Scalastyle

Rules

This is a collection of all the Scalastyle rules created by sonar-scala in the Scalastyle rules repository.

Avoid block imports Minor
Checks that block imports are not used.
Block imports, e.g. import a.{b, c} can lead to annoying merge errors in large code bases that are maintained by lot of developers. This rule allows to ensure that only single imports are used in order to minimize merge errors in import declarations.
org.scalastyle.scalariform.BlockImportChecker
Avoid curlies imports Minor
Checks that curlies imports are not used.
Curlies imports, e.g. import a.{b, c}, can lead to annoying merge errors in large code bases that are maintained by lot of developers. This rule allows to ensure that only single imports, no renaming and no hiding imports are used in order to minimize merge errors in import declarations.
org.scalastyle.scalariform.CurliesImportChecker
Avoid wildcard imports Minor
Avoid wildcard imports.
Importing all classes from a package or static members from a class leads to tight coupling between packages or classes and might lead to problems when a new version of a library introduces name clashes.
org.scalastyle.scalariform.UnderscoreImportChecker
Class name Minor
Check that class names match a regular expression.
The Scala style guide recommends that class names conform to certain standards.
org.scalastyle.scalariform.ClassNamesChecker
Class type parameter name Minor
Checks that type parameter to a class matches a regular expression.
Scala generic type names are generally single upper case letters. This check checks for classes and traits. Note that this check only checks the innermost type parameter, to allow for List[T].
org.scalastyle.scalariform.ClassTypeParameterChecker
Clone method Minor
Check that classes and objects do not define the clone() method.
The clone method is difficult to get right. You can use the copy constructor of case classes rather than implementing clone. For more information on clone(), see Effective Java by Joshua Bloch pages.
org.scalastyle.scalariform.NoCloneChecker
Covariant equals Minor
Check that classes and objects do not define equals without overriding equals(java.lang.Object).
Mistakenly defining a covariant equals() method without overriding method equals(java.lang.Object) can produce unexpected runtime behaviour.
org.scalastyle.scalariform.CovariantEqualsChecker
Cyclomatic complexity Minor
Checks that the cyclomatic complexity of a method does exceed a value.
If the code is too complex, then this can make code hard to read.
org.scalastyle.scalariform.CyclomaticComplexityChecker
Empty interpolated string Minor
The interpolation for this string literal is not necessary.
Empty interpolated strings are harder to read and not necessary.
org.scalastyle.scalariform.EmptyInterpolatedStringChecker
Equals hashCode Minor
Check that if a class implements either equals or hashCode, it should implement the other.
Defining either equals or hashCode in a class without defining the is a known source of bugs. Usually, when you define one, you should also define the other.
org.scalastyle.scalariform.EqualsHashCodeChecker
Field name Minor
Check that field names match a regular expression.
A consistent naming convention for field names can make code easier to read and understand.
org.scalastyle.scalariform.FieldNamesChecker
File length Minor
Check the number of lines in a file.
Files which are too long can be hard to read and understand.
org.scalastyle.file.FileLengthChecker
File line length Minor
Check the number of characters in a line.
Lines that are too long can be hard to read and horizontal scrolling is annoying.
org.scalastyle.file.FileLineLengthChecker
Finalize method Minor
Check that classes and objects do not define the finalize() method.
finalize() is called when the object is garbage collected, and garbage collection is not guaranteed to happen. It is therefore unwise to rely on code in finalize() method.
org.scalastyle.scalariform.NoFinalizeChecker
Group imports Minor
Checks that imports are grouped together, not throughout the file.
If imports are spread throughout the file, knowing what is in scope at any one place can be difficult to work out.
org.scalastyle.scalariform.ImportGroupingChecker
If block braces Minor
Checks that if statements have braces.
Some people find if clauses with braces easier to read.
The singleLineAllowed property allows if constructions of the type:
```
if (bool_expression) expression1 else expression2
```
The doubleLineAllowed property allows if constructions of the type:
```
if (bool_expression) expression1 else expression2
```
Note: If you intend to enable only if expressions in the format below, disable the IfBraceChecker altogether.
```
if (bool_expression) expression1 else expression2
```
org.scalastyle.scalariform.IfBraceChecker
Illegal imports Minor
Check that a class does not import certain classes.
