Highlighting unused type parameter.

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

@@ -120,6 +120,7 @@ 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
+unused.type.parameter=Type parameter ''{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

@@ -49,6 +49,8 @@ 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
+import org.jetbrains.kotlin.psi.JetTypeParameter
+import org.jetbrains.kotlin.idea.search.usagesSearch.DefaultSearchHelper
 
 public class UnusedSymbolInspection : AbstractKotlinInspection() {
     private val javaInspection = UnusedDeclarationInspection()
@@ -120,6 +122,18 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
                         ProblemHighlightType.LIKE_UNUSED_SYMBOL
                 ) // TODO add quick fix to delete it
             }
+
+            override fun visitTypeParameter(parameter: JetTypeParameter) {
+                if (parameter.getName() == null) return
+
+                if (hasNonTrivialUsages(parameter)) return
+
+                holder.registerProblem(
+                        parameter.getNameIdentifier(),
+                        JetBundle.message("unused.type.parameter", parameter.getName()),
+                        ProblemHighlightType.LIKE_UNUSED_SYMBOL
+                ) // TODO add quick fix to delete it
+            }
         }
     }
 
@@ -177,7 +191,7 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
             is JetClass -> ClassUsagesSearchHelper(constructorUsages = true, nonConstructorUsages = true, skipImports = true)
             is JetNamedFunction -> FunctionUsagesSearchHelper(skipImports = true)
             is JetProperty, is JetParameter -> PropertyUsagesSearchHelper(skipImports = true)
-            else -> return false
+            else -> DefaultSearchHelper<JetNamedDeclaration>()
         }
 
         val request = searchHelper.newRequest(UsagesSearchTarget(declaration, useScope))

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

@@ -0,0 +1,19 @@
+<problems>
+  <problem>
+    <file>unusedFunctionTypeParameter.kt</file>
+    <line>1</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/unusedFunctionTypeParameter.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Type parameter 'T' is never used</description>
+  </problem>
+
+  <problem>
+    <file>unusedClassTypeParameter.kt</file>
+    <line>1</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/unusedClassTypeParameter.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Type parameter 'T' is never used</description>
+  </problem>
+</problems>

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

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

idea/testData/inspections/unusedSymbol/typeParameter/unusedClassTypeParameter.kt

@@ -0,0 +1,9 @@
+class UnusedClassTypeParameter<T>(p: String) {
+    {
+        println(p)
+    }
+}
+
+fun main(args: Array<String>) {
+    UnusedClassTypeParameter("")
+}

idea/testData/inspections/unusedSymbol/typeParameter/unusedFunctionTypeParameter.kt

@@ -0,0 +1,6 @@
+fun <T> unusedFunctionTypeParameter(p: String) {
+}
+
+fun main(args: Array<String>) {
+    unusedFunctionTypeParameter("")
+}

idea/testData/inspections/unusedSymbol/typeParameter/usedClassTypeParameter.kt

@@ -0,0 +1,9 @@
+class UsedClassTypeParameter<T>(t: T) {
+    {
+        println(t)
+    }
+}
+
+fun main(args: Array<String>) {
+    UsedClassTypeParameter("")
+}

idea/testData/inspections/unusedSymbol/typeParameter/usedFunctionTypeParameter.kt

@@ -0,0 +1,6 @@
+fun <T> usedFunctionTypeParameter(t: T) {
+}
+
+fun main(args: Array<String>) {
+    usedFunctionTypeParameter("")
+}

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

@@ -101,5 +101,11 @@ public class JetInspectionTestGenerated extends AbstractJetInspectionTest {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/inspections/unusedSymbol/property/inspectionData/inspections.test");
             doTest(fileName);
         }
+
+        @TestMetadata("unusedSymbol/typeParameter/inspectionData/inspections.test")
+        public void testUnusedSymbol_typeParameter_inspectionData_Inspections_test() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/inspections/unusedSymbol/typeParameter/inspectionData/inspections.test");
+            doTest(fileName);
+        }
     }
 }