Completion sorts items by name similarity in intializer of variable with no explicit type

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

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.ClassifierDescriptor
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.idea.completion.smart.toExpressionWithType
 import org.jetbrains.kotlin.idea.core.SmartCastCalculator
 import org.jetbrains.kotlin.idea.project.ProjectStructureUtil
 import org.jetbrains.kotlin.idea.stubindex.PackageIndexUtil
@@ -284,7 +285,8 @@ class BasicCompletionSession(configuration: CompletionSessionConfiguration,
         }
 
         if (expression != null) {
-            val expectedInfos = ExpectedInfos(bindingContext, resolutionFacade, moduleDescriptor).calculate(expression)
+            val expressionWithType = expression.toExpressionWithType()
+            val expectedInfos = ExpectedInfos(bindingContext, resolutionFacade, moduleDescriptor).calculate(expressionWithType)
 
             if (expectedInfos != null && expectedInfos.isNotEmpty()) {
                 val smartCastCalculator = SmartCastCalculator(bindingContext, moduleDescriptor, expression)

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

@@ -71,10 +71,18 @@ data class ItemOptions(val starPrefix: Boolean) {
 
 interface ByTypeFilter {
     fun matchingSubstitutor(descriptorType: FuzzyType): TypeSubstitutor?
+
+    object All : ByTypeFilter {
+        override fun matchingSubstitutor(descriptorType: FuzzyType) = TypeSubstitutor.EMPTY
+    }
 }
 
 class ByExpectedTypeFilter(val fuzzyType: FuzzyType) : ByTypeFilter {
     override fun matchingSubstitutor(descriptorType: FuzzyType) = descriptorType.checkIsSubtypeOf(fuzzyType)
+
+    override fun equals(other: Any?) = other is ByExpectedTypeFilter && fuzzyType == other.fuzzyType
+
+    override fun hashCode() = fuzzyType.hashCode()
 }
 
 open data class ExpectedInfo(val filter: ByTypeFilter, val expectedName: String?, val tail: Tail?, val itemOptions: ItemOptions = ItemOptions.DEFAULT) {
@@ -107,7 +115,14 @@ class ArgumentExpectedInfo(type: JetType, name: String?, tail: Tail?, val functi
             = function.hashCode()
 }
 
-class ReturnValueExpectedInfo(type: JetType, val callable: CallableDescriptor) : ExpectedInfo(type, callable.getName().asString(), null) {
+class ReturnValueExpectedInfo(
+        type: JetType?,
+        val callable: CallableDescriptor
+) : ExpectedInfo(
+        if (type != null) ByExpectedTypeFilter(FuzzyType(type, emptyList())) else ByTypeFilter.All,
+        callable.name.asString(),
+        null
+) {
     override fun equals(other: Any?)
             = other is ReturnValueExpectedInfo && super.equals(other) && callable == other.callable
 
@@ -413,30 +428,39 @@ class ExpectedInfos(
         val property = expressionWithType.getParent() as? JetProperty ?: return null
         if (expressionWithType != property.getInitializer()) return null
         val propertyDescriptor = bindingContext[BindingContext.DECLARATION_TO_DESCRIPTOR, property] as? VariableDescriptor ?: return null
-        return listOf(ExpectedInfo(propertyDescriptor.getType(), propertyDescriptor.getName().asString(), null))
+        val expectedName = propertyDescriptor.name.asString()
+        val expectedInfo = if (property.typeReference != null)
+            ExpectedInfo(propertyDescriptor.getType(), expectedName, null)
+        else
+            ExpectedInfo(ByTypeFilter.All, expectedName, null) // no explicit type - only expected name known
+        return listOf(expectedInfo)
     }
 
     private fun calculateForExpressionBody(expressionWithType: JetExpression): Collection<ExpectedInfo>? {
         val declaration = expressionWithType.getParent() as? JetDeclarationWithBody ?: return null
         if (expressionWithType != declaration.getBodyExpression() || declaration.hasBlockBody()) return null
         val descriptor = bindingContext[BindingContext.DECLARATION_TO_DESCRIPTOR, declaration] as? FunctionDescriptor ?: return null
-        return functionReturnValueExpectedInfo(descriptor).toList()
+        return functionReturnValueExpectedInfo(descriptor, expectType = declaration.hasDeclaredReturnType()).toList()
     }
 
     private fun calculateForReturn(expressionWithType: JetExpression): Collection<ExpectedInfo>? {
         val returnExpression = expressionWithType.getParent() as? JetReturnExpression ?: return null
         val descriptor = returnExpression.getTargetFunctionDescriptor(bindingContext) ?: return null
-        return functionReturnValueExpectedInfo(descriptor).toList()
+        return functionReturnValueExpectedInfo(descriptor, expectType = true).toList()
     }
 
