax.noThrows = false
DisableSyntax.noNulls = false
DisableSyntax.noReturns = false
DisableSyntax.noWhileLoops = false
DisableSyntax.noAsInstanceOf = false
DisableSyntax.noIsInstanceOf = false
DisableSyntax.noXml = false
DisableSyntax.noDefaultArgs = false
DisableSyntax.noFinalVal = false
DisableSyntax.noFinalize = false
DisableSyntax.noValPatterns = false
DisableSyntax.noUniversalEquality = false
DisableSyntax.noUniversalEqualityMessage = == and != are unsafe since they allow comparing two unrelated types
DisableSyntax.regex = []

Examples

DisableSyntax.noUniversalEquality = true
DisableSyntax.noUniversalEqualityMessage = "use === instead of =="
DisableSyntax.regex = [
  {
    id = "offensive"
    pattern = "[Pp]imp"
    message = "Please consider a less offensive word such as 'extension' or 'enrichment'"
  }
]

Regex

Regex patterns have 3 available ways to be configured. The example below shows 1 of each way.

DisableSyntax.regex = [
  {
    id = offensive
    pattern = "[Pp]imp"
    message = "Please consider a less offensive word than ${0} such as Extension"
  }
  "Await\\.result"
  {
    id = magicNumbers
    regex = {
      pattern = "(?:(?:[,(]\\s)|(?:^\\s*))+(\\d+(\\.\\d+)?)"
      captureGroup = 1
    }
    message = "Numbers ({$1} in this instance) should always have a named parameter attached, or be assigned to a val."
  }
]

1. The first way has an object providing an id, pattern, and message.
2. The second way is just the pattern. When this is used, the id is set equal to the pattern, and a generic message is provided for you.
3. The third way allows you to specify what capture-group the problematic piece of code is in, in case your regex is complicated and also matches characters not useful in an error message.

Error Messages

Error messages have access to the capture groups of the regex. To access the capture groups of the regex, use {$n} where n is the index of the capture group you wish to appear in that part of the message.

You can see this used in the 3rd example.