Ordinary completion prefers item matching expected name

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

@@ -21,20 +21,15 @@ import com.intellij.codeInsight.lookup.LookupElementWeigher
 import com.intellij.codeInsight.lookup.WeighingContext
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
-import org.jetbrains.kotlin.idea.completion.smart.SMART_COMPLETION_ITEM_PRIORITY_KEY
-import org.jetbrains.kotlin.idea.completion.smart.SmartCompletionItemPriority
-import org.jetbrains.kotlin.idea.completion.smart.fuzzyTypesForSmartCompletion
+import org.jetbrains.kotlin.idea.completion.smart.*
 import org.jetbrains.kotlin.idea.core.SmartCastCalculator
 import org.jetbrains.kotlin.idea.core.completion.DeclarationLookupObject
 import org.jetbrains.kotlin.idea.util.FuzzyType
 import org.jetbrains.kotlin.idea.util.ImportInsertHelper
-import org.jetbrains.kotlin.idea.util.makeNotNullable
-import org.jetbrains.kotlin.idea.util.nullability
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.platform.JavaToKotlinClassMap
 import org.jetbrains.kotlin.psi.JetFile
 import org.jetbrains.kotlin.resolve.ImportPath
-import org.jetbrains.kotlin.types.typeUtil.TypeNullability
 import java.util.HashSet
 
 object PriorityWeigher : LookupElementWeigher("kotlin.priority") {
@@ -194,30 +189,47 @@ class ExpectedInfoMatchWeigher(
         private val expectedInfos: Collection<ExpectedInfo>,
         private val smartCastCalculator: SmartCastCalculator
 ) : LookupElementWeigher("kotlin.expectedInfoMatch") {
-    private enum class Weight {
-        matches,
-        matchesIfNotNull,
-        doesNotMatch
+
+    private val NO_MATCH = 0L
+
+    private fun fullMatch(nameSimilarity: Int): Long {
+        return -((2L shl 32) + nameSimilarity)
     }
 
-    override fun weigh(element: LookupElement): Weight {
+    private fun ifNotNullMatch(nameSimilarity: Int): Long {
+        return -((1L shl 32) + nameSimilarity)
+    }
+
+    override fun weigh(element: LookupElement): Long {
         // TODO: keywords with type
         val o = element.`object`
-        val fuzzyTypes = when (o) {
+        val (fuzzyTypes, name) = when (o) {
             is DeclarationLookupObject -> {
-                val descriptor = o.descriptor ?: return Weight.doesNotMatch
-                descriptor.fuzzyTypesForSmartCompletion(smartCastCalculator)
+                val descriptor = o.descriptor ?: return NO_MATCH
+                descriptor.fuzzyTypesForSmartCompletion(smartCastCalculator) to descriptor.name
             }
 
-            is ThisItemLookupObject -> smartCastCalculator.types(o.receiverParameter).map { FuzzyType(it, emptyList()) }
+            is ThisItemLookupObject -> smartCastCalculator.types(o.receiverParameter).map { FuzzyType(it, emptyList()) } to null
 
-            else -> return Weight.doesNotMatch
+            else -> return NO_MATCH
         }
 
-        return when {
-            fuzzyTypes.any { type -> expectedInfos.any { it.matchingSubstitutor(type) != null } } -> Weight.matches
-            fuzzyTypes.any { type -> type.nullability() == TypeNullability.NULLABLE && expectedInfos.any { it.matchingSubstitutor(type.makeNotNullable()) != null } } -> Weight.matchesIfNotNull
-            else -> Weight.doesNotMatch
+        if (fuzzyTypes.isEmpty()) return NO_MATCH
+
+        val classified: Collection<Pair<ExpectedInfo, ExpectedInfoClassification>> = expectedInfos.map { it to fuzzyTypes.classifyExpectedInfo(it) }
+        if (classified.all { it.second == ExpectedInfoClassification.noMatch }) return NO_MATCH
+
+        val nameSimilarity = if (name != null) {
+            val matchingInfos = classified.filter { it.second != ExpectedInfoClassification.noMatch }.map { it.first }
+            calcNameSimilarity(name.asString(), matchingInfos)
         }
+        else {
+            0
+        }
+
+        return if (classified.any { it.second.isMatch() })
+            fullMatch(nameSimilarity)
+        else
+            ifNotNullMatch(nameSimilarity)
     }
 }

