From cd7f58ae22a760546ad3c4e33463113873f43ed2 Mon Sep 17 00:00:00 2001
From: Ilya Vlasov <55441714+GirZ0n@users.noreply.github.com>
Date: Thu, 16 Nov 2023 15:28:48 +0400
Subject: [PATCH] docs: add a readme with inspection descriptions
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+# Inspection descriptions
+This README file contains descriptions of all inspections in the [config](./Custom_Inspections.xml) file.
+
+> [!NOTE]
+> This file, as well as the config file, contains only the most common inspections, that have been adapted for better teaching experience.
+> For a complete list of inspections available in the IntelliJ platform, see the Kotlin Inspections tab (Settings -> Editor -> Inspections -> Kotlin).
+
+The `Severity` field (`level` in the config file) indicates how the inspections will be displayed in the upper right corner of the editor and in the Problems tab. Some of the possible values are:
+| Name | Config name | Example |
+|--------------|--------------|-----------------------------------------------------------------------------------------------------------------------------------------------------|
+| Error | ERROR | 
|
+| Warning | WARNING | 
|
+| Weak Warning | WEAK WARNING | 
|
+
+The `Highlighting` field (`editorAttributes` in the config file) indicates how the inspection will be highlighted in the IDE. Some of the possible values are:
+| Name | Config name | Example |
+|---------------|-------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------|
+| Error | ERRORS_ATTRIBUTES | 
|
+| Warning | WARNING_ATTRIBUTES | 
|
+| Weak Warning | INFO_ATTRIBUTES | 
|
+| Strikethrough | MARKED_FOR_REMOVAL_ATTRIBUTES | 
|
+
+> [!NOTE]
+> To add a new inspection to the config file please use the Kotlin Inspections tab
+> where you could turn on/off an inspection and choose its severity and/or highlighting.
+
+## AddOperatorModifier
+
+**Severity**: Weak Warning
+**Highlighting**: Weak Warning
+
+
+Function should have 'operator' modifier
+
+Reports a function that matches one of the operator conventions but lacks the `operator` keyword.
+By adding the `operator` modifier, you might allow function consumers to write idiomatic Kotlin code.
+
+**Example:**
+
+```kotlin
+class Complex(val real: Double, val imaginary: Double) {
+ fun plus(other: Complex) =
+ Complex(real + other.real, imaginary + other.imaginary)
+}
+
+fun usage(a: Complex, b: Complex) {
+ a.plus(b)
+}
+```
+
+The quick-fix adds the `operator` modifier keyword:
+
+```kotlin
+class Complex(val real: Double, val imaginary: Double) {
+ operator fun plus(other: Complex) =
+ Complex(real + other.real, imaginary + other.imaginary)
+}
+
+fun usage(a: Complex, b: Complex) {
+ a + b
+}
+```
+
+
+
+## AddVarianceModifier
+
+**Severity**: Weak Warning
+**Highlighting**: Weak Warning
+
+
+Type parameter can have 'in' or 'out' variance
+
+Reports type parameters that can have `in` or `out` variance.
+Using `in` and `out` variance provides more precise type inference in Kotlin and clearer code semantics.
+
+**Example:**
+
+```kotlin
+class Box(val obj: T)
+
+fun consumeString(box: Box) {}
+fun consumeCharSequence(box: Box) {}
+
+fun usage(box: Box) {
+ consumeString(box)
+ consumeCharSequence(box) // Compilation error
+}
+```
+
+The quick-fix adds the matching variance modifier:
+
+```kotlin
+class Box(val obj: T)
+
+fun consumeString(box: Box) {}
+fun consumeCharSequence(box: Box) {}
+
+fun usage(box: Box) ++{
+ consumeString(box)
+ consumeCharSequence(box) // OK
+}
+```
+
+
+
+## CanBeParameter
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Constructor parameter is never used as a property
+
+Reports primary constructor parameters that can have `val` or `var` removed.
+
+Class properties declared in the constructor increase memory consumption.
+If the parameter value is only used in the constructor, you can omit them.
+
+Note that the referenced object might be garbage-collected earlier.
+
+**Example:**
+
+```kotlin
+class Task(val name: String) {
+ init {
+ print("Task created: $name")
+ }
+}
+```
+
+The quick-fix removes the extra `val` or `var` keyword:
+
+```kotlin
+class Task(name: String) {
+ init {
+ print("Task created: $name")
+ }
+}
+```
+
+
+
+## CanBePrimaryConstructorProperty
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Property is explicitly assigned to constructor parameter
+
+Reports properties that are explicitly assigned to primary constructor parameters.
+Properties can be declared directly in the primary constructor, reducing the amount of code and increasing code readability.
+
+**Example:**
+
+```kotlin
+class User(name: String) {
+ val name = name
+}
+```
+
+The quick-fix joins the parameter and property declaration into a primary constructor parameter:
+
+```kotlin
+class User(val name: String) {
+}
+```
+
+
+
+## CanBeVal
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Local 'var' is never modified and can be declared as 'val'
+
+Reports local variables declared with the `var` keyword that are never modified.
+Kotlin encourages to declare practically immutable variables using the `val` keyword, ensuring that their value will never change.