Use of some classes can be discouraged for a project. For instance, use of sun._ is generally discouraged because they are internal to the JDK and can be changed.
org.scalastyle.scalariform.IllegalImportsChecker
Import Order Minor
Checks that imports are grouped and ordered according to the style configuration.
Consistent import ordering improves code readability and reduces unrelated changes in patches.
org.scalastyle.scalariform.ImportOrderChecker
Line contains Tab Minor
Check that there are no tabs in a file.
Some say that tabs are evil.
org.scalastyle.file.FileTabChecker
Literal passed as argument without name Minor
Checks that argument literals are named.
Nameless literals make code harder to understand (consider updateEntity(1, true) and updateEntity(id = 1, enabled = true)).
org.scalastyle.scalariform.NamedArgumentChecker
Long literal uppercase L Minor
Checks that if a long literal is used, then an uppercase L is used.
A lowercase L (l) can look similar to a number 1 with some fonts.
org.scalastyle.scalariform.UppercaseLChecker
Lowercase pattern match Minor
Checks that a case statement pattern match is not lower case, as this can cause confusion.
A lower case pattern match clause with no other tokens is the same as _; this is not true for patterns which start with an upper case letter. This can cause confusion, and may not be what was intended:
```
val foo = "foo"
val Bar = "bar"
"bar" match { case Bar => "we got bar" } // result = "we got bar"
"bar" match { case foo => "we got foo" } // result = "we got foo"
"bar" match { case `foo` => "we got foo" } // result = MatchError
```
This checker raises a warning with the second match. To fix it, use an identifier which starts with an upper case letter (best), use case _ or, if you wish to refer to the value, add a type : Any, e.g.:
```
val lc = "lc"
"something" match { case lc: Any => "lc" } // result = "lc"
"something" match { case _ => "lc" } // result = "lc"
```
org.scalastyle.scalariform.LowercasePatternMatchChecker
Magic Number Minor
Checks for use of magic numbers.
Replacing a magic number with a named constant can make code easier to read and understand, and can avoid some subtle bugs.
A simple assignment to a val is not considered to be a magic number, for example: val foo = 4 is not a magic number, but var foo = 4 is considered to be a magic number.
org.scalastyle.scalariform.MagicNumberChecker
Maximum parameters Minor
Maximum number of parameters for a method.
A method which has more than a certain number of parameters can be hard to understand.
org.scalastyle.scalariform.ParameterNumberChecker
Method argument name Minor
Check that method argument names match a regular expression.
The Scala style guide recommends that method argument names conform to certain standards.
org.scalastyle.scalariform.MethodArgumentNamesChecker
Method length Minor
Checks that methods do not exceed a maximum length.
Long methods can be hard to read and understand.
org.scalastyle.scalariform.MethodLengthChecker
Method name Minor
Check that method names match a regular expression.
The Scala style guide recommends that method names conform to certain standards. If the methods are overriding another method, and the overridden method cannot be changed, then use the ignoreOverride parameter.
org.scalastyle.scalariform.MethodNamesChecker
Multiple string literals Minor
Checks that a string literal does not appear multiple times.
Code duplication makes maintenance more difficult, so it can be better to replace the multiple occurrences with a constant.
org.scalastyle.scalariform.MultipleStringLiteralsChecker
Newline at EOF Minor
Checks that a file ends with a newline character.
Some version control systems don't cope well with files which don't end with a newline character.
org.scalastyle.file.NewLineAtEofChecker
No Newline at EOF Minor
Checks that a file does not end with a newline character.
Because Mirco Dotta wanted it.
org.scalastyle.file.NoNewLineAtEofChecker
No mutable fields Minor
Checks that classes and objects do not define mutable fields.
var (mutable fields) are deprecated if you're using a strict functional style.
org.scalastyle.scalariform.VarFieldChecker
No mutable local variables Minor
Checks that functions do not define mutable variables.
var (mutable local variables) are deprecated if you're using a strict functional style.
org.scalastyle.scalariform.VarLocalChecker
No redundant if expressions Minor
Checks that if expressions are not redundant, i.e. easily replaced by a variant of the condition.
If expressions with boolean constants in both branches can be eliminated without affecting readability. Prefer simply cond to if (cond) true else false and !cond to if (cond) false else true.
org.scalastyle.scalariform.RedundantIfChecker
No space after tokens Minor
Ensure single space after certain token(s).