-    private fun functionReturnValueExpectedInfo(descriptor: FunctionDescriptor): ReturnValueExpectedInfo? {
+    private fun functionReturnValueExpectedInfo(descriptor: FunctionDescriptor, expectType: Boolean): ReturnValueExpectedInfo? {
         return when (descriptor) {
-            is SimpleFunctionDescriptor -> ReturnValueExpectedInfo(descriptor.getReturnType() ?: return null, descriptor)
+            is SimpleFunctionDescriptor -> {
+                val expectedType = if (expectType) descriptor.returnType else null
+                ReturnValueExpectedInfo(expectedType, descriptor)
+            }
 
             is PropertyGetterDescriptor -> {
                 if (descriptor !is PropertyGetterDescriptor) return null
                 val property = descriptor.getCorrespondingProperty()
-                ReturnValueExpectedInfo(property.getType(), property)
+                val expectedType = if (expectType) property.type else null
+                ReturnValueExpectedInfo(expectedType, property)
             }
 
             else -> null

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

@@ -184,7 +184,6 @@ class DeclarationRemotenessWeigher(private val file: JetFile) : LookupElementWei
     }
 }
 
-//TODO: prefer by name too (and only by name too)
 class ExpectedInfoMatchWeigher(
         private val expectedInfos: Collection<ExpectedInfo>,
         private val smartCastCalculator: SmartCastCalculator

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/smart/Utils.kt

@@ -29,6 +29,9 @@ import org.jetbrains.kotlin.idea.completion.handlers.WithExpressionPrefixInsertH
 import org.jetbrains.kotlin.idea.completion.handlers.WithTailInsertHandler
 import org.jetbrains.kotlin.idea.core.SmartCastCalculator
 import org.jetbrains.kotlin.idea.util.*
+import org.jetbrains.kotlin.psi.JetExpression
+import org.jetbrains.kotlin.psi.JetSimpleNameExpression
+import org.jetbrains.kotlin.psi.psiUtil.getReceiverExpression
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
 import org.jetbrains.kotlin.types.JetType
@@ -341,3 +344,7 @@ fun DeclarationDescriptor.fuzzyTypesForSmartCompletion(smartCastCalculator: Smar
         return emptyList()
     }
 }
+
+fun JetExpression.toExpressionWithType(): JetExpression {
+    return (this as? JetSimpleNameExpression)?.getReceiverExpression()?.parent as? JetExpression ?: this
+}

idea/idea-completion/testData/weighers/basic/expectedInfo/ExpectedType2.kt

@@ -0,0 +1,13 @@
+interface I {
+    fun takeXxx(): Int = 0
+    fun takeYyy(): String = ""
+    fun takeZzz(): Int = 0
+}
+
+fun foo(i: I): String {
+    return i.take<caret>
+}
+
+// ORDER: takeYyy
+// ORDER: takeXxx
+// ORDER: takeZzz

idea/idea-completion/testData/weighers/basic/expectedInfo/NameSimilarityAndNoExpectedType.kt

@@ -0,0 +1,13 @@
+interface I {
+    fun takeXxx(): Int = 0
+    fun takeYyy(): Int = 0
+    fun takeZzz(): Int = 0
+}
+
+fun foo(i: I) {
+    val yyy = i.take<caret>
+}
+
+// ORDER: takeYyy
+// ORDER: takeXxx
+// ORDER: takeZzz

idea/idea-completion/testData/weighers/basic/expectedInfo/NameSimilarityAndNoExpectedType2.kt

@@ -0,0 +1,11 @@
+interface I {
+    fun takeXxx(): Int = 0
+    fun takeYyy(): Int = 0
+    fun takeZzz(): Int = 0
+}
+
+fun takeYyy(i: I) = i.take<caret>
+
+// ORDER: takeYyy
+// ORDER: takeXxx
+// ORDER: takeZzz

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/weighers/BasicCompletionWeigherTestGenerated.java

@@ -157,12 +157,30 @@ public class BasicCompletionWeigherTestGenerated extends AbstractBasicCompletion
             doTest(fileName);
         }
 
+        @TestMetadata("ExpectedType2.kt")
+        public void testExpectedType2() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/weighers/basic/expectedInfo/ExpectedType2.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("NameSimilarity.kt")
         public void testNameSimilarity() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/weighers/basic/expectedInfo/NameSimilarity.kt");
             doTest(fileName);
         }
 
+        @TestMetadata("NameSimilarityAndNoExpectedType.kt")
+        public void testNameSimilarityAndNoExpectedType() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/weighers/basic/expectedInfo/NameSimilarityAndNoExpectedType.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("NameSimilarityAndNoExpectedType2.kt")
+        public void testNameSimilarityAndNoExpectedType2() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/weighers/basic/expectedInfo/NameSimilarityAndNoExpectedType2.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("PreferMatchingThis.kt")
         public void testPreferMatchingThis() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/weighers/basic/expectedInfo/PreferMatchingThis.kt");