Style issues
- ''{0}'' can be used
Reports collection literals that can be replaced with an explicit Type.of(...) call.
- 'addAll(map/filter {})' can be replaced with 'mapTo/filterTo'
Reports calls to MutableCollection.addAll / += where the argument is a call to Iterable.map/filter.
- 'associate' can be replaced with 'associateBy' or 'associateWith'
Reports calls to associate() and associateTo() that can be replaced with associateBy() or associateWith().
- 'filterIsInstance' call with a class literal argument
Reports calls of the Kotlin standard library function filterIsInstance with a class literal argument.
- 'if' expression can be replaced with 'firstOrNull()'
Reports if expressions that check whether a list, array, or string is not empty and then return the first element or null.
- 'map' call can be replaced with 'forEach'
Reports map calls whose results are ignored and can be replaced with forEach.
- 'map.getOrDefault()' can be replaced with indexing and elvis operator
Replaces map.getOrDefault(key, defaultValue) function calls with an indexing and elvis operator (map[key] ?: defaultValue).
- 'rangeTo' or the '..' call should be replaced with '..<'
Reports calls to rangeTo or the .
- 'rangeTo' or the '..' call should be replaced with 'until'
Reports calls to rangeTo or the .
- 'readLine' can be replaced with 'readln' or 'readlnOrNull'
Reports calls to readLine() that can be replaced with readln() or readlnOrNull().
- Assert boolean could be replaced with assert equality
Reports calls to assertTrue() and assertFalse() that can be replaced with assert equality functions.
- Boolean expression can be simplified
Reports boolean expression parts that can be reduced to constants.
- Call chain on collection could be converted into 'Sequence' to improve performance
Reports call chain on a Collection that should be converted into Sequence.
- Call of 'toString' could be replaced with string template
Reports toString function calls that can be replaced with a string template.
- Collection literal can be replaced with a function call
Detects collection literals.
- Collection literal can be used
Reports calls to a companion object's of operator function that can be replaced with a collection literal.
- Collection literals can be used
Reports calls to collection factory functions that can be replaced with collection literal syntax.
- Convert to comparisons
Converts a range check (in) to two consecutive comparisons.
- Explicit backing fields can be used
Detects properties with backing fields and suggests a refactoring introducing backing fields explicitly using a field keyword.
- Explicit context argument can be implicit
Reports an explicit context argument that can be converted to an implicit one by wrapping the call in a context(...) { } block.
- Implicit context argument can be explicit
Reports an implicit context argument that can be converted to an explicit named argument.
- Multiple operators with different precedence
Reports binary expressions that consist of different operators without parentheses.
- Negated boolean expression can be simplified
Reports negated boolean expressions that can be simplified.
- Non-canonical modifier order
Reports modifiers that do not follow the order recommended by the style guide.
- Not-null assertion can be replaced with 'error()'
Reports not-null assertion (!!) calls that can be replaced with the elvis operator and error(...).
- Nullable value 'hashCode()' can be simplified
Reports value?.hashCode() ?: 0 and suggests replacing it with value.hashCode().
- Object literal can be converted to lambda
Reports anonymous object literals implementing a Java interface with a single abstract method that can be converted into a call with a lambda expression.
- Range can be converted to indices or iteration
Reports until and rangeTo operators that can be replaced with Collection.indices or iteration over collection inside for loop.
- Redundant parentheses
Reports expressions containing redundant parentheses.
- Replace 'contains' call with 'in' operator
Replaces contains member calls with an in operator.
- Replace 'map { it.key }.toSet()' with 'keys'
Reports map { it.key }.toSet() call chains on map receivers that could be replaced with keys.
- Replace 'mapIndexed' with List generator
Reports a mapIndexed call that can be replaced by List generator.
- Replace 'until' with '..<' operator
Reports until that can be replaced with ..< operator.
- Replace explicit backing field with private property
Detects explicit backing fields.
- Safe cast with 'return' should be replaced with 'if' type check
Reports safe cast with return that can be replaced with if type check.
- Sealed class can be converted to sealed interface
Reports sealed classes that have no properties and can be converted to sealed interfaces.
- Sealed interface can be converted to sealed class
Reports sealed interfaces that have no properties and can be converted to sealed classes.
- Suspicious 'asDynamic' member invocation
Reports usages of asDynamic function on a receiver of dynamic type.
- Trailing comma recommendations
Reports trailing commas that do not follow the recommended style guide.
- Two comparisons should be converted to a range check
Reports two consecutive comparisons that can be converted to a range check.
- Type conversion on collection literal can be removed
Flags chain expressions with collection literals that change the expression's type.
- Unsafe cast with 'return' should be replaced with the safe one
Reports an unsafe cast with return in variable assignments or in value arguments that can be replaced with a safe cast.
- Use destructuring declaration
Reports declarations that can be destructured.
- Variable declaration could be moved into 'when'
Reports variable declarations that can be moved inside a when expression.