Correct formatting can help readability.
org.scalastyle.scalariform.EnsureSingleSpaceAfterTokenChecker
No space before tokens Minor
Ensure single space before certain token(s).
Correct formatting can help readability.
org.scalastyle.scalariform.EnsureSingleSpaceBeforeTokenChecker
No use of Java @Deprecated Minor
Checks that Java @Deprecated is not used, Scala @deprecated should be used instead.
You should be using the Scala @deprecated instead.
org.scalastyle.scalariform.DeprecatedJavaChecker
No use of Java @Override Minor
Checks that Java @Override is not used.
You should be using the Scala override keyword instead.
org.scalastyle.scalariform.OverrideJavaChecker
No while loops Minor
Checks that while is not used.
while loops are deprecated if you're using a strict functional style.
org.scalastyle.scalariform.WhileChecker
No whitespace after left bracket ''['' Minor
No whitespace after left bracket ''[''.
If there is whitespace after a left bracket, this can be confusing to the reader.
org.scalastyle.scalariform.NoWhitespaceAfterLeftBracketChecker
No whitespace before left bracket ''['' Minor
No whitespace before left bracket ''[''.
If there is whitespace before a left bracket, this can be confusing to the reader.
org.scalastyle.scalariform.NoWhitespaceBeforeLeftBracketChecker
No whitespace before right bracket '']'' Minor
No whitespace before right bracket '']''.
If there is whitespace before a right bracket, this can be confusing to the reader.
org.scalastyle.scalariform.NoWhitespaceBeforeRightBracketChecker
Non ASCII characters are not allowed Minor
Some editors are unfriendly to non ASCII characters.
Scala allows unicode characters as operators and some editors misbehave when they see non-ascii character. In a project collaborated by a community of developers. This check can be helpful in such situations.
```
"value" match {
  case "value" => println("matched")
  ...
}
```
is preferred to
```
"value" match {
  case "value" ⇒ println("matched")
  ...
}
```
To fix it, replace the (unicode operator) ⇒ with =>.
org.scalastyle.scalariform.NonASCIICharacterChecker
Null Minor
Check that null is not used.
Scala discourages use of null, preferring Option.
org.scalastyle.scalariform.NullChecker
Number of methods in type Minor
Check that a class / trait / object does not have too many methods.
If a type declares too many methods, this can be an indication of bad design.
org.scalastyle.scalariform.NumberOfMethodsInTypeChecker
Number of types Minor
Checks that there are not too many types declared in a file.
If there are too many classes/objects defined in a single file, this can cause the code to be difficult to understand.
org.scalastyle.scalariform.NumberOfTypesChecker
Object name Minor
Check that object names match a regular expression.
The Scala style guide recommends that object names conform to certain standards.
org.scalastyle.scalariform.ObjectNamesChecker
Omit braces in case clauses Minor
Checks that braces aren't used in case clauses.
Braces aren't required in case clauses. They should be omitted according to Scala Style Guide.
org.scalastyle.scalariform.CaseBraceChecker
Package name Minor
Check that package names match a regular expression.
The Scala style guide recommends that package names conform to certain standards.
org.scalastyle.scalariform.PackageNamesChecker
Package object name Minor
Check that package object names match a regular expression.
The Scala style guide recommends that package object names conform to certain standards.
org.scalastyle.scalariform.PackageObjectNamesChecker
Pattern match align Minor
Check that pattern match arrows align.
Correct formatting can help readability.
org.scalastyle.scalariform.PatternMatchAlignChecker
Public method must have type Minor
Check that a method has an explicit return type, it is not inferred.
A public method declared on a type is effectively an API declaration. Explicitly declaring a return type means that other code which depends on that type won't break unexpectedly.
org.scalastyle.scalariform.PublicMethodsHaveTypeChecker
Redundant braces in class definition Minor
If a class/trait has no members, the braces are unnecessary.
If a class / trait has no members, then braces are unnecessary, and can be removed.
org.scalastyle.scalariform.EmptyClassChecker
Regular expression in a token Minor
Checks that a regular expression cannot be matched in a token, if found reports this.
Some checks can be carried by just the presence of a particular token.
org.scalastyle.scalariform.TokenChecker
Return Minor
Check that return is not used.
Use of return is not usually necessary in Scala. In fact, use of return can discourage a functional style of programming.
org.scalastyle.scalariform.ReturnChecker
Simplify Boolean expression Minor
Boolean expression can be simplified.