+
+**Example:**
+
+```kotlin
+fun example() {
+ var primeNumbers = listOf(1, 2, 3, 5, 7, 11, 13)
+ var fibonacciNumbers = listOf(1, 1, 2, 3, 5, 8, 13)
+ print("Same numbers: " + primeNumbers.intersect(fibonacciNumbers))
+}
+```
+
+The quick-fix replaces the `var` keyword with `val`:
+
+```kotlin
+fun example() {
+ val primeNumbers = listOf(1, 2, 3, 5, 7, 11, 13)
+ val fibonacciNumbers = listOf(1, 1, 2, 3, 5, 8, 13)
+ print("Same numbers: " + primeNumbers.intersect(fibonacciNumbers))
+}
+```
+
+
+
+## CascadeIf
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Cascade 'if' can be replaced with 'when'
+
+Reports `if` statements with three or more branches that can be replaced with the `when` expression.
+**Example:**
+
+```kotlin
+fun checkIdentifier(id: String) {
+ fun Char.isIdentifierStart() = this in 'A'..'z'
+ fun Char.isIdentifierPart() = isIdentifierStart() || this in '0'..'9'
+
+ if (id.isEmpty()) {
+ print("Identifier is empty")
+ } else if (!id.first().isIdentifierStart()) {
+ print("Identifier should start with a letter")
+ } else if (!id.subSequence(1, id.length).all(Char::isIdentifierPart)) {
+ print("Identifier should contain only letters and numbers")
+ }
+}
+```
+
+The quick-fix converts the `if` expression to `when`:
+
+```kotlin
+fun checkIdentifier(id: String) {
+ fun Char.isIdentifierStart() = this in 'A'..'z'
+ fun Char.isIdentifierPart() = isIdentifierStart() || this in '0'..'9'
+
+ when {
+ id.isEmpty() -> {
+ print("Identifier is empty")
+ }
+ !id.first().isIdentifierStart() -> {
+ print("Identifier should start with a letter")
+ }
+ !id.subSequence(1, id.length).all(Char::isIdentifierPart) -> {
+ print("Identifier should contain only letters and numbers")
+ }
+ }
+}
+```
+
+
+
+## ClassName
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Class naming convention
+
+Reports class names that do not follow the recommended naming conventions.
+
+Consistent naming allows for easier code reading and understanding.
+According to the [Kotlin official style guide](https://kotlinlang.org/docs/coding-conventions.html#naming-rules),
+class names should start with an uppercase letter and use camel case.
+
+It is possible to introduce other naming rules by changing the "Pattern" regular expression.
+
+**Example:**
+
+```kotlin
+class user(val name: String)
+```
+
+The quick-fix renames the class according to the Kotlin naming conventions:
+
+```kotlin
+class User(val name: String)
+```
+
+
+
+## ControlFlowWithEmptyBody
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Control flow with empty body
+
+Reports `if`, `while`, `do` or `for` statements with empty bodies.
+While occasionally intended, this construction is confusing and often the result of a typo.
+
+The quick-fix removes a statement.
+
+**Example:**
+
+```kotlin
+if (a > b) {}
+```
+
+
+
+## ConvertLambdaToReference
+
+**Severity**: Information
+**Highlighting**: None
+
+
+Can be replaced with function reference
+
+Reports function literal expressions that can be replaced with function references.
+Replacing lambdas with function references often makes code look more concise and understandable.
+
+**Example:**
+
+```kotlin
+fun Int.isEven() = this % 2 == 0
+
+fun example() {
+ val numbers = listOf(1, 2, 4, 7, 9, 10)
+ val evenNumbers = numbers.filter { it.isEven() }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun Int.isEven() = this % 2 == 0
+
+fun example() {
+ val numbers = listOf(1, 2, 4, 7, 9, 10)
+ val evenNumbers = numbers.filter(Int::isEven)
+}
+```
+
+
+
+## ConvertPairConstructorToToFunction
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Convert Pair constructor to 'to' function
+
+Reports a `Pair` constructor invocation that can be replaced with a `to()` infix function call.
+
+Explicit constructor invocations may add verbosity, especially if they are used multiple times.
+Replacing constructor calls with `to()` makes code easier to read and maintain.
+
+**Example:**
+
+```kotlin
+val countries = mapOf(
+ Pair("France", "Paris"),
+ Pair("Spain", "Madrid"),
+ Pair("Germany", "Berlin")
+)
+```
+
+After the quick-fix is applied:
+
+```kotlin
+val countries = mapOf(
+ "France" to "Paris",
+ "Spain" to "Madrid",
+ "Germany" to "Berlin"
+)
+```
+
+
+
+## ConvertReferenceToLambda
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Can be replaced with lambda
+
+Reports a function reference expression that can be replaced with a function literal (lambda).
+
+Sometimes, passing a lambda looks more straightforward and more consistent with the rest of the code.
+Also, the fix might be handy if you need to replace a simple call with something more complex.
+
+**Example:**
+
+```kotlin
+fun Int.isEven() = this % 2 == 0
+
+fun example() {
+ val numbers = listOf(1, 2, 4, 7, 9, 10)
+ val evenNumbers = numbers.filter(Int::isEven)
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun Int.isEven() = this % 2 == 0
+
+fun example() {
+ val numbers = listOf(1, 2, 4, 7, 9, 10)
+ val evenNumbers = numbers.filter { it.isEven() }
+}
+```
+
+
+
+## ConvertTwoComparisonsToRangeCheck
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Two comparisons should be converted to a range check
+
+Reports two consecutive comparisons that can be converted to a range check.
+Checking against a range makes code simpler by removing test subject duplication.
