Introduce "Redundant return label" inspection #KT-25270 Fixed

idea/testData/inspectionsLocal/redundantReturnLabel/.inspection

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

idea/testData/inspectionsLocal/redundantReturnLabel/inAnonymousFunction.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+fun foo(f: (String?) -> Int) {}
+
+fun test() {
+    foo(fun(it: String?): Int {
+        if (it != null) return@foo<caret> 1
+        return 0
+    })
+}

idea/testData/inspectionsLocal/redundantReturnLabel/inFunction.kt

@@ -0,0 +1,3 @@
+fun test() {
+    return@test<caret>
+}

idea/testData/inspectionsLocal/redundantReturnLabel/inFunction.kt.after

@@ -0,0 +1,3 @@
+fun test() {
+    return
+}

idea/testData/inspectionsLocal/redundantReturnLabel/inFunction2.kt

@@ -0,0 +1,6 @@
+fun test(s: String?): Int {
+    if (s != null) {
+        return@test<caret> 1
+    }
+    return 0
+}

idea/testData/inspectionsLocal/redundantReturnLabel/inFunction2.kt.after

@@ -0,0 +1,6 @@
+fun test(s: String?): Int {
+    if (s != null) {
+        return 1
+    }
+    return 0
+}

idea/testData/inspectionsLocal/redundantReturnLabel/inLambda.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+fun foo(f: (String?) -> Int) {}
+
+fun test() {
+    foo {
+        if (it != null) return@foo<caret> 1
+        0
+    }
+}