A boolean expression which can be simplified can make code easier to read.
org.scalastyle.scalariform.SimplifyBooleanExpressionChecker
Space after plus Minor
Check that the plus sign is followed by a space.
An expression with spaces around + can be easier to read.
org.scalastyle.scalariform.SpacesAfterPlusChecker
Space after the start of the comment Minor
Checks a space after the start of the comment.
To bring consistency with how comments should be formatted, leave a space right after the beginning of the comment.
```
package foobar

object Foobar {
  /**WRONG
    *
    */
  /** Correct
    *
    */
  val d = 2 /*Wrong*/ //Wrong
  /**
    * Correct
    */
  val e = 3 /** Correct*/ // Correct
}
```
org.scalastyle.scalariform.SpaceAfterCommentStartChecker
Space after tokens Minor
Disallow space after certain token(s).
Correct formatting can help readability.
org.scalastyle.scalariform.DisallowSpaceAfterTokenChecker
Space before plus Minor
Check that the plus sign is preceded by a space.
An expression with spaces around + can be easier to read.
org.scalastyle.scalariform.SpacesBeforePlusChecker
Space before tokens Minor
Disallow space before certain token(s).
Correct formatting can help readability.
org.scalastyle.scalariform.DisallowSpaceBeforeTokenChecker
Structural type Minor
Check that structural types are not used.
Structural types in Scala can use reflection - this can have unexpected performance consequences. Warning: This check can also wrongly pick up type lamdbas and other such constructs. This checker should be used with care. You always have the alternative of the scalac checking for structural types.
org.scalastyle.scalariform.StructuralTypeChecker
TODO/FIXME comment Minor
Check for use of TODO/FIXME single line comments.
Some projects may consider TODO or FIXME comments in a code bad style. They would rather you fix the problem.
org.scalastyle.scalariform.TodoCommentChecker
Usage of ??? operator Minor
Checks that the code does not have ??? operators.
The ??? operator denotes that an implementation is missing. This rule helps to avoid potential runtime errors because of not implemented code.
org.scalastyle.scalariform.NotImplementedErrorUsage
Use : Unit = for procedures Minor
Use a : Unit = for procedure declarations.
A procedure style declaration can cause confusion - the developer may have simply forgotten to add a =, and now their method returns Unit rather than the inferred type:
```
def foo() { println("hello"); 5 }
```
This checker raises a warning with the first line. To fix it, use an explicit return type, or add a = before the body.
```
def foo() = { println("hello"); 5 }
```
org.scalastyle.scalariform.ProcedureDeclarationChecker
Use braces in for comprehensions Minor
Checks that braces are used in for comprehensions.
Usage of braces (rather than parentheses) within a for comprehension mean that you don't have to specify a semi-colon at the end of every line:
```
for { // braces
  t <- List(1,2,3)
  if (t % 2 == 0)
} yield t
```
is preferred to
```
for ( // parentheses
  t <- List(1,2,3);
  if (t % 2 == 0)
) yield t
```
To fix it, replace the () with {}. And then remove the ; at the end of the lines.
The singleLineAllowed property allows for constructions of the type:
```
for (i <- List(1,2,3)) yield i
```
org.scalastyle.scalariform.ForBraceChecker
Use correct indentation Minor
Checks that lines are indented by a multiple of the tab size.
Code that is not indented consistently can be hard to read.
org.scalastyle.file.IndentationChecker
Use parentheses in for loops Minor
Checks that parentheses are used in for loops.
For-comprehensions which lack a yield clause is actually a loop rather than a functional comprehension and it is usually more readable to string the generators together between parentheses rather than using the syntactically-confusing } { construct:
```
for (x <- board.rows; y <- board.files) {
  printf("(%d, %d)", x, y)
}
```
is preferred to
```
for {
  x <- board.rows
  y <- board.files
} {
  printf("(%d, %d)", x, y)
}
```
org.scalastyle.scalariform.ForLoopChecker
While body should have braces Minor
Checks that while body have braces.
While cannot be used in a pure-functional manner, that's why it's recommended to never omit braces according to Scala Style Guide.
org.scalastyle.scalariform.WhileBraceChecker
Whitespace at end of line Minor
Check that there is no trailing whitespace at the end of lines.