+
+**Example:**
+
+```kotlin
+fun checkMonth(month: Int): Boolean {
+ return month >= 1 && month <= 12
+}
+```
+
+The quick-fix replaces the comparison-based check with a range one:
+
+```kotlin
+fun checkMonth(month: Int): Boolean {
+ return month in 1..12
+}
+```
+
+
+
+## Destructure
+
+**Severity**: Weak Warning
+**Highlighting**: Weak Warning
+
+
+Use destructuring declaration
+
+Reports declarations that can be destructured.
+**Example:**
+
+```kotlin
+data class My(val first: String, val second: Int, val third: Boolean)
+
+fun foo(list: List) {
+ list.forEach { my ->
+ println(my.second)
+ println(my.third)
+ }
+}
+```
+
+The quick-fix destructures the declaration and introduces new variables with names from the corresponding class:
+
+```kotlin
+data class My(val first: String, val second: Int, val third: Boolean)
+
+fun foo(list: List) {
+ list.forEach { (_, second, third) ->
+ println(second)
+ println(third)
+ }
+}
+```
+
+
+
+## ExplicitThis
+
+**Severity**: Error
+**Highlighting**: Strikethrough
+
+
+Redundant explicit 'this'
+
+Reports an explicit `this` when it can be omitted.
+**Example:**
+
+```kotlin
+class C {
+ private val i = 1
+ fun f() = this.i
+}
+```
+
+The quick-fix removes the redundant `this`:
+
+```kotlin
+class C {
+ private val i = 1
+ fun f() = i
+}
+```
+
+
+
+## ForEachParameterNotUsed
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Iterated elements are not used in forEach
+
+Reports `forEach` loops that do not use iterable values.
+**Example:**
+
+```kotlin
+listOf(1, 2, 3).forEach { }
+```
+
+The quick fix introduces anonymous parameter in the `forEach` section:
+
+```kotlin
+listOf(1, 2, 3).forEach { _ -> }
+```
+
+
+
+## FunctionName
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Function naming convention
+
+Reports function names that do not follow the recommended naming conventions.
+**Example:**
+
+```kotlin
+fun Foo() {}
+```
+
+To fix the problem change the name of the function to match the recommended naming conventions.
+
+
+
+## HasPlatformType
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Function or property has platform type
+
+Reports functions and properties that have a platform type.
+To prevent unexpected errors, the type should be declared explicitly.
+
+**Example:**
+
+```kotlin
+fun foo() = java.lang.String.valueOf(1)
+```
+
+The quick fix allows you to specify the return type:
+
+```kotlin
+fun foo(): String = java.lang.String.valueOf(1)
+```
+
+
+
+## ImplicitThis
+
+**Severity**: Weak Warning
+**Highlighting**: Weak Warning
+
+
+Implicit 'this'
+
+Reports usages of implicit **this**.
+**Example:**
+
+```kotlin
+class Foo {
+ fun s() = ""
+
+ fun test() {
+ s()
+ }
+}
+```
+
+The quick fix specifies **this** explicitly:
+
+```kotlin
+class Foo {
+ fun s() = ""
+
+ fun test() {
+ this.s()
+ }
+}
+```
+
+
+
+## IncompleteDestructuring
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Incomplete destructuring declaration
+
+Reports incomplete destructuring declaration.
+**Example:**
+
+```kotlin
+data class Person(val name: String, val age: Int)
+val person = Person("", 0)
+val (name) = person
+```
+
+The quick fix completes destructuring declaration with new variables:
+
+```kotlin
+data class Person(val name: String, val age: Int)
+val person = Person("", 0)
+val (name, age) = person
+```
+
+
+
+## IntroduceWhenSubject
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+when' that can be simplified by introducing an argument
+
+Reports a `when` expression that can be simplified by introducing a subject argument.
+**Example:**
+
+```kotlin
+fun test(obj: Any): String {
+ return when {
+ obj is String -> "string"
+ obj is Int -> "int"
+ else -> "unknown"
+ }
+}
+```
+
+The quick fix introduces a subject argument:
+
+```kotlin
+fun test(obj: Any): String {
+ return when (obj) {
+ is String -> "string"
+ is Int -> "int"
+ else -> "unknown"
+ }
+}
+```
+
+
+
+## JoinDeclarationAndAssignment
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Join declaration and assignment
+
+Reports property declarations that can be joined with the following assignment.
+**Example:**
+
+```kotlin
+val x: String
+x = System.getProperty("")
+```
+
+The quick fix joins the declaration with the assignment:
+
+```kotlin
+val x = System.getProperty("")
+```
+
+Configure the inspection:
+
+You can disable the option **Report with complex initialization of member properties** to skip properties with complex initialization. This covers two cases:
+
+1. The property initializer is complex (it is a multiline or a compound/control-flow expression)
+2. The property is first initialized and then immediately used in subsequent code (for example, to call additional initialization methods)
+
+
+
+## KDocUnresolvedReference
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Unresolved reference in KDoc
+
+Reports unresolved references in KDoc comments.
+**Example:**
+
+```kotlin
+/**
+ * [unresolvedLink]
+ */
+fun foo() {}
+```
+
+To fix the problem make the link valid.
+
+
+
+## KotlinConstantConditions
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Constant conditions
+
+Reports non-trivial conditions and values that are statically known to be always true, false, null or zero.
+While sometimes intended, often this is a sign of logical error in the program. Additionally,
+reports never reachable `when` branches and some expressions that are statically known to fail always.
