Call method references search in UnusedSymbolInspection.hasReferences to fix secondary constructor search

Makes #KT-12500 Fixed
Makes #KT-12501 Fixed

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

@@ -40,6 +40,7 @@ import com.intellij.psi.search.PsiSearchHelper
 import com.intellij.psi.search.PsiSearchHelper.SearchCostResult.*
 import com.intellij.psi.search.SearchScope
 import com.intellij.psi.search.searches.DefinitionsScopedSearch
+import com.intellij.psi.search.searches.MethodReferencesSearch
 import com.intellij.psi.search.searches.ReferencesSearch
 import com.intellij.refactoring.safeDelete.SafeDeleteHandler
 import org.jetbrains.kotlin.asJava.LightClassUtil
@@ -243,7 +244,8 @@ class UnusedSymbolInspection : AbstractKotlinInspection() {
     }
 
     private fun hasReferences(declaration: KtNamedDeclaration, useScope: SearchScope): Boolean {
-        return !ReferencesSearch.search(declaration, useScope).forEach(fun (ref: PsiReference): Boolean {
+
+        fun checkReference(ref: PsiReference): Boolean {
             if (declaration.isAncestor(ref.element)) return true // usages inside element's declaration are not counted
 
             if (ref.element.parent is KtValueArgumentName) return true // usage of parameter in form of named argument is not counted
@@ -273,7 +275,16 @@ class UnusedSymbolInspection : AbstractKotlinInspection() {
             }
 
             return false
-        })
+        }
+
+        if (declaration is KtCallableDeclaration) {
+            val lightMethods = declaration.toLightMethods()
+            for (method in lightMethods) {
+                if (!MethodReferencesSearch.search(method).forEach(::checkReference)) return true
+            }
+        }
+
+        return !ReferencesSearch.search(declaration, useScope).forEach(::checkReference)
     }
 
     private fun hasOverrides(declaration: KtNamedDeclaration, useScope: SearchScope): Boolean {
@@ -347,7 +358,7 @@ class UnusedSymbolInspection : AbstractKotlinInspection() {
 }
 
 class SafeDeleteFix(declaration: KtDeclaration) : LocalQuickFix {
-    private val name =
+    private val name: String =
             if (declaration is KtConstructor<*>) "Safe delete constructor"
             else QuickFixBundle.message("safe.delete.text", declaration.name)
 

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

@@ -0,0 +1,20 @@
+class CtorUsedByOtherCtor {
+    constructor()
+
+    constructor(p: String): this()
+}
+
+open class CtorUsedParent {
+    constructor()
+}
+
+class CtorUsedChild : CtorUsedParent {
+    constructor() : super()
+}
+
+@test.anno.EntryPoint
+fun use(): Int {
+    val first = CtorUsedByOtherCtor("")
+    val second = CtorUsedChild(true)
+    return first.hashCode() + second.hashCode()
+}

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

@@ -2,4 +2,9 @@ class RandomJavaClass {
     void g() {
         foo.UsedInJavaKt.usedInJava();
     }
+
+    public void context() {
+        foo.Ctor c = new foo.Ctor(0);
+        c.justCompare();
+    }
 }

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

@@ -1,4 +1,9 @@
 package foo
 
 fun usedInJava() {
-}
+}
+
+class Ctor {
+    constructor(p: Int)
+    fun justCompare() {}
+}

idea/testData/quickfix/removeUnused/secondaryConstructorFromJava.before.Dependency.java

@@ -0,0 +1,6 @@
+class RandomJavaClass {
+    public void context() {
+        Ctor c = new Ctor(0);
+        c.justCompare();
+    }
+}

idea/testData/quickfix/removeUnused/secondaryConstructorFromJava.before.Main.kt

@@ -0,0 +1,11 @@
+// "Safe delete constructor" "false"
+// ACTION: Convert to primary constructor
+// ACTION: Make internal
+// ACTION: Make private
+// ACTION: Make protected
+
+class Ctor {
+    <caret>constructor(p: Int)
+
+    fun justCompare() {}
+}

idea/testData/quickfix/removeUnused/secondaryConstructorFromJavaDelegate.before.Dependency.java

@@ -0,0 +1,5 @@
+class RandomJavaClass extends Ctor {
+    RandomJavaClass() {
+        super(42);
+    }
+}

idea/testData/quickfix/removeUnused/secondaryConstructorFromJavaDelegate.before.Main.kt

@@ -0,0 +1,9 @@
+// "Safe delete constructor" "false"
+// ACTION: Convert to primary constructor
+// ACTION: Make internal
+// ACTION: Make private
+// ACTION: Make protected
+
+open class Ctor {
+    <caret>constructor(p: Int)
+}

idea/testData/quickfix/removeUnused/unusedDelegatedConstructor.kt

@@ -0,0 +1,11 @@
+// "Safe delete constructor" "false"
+// ACTION: Convert to primary constructor
+// ACTION: Make internal
+// ACTION: Make private
+// ACTION: Make protected
+
+class CtorUsedByOtherCtor {
+    <caret>constructor()
+
+    constructor(p: String): this()
+}

idea/testData/quickfix/removeUnused/unusedDelegatedConstructorSuper.kt

@@ -0,0 +1,13 @@
+// "Safe delete constructor" "false"
+// ACTION: Convert to primary constructor
+// ACTION: Make internal
+// ACTION: Make private
+// ACTION: Make protected
+
+open class CtorUsedParent {
+    <caret>constructor()
+}
+
+class CtorUsedChild : CtorUsedParent {
+    constructor() : super()
+}

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixMultiFileTestGenerated.java

@@ -1831,6 +1831,18 @@ public class QuickFixMultiFileTestGenerated extends AbstractQuickFixMultiFileTes
             doTestWithExtraFile(fileName);
         }
 
+        @TestMetadata("secondaryConstructorFromJava.before.Main.kt")
+        public void testSecondaryConstructorFromJava() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/removeUnused/secondaryConstructorFromJava.before.Main.kt");
+            doTestWithExtraFile(fileName);
+        }
+
+        @TestMetadata("secondaryConstructorFromJavaDelegate.before.Main.kt")
+        public void testSecondaryConstructorFromJavaDelegate() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/removeUnused/secondaryConstructorFromJavaDelegate.before.Main.kt");
+            doTestWithExtraFile(fileName);
+        }
+
         @TestMetadata("usedObjectAsAliasMulti.before.Main.kt")
         public void testUsedObjectAsAliasMulti() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/removeUnused/usedObjectAsAliasMulti.before.Main.kt");

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -7524,6 +7524,18 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("unusedDelegatedConstructor.kt")
+        public void testUnusedDelegatedConstructor() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/removeUnused/unusedDelegatedConstructor.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("unusedDelegatedConstructorSuper.kt")
+        public void testUnusedDelegatedConstructorSuper() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/removeUnused/unusedDelegatedConstructorSuper.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("unusedFunction.kt")
         public void testUnusedFunction() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/removeUnused/unusedFunction.kt");