Whitespace at the end of a line can cause problems when diffing between files or between versions.
org.scalastyle.file.WhitespaceEndOfLineChecker
XML literals Minor
Check that XML literals are not used.
Some projects prefer not to have XML literals. They could use a templating engine instead.
org.scalastyle.scalariform.XmlLiteralChecker

Templates

Class name Minor template
Check that class names match a regular expression.
The Scala style guide recommends that class names conform to certain standards.
org.scalastyle.scalariform.ClassNamesChecker-template
Class type parameter name Minor template
Checks that type parameter to a class matches a regular expression.
Scala generic type names are generally single upper case letters. This check checks for classes and traits. Note that this check only checks the innermost type parameter, to allow for List[T].
org.scalastyle.scalariform.ClassTypeParameterChecker-template
Cyclomatic complexity Minor template
Checks that the cyclomatic complexity of a method does exceed a value.
If the code is too complex, then this can make code hard to read.
org.scalastyle.scalariform.CyclomaticComplexityChecker-template
Field name Minor template
Check that field names match a regular expression.
A consistent naming convention for field names can make code easier to read and understand.
org.scalastyle.scalariform.FieldNamesChecker-template
File length Minor template
Check the number of lines in a file.
Files which are too long can be hard to read and understand.
org.scalastyle.file.FileLengthChecker-template
File line length Minor template
Check the number of characters in a line.
Lines that are too long can be hard to read and horizontal scrolling is annoying.
org.scalastyle.file.FileLineLengthChecker-template
If block braces Minor template
Checks that if statements have braces.
Some people find if clauses with braces easier to read.
The singleLineAllowed property allows if constructions of the type:
```
if (bool_expression) expression1 else expression2
```
The doubleLineAllowed property allows if constructions of the type:
```
if (bool_expression) expression1 else expression2
```
Note: If you intend to enable only if expressions in the format below, disable the IfBraceChecker altogether.
```
if (bool_expression) expression1 else expression2
```
org.scalastyle.scalariform.IfBraceChecker-template
Illegal imports Minor template
Check that a class does not import certain classes.
Use of some classes can be discouraged for a project. For instance, use of sun._ is generally discouraged because they are internal to the JDK and can be changed.
org.scalastyle.scalariform.IllegalImportsChecker-template
Literal passed as argument without name Minor template
Checks that argument literals are named.
Nameless literals make code harder to understand (consider updateEntity(1, true) and updateEntity(id = 1, enabled = true)).
org.scalastyle.scalariform.NamedArgumentChecker-template
Magic Number Minor template
Checks for use of magic numbers.
Replacing a magic number with a named constant can make code easier to read and understand, and can avoid some subtle bugs.
A simple assignment to a val is not considered to be a magic number, for example: val foo = 4 is not a magic number, but var foo = 4 is considered to be a magic number.
org.scalastyle.scalariform.MagicNumberChecker-template
Match Header Minor template
Check the first lines of each file matches the text.
A lot of projects require a header with a copyright notice, or they require a license in each file. This does a simple text comparison between the header and the first lines of the file. You can have multiple lines, but make sure you surround the text with a CDATA section. You can also specify a regular expression, as long as you set the regex parameter to true.
org.scalastyle.file.HeaderMatchesChecker-template
Maximum parameters Minor template
Maximum number of parameters for a method.
A method which has more than a certain number of parameters can be hard to understand.
org.scalastyle.scalariform.ParameterNumberChecker-template
Method argument name Minor template
Check that method argument names match a regular expression.
The Scala style guide recommends that method argument names conform to certain standards.
org.scalastyle.scalariform.MethodArgumentNamesChecker-template
Method length Minor template
Checks that methods do not exceed a maximum length.
Long methods can be hard to read and understand.
org.scalastyle.scalariform.MethodLengthChecker-template
Method name Minor template
Check that method names match a regular expression.
The Scala style guide recommends that method names conform to certain standards. If the methods are overriding another method, and the overridden method cannot be changed, then use the ignoreOverride parameter.
org.scalastyle.scalariform.MethodNamesChecker-template
Missing or badly formed ScalaDoc Minor template
Checks that the ScalaDoc on documentable members is well-formed.
Scaladoc is generally considered a good thing. Within reason.