+Examples:
+
+```kotlin
+fun process(x: Int?) {
+ val isNull = x == null
+ if (!isNull) {
+ if (x != null) {} // condition is always true
+ require(x!! < 0 && x > 10) // condition is always false
+ } else {
+ println(x!!) // !! operator will always fail
+ }
+}
+fun process(v: Any) {
+ when(v) {
+ is CharSequence -> println(v as Int) // cast will always fail
+ is String -> println(v) // branch is unreachable
+ }
+}
+```
+
+Uncheck the "Warn when constant is stored in variable" option to avoid reporting of variables having constant values not in conditions.
+
+New in 2021.3
+
+
+
+## KotlinDeprecation
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Usage of redundant or deprecated syntax or deprecated symbols
+
+Reports obsolete language features and unnecessarily verbose code constructs during the code cleanup operation (**Code | Code Cleanup**).
+
+The quick-fix automatically replaces usages of obsolete language features or unnecessarily verbose code constructs with compact and up-to-date syntax.
+
+It also replaces deprecated symbols with their proposed substitutions.
+
+
+
+## KotlinEqualsBetweenInconvertibleTypes
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+equals()' between objects of inconvertible types
+
+Reports calls to `equals()` where the receiver and the argument are
+of incompatible primitive, enum, or string types.
+
+While such a call might theoretically be useful, most likely it represents a bug.
+
+**Example:**
+
+```kotlin
+5.equals("");
+```
+
+
+
+## KotlinUnusedImport
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Unused import directive
+
+Reports redundant `import` statements.
+
+Default and unused imports can be safely removed.
+
+**Example:**
+
+```kotlin
+import kotlin.*
+import kotlin.collections.*
+import kotlin.comparisons.*
+import kotlin.io.*
+import kotlin.ranges.*
+import kotlin.sequences.*
+import kotlin.text.*
+
+// jvm specific
+import java.lang.*
+import kotlin.jvm.*
+
+// js specific
+import kotlin.js.*
+
+import java.io.* // this import is unused and could be removed
+import java.util.*
+
+fun foo(list: ArrayList) {
+ list.add("")
+}
+```
+
+
+
+## LiftReturnOrAssignment
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Return or assignment can be lifted out
+
+Reports `if`, `when`, and `try` statements that can be converted to expressions
+by lifting the `return` statement or an assignment out.
+**Example:**
+
+```kotlin
+fun foo(arg: Int): String {
+ when (arg) {
+ 0 -> return "Zero"
+ 1 -> return "One"
+ else -> return "Multiple"
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(arg: Int): String {
+ return when (arg) {
+ 0 -> "Zero"
+ 1 -> "One"
+ else -> "Multiple"
+ }
+}
+```
+
+If you would like this inspection to highlight more complex code with multi-statement branches, uncheck the option "Report only if each branch is a single statement".
+
+
+
+## LocalVariableName
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Local variable naming convention
+
+Reports local variables that do not follow the naming conventions.
+You can specify the required pattern in the inspection options.
+
+[Recommended naming conventions](https://kotlinlang.org/docs/coding-conventions.html#function-names): it has to start with a lowercase letter, use camel case and no underscores.
+
+**Example:**
+
+```kotlin
+fun fibonacciNumber(index: Int): Long = when(index) {
+ 0 -> 0
+ else -> {
+ // does not follow naming conventions: contains underscore symbol (`_`)
+ var number_one: Long = 0
+ // does not follow naming conventions: starts with an uppercase letter
+ var NUMBER_TWO: Long = 1
+ // follow naming conventions: starts with a lowercase letter, use camel case and no underscores.
+ var numberThree: Long = number_one + NUMBER_TWO
+
+ for(currentIndex in 2..index) {
+ numberThree = number_one + NUMBER_TWO
+ number_one = NUMBER_TWO
+ NUMBER_TWO = numberThree
+ }
+ numberThree
+ }
+}
+```
+
+
+
+## LoopToCallChain
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Loop can be replaced with stdlib operations
+
+Reports `for` loops that can be replaced with a sequence of stdlib operations (like `map`, `filter`, and so on).
+**Example:**
+
+```kotlin
+fun foo(list: List): List {
+ val result = ArrayList()
+ for (s in list) {
+ if (s.length > 0)
+ result.add(s.hashCode())
+ }
+ return result
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(list: List): List {
+ val result = list
+ .filter { it.length > 0 }
+ .map { it.hashCode() }
+ return result
+}
+```
+
+
+
+## MayBeConstant
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Might be 'const'
+
+Reports top-level `val` properties in objects that might be declared as `const`
+for better performance and Java interoperability.
+**Example:**
+
+```kotlin
+object A {
+ val foo = 1
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+object A {
+ const val foo = 1
+}
+```
+
+
+
+## MemberVisibilityCanBePrivate
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Class member can have 'private' visibility
+
+Reports declarations that can be made `private` to follow the encapsulation principle.
+**Example:**
+
+```kotlin
+class Service(val url: String) {
+ fun connect(): URLConnection = URL(url).openConnection()
+}
+```
+
+After the quick-fix is applied (considering there are no usages of `url` outside of `Service` class):
+
+```kotlin
+class Service(private val url: String) {
+ fun connect(): URLConnection = URL(url).openConnection()
+}
+```
+
+
+
+## MoveVariableDeclarationIntoWhen
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Variable declaration could be moved inside 'when'
+
+Reports variable declarations that can be moved inside a `when` expression.
+**Example:**
+
+```kotlin
+fun someCalc(x: Int) = x * 42
+
+fun foo(x: Int): Int {
+ val a = someCalc(x)
+ return when (a) {
+ 1 -> a
+ 2 -> 2 * a
+ else -> 24
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(x: Int): Int {
+ return when (val a = someCalc(x)) {
+ 1 -> a
+ 2 -> 2 * a
+ else -> 24
+ }
+}
+```
+
+
+
+## NestedLambdaShadowedImplicitParameter
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Nested lambda has shadowed implicit parameter
+
+Reports nested lambdas with shadowed implicit parameters.