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

@@ -54,7 +54,7 @@ object KeywordValues {
 
         if (!skipTrueFalse) {
             val booleanInfoClassifier = { info: ExpectedInfo ->
-                if (info.fuzzyType?.type == KotlinBuiltIns.getInstance().getBooleanType()) ExpectedInfoClassification.matches(TypeSubstitutor.EMPTY) else ExpectedInfoClassification.notMatches
+                if (info.fuzzyType?.type == KotlinBuiltIns.getInstance().getBooleanType()) ExpectedInfoClassification.match(TypeSubstitutor.EMPTY) else ExpectedInfoClassification.noMatch
             }
             collection.addLookupElements(null, expectedInfos, booleanInfoClassifier) { LookupElementBuilder.create("true").bold().assignSmartCompletionPriority(SmartCompletionItemPriority.TRUE) }
             collection.addLookupElements(null, expectedInfos, booleanInfoClassifier) { LookupElementBuilder.create("false").bold().assignSmartCompletionPriority(SmartCompletionItemPriority.FALSE) }
@@ -62,9 +62,9 @@ object KeywordValues {
 
         val classifier = { info: ExpectedInfo ->
             if (info.fuzzyType != null && info.fuzzyType!!.type.isMarkedNullable())
-                ExpectedInfoClassification.matches(TypeSubstitutor.EMPTY)
+                ExpectedInfoClassification.match(TypeSubstitutor.EMPTY)
             else
-                ExpectedInfoClassification.notMatches
+                ExpectedInfoClassification.noMatch
         }
         collection.addLookupElements(null, expectedInfos, classifier) {
             LookupElementBuilder.create("null").bold().assignSmartCompletionPriority(SmartCompletionItemPriority.NULL)

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

@@ -75,7 +75,7 @@ class StaticMembers(
                 classifier = { expectedInfo -> returnType.classifyExpectedInfo(expectedInfo) }
             }
             else if (DescriptorUtils.isEnumEntry(descriptor) && !enumEntriesToSkip.contains(descriptor)) {
-                classifier = { ExpectedInfoClassification.matches(TypeSubstitutor.EMPTY) } /* we do not need to check type of enum entry because it's taken from proper enum */
+                classifier = { ExpectedInfoClassification.match(TypeSubstitutor.EMPTY) } /* we do not need to check type of enum entry because it's taken from proper enum */
             }
             else {
                 return

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

@@ -124,10 +124,12 @@ private constructor(
         val substitutor: TypeSubstitutor?,
         val makeNotNullable: Boolean
 ) {
+    fun isMatch() = substitutor != null && !makeNotNullable
+
     companion object {
-        val notMatches = ExpectedInfoClassification(null, false)
-        fun matches(substitutor: TypeSubstitutor) = ExpectedInfoClassification(substitutor, false)
-        fun matchesIfNotNullable(substitutor: TypeSubstitutor) = ExpectedInfoClassification(substitutor, true)
+        val noMatch = ExpectedInfoClassification(null, false)
+        fun match(substitutor: TypeSubstitutor) = ExpectedInfoClassification(substitutor, false)
+        fun ifNotNullMatch(substitutor: TypeSubstitutor) = ExpectedInfoClassification(substitutor, true)
     }
 }
 
@@ -135,17 +137,17 @@ fun Collection<FuzzyType>.classifyExpectedInfo(expectedInfo: ExpectedInfo): Expe
     val sequence = asSequence()
     val substitutor = sequence.map { expectedInfo.matchingSubstitutor(it) }.firstOrNull()
     if (substitutor != null) {
-        return ExpectedInfoClassification.matches(substitutor)
+        return ExpectedInfoClassification.match(substitutor)
     }
 
     if (sequence.any { it.nullability() == TypeNullability.NULLABLE }) {
         val substitutor2 = sequence.map { expectedInfo.matchingSubstitutor(it.makeNotNullable()) }.firstOrNull()
         if (substitutor2 != null) {
-            return ExpectedInfoClassification.matchesIfNotNullable(substitutor2)
+            return ExpectedInfoClassification.ifNotNullMatch(substitutor2)
         }
     }
 
-    return ExpectedInfoClassification.notMatches
+    return ExpectedInfoClassification.noMatch
 }
 
 fun FuzzyType.classifyExpectedInfo(expectedInfo: ExpectedInfo) = listOf(this).classifyExpectedInfo(expectedInfo)

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

@@ -0,0 +1,10 @@
+fun foo(xxx1: String?, xxx2: String, xxx3: Any, xp: String?) {
+    bar(x<caret>)
+}
+
+fun bar(pXxx: String){}
+
+// ORDER: xxx2
+// ORDER: xxx1
+// ORDER: xp
+// ORDER: xxx3

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

@@ -157,6 +157,12 @@ public class BasicCompletionWeigherTestGenerated extends AbstractBasicCompletion
             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("PreferMatchingThis.kt")
         public void testPreferMatchingThis() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/idea-completion/testData/weighers/basic/expectedInfo/PreferMatchingThis.kt");