Refactoring: "introduce when subject" is now an inspection

idea/testData/inspectionsLocal/branched/introduceWhenSubject/.inspection

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.inspections.branchedTransformations.IntroduceWhenSubjectInspection

idea/testData/inspectionsLocal/branched/introduceWhenSubject/lineBreaksAndComments.kt

@@ -0,0 +1,13 @@
+class Klass<T>
+
+fun test(obj: Any): String {
+    return <caret>when {
+        obj is String -> "string" // return "string"
+
+        // it's an Int
+        obj is Int -> "int"
+
+        // otherwise
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/lineBreaksAndComments.kt.after

@@ -0,0 +1,13 @@
+class Klass<T>
+
+fun test(obj: Any): String {
+    return when (obj) {
+        is String -> "string" // return "string"
+
+    // it's an Int
+        is Int -> "int"
+
+    // otherwise
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithEqualityTests.kt

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when {
+        n == 0 -> "zero"
+        n == 1 -> "one"
+        n == 2 -> "two"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithEqualityTests.kt.after

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when (n) {
+        0 -> "zero"
+        1 -> "one"
+        2 -> "two"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithMultipleConditionTypes.kt

@@ -0,0 +1,13 @@
+fun test(n: Int): String {
+    return <caret>when {
+        n !is Int -> "???"
+        n in 0..10 -> "small"
+        n in 10..100 -> "average"
+        n in 100..1000 -> "big"
+        n == 1000000 -> "million"
+        2000000 == n -> "two millions"
+        n !in -100..-10 -> "good"
+        n is Int -> "unknown"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithMultipleConditionTypes.kt.after

@@ -0,0 +1,13 @@
+fun test(n: Int): String {
+    return <caret>when (n) {
+        !is Int -> "???"
+        in 0..10 -> "small"
+        in 10..100 -> "average"
+        in 100..1000 -> "big"
+        1000000 -> "million"
+        2000000 -> "two millions"
+        !in -100..-10 -> "good"
+        is Int -> "unknown"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithNegativePatterns.kt

@@ -0,0 +1,8 @@
+fun test(obj: Any): String {
+    return <caret>when {
+        obj !is Iterable<*> -> "not iterable"
+        obj !is Collection<*> -> "not collection"
+        obj !is MutableCollection<*> -> "not mutable collection"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithNegativePatterns.kt.after

@@ -0,0 +1,8 @@
+fun test(obj: Any): String {
+    return <caret>when (obj) {
+        !is Iterable<*> -> "not iterable"
+        !is Collection<*> -> "not collection"
+        !is MutableCollection<*> -> "not mutable collection"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithNegativeRangeTests.kt

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when {
+        n !in 0..1000 -> "unknown"
+        n !in 0..100 -> "big"
+        n !in 0..10 -> "average"
+        else -> "small"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithNegativeRangeTests.kt.after

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when (n) {
+        !in 0..1000 -> "unknown"
+        !in 0..100 -> "big"
+        !in 0..10 -> "average"
+        else -> "small"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithNondivisibleConditions.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+fun test(n: Int): String {
+    return <caret>when {
+        n in 0..10 -> "small"
+        n >= 10 && n <= 100 -> "average"
+        n < 0 || n > 1000 -> "unknown"
+        else -> "big"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithPatterns.kt

@@ -0,0 +1,10 @@
+class Klass<T>
+
+fun test(obj: Any): String {
+    return <caret>when {
+        obj is String -> "string"
+        obj is Int -> "int"
+        obj is Klass<*> -> "class"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithPatterns.kt.after

@@ -0,0 +1,10 @@
+class Klass<T>
+
+fun test(obj: Any): String {
+    return <caret>when (obj) {
+        is String -> "string"
+        is Int -> "int"
+        is Klass<*> -> "class"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithRangeTests.kt

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when {
+        n in 0..10 -> "small"
+        n in 10..100 -> "average"
+        n in 100..1000 -> "big"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithRangeTests.kt.after

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when (n) {
+        in 0..10 -> "small"
+        in 10..100 -> "average"
+        in 100..1000 -> "big"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithSubject.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+fun test(n: Int): String {
+    return <caret>when(n) {
+        in 0..10 -> "small"
+        in 10..100 -> "average"
+        in 100..1000 -> "big"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithSwappedEqualityTests.kt

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when {
+        n == 0 -> "zero"
+        1 == n -> "one"
+        n == 2 -> "two"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithSwappedEqualityTests.kt.after

@@ -0,0 +1,8 @@
+fun test(n: Int): String {
+    return <caret>when (n) {
+        0 -> "zero"
+        1 -> "one"
+        2 -> "two"
+        else -> "unknown"
+    }
+}

idea/testData/inspectionsLocal/branched/introduceWhenSubject/whenWithUnmatchedCandidateSubjects.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+fun test(n: Int): String {
+    return <caret>when {
+        n in 0..10 -> "n is small"
+        n/10 in 0..10 -> "m is average"
+        n/100 in 0..10 -> "n is big"
+        else -> "unknown"
+    }
+}