+**Example:**
+
+```kotlin
+fun foo(listOfLists: List>) {
+ listOfLists.forEach {
+ it.forEach {
+ println(it)
+ }
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(listOfLists: List>) {
+ listOfLists.forEach {
+ it.forEach { it1 ->
+ println(it1)
+ }
+ }
+}
+```
+
+
+
+## PrivatePropertyName
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Private property naming convention
+
+Reports private property names that do not follow the recommended naming conventions.
+
+Consistent naming allows for easier code reading and understanding.
+According to the [Kotlin official style guide](https://kotlinlang.org/docs/coding-conventions.html#naming-rules),
+private property names should start with a lowercase letter and use camel case.
+Optionally, underscore prefix is allowed but only for **private** properties.
+
+It is possible to introduce other naming rules by changing the "Pattern" regular expression.
+
+**Example:**
+
+```kotlin
+val _My_Cool_Property = ""
+```
+
+The quick-fix renames the class according to the Kotlin naming conventions:
+
+```kotlin
+val _myCoolProperty = ""
+```
+
+
+
+## PublicApiImplicitType
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Public API declaration with implicit return type
+
+Reports `public` and `protected` functions and properties that have an implicit return type.
+For API stability reasons, it's recommended to specify such types explicitly.
+
+**Example:**
+
+```kotlin
+fun publicFunctionWhichAbusesTypeInference() =
+ otherFunctionWithNotObviousReturnType() ?: yetAnotherFunctionWithNotObviousReturnType()
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun publicFunctionWhichAbusesTypeInference(): **Api** =
+ otherFunctionWithNotObviousReturnType() ?: yetAnotherFunctionWithNotObviousReturnType()
+```
+
+
+
+## RedundantElseInIf
+
+**Severity**: Error
+**Highlighting**: Strikethrough
+
+
+Redundant 'else' in 'if'
+
+Reports redundant `else` in `if` with `return`
+
+**Example:**
+
+```kotlin
+fun foo(arg: Boolean): Int {
+ if (arg) return 0
+ else { // This else is redundant, code in braces could be just shifted left
+ someCode()
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(arg: Boolean): Int {
+ if (arg) return 0
+ someCode()
+}
+```
+
+
+
+## RedundantExplicitType
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Obvious explicit type
+
+Reports local variables' explicitly given types which are obvious and thus redundant, like `val f: Foo = Foo()`.
+
+**Example:**
+
+```kotlin
+class Point(val x: Int, val y: Int)
+
+fun foo() {
+ val t: **Boolean** = true
+ val p: **Point** = Point(1, 2)
+ val i: **Int** = 42
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+class Point(val x: Int, val y: Int)
+
+fun foo() {
+ val t = true
+ val p = Point(1, 2)
+ val i = 42
+}
+```
+
+
+
+## RedundantIf
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Redundant 'if' statement
+
+Reports `if` statements which can be simplified to a single statement.
+
+**Example:**
+
+```kotlin
+fun test(): Boolean {
+ if (foo()) {
+ return true
+ } else {
+ return false
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun test(): Boolean {
+ return foo()
+}
+```
+
+
+
+## RedundantNullableReturnType
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Redundant nullable return type
+
+Reports functions and variables with nullable return type which never return or become `null`.
+**Example:**
+
+```kotlin
+fun greeting(user: String): String? = "Hello, $user!"
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun greeting(user: String): String = "Hello, $user!"
+```
+
+
+
+## RedundantSemicolon
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Redundant semicolon
+
+Reports redundant semicolons (`;`) that can be safely removed.
+
+Kotlin does not require a semicolon at the end of each statement or expression.
+The quick-fix is suggested to remove redundant semicolons.
+
+**Example:**
+
+```kotlin
+val myMap = mapOf("one" to 1, "two" to 2);
+myMap.forEach { (key, value) -> print("$key -> $value")};
+```
+
+After the quick-fix is applied:
+
+```kotlin
+val myMap = mapOf("one" to 1, "two" to 2)
+myMap.forEach { (key, value) -> print("$key -> $value")}
+```
+
+There are two cases though where a semicolon is required:
+
+1. Several statements placed on a single line need to be separated with semicolons:
+
+```kotlin
+map.forEach { val (key, value) = it; println("$key -> $value") }
+```
+
+2. `enum` classes that also declare properties or functions, require a semicolon after the list of enum constants:
+
+```kotlin
+enum class Mode {
+ SILENT, VERBOSE;
+
+ fun isSilent(): Boolean = this == SILENT
+}
+```
+
+
+
+## RedundantVisibilityModifier
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Redundant visibility modifier
+
+Reports visibility modifiers that match the default visibility of an element
+(`public` for most elements, `protected` for members that override a protected member).
+
+
+
+## RemoveCurlyBracesFromTemplate
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Redundant curly braces in string template
+
+Reports usages of curly braces in string templates around simple identifiers.
+Use the 'Remove curly braces' quick-fix to remove the redundant braces.
