Introduce "use expression body" inspection #KT-16063 Fixed

Converted from the relevant intention
Reported cases: one-liners, whens
Also, more exact caret detection in local inspection tests

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/anonymousObjectExpression.kt

@@ -0,0 +1,11 @@
+interface I {
+    fun foo(): String
+}
+
+fun bar(): I {
+    <caret>return object: I {
+        override fun foo(): String {
+            return "a"
+        }
+    }
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/anonymousObjectExpression.kt.after

@@ -0,0 +1,9 @@
+interface I {
+    fun foo(): String
+}
+
+fun bar()<selection>: I</selection> = object: I {
+    override fun foo(): String {
+        return "a"
+    }
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/assignPlus.kt

@@ -0,0 +1,7 @@
+// PROBLEM: none
+
+var x = 0
+
+fun <caret>foo() {
+    x += 1
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/assignment.kt

@@ -0,0 +1,8 @@
+// PROBLEM: none
+
+var a = 1
+var b = 2
+
+fun foo() {
+    <caret>a = b
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/constructorWithEmptyBody.kt

@@ -0,0 +1,5 @@
+// PROBLEM: none
+
+class C {
+    constructor()<caret> {}
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/declaration.kt

@@ -0,0 +1,5 @@
+// PROBLEM: none
+
+fun foo() {
+    <caret>val v = 1
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/elvisIfElseUnit.kt

@@ -0,0 +1,9 @@
+// IS_APPLICABLE: true
+
+fun nullable() {}
+
+fun bar() {}
+
+fun foo(f: Boolean) {
+    <caret>nullable() ?: if (f) bar() else bar()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/elvisIfElseUnit.kt.after

@@ -0,0 +1,7 @@
+// IS_APPLICABLE: true
+
+fun nullable() {}
+
+fun bar() {}
+
+fun foo(f: Boolean) = nullable() ?: if (f) bar() else bar()

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/elvisIfUnit.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+
+fun nullable() {}
+
+fun bar() {}
+
+fun foo(f: Boolean) {
+    <caret>nullable() ?: if (f) bar()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/elvisWhenUnitNonExhaustive.kt

@@ -0,0 +1,10 @@
+// PROBLEM: none
+
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(access: AccessMode) {
+    <caret>println("result") ?: when (access) {
+        AccessMode.READ -> println("read")
+        AccessMode.WRITE -> println("write")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/emptyList.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun foo(): List<String> {
+    ret<caret>urn emptyList()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/emptyList.kt.after

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+fun foo(): List<String> = emptyList()

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/expressionWithReturns1.kt

@@ -0,0 +1,7 @@
+// PROBLEM: none
+
+fun foo(p: Boolean): String {
+    <caret>return bar() ?: return "a"
+}
+
+fun bar(): String? = null

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/expressionWithReturns2.kt

@@ -0,0 +1,10 @@
+// PROBLEM: none
+
+fun foo(p: Boolean): String {
+    if (p) {
+        <caret>return "abc"
+    }
+    else {
+        return "def"
+    }
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithEmptyBody.kt

@@ -0,0 +1,2 @@
+fun <caret>foo() {
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithEmptyBody.kt.after

@@ -0,0 +1 @@
+fun foo() = Unit

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithEmptyBody2.kt

@@ -0,0 +1,2 @@
+fun <caret>foo(): Unit {
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithEmptyBody2.kt.after

@@ -0,0 +1 @@
+fun foo(): Unit = Unit

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithImplicitUnitTypeWithThrow.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun foo() {
+    <caret>throw UnsupportedOperationException()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithImplicitUnitTypeWithThrow.kt.after

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+fun foo()<selection>: Unit</selection> = throw UnsupportedOperationException()

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithNoBlock.kt

@@ -0,0 +1,3 @@
+// PROBLEM: none
+
+fun foo() = <caret>"abc"

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithNothingType.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun foo(): Nothing {
+    <caret>throw UnsupportedOperationException()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithNothingType.kt.after

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+fun foo()<selection>: Nothing</selection> = throw UnsupportedOperationException()

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithReturn.kt

@@ -0,0 +1,3 @@
+fun foo(): String {
+    <caret>return "abc"
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithReturn.kt.after

@@ -0,0 +1 @@
+fun foo()<selection>: String</selection> = "abc"

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithUnitType.kt

@@ -0,0 +1,5 @@
+fun foo() {
+    <caret>bar()
+}
+
+fun bar() { }

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithUnitType.kt.after

@@ -0,0 +1,3 @@
+fun foo() = bar()
+
+fun bar() { }

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithUnitType2.kt

@@ -0,0 +1,7 @@
+// PROBLEM: none
+
+fun foo() {
+    <caret>bar()
+}
+
+fun bar(): String = "abc"

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithUnitTypeWithThrow.kt

@@ -0,0 +1,5 @@
+// WITH_RUNTIME
+
+fun foo(): Unit {
+    <caret>throw UnsupportedOperationException()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/funWithUnitTypeWithThrow.kt.after

