Add quickfix to add 'toString' (#866)

Fixes #KT-12121

core/descriptors/src/org/jetbrains/kotlin/builtins/KotlinBuiltIns.java

@@ -879,6 +879,14 @@ public abstract class KotlinBuiltIns {
         return type != null && isNotNullConstructedFromGivenClass(type, FQ_NAMES.string);
     }
 
+    public static boolean isCharSequenceOrNullableCharSequence(@Nullable KotlinType type) {
+        return type != null && isConstructedFromGivenClass(type, FQ_NAMES.charSequence);
+    }
+
+    public static boolean isStringOrNullableString(@Nullable KotlinType type) {
+        return type != null && isConstructedFromGivenClass(type, FQ_NAMES.string);
+    }
+
     public static boolean isCollectionOrNullableCollection(@NotNull KotlinType type) {
         return isConstructedFromGivenClass(type, FQ_NAMES._collection);
     }

idea/src/org/jetbrains/kotlin/idea/quickfix/AddToStringFix.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2016 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.jetbrains.kotlin.idea.quickfix
+
+import com.intellij.openapi.editor.Editor
+import com.intellij.openapi.project.Project
+import org.jetbrains.kotlin.idea.core.replaced
+import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.psi.KtPsiFactory
+import org.jetbrains.kotlin.psi.createExpressionByPattern
+import org.jetbrains.kotlin.psi.psiUtil.endOffset
+
+class AddToStringFix(element: KtExpression, private val nullable: Boolean) : KotlinQuickFixAction<KtExpression>(element) {
+    override fun getFamilyName() = "Add 'toString()' call"
+    override fun getText() = if (nullable) "Add safe '?.toString()' call" else "Add 'toString()' call"
+
+    override fun invoke(project: Project, editor: Editor?, file: KtFile) {
+        val pattern = if (nullable) "$0?.toString()" else "$0.toString()"
+        val expressionToInsert = KtPsiFactory(file).createExpressionByPattern(pattern, element)
+        val newExpression = element.replaced(expressionToInsert)
+        editor?.caretModel?.moveToOffset(newExpression.endOffset)
+    }
+}

idea/src/org/jetbrains/kotlin/idea/quickfix/QuickFixFactoryForTypeMismatchError.kt

@@ -86,6 +86,14 @@ class QuickFixFactoryForTypeMismatchError : KotlinIntentionActionsFactory() {
             actions.add(NumberConversionFix(diagnosticElement, expectedType))
         }
 
+        if (KotlinBuiltIns.isCharSequenceOrNullableCharSequence(expectedType)
+            || KotlinBuiltIns.isStringOrNullableString(expectedType)) {
+            actions.add(AddToStringFix(diagnosticElement, false))
+            if (expectedType.isMarkedNullable && expressionType.isMarkedNullable) {
+                actions.add(AddToStringFix(diagnosticElement, true))
+            }
+        }
+
         if (expectedType.isInterface()) {
             val expressionTypeDeclaration = expressionType.constructor.declarationDescriptor?.let {
                 DescriptorToSourceUtils.descriptorToDeclaration(it)

idea/testData/quickfix/toString/notNullableExpectedNullable.kt

@@ -0,0 +1,9 @@
+// "Add 'toString()' call" "true"
+// ACTION: Add 'toString()' call
+
+fun foo() {
+    bar(Any()<caret>)
+}
+
+fun bar(a: String?) {
+}

idea/testData/quickfix/toString/notNullableExpectedNullable.kt.after

@@ -0,0 +1,9 @@
+// "Add 'toString()' call" "true"
+// ACTION: Add 'toString()' call
+
+fun foo() {
+    bar(Any().toString()<caret>)
+}
+
+fun bar(a: String?) {
+}

idea/testData/quickfix/toString/nullableExpectedNotNullable.kt

@@ -0,0 +1,9 @@
+// "Add 'toString()' call" "true"
+// ACTION: Add 'toString()' call
+
+fun foo() {
+    bar(null as Any?<caret>)
+}
+
+fun bar(a: String) {
+}

idea/testData/quickfix/toString/nullableExpectedNotNullable.kt.after

@@ -0,0 +1,9 @@
+// "Add 'toString()' call" "true"
+// ACTION: Add 'toString()' call
+
+fun foo() {
+    bar((null as Any?).toString()<caret>)
+}
+
+fun bar(a: String) {
+}

idea/testData/quickfix/toString/nullableExpectedNullable.kt

@@ -0,0 +1,10 @@
+// "Add safe '?.toString()' call" "true"
+// ACTION: Add 'toString()' call
+// ACTION: Add safe '?.toString()' call
+
+fun foo() {
+    bar(null as Any?<caret>)
+}
+
+fun bar(a: String?) {
+}

idea/testData/quickfix/toString/nullableExpectedNullable.kt.after

@@ -0,0 +1,10 @@
+// "Add safe '?.toString()' call" "true"
+// ACTION: Add 'toString()' call
+// ACTION: Add safe '?.toString()' call
+
+fun foo() {
+    bar((null as Any?)?.toString()<caret>)
+}
+
+fun bar(a: String?) {
+}

idea/testData/quickfix/toString/simple.kt

@@ -0,0 +1,8 @@
+// "Add 'toString()' call" "true"
+
+fun foo() {
+    bar(Any()<caret>)
+}
+
+fun bar(a: String) {
+}

idea/testData/quickfix/toString/simple.kt.after

@@ -0,0 +1,8 @@
+// "Add 'toString()' call" "true"
+
+fun foo() {
+    bar(Any().toString()<caret>)
+}
+
+fun bar(a: String) {
+}

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

@@ -7265,6 +7265,39 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
         }
     }
 
+    @TestMetadata("idea/testData/quickfix/toString")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class ToString extends AbstractQuickFixTest {
+        public void testAllFilesPresentInToString() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/testData/quickfix/toString"), Pattern.compile("^([\\w\\-_]+)\\.kt$"), true);
+        }
+
+        @TestMetadata("notNullableExpectedNullable.kt")
+        public void testNotNullableExpectedNullable() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/toString/notNullableExpectedNullable.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableExpectedNotNullable.kt")
+        public void testNullableExpectedNotNullable() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/toString/nullableExpectedNotNullable.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nullableExpectedNullable.kt")
+        public void testNullableExpectedNullable() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/toString/nullableExpectedNullable.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("simple.kt")
+        public void testSimple() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/toString/simple.kt");
+            doTest(fileName);
+        }
+    }
+
     @TestMetadata("idea/testData/quickfix/typeAddition")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)