+
+**Examples:**
+
+```kotlin
+fun redundant() {
+ val x = 4
+ val y = "${x}" // <== redundant
+}
+
+fun correctUsage() {
+ val x = "x"
+ val y = "${x.length}" // <== Ok
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun redundant() {
+ val x = 4
+ val y = "$x"
+}
+
+fun correctUsage() {
+ val x = "x" <== Updated
+ val y = "${x.length}"
+}
+```
+
+
+
+## RemoveEmptyParenthesesFromLambdaCall
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Unnecessary parentheses in function call with lambda
+
+Reports redundant empty parentheses of function calls where the only parameter is a lambda that's outside the parentheses.
+Use the 'Remove unnecessary parentheses from function call with lambda' quick-fix to clean up the code.
+
+**Examples:**
+
+```kotlin
+fun foo() {
+ listOf(1).forEach() { }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo() {
+ listOf(1).forEach { }
+}
+```
+
+
+
+## RemoveEmptyPrimaryConstructor
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Redundant empty primary constructor
+
+Reports empty primary constructors when they are implicitly available anyway.
+
+A primary constructor is redundant and can be safely omitted when it does not have any annotations or visibility modifiers.
+Use the 'Remove empty primary constructor' quick-fix to clean up the code.
+
+**Examples:**
+
+```kotlin
+class MyClassA constructor() // redundant, can be replaced with 'class MyClassA'
+
+annotation class MyAnnotation
+class MyClassB @MyAnnotation constructor() // required because of annotation
+
+class MyClassC private constructor() // required because of visibility modifier
+```
+
+
+
+## RemoveExplicitTypeArguments
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Unnecessary type argument
+
+Reports function calls with type arguments that can be automatically inferred. Such type arguments are redundant and can be safely omitted.
+Use the 'Remove explicit type arguments' quick-fix to clean up the code.
+
+**Examples:**
+
+```kotlin
+// 'String' type can be inferred here
+fun foo(): MutableList = mutableListOf()
+
+// Here 'String' cannot be inferred, type argument is required.
+fun bar() = mutableListOf()
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(): MutableList = mutableListOf() <== Updated
+
+fun bar() = mutableListOf()
+```
+
+
+
+## RemoveForLoopIndices
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Unused loop index
+
+Reports `for` loops iterating over a collection using the `withIndex()` function and not using the index variable.
+Use the "Remove indices in 'for' loop" quick-fix to clean up the code.
+
+**Examples:**
+
+```kotlin
+fun foo(bar: List) {
+ for ((index : Int, value: String) in bar.withIndex()) { // <== 'index' is unused
+ println(value)
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(bar: List) {
+ for (value: String in bar) { // <== '.withIndex()' and 'index' are removed
+ println(value)
+ }
+}
+```
+
+
+
+## RemoveRedundantCallsOfConversionMethods
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Redundant call of conversion method
+
+Reports redundant calls to conversion methods (for example, `toString()` on a `String` or `toDouble()`
+on a `Double`).
+Use the 'Remove redundant calls of the conversion method' quick-fix to clean up the code.
+
+
+
+## RemoveRedundantQualifierName
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Redundant qualifier name
+
+Reports redundant qualifiers (or their parts) on class names, functions, and properties.
+
+A fully qualified name is an unambiguous identifier that specifies which object, function, or property a call refers to.
+In the contexts where the name can be shortened, the inspection informs on the opportunity and the associated
+'Remove redundant qualifier name' quick-fix allows amending the code.
+
+**Examples:**
+
+```kotlin
+package my.simple.name
+import kotlin.Int.Companion.MAX_VALUE
+
+class Foo
+
+fun main() {
+ val a = my.simple.name.Foo() // 'Foo' resides in the declared 'my.simple.name' package, qualifier is redundant
+ val b = kotlin.Int.MAX_VALUE // Can be replaced with 'MAX_VALUE' since it's imported
+ val c = kotlin.Double.MAX_VALUE // Can be replaced with 'Double.MAX_VALUE' since built-in types are imported automatically
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+package my.simple.name
+import kotlin.Int.Companion.MAX_VALUE
+
+class Foo
+
+fun main() {
+ val a = Foo()
+ val b = MAX_VALUE
+ val c = Double.MAX_VALUE
+}
+```
+
+
+
+## RemoveSingleExpressionStringTemplate
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Redundant string template
+
+Reports single-expression string templates that can be safely removed.
+**Example:**
+
+```kotlin
+val x = "Hello"
+val y = "$x"
+```
+
+After the quick-fix is applied:
+
+```kotlin
+val x = "Hello"
+val y = x // <== Updated
+```
+
+
+
+## RemoveToStringInStringTemplate
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Redundant call to 'toString()' in string template
+
+Reports calls to `toString()` in string templates that can be safely removed.
+**Example:**
+
+```kotlin
+fun foo(a: Int, b: Int) = a + b
+
+fun test(): String {
+ return "Foo: ${foo(0, 4).toString()}" // 'toString()' is redundant
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(a: Int, b: Int) = a + b
+
+fun test(): String {
+ return "Foo: ${foo(0, 4)}"
+}
+```
+
+
+
+## ReplaceCallWithBinaryOperator
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Can be replaced with binary operator
+
+Reports function calls that can be replaced with binary operators, in particular comparison-related ones.
+**Example:**
+
+```kotlin
+fun test(): Boolean {
+ return 2.compareTo(1) > 0 // replaceable 'compareTo()'
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun test(): Boolean {
+ return 2 > 1
+}
+```
+
+
+
+## ReplaceCollectionCountWithSize
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Collection count can be converted to size
+
+Reports calls to `Collection.count()`.
+
+This function call can be replaced with `.size`.
+
+`.size` form ensures that the operation is O(1) and won't allocate extra objects, whereas
+`count()` could be confused with `Iterable.count()`, which is O(n) and allocating.