@@ -0,0 +1,3 @@
+// WITH_RUNTIME
+
+fun foo()<selection>: Unit</selection> = throw UnsupportedOperationException()

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/functionLiteral.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+
+fun foo(handler: () -> Unit) { }
+
+fun bar() {
+    foo { <caret>zoo() }
+}
+
+fun zoo(){}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/getWithReturn.kt

@@ -0,0 +1,4 @@
+val foo: String
+    get() {
+        <caret>return "abc"
+    }

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/getWithReturn.kt.after

@@ -0,0 +1,2 @@
+val foo: String
+    get() = "abc"

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/ifElseUnit.kt

@@ -0,0 +1,7 @@
+// IS_APPLICABLE: true
+
+fun bar() {}
+
+fun foo(f: Boolean) {
+    <caret>if (f) bar() else bar()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/ifElseUnit.kt.after

@@ -0,0 +1,5 @@
+// IS_APPLICABLE: true
+
+fun bar() {}
+
+fun foo(f: Boolean) = if (f) bar() else bar()

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/ifUnit.kt

@@ -0,0 +1,7 @@
+// PROBLEM: none
+
+fun bar() {}
+
+fun foo(f: Boolean) {
+    <caret>if (f) bar()
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/ifWhenUnitExhaustive.kt

@@ -0,0 +1,19 @@
+// IS_APPLICABLE: true
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(mode: Boolean, access: AccessMode) {
+    <caret>if (mode) {
+        when (access) {
+            AccessMode.READ -> println("read")
+            AccessMode.WRITE -> println("write")
+            AccessMode.RW -> println("both")
+        }
+    }
+    else {
+        when (access) {
+            AccessMode.READ -> println("noread")
+            AccessMode.WRITE -> println("nowrite")
+            AccessMode.RW -> println("no both")
+        }
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/ifWhenUnitExhaustive.kt.after

@@ -0,0 +1,17 @@
+// IS_APPLICABLE: true
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(mode: Boolean, access: AccessMode) = if (mode) {
+    when (access) {
+        AccessMode.READ -> println("read")
+        AccessMode.WRITE -> println("write")
+        AccessMode.RW -> println("both")
+    }
+}
+else {
+    when (access) {
+        AccessMode.READ -> println("noread")
+        AccessMode.WRITE -> println("nowrite")
+        AccessMode.RW -> println("no both")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/ifWhenUnitNonExhaustive.kt

@@ -0,0 +1,19 @@
+// PROBLEM: none
+
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(mode: Boolean, access: AccessMode) {
+    <caret>if (mode) {
+        when (access) {
+            AccessMode.READ -> println("read")
+            AccessMode.WRITE -> println("write")
+        }
+    }
+    else {
+        when (access) {
+            AccessMode.READ -> println("noread")
+            AccessMode.WRITE -> println("nowrite")
+            AccessMode.RW -> println("no both")
+        }
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/1.kt

@@ -0,0 +1,3 @@
+fun getText(): String {
+    <caret>return "xxx" //TODO
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/1.kt.after

@@ -0,0 +1 @@
+fun getText(): String = "xxx" //TODO

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/2.kt

@@ -0,0 +1,4 @@
+fun getText(): String {
+    // let's return xxx
+    <caret>return "xxx" //TODO
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/2.kt.after

@@ -0,0 +1,2 @@
+fun getText(): String = // let's return xxx
+        "xxx" //TODO

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/3.kt

@@ -0,0 +1,3 @@
+fun getText(): String { // let's return xxx
+    <caret>return "xxx"
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/3.kt.after

@@ -0,0 +1,2 @@
+fun getText(): String = // let's return xxx
+        "xxx"

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/4.kt

@@ -0,0 +1,4 @@
+fun getText(): String {
+    /* let's return xxx */
+    <caret>return "xxx" /* TODO */
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/keepComments/4.kt.after

@@ -0,0 +1,2 @@
+fun getText(): String = /* let's return xxx */
+        "xxx" /* TODO */

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/lambdaIfUnit.kt

@@ -0,0 +1,12 @@
+// IS_APPLICABLE: true
+
+fun <T> run(f: () -> T) = f()
+fun whenExpr(flag: Boolean) {
+    <caret>run {
+        println("run")
+        if (flag) {
+            println("flag")
+        }
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/lambdaIfUnit.kt.after

@@ -0,0 +1,10 @@
+// IS_APPLICABLE: true
+
+fun <T> run(f: () -> T) = f()
+fun whenExpr(flag: Boolean) = run {
+    println("run")
+    if (flag) {
+        println("flag")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/lambdaWhenUnitNonExhaustive.kt

@@ -0,0 +1,13 @@
+// IS_APPLICABLE: true
+enum class AccessMode { READ, WRITE, RW }
+fun <T> run(f: () -> T) = f()
+fun whenExpr(access: AccessMode) {
+    <caret>run {
+        println("run")
+        when (access) {
+            AccessMode.READ -> println("read")
+            AccessMode.WRITE -> println("write")
+        }
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/lambdaWhenUnitNonExhaustive.kt.after

