KT-12068 Special completion item for "[]" get-operator access

#KT-12068 Fixed

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/CompletionUtils.kt

@@ -67,6 +67,7 @@ tailrec fun <T : Any> LookupElement.getUserDataDeep(key: Key<T>): T? {
 enum class ItemPriority {
     SUPER_METHOD_WITH_ARGUMENTS,
     FROM_UNRESOLVED_NAME_SUGGESTION,
+    GET_OPERATOR,
     DEFAULT,
     IMPLEMENT,
     OVERRIDE,

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/LookupElementFactory.kt

@@ -16,6 +16,7 @@
 
 package org.jetbrains.kotlin.idea.completion
 
+import com.intellij.codeInsight.AutoPopupController
 import com.intellij.codeInsight.completion.InsertionContext
 import com.intellij.codeInsight.lookup.LookupElement
 import com.intellij.codeInsight.lookup.LookupElementDecorator
@@ -27,6 +28,7 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.idea.completion.handlers.GenerateLambdaInfo
 import org.jetbrains.kotlin.idea.completion.handlers.KotlinFunctionInsertHandler
 import org.jetbrains.kotlin.idea.completion.handlers.lambdaPresentation
+import org.jetbrains.kotlin.idea.core.moveCaret
 import org.jetbrains.kotlin.idea.util.CallType
 import org.jetbrains.kotlin.idea.util.toFuzzyType
 import org.jetbrains.kotlin.renderer.DescriptorRenderer
@@ -42,6 +44,7 @@ import org.jetbrains.kotlin.synthetic.SyntheticJavaPropertyDescriptor
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
 import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
+import org.jetbrains.kotlin.util.OperatorNameConventions
 import org.jetbrains.kotlin.utils.addIfNotNull
 
 interface AbstractLookupElementFactory {
@@ -100,6 +103,31 @@ class LookupElementFactory(
             }
         }
 
+        // special "[]" item for get-operator
+        if (callType == CallType.DOT && descriptor is FunctionDescriptor && descriptor.isOperator() && descriptor.name == OperatorNameConventions.GET) {
+            val baseLookupElement = createLookupElement(descriptor, useReceiverTypes)
+            val lookupElement = object : LookupElementDecorator<LookupElement>(baseLookupElement) {
+                override fun getLookupString() = "[]"
+                override fun getAllLookupStrings() = setOf(lookupString)
+
+                override fun renderElement(presentation: LookupElementPresentation) {
+                    super.renderElement(presentation)
+                    presentation.itemText = lookupString
+                }
+
+                override fun handleInsert(context: InsertionContext) {
+                    val startOffset = context.startOffset
+                    assert(context.document.charsSequence[startOffset - 1] == '.')
+                    context.document.deleteString(startOffset - 1, startOffset)
+                    context.editor.moveCaret(startOffset)
+
+                    AutoPopupController.getInstance(context.project)?.autoPopupParameterInfo(context.editor, null)
+                }
+            }
+            lookupElement.assignPriority(ItemPriority.GET_OPERATOR)
+            result.add(lookupElement)
+        }
+
         return result.map(standardLookupElementsPostProcessor)
     }
 

idea/idea-completion/testData/basic/common/getOperator/Extension.kt

@@ -0,0 +1,11 @@
+package p
+
+class C
+
+operator fun C.get(p: Int): Int = 0
+
+fun foo(c: C) {
+    c.<caret>
+}
+
+// EXIST: { lookupString: "[]", itemText: "[]", tailText: "(p: Int) for C in p", typeText: "Int", attributes: "bold" }

idea/idea-completion/testData/basic/common/getOperator/NotForSafeCall.kt

@@ -0,0 +1,5 @@
+fun some(list: List<String>?) {
+    list?.<caret>
+}
+
+// ABSENT: "[]"

idea/idea-completion/testData/basic/common/getOperator/Simple.kt

@@ -0,0 +1,5 @@
+fun some(list: List<String>) {
+    list.<caret>
+}
+
+// EXIST: { lookupString: "[]", itemText: "[]", tailText: "(index: Int)", typeText: "String", attributes: "bold" }

