Finding unused functions.

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

@@ -118,6 +118,7 @@ goto.super.property.chooser.title=Choose super property
 goto.super.class.chooser.title=Choose super class or interface
 
 unused.class=Class ''{0}'' is never used
+unused.function=Function ''{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

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.idea.search.usagesSearch.UsagesSearch
 import org.jetbrains.kotlin.idea.JetBundle
 import com.intellij.codeInspection.ProblemHighlightType
 import com.intellij.codeInspection.deadCode.UnusedDeclarationInspection
+import org.jetbrains.kotlin.asJava.LightClassUtil
 import org.jetbrains.kotlin.idea.findUsages.handlers.KotlinFindClassUsagesHandler
 import com.intellij.psi.search.GlobalSearchScope
 import org.jetbrains.kotlin.psi.JetNamedDeclaration
@@ -49,7 +50,7 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
             override fun visitClass(klass: JetClass) {
                 if (klass.getName() == null) return
 
-                if (classIsEntryPoint(klass)) return
+                if (isEntryPoint(klass)) return
                 if (hasNonTrivialUsages(klass)) return
                 if (classHasTextUsages(klass)) return
 
@@ -59,13 +60,30 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
                         ProblemHighlightType.LIKE_UNUSED_SYMBOL
                 ) // TODO add quick fix to delete it
             }
+
+            override fun visitNamedFunction(function: JetNamedFunction) {
+                if (function.getName() == null) return
+
+                if (function.hasModifier(JetTokens.OVERRIDE_KEYWORD)) return
+                if (isEntryPoint(function)) return
+                if (hasNonTrivialUsages(function)) return
+
+                holder.registerProblem(
+                        function.getNameIdentifier(),
+                        JetBundle.message("unused.function", function.getName()),
+                        ProblemHighlightType.LIKE_UNUSED_SYMBOL
+                ) // TODO add quick fix to delete it
+            }
         }
     }
 
-    private fun classIsEntryPoint(klass: JetClass): Boolean {
+    private fun isEntryPoint(declaration: JetNamedDeclaration): Boolean {
-        val lightClass = klass.toLightClass()
+        val lightElement: PsiElement? = when (declaration) {
-        if (lightClass != null && javaInspection.isEntryPoint(lightClass)) return true
+            is JetClass ->  declaration.toLightClass()
-        return false
+            is JetNamedFunction -> LightClassUtil.getLightClassMethod(declaration)
+            else -> null
+        }
+        return lightElement != null && javaInspection.isEntryPoint(lightElement)
     }
 
     private fun classHasTextUsages(klass: JetClass): Boolean {
@@ -88,6 +106,7 @@ public class UnusedSymbolInspection : AbstractKotlinInspection() {
     private fun hasNonTrivialUsages(declaration: JetNamedDeclaration): Boolean {
         val searchHelper: UsagesSearchHelper<out JetNamedDeclaration> = when (declaration) {
             is JetClass -> ClassUsagesSearchHelper(constructorUsages = true, nonConstructorUsages = true, skipImports = true)
+            is JetNamedFunction -> FunctionUsagesSearchHelper(skipImports = true)
             else -> return false
         }
 

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

@@ -1,4 +1,4 @@
-fun f() {
+fun main(args: Array<String>) {
     class Local {
     }
 }

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

@@ -1,4 +1,4 @@
-fun f() {
+fun main(args: Array<String>) {
     class Local {
 
     }

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

@@ -1,4 +1,5 @@
 class A
 
-fun f(): A {
+fun main(args: Array<String>) {
+    val x: A? = null
 }

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

@@ -1,4 +1,3 @@
 class A {
-    fun f(other: A) {
+    val x: A? = null
-    }
 }

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

@@ -0,0 +1,10 @@
+open class Klass {
+    fun used() {
+    }
+}
+
+class Subklass: Klass()
+
+fun main(args: Array<String>) {
+    Subklass().used()
+}

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

@@ -0,0 +1,13 @@
+open class Klass {
+    open fun used() {
+    }
+}
+
+class Subklass: Klass() {
+    override fun used() {
+    }
+}
+
+fun main(args: Array<String>) {
+    Subklass().used()
+}

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

@@ -0,0 +1,9 @@
+class Klass: Iterable<String> {
+    override fun iterator(): Iterator<String> {
+        throw UnsupportedOperationException()
+    }
+}
+
+fun main(args: Array<String>) {
+    Klass()
+}

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

@@ -0,0 +1,8 @@
+class Klass {
+    fun unused() {
+    }
+}
+
+fun main(args: Array<String>) {
+    Klass()
+}

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

@@ -0,0 +1,8 @@
+class Klass {
+    fun used() {
+    }
+}
+
+fun main(args: Array<String>) {
+    Klass().used()
+}

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

@@ -0,0 +1,54 @@
+<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>Function '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>Function 'onlyInImport' is never used</description>
+  </problem>
+
+  <problem>
+    <file>local.kt</file>
+    <line>2</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/local.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Function 'local' is never used</description>
+  </problem>
+  <problem>
+    <file>local.kt</file>
+    <line>1</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/local.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Function 'outer' is never used</description>
+  </problem>
+
+  <problem>
+    <file>usedOnlyRecursively.kt</file>
+    <line>1</line>
+    <module>light_idea_test_case</module>
+    <entry_point TYPE="file" FQNAME="temp:///src/usedOnlyRecursively.kt" />
+    <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused Symbol</problem_class>
+    <description>Function 'usedOnlyRecursively' 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>Function 'unused' is never used</description>
+  </problem>
+</problems>

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

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

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

@@ -0,0 +1,5 @@
+fun outer() {
+    fun local() {
+
+    }
+}

idea/testData/inspections/unusedSymbol/function/topLevelMain.kt

@@ -0,0 +1,3 @@
+fun main(args: Array<String>) {
+
+}

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

@@ -0,0 +1,7 @@
+package foo
+
+import foo.onlyInImport
+
+fun onlyInImport() {
+
+}

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

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

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

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

idea/testData/inspections/unusedSymbol/function/usedOnlyRecursively.kt

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

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

@@ -83,5 +83,11 @@ public class JetInspectionTestGenerated extends AbstractJetInspectionTest {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/inspections/unusedSymbol/class/inspectionData/inspections.test");
             doTest(fileName);
         }
+
+        @TestMetadata("unusedSymbol/function/inspectionData/inspections.test")
+        public void testUnusedSymbol_function_inspectionData_Inspections_test() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/testData/inspections/unusedSymbol/function/inspectionData/inspections.test");
+            doTest(fileName);
+        }
     }
 }