KT-12019 Highlighting of redundant 'if' statements (#871)

idea/testData/inspections/redundantIf/inspectionData/expected.xml

@@ -0,0 +1,18 @@
+<problems>
+    <problem>
+        <file>redundantIf.kt</file>
+        <line>2</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="redundantIf.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'if' statement</problem_class>
+        <description>Redundant 'if' statement</description>
+    </problem>
+    <problem>
+        <file>redundantIf.kt</file>
+        <line>10</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="redundantIf.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Redundant 'if' statement</problem_class>
+        <description>Redundant 'if' statement</description>
+    </problem>
+</problems>

idea/testData/inspections/redundantIf/inspectionData/inspections.test

@@ -0,0 +1 @@
+// INSPECTION_CLASS: org.jetbrains.kotlin.idea.inspections.RedundantIfInspection

idea/testData/inspections/redundantIf/redundantIf.kt

@@ -0,0 +1,11 @@
+fun foo() {
+    if (value % 2 == 0) {
+        return true
+    } else {
+        return false
+    }
+}
+
+fun bar() {
+    if (value % 2 == 0) return true else return false
+}

idea/testData/quickfix/redundantIf/.inspection

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

idea/testData/quickfix/redundantIf/simple.kt

@@ -0,0 +1,8 @@
+// "Remove redundant 'if' statement" "true"
+fun bar() {
+    <caret>if (value % 2 == 0) {
+        return true
+    } else {
+        return false
+    }
+}

idea/testData/quickfix/redundantIf/simplet.kt.after

@@ -0,0 +1,4 @@
+// "Remove redundant 'if' statement" "true"
+fun bar() {
+    return value % 2 == 0
+}