Searching for properties declared in class constructor signature.

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

@@ -47,6 +47,8 @@ import org.jetbrains.kotlin.psi.JetEnumEntry
 import org.jetbrains.kotlin.psi.JetProperty
 import org.jetbrains.kotlin.idea.search.usagesSearch.PropertyUsagesSearchHelper
 import org.jetbrains.kotlin.idea.search.usagesSearch.getAccessorNames
+import org.jetbrains.kotlin.psi.JetParameter
+import org.jetbrains.kotlin.idea.search.usagesSearch.dataClassComponentFunctionName
 
 public class UnusedSymbolInspection : AbstractKotlinInspection() {
     private val javaInspection = UnusedDeclarationInspection()
@@ -100,6 +102,24 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
                         ProblemHighlightType.LIKE_UNUSED_SYMBOL
                 ) // TODO add quick fix to delete it
             }
+
+            override fun visitParameter(parameter: JetParameter) {
+                if (parameter.getName() == null) return
+
+                if (parameter.getParent()?.getParent() !is JetClass || !parameter.hasValOrVarNode()) return
+
+                // properties can be referred by component1/component2, which is too expensive to search, don't mark them as unused
+                if (parameter.dataClassComponentFunctionName() != null) return
+
+                if (parameter.hasModifier(JetTokens.OVERRIDE_KEYWORD)) return
+                if (hasNonTrivialUsages(parameter)) return
+
+                holder.registerProblem(
+                        parameter.getNameIdentifier(),
+                        JetBundle.message("unused.property", parameter.getName()),
+                        ProblemHighlightType.LIKE_UNUSED_SYMBOL
+                ) // TODO add quick fix to delete it
+            }
         }
     }
 
@@ -156,7 +176,7 @@ 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)
+            is JetProperty, is JetParameter -> PropertyUsagesSearchHelper(skipImports = true)
             else -> return false
         }
 

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

@@ -0,0 +1,10 @@
+<problems>
+  <problem>
+    <file>paramPropertyUnused.kt</file>
+    <line>1</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/paramPropertyUnused.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Property 'param' is never used</description>
+  </problem>
+</problems>

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

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

idea/testData/inspections/unusedSymbol/parameter/paramPropertyDataClass.kt

@@ -0,0 +1,6 @@
+// properties can be referred by component1/component2, which is too expensive to search, don't mark them as unused
+data class MyClass(val param1: String, var param2: String)
+
+fun main(args: Array<String>) {
+    MyClass()
+}

idea/testData/inspections/unusedSymbol/parameter/paramPropertyOverriddenUsed.kt

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

idea/testData/inspections/unusedSymbol/parameter/paramPropertyOverride.kt

@@ -0,0 +1,10 @@
+trait Trait {
+    val member: String
+}
+
+class Klass(override val member: String)
+
+fun main(args: Array<String>) {
+    val t: Trait = Klass()
+    println(t.member)
+}

idea/testData/inspections/unusedSymbol/parameter/paramPropertyUnused.kt

@@ -0,0 +1,5 @@
+class MyClass(val param: String)
+
+fun main(args: Array<String>) {
+    MyClass()
+}

idea/testData/inspections/unusedSymbol/parameter/paramPropertyUsed.kt

@@ -0,0 +1,5 @@
+class MyClass(val param: String)
+
+fun main(args: Array<String>) {
+    MyClass().param
+}

idea/testData/inspections/unusedSymbol/parameter/usedInJava.java

@@ -0,0 +1,10 @@
+package test;
+
+import foo.UsedInJava;
+
+class usedInJava {
+    public static void main(String[] args) {
+        new UsedInJava("a", "b").getUsedByGetter();
+        new UsedInJava("a", "b").setUsedBySetter(":|");
+    }
+}

idea/testData/inspections/unusedSymbol/parameter/usedInJava.kt

@@ -0,0 +1,3 @@
+package foo
+
+class UsedInJava(val usedByGetter: String, var usedBySetter: String)

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

@@ -90,6 +90,12 @@ public class JetInspectionTestGenerated extends AbstractJetInspectionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("unusedSymbol/parameter/inspectionData/inspections.test")
+        public void testUnusedSymbol_parameter_inspectionData_Inspections_test() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/inspections/unusedSymbol/parameter/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");