+
+**Example:**
+
+```kotlin
+fun foo() {
+ var list = listOf(1,2,3)
+ list.count() // replaceable 'count()'
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo() {
+ var list = listOf(1,2,3)
+ list.size
+}
+```
+
+
+
+## ReplaceGetOrSet
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Explicit 'get' or 'set' call
+
+Reports explicit calls to `get` or `set` functions which can be replaced by an indexing operator `[]`.
+
+Kotlin allows custom implementations for the predefined set of operators on types.
+To overload an operator, you can mark the corresponding function with the `operator` modifier:
+
+```kotlin
+operator fun get(index: Int) {}
+operator fun set(index: Int, value: Int) {}
+```
+
+The functions above correspond to the indexing operator.
+
+**Example:**
+
+```kotlin
+class Test {
+ operator fun get(i: Int): Int = 0
+}
+
+fun test() {
+ Test().get(0) // replaceable 'get()'
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+class Test {
+ operator fun get(i: Int): Int = 0
+}
+
+fun test() {
+ Test()[0]
+}
+```
+
+
+
+## ReplaceGuardClauseWithFunctionCall
+
+**Severity**: Error
+**Highlighting**: Strikethrough
+
+
+Guard clause can be replaced with Kotlin's function call
+
+Reports guard clauses that can be replaced with a function call.
+**Example:**
+
+```kotlin
+fun test(foo: Int?) {
+ if (foo == null) throw IllegalArgumentException("foo") // replaceable clause
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun test(foo: Int?) {
+ checkNotNull(foo)
+}
+```
+
+
+
+## ReplaceManualRangeWithIndicesCalls
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+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.
+Using syntactic sugar makes your code simpler.
+
+The quick-fix replaces the manual range with the corresponding construction.
+
+**Example:**
+
+```kotlin
+fun main(args: Array) {
+ for (index in 0..args.size - 1) {
+ println(args[index])
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun main(args: Array) {
+ for (element in args) {
+ println(element)
+ }
+}
+```
+
+
+
+## ReplaceRangeToWithUntil
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+rangeTo' or the '..' call should be replaced with 'until'
+
+Reports calls to `rangeTo` or the `..` operator instead of calls to `until`.
+Using corresponding functions makes your code simpler.
+
+The quick-fix replaces `rangeTo` or the `..` call with `until`.
+
+**Example:**
+
+```kotlin
+fun foo(a: Int) {
+ for (i in 0..a - 1) {
+
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(a: Int) {
+ for (i in 0 until a) {
+
+ }
+}
+```
+
+
+
+## ReplaceReadLineWithReadln
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+readLine' can be replaced with 'readln' or 'readlnOrNull'
+
+Reports calls to `readLine()` that can be replaced with `readln()` or `readlnOrNull()`.
+
+Using corresponding functions makes your code simpler.
+
+The quick-fix replaces `readLine()!!` with `readln()` and `readLine()` with `readlnOrNull()`.
+
+**Examples:**
+
+```kotlin
+val x = readLine()!!
+val y = readLine()?.length
+```
+
+After the quick-fix is applied:
+
+```kotlin
+val x = readln()
+val y = readlnOrNull()?.length
+```
+
+
+
+## ReplaceSizeCheckWithIsNotEmpty
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Size check can be replaced with 'isNotEmpty()'
+
+Reports size checks of `Collections/Array/String` that should be replaced with `isNotEmpty()`.
+Using `isNotEmpty()` makes your code simpler.
+
+The quick-fix replaces the size check with `isNotEmpty()`.
+
+**Example:**
+
+```kotlin
+fun foo() {
+ val arrayOf = arrayOf(1, 2, 3)
+ arrayOf.size > 0
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo() {
+ val arrayOf = arrayOf(1, 2, 3)
+ arrayOf.isNotEmpty()
+}
+```
+
+
+
+## ReplaceSizeZeroCheckWithIsEmpty
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Size zero check can be replaced with 'isEmpty()'
+
+Reports `size == 0` checks on `Collections/Array/String` that should be replaced with `isEmpty()`.
+Using `isEmpty()` makes your code simpler.
+
+The quick-fix replaces the size check with `isEmpty()`.
+
+**Example:**
+
+```kotlin
+fun foo() {
+ val arrayOf = arrayOf(1, 2, 3)
+ arrayOf.size == 0
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo() {
+ val arrayOf = arrayOf(1, 2, 3)
+ arrayOf.isEmpty()
+}
+```
+
+
+
+## ReplaceSubstringWithTake
+
+**Severity**: Error
+**Highlighting**: Strikethrough
+
+
+substring' call should be replaced with 'take' call
+
+Reports calls like `s.substring(0, x)` that can be replaced with `s.take(x)`.
+Using `take()` makes your code simpler.
+
+The quick-fix replaces the `substring` call with `take()`.
+
+**Example:**
+
+```kotlin
+fun foo(s: String) {
+ s.substring(0, 10)
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo(s: String) {
+ s.take(10)
+}
+```
+
+
+
+## ReplaceToStringWithStringTemplate
+
+**Severity**: Information
+**Highlighting**: None
+
+
+Call of 'toString' could be replaced with string template
+
+Reports `toString` function calls that can be replaced with a string template.
+Using string templates makes your code simpler.
+
+The quick-fix replaces `toString` with a string template.