Ignore tokens is a comma separated string that may include the following: PatDefOrDcl (variables), TmplDef (classes, traits), TypeDefOrDcl (type definitions), FunDefOrDcl (functions). Supported indentation styles are "scaladoc" (for ScalaDoc-style comments, with two spaces before the asterisk), "javadoc" (for JavaDoc-style comments, with a single space before the asterisk) or "anydoc" to support any style (any number of spaces before the asterisk). For backwards compatibility, if left empty, "anydoc" will be assumed.
org.scalastyle.scalariform.ScalaDocChecker-template
Multiple string literals Minor template
Checks that a string literal does not appear multiple times.
Code duplication makes maintenance more difficult, so it can be better to replace the multiple occurrences with a constant.
org.scalastyle.scalariform.MultipleStringLiteralsChecker-template
Non ASCII characters are not allowed Minor template
Some editors are unfriendly to non ASCII characters.
Scala allows unicode characters as operators and some editors misbehave when they see non-ascii character. In a project collaborated by a community of developers. This check can be helpful in such situations.
```
"value" match {
  case "value" => println("matched")
  ...
}
```
is preferred to
```
"value" match {
  case "value" ⇒ println("matched")
  ...
}
```
To fix it, replace the (unicode operator) ⇒ with =>.
org.scalastyle.scalariform.NonASCIICharacterChecker-template
Null Minor template
Check that null is not used.
Scala discourages use of null, preferring Option.
org.scalastyle.scalariform.NullChecker-template
Number of methods in type Minor template
Check that a class / trait / object does not have too many methods.
If a type declares too many methods, this can be an indication of bad design.
org.scalastyle.scalariform.NumberOfMethodsInTypeChecker-template
Number of types Minor template
Checks that there are not too many types declared in a file.
If there are too many classes/objects defined in a single file, this can cause the code to be difficult to understand.
org.scalastyle.scalariform.NumberOfTypesChecker-template
Object name Minor template
Check that object names match a regular expression.
The Scala style guide recommends that object names conform to certain standards.
org.scalastyle.scalariform.ObjectNamesChecker-template
Package name Minor template
Check that package names match a regular expression.
The Scala style guide recommends that package names conform to certain standards.
org.scalastyle.scalariform.PackageNamesChecker-template
Package object name Minor template
Check that package object names match a regular expression.
The Scala style guide recommends that package object names conform to certain standards.
org.scalastyle.scalariform.PackageObjectNamesChecker-template
Public method must have type Minor template
Check that a method has an explicit return type, it is not inferred.
A public method declared on a type is effectively an API declaration. Explicitly declaring a return type means that other code which depends on that type won't break unexpectedly.
org.scalastyle.scalariform.PublicMethodsHaveTypeChecker-template
Regular expression Minor template
Checks that a regular expression cannot be matched, if found reports this.
Some checks can be carried out with a regular expression.
org.scalastyle.file.RegexChecker-template
Regular expression in a token Minor template
Checks that a regular expression cannot be matched in a token, if found reports this.
Some checks can be carried by just the presence of a particular token.
org.scalastyle.scalariform.TokenChecker-template
TODO/FIXME comment Minor template
Check for use of TODO/FIXME single line comments.
Some projects may consider TODO or FIXME comments in a code bad style. They would rather you fix the problem.
org.scalastyle.scalariform.TodoCommentChecker-template
Use braces in for comprehensions Minor template
Checks that braces are used in for comprehensions.
Usage of braces (rather than parentheses) within a for comprehension mean that you don't have to specify a semi-colon at the end of every line:
```
for { // braces
  t <- List(1,2,3)
  if (t % 2 == 0)
} yield t
```
is preferred to
```
for ( // parentheses
  t <- List(1,2,3);
  if (t % 2 == 0)
) yield t
```
To fix it, replace the () with {}. And then remove the ; at the end of the lines.
The singleLineAllowed property allows for constructions of the type:
```
for (i <- List(1,2,3)) yield i
```
org.scalastyle.scalariform.ForBraceChecker-template
Use correct indentation Minor template
Checks that lines are indented by a multiple of the tab size.
Code that is not indented consistently can be hard to read.
org.scalastyle.file.IndentationChecker-template
Whitespace at end of line Minor template
Check that there is no trailing whitespace at the end of lines.
Whitespace at the end of a line can cause problems when diffing between files or between versions.
org.scalastyle.file.WhitespaceEndOfLineChecker-template

#Rules

#Templates

Rules

Templates