Finding unused properties.

idea/idea-analysis/src/org/jetbrains/kotlin/idea/JetBundle.properties

@@ -119,6 +119,7 @@ goto.super.class.chooser.title=Choose super class or interface
 
 unused.class=Class ''{0}'' is never used
 unused.function=Function ''{0}'' is never used
+unused.property=Property ''{0}'' is never used
 
 livetemplate.description.main=main() function
 livetemplate.description.soutp=Prints function parameter names and values to System.out

idea/src/org/jetbrains/kotlin/idea/inspections/UnusedSymbolInspection.kt

@@ -44,6 +44,8 @@ import com.intellij.psi.search.PsiSearchHelper.SearchCostResult.*
 import org.jetbrains.kotlin.idea.search.usagesSearch.getOperationSymbolsToSearch
 import org.jetbrains.kotlin.idea.search.usagesSearch.INVOKE_OPERATION_NAME
 import org.jetbrains.kotlin.psi.JetEnumEntry
+import org.jetbrains.kotlin.psi.JetProperty
+import org.jetbrains.kotlin.idea.search.usagesSearch.PropertyUsagesSearchHelper
 
 public class UnusedSymbolInspection : AbstractKotlinInspection() {
     private val javaInspection = UnusedDeclarationInspection()
@@ -82,6 +84,21 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
                         ProblemHighlightType.LIKE_UNUSED_SYMBOL
                 ) // TODO add quick fix to delete it
             }
+
+            override fun visitProperty(property: JetProperty) {
+                if (property.getName() == null) return
+
+                if (property.isLocal()) return
+
+                if (property.hasModifier(JetTokens.OVERRIDE_KEYWORD)) return
+                if (hasNonTrivialUsages(property)) return
+
+                holder.registerProblem(
+                        property.getNameIdentifier(),
+                        JetBundle.message("unused.property", property.getName()),
+                        ProblemHighlightType.LIKE_UNUSED_SYMBOL
+                ) // TODO add quick fix to delete it
+            }
         }
     }
 
@@ -132,6 +149,7 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
         val searchHelper: UsagesSearchHelper<out JetNamedDeclaration> = when (declaration) {
             is JetClass -> ClassUsagesSearchHelper(constructorUsages = true, nonConstructorUsages = true, skipImports = true)
             is JetNamedFunction -> FunctionUsagesSearchHelper(skipImports = true)
+            is JetProperty -> PropertyUsagesSearchHelper(skipImports = true)
             else -> return false
         }
 

idea/testData/inspections/unusedSymbol/class/usedOnlyInside.kt

@@ -1,3 +1,5 @@
 class A {
-    val x: A? = null
+    {
+        val x: A? = null
+    }
 }

idea/testData/inspections/unusedSymbol/property/classMemberInheritedUsed.kt

@@ -0,0 +1,9 @@
+open class Klass {
+    val used = ":)"
+}
+
+class Subklass: Klass()
+
+fun main(args: Array<String>) {
+    Subklass().used
+}

idea/testData/inspections/unusedSymbol/property/classMemberOverriddenUsed.kt

@@ -0,0 +1,11 @@
+open class Klass {
+    open val used = ":)"
+}
+
+class Subklass: Klass() {
+    override fun used = ":|"
+}
+
+fun main(args: Array<String>) {
+    Subklass().used
+}

idea/testData/inspections/unusedSymbol/property/classMemberOverride.kt

@@ -0,0 +1,12 @@
+trait Trait {
+    val member: String
+}
+
+class Klass: Trait {
+    override val member: String = ":)"
+}
+
+fun main(args: Array<String>) {
+    val t: Trait = Klass()
+    println(t.member)
+}

idea/testData/inspections/unusedSymbol/property/classMemberUnused.kt

@@ -0,0 +1,7 @@
+class Klass {
+    val unused = ":("
+}
+
+fun main(args: Array<String>) {
+    Klass()
+}

idea/testData/inspections/unusedSymbol/property/classMemberUsed.kt

@@ -0,0 +1,7 @@
+class Klass {
+    fun used = ":)"
+}
+
+fun main(args: Array<String>) {
+    Klass().used
+}

idea/testData/inspections/unusedSymbol/property/inspectionData/expected.xml

@@ -0,0 +1,28 @@
+<problems>
+  <problem>
+    <file>topLevelUnused.kt</file>
+    <line>1</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/topLevelUnused.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Property 'unused' is never used</description>
+  </problem>
+
+  <problem>
+    <file>topLevelOnlyInImport.kt</file>
+    <line>5</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/topLevelOnlyInImport.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Property 'onlyInImport' is never used</description>
+  </problem>
+
+  <problem>
+    <file>classMemberUnused.kt</file>
+    <line>2</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/classMemberUnused.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Property 'unused' is never used</description>
+  </problem>
+</problems>

idea/testData/inspections/unusedSymbol/property/inspectionData/inspections.test

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

idea/testData/inspections/unusedSymbol/property/local.kt

@@ -0,0 +1,3 @@
+fun main(args: Array<String>) {
+    val local = ":(" // it is unused, but marked by front-end instead of inspection
+}

idea/testData/inspections/unusedSymbol/property/topLevelOnlyInImport.kt

@@ -0,0 +1,5 @@
+package foo
+
+import foo.onlyInImport
+
+val onlyInImport = ":("

idea/testData/inspections/unusedSymbol/property/topLevelUnused.kt

@@ -0,0 +1 @@
+val unused = ":("

idea/testData/inspections/unusedSymbol/property/topLevelUsed.kt

@@ -0,0 +1,5 @@
+fun used = ":)"
+
+fun main(args: Array<String>) {
+    println(used)
+}

idea/tests/org/jetbrains/kotlin/idea/codeInsight/JetInspectionTestGenerated.java

@@ -89,5 +89,11 @@ public class JetInspectionTestGenerated extends AbstractJetInspectionTest {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/inspections/unusedSymbol/function/inspectionData/inspections.test");
             doTest(fileName);
         }
+
+        @TestMetadata("unusedSymbol/property/inspectionData/inspections.test")
+        public void testUnusedSymbol_property_inspectionData_Inspections_test() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/inspections/unusedSymbol/property/inspectionData/inspections.test");
+            doTest(fileName);
+        }
     }
 }