@@ -0,0 +1,11 @@
+// IS_APPLICABLE: true
+enum class AccessMode { READ, WRITE, RW }
+fun <T> run(f: () -> T) = f()
+fun whenExpr(access: AccessMode) = run {
+    println("run")
+    when (access) {
+        AccessMode.READ -> println("read")
+        AccessMode.WRITE -> println("write")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/multipleStatements.kt

@@ -0,0 +1,6 @@
+// PROBLEM: none
+
+fun foo(): String {
+    val v = 1
+    <caret>return "abc"
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/overridePublicFun.kt

@@ -0,0 +1,9 @@
+open class A {
+    public open fun foo(): String = ""
+}
+
+class B : A() {
+    public override fun foo(): String {
+        <caret>return "abc"
+    }
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/overridePublicFun.kt.after

@@ -0,0 +1,7 @@
+open class A {
+    public open fun foo(): String = ""
+}
+
+class B : A() {
+    public override fun foo()<selection>: String</selection> = "abc"
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/returnFromLambda.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+
+public fun List<String>.fn() : List<String> {
+    <caret>return map {
+        if (it.isEmpty()) return@map "<empty>"
+        it
+    }
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/returnFromLambda.kt.after

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+
+public fun List<String>.fn() <selection>: List<String></selection><caret> = map {
+    if (it.isEmpty()) return@map "<empty>"
+    it
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/returnFromLambda2.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+
+public fun List<String>.fn() : List<String> {
+    <caret>return map {
+        if (it.isEmpty()) return emptyList()
+        it
+    }
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/returnFromLambda2.kt.after

@@ -0,0 +1,6 @@
+// WITH_RUNTIME
+
+public fun List<String>.fn() : List<String> = map {
+    if (it.isEmpty()) return emptyList()
+    it
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/returnWithNoValue.kt

@@ -0,0 +1,5 @@
+// PROBLEM: none
+
+fun foo() {
+    <caret>return
+}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenIfUnitExhaustive.kt

@@ -0,0 +1,10 @@
+// IS_APPLICABLE: true
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(mode: Boolean, access: AccessMode) {
+    <caret>when (access) {
+        AccessMode.READ -> if (mode) println("read") else println("noread")
+        AccessMode.WRITE -> if (mode) println("write") else println("nowrite")
+        AccessMode.RW -> if (mode) println("both") else println("no both")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenIfUnitExhaustive.kt.after

@@ -0,0 +1,8 @@
+// IS_APPLICABLE: true
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(mode: Boolean, access: AccessMode) = when (access) {
+    AccessMode.READ -> if (mode) println("read") else println("noread")
+    AccessMode.WRITE -> if (mode) println("write") else println("nowrite")
+    AccessMode.RW -> if (mode) println("both") else println("no both")
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenIfUnitNonExhaustive.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(mode: Boolean, access: AccessMode) {
+    <caret>when (access) {
+        AccessMode.READ -> if (mode) println("read") else println("noread")
+        AccessMode.WRITE -> if (mode) println("write")
+        AccessMode.RW -> if (mode) println("both") else println("no both")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenUnitExhaustive.kt

@@ -0,0 +1,9 @@
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(access: AccessMode) {
+    <caret>when (access) {
+        AccessMode.READ -> println("read")
+        AccessMode.WRITE -> println("write")
+        AccessMode.RW -> println("rw")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenUnitExhaustive.kt.after

@@ -0,0 +1,7 @@
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(access: AccessMode) = when (access) {
+    AccessMode.READ -> println("read")
+    AccessMode.WRITE -> println("write")
+    AccessMode.RW -> println("rw")
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenUnitNonExhaustive.kt

@@ -0,0 +1,10 @@
+// PROBLEM: none
+
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(access: AccessMode) {
+    <caret>when (access) {
+        AccessMode.READ -> println("read")
+        AccessMode.WRITE -> println("write")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenUnitWithElse.kt

@@ -0,0 +1,9 @@
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(access: AccessMode) {
+    <caret>when (access) {
+        AccessMode.READ -> println("read")
+        AccessMode.WRITE -> println("write")
+        else -> println("else")
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenUnitWithElse.kt.after

@@ -0,0 +1,7 @@
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(access: AccessMode) = when (access) {
+    AccessMode.READ -> println("read")
+    AccessMode.WRITE -> println("write")
+    else -> println("else")
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/whenWhenNonExhaustive.kt

@@ -0,0 +1,19 @@
+// PROBLEM: none
+
+enum class AccessMode { READ, WRITE, RW }
+fun whenExpr(mode: Boolean, access: AccessMode) {
+    <caret>when (access) {
+        AccessMode.READ -> when (mode) {
+            true -> println("read")
+            false -> println("noread")
+        }
+        AccessMode.WRITE -> when (mode) {
+            true -> println("write")
+        }
+        AccessMode.RW -> when (mode) {
+            true -> println("both")
+            else -> println("no both")
+        }
+    }
+}
+fun println(s: String) {}

idea/testData/inspectionsLocal/useExpressionBody/convertToExpressionBody/while.kt

@@ -0,0 +1,5 @@
+// PROBLEM: none
+
+fun foo(p: Boolean): String {
+    <caret>while(true) { }
+}