+
+**Example:**
+
+```kotlin
+fun test(): String {
+ val x = 1
+ return x.toString()
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun test(): String {
+ val x = 1
+ return "$x"
+}
+```
+
+
+
+## ReplaceWithOperatorAssignment
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Assignment can be replaced with operator assignment
+
+Reports modifications of variables with a simple assignment (such as `y = y + x`) that can be replaced with an operator assignment.
+The quick-fix replaces the assignment with an assignment operator.
+
+**Example:**
+
+```kotlin
+fun foo() {
+ val list = mutableListOf(1, 2, 3)
+ list = list + 4
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun foo() {
+ val list = mutableListOf(1, 2, 3)
+ list += 4
+}
+```
+
+
+
+## ScopeFunctionConversion
+
+**Severity**: Information
+**Highlighting**: None
+
+
+Scope function can be converted to another one
+
+Reports scope functions (`let`, `run`, `apply`, `also`) that can be converted between each other.
+Using corresponding functions makes your code simpler.
+
+The quick-fix replaces the scope function to another one.
+
+**Example:**
+
+```kotlin
+val x = "".let {
+ it.length
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+val x = "".run {
+ length
+}
+```
+
+
+
+## SelfAssignment
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Redundant assignment
+
+Reports assignments of a variable to itself.
+The quick-fix removes the redundant assignment.
+
+**Example:**
+
+```kotlin
+fun test() {
+ var bar = 1
+ bar = bar
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun test() {
+ var bar = 1
+}
+```
+
+
+
+## SimplifiableCallChain
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Call chain on collection type can be simplified
+
+Reports two-call chains replaceable by a single call.
+It can help you to avoid redundant code execution.
+
+The quick-fix replaces the call chain with a single call.
+
+**Example:**
+
+```kotlin
+fun main() {
+ listOf(1, 2, 3).filter { it > 1 }.count()
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun main() {
+ listOf(1, 2, 3).count { it > 1 }
+}
+```
+
+
+
+## SimplifyBooleanWithConstants
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Boolean expression can be simplified
+
+Reports boolean expression parts that can be reduced to constants.
+The quick-fix simplifies the condition.
+
+**Example:**
+
+```kotlin
+fun use(arg: Boolean) {
+ if (false == arg) {
+
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun use(arg: Boolean) {
+ if (!arg) {
+
+ }
+}
+```
+
+
+
+## TrailingComma
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Trailing comma recommendations
+
+Reports trailing commas that do not follow the recommended [style guide](https://kotlinlang.org/docs/coding-conventions.html#trailing-commas).
+
+
+
+## UnlabeledReturnInsideLambda
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Unlabeled return inside lambda
+
+Reports unlabeled `return` expressions inside inline lambda.
+Such expressions can be confusing because it might be unclear which scope belongs to `return`.
+
+**Change to return@…** quick-fix can be used to amend the code automatically.
+
+Example:
+
+```kotlin
+fun test(list: List) {
+ list.forEach {
+ // This return expression returns from the function test
+ // One can change it to return@forEach to change the scope
+ if (it == 10) return
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun test(list: List) {
+ list.forEach {
+ if (it == 10) return@test
+ }
+}
+```
+
+
+
+## UnnecessaryVariable
+
+**Severity**: Weak Warning
+**Highlighting**: Strikethrough
+
+
+Unnecessary local variable
+
+Reports local variables that are used only in the very next `return` statement or are exact copies of other variables.
+Such variables can be safely inlined to make the code more clear.
+
+**Example:**
+
+```kotlin
+fun sum(a: Int, b: Int): Int {
+ val c = a + b
+ return c
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun sum(a: Int, b: Int): Int {
+ return a + b
+}
+```
+
+Configure the inspection:
+
+Use the **Report immediately returned variables** option to report immediately returned variables.
+When given descriptive names, such variables may improve the code readability in some cases, that's why this option is disabled by default.
+
+
+
+## UnusedEquals
+
+**Severity**: Error
+**Highlighting**: Error
+
+
+Unused equals expression
+
+Reports unused `equals`(`==`) expressions.
+
+
+
+## UnusedReceiverParameter
+
+**Severity**: Warning
+**Highlighting**: Strikethrough
+
+
+Unused receiver parameter
+
+Reports receiver parameter of extension functions and properties that is not used.
+**Remove redundant receiver parameter** can be used to amend the code automatically.
+
+
+
+## UseExpressionBody
+
+**Severity**: Warning
+**Highlighting**: Warning
+
+
+Expression body syntax is preferable here
+
+Reports `return` expressions (one-liners or `when`) that can be replaced with expression body syntax.
+Expression body syntax is recommended by the [style guide](https://kotlinlang.org/docs/coding-conventions.html#functions).
+
+**Convert to expression body** quick-fix can be used to amend the code automatically.
+
+Example:
+
+```kotlin
+fun sign(x: Int): Int {
+ return when { // <== can be simplified
+ x < 0 -> -1
+ x > 0 -> 1
+ else -> 0
+ }
+}
+```
+
+After the quick-fix is applied:
+
+```kotlin
+fun sign(x: Int): Int = when {
+ x < 0 -> -1
+ x > 0 -> 1
+ else -> 0
+}
+```
+
+
+
+## WarningOnMainUnusedParameterMigration
+
+**Severity**: Weak Warning
+**Highlighting**: Weak Warning
+
+
+Unused 'args' on 'main' since 1.4
+
+Reports `main` function with an unused single parameter.
+Since Kotlin 1.4, it is possible to use the `main` function without parameter as the entry point to the Kotlin program.
+The compiler reports a warning for the `main` function with an unused parameter.
+
+
+