idea/idea-completion/testData/handlers/basic/GetOperator.kt

@@ -0,0 +1,5 @@
+fun some(list: List<String>) {
+    list.<caret>
+}
+
+// ELEMENT: "[]"

idea/idea-completion/testData/handlers/basic/GetOperator.kt.after

@@ -0,0 +1,5 @@
+fun some(list: List<String>) {
+    list[<caret>]
+}
+
+// ELEMENT: "[]"

idea/idea-completion/testData/smart/GetOperator.kt

@@ -0,0 +1,5 @@
+fun some(list: List<String>): String {
+    return list.<caret>
+}
+
+// EXIST: { lookupString: "[]", itemText: "[]", tailText: "(index: Int)", typeText: "String", attributes: "bold" }

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JSBasicCompletionTestGenerated.java

@@ -1519,6 +1519,33 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
             }
         }
 
+        @TestMetadata("idea/idea-completion/testData/basic/common/getOperator")
+        @TestDataPath("$PROJECT_ROOT")
+        @RunWith(JUnit3RunnerWithInners.class)
+        public static class GetOperator extends AbstractJSBasicCompletionTest {
+            public void testAllFilesPresentInGetOperator() throws Exception {
+                KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/idea-completion/testData/basic/common/getOperator"), Pattern.compile("^(.+)\\.kt$"), true);
+            }
+
+            @TestMetadata("Extension.kt")
+            public void testExtension() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/getOperator/Extension.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("NotForSafeCall.kt")
+            public void testNotForSafeCall() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/getOperator/NotForSafeCall.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("Simple.kt")
+            public void testSimple() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/getOperator/Simple.kt");
+                doTest(fileName);
+            }
+        }
+
         @TestMetadata("idea/idea-completion/testData/basic/common/highOrderFunctions")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JvmBasicCompletionTestGenerated.java

@@ -1519,6 +1519,33 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
             }
         }
 
+        @TestMetadata("idea/idea-completion/testData/basic/common/getOperator")
+        @TestDataPath("$PROJECT_ROOT")
+        @RunWith(JUnit3RunnerWithInners.class)
+        public static class GetOperator extends AbstractJvmBasicCompletionTest {
+            public void testAllFilesPresentInGetOperator() throws Exception {
+                KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("idea/idea-completion/testData/basic/common/getOperator"), Pattern.compile("^(.+)\\.kt$"), true);
+            }
+
+            @TestMetadata("Extension.kt")
+            public void testExtension() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/getOperator/Extension.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("NotForSafeCall.kt")
+            public void testNotForSafeCall() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/getOperator/NotForSafeCall.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("Simple.kt")
+            public void testSimple() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/basic/common/getOperator/Simple.kt");
+                doTest(fileName);
+            }
+        }
+
         @TestMetadata("idea/idea-completion/testData/basic/common/highOrderFunctions")
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JvmSmartCompletionTestGenerated.java

@@ -149,6 +149,12 @@ public class JvmSmartCompletionTestGenerated extends AbstractJvmSmartCompletionT
         doTest(fileName);
     }
 
+    @TestMetadata("GetOperator.kt")
+    public void testGetOperator() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/smart/GetOperator.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("GroupBySubstitutor.kt")
     public void testGroupBySubstitutor() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/smart/GroupBySubstitutor.kt");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/handlers/BasicCompletionHandlerTestGenerated.java

@@ -119,6 +119,12 @@ public class BasicCompletionHandlerTestGenerated extends AbstractBasicCompletion
         doTest(fileName);
     }
 
+    @TestMetadata("GetOperator.kt")
+    public void testGetOperator() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/handlers/basic/GetOperator.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("InterfaceNameBeforeRunBug.kt")
     public void testInterfaceNameBeforeRunBug() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/idea-completion/testData/handlers/basic/InterfaceNameBeforeRunBug.kt");