Uast: create KotlinULambdaExpression for in-place lambdas (KT-25297)

and provide appropriate functionalInterface

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/KotlinUastLanguagePlugin.kt

@@ -184,7 +184,10 @@ class KotlinUastLanguagePlugin : UastLanguagePlugin {
                 is KtFunction ->
                     if (original.isLocal) {
                         el<ULambdaExpression> {
-                            if (original.name.isNullOrEmpty() || original.parent is KtLambdaExpression) {
+                            val parent = original.parent
+                            if (parent is KtLambdaExpression) {
+                                KotlinULambdaExpression(parent, givenParent) // your parent is the ULambdaExpression
+                            } else if (original.name.isNullOrEmpty()) {
                                 createLocalFunctionLambdaExpression(original, givenParent)
                             }
                             else {

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/KotlinUastLanguagePlugin.kt.172

@@ -179,7 +179,10 @@ class KotlinUastLanguagePlugin : UastLanguagePlugin {
                 is KtFunction ->
                     if (original.isLocal) {
                         el<ULambdaExpression> {
-                            if (original.name.isNullOrEmpty() || original.parent is KtLambdaExpression) {
+                            val parent = original.parent
+                            if (parent is KtLambdaExpression) {
+                                KotlinULambdaExpression(parent, givenParent) // your parent is the ULambdaExpression
+                            } else if (original.name.isNullOrEmpty()) {
                                 createLocalFunctionLambdaExpression(original, givenParent)
                             }
                             else {

plugins/uast-kotlin/src/org/jetbrains/uast/kotlin/KotlinUastLanguagePlugin.kt.173

@@ -183,7 +183,10 @@ class KotlinUastLanguagePlugin : UastLanguagePlugin {
                 is KtFunction ->
                     if (original.isLocal) {
                         el<ULambdaExpression> {
-                            if (original.name.isNullOrEmpty() || original.parent is KtLambdaExpression) {
+                            val parent = original.parent
+                            if (parent is KtLambdaExpression) {
+                                KotlinULambdaExpression(parent, givenParent) // your parent is the ULambdaExpression
+                            } else if (original.name.isNullOrEmpty()) {
                                 createLocalFunctionLambdaExpression(original, givenParent)
                             }
                             else {

plugins/uast-kotlin/testData/Lambdas.kt

@@ -0,0 +1,5 @@
+import java.util.stream.Stream
+
+fun foo() {
+    Stream.empty<String>().filter { it.isEmpty() }
+}

plugins/uast-kotlin/tests/KotlinUastApiTest.kt

@@ -7,6 +7,7 @@ import org.jetbrains.kotlin.asJava.toLightAnnotation
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.test.testFramework.KtUsefulTestCase
+import org.jetbrains.kotlin.utils.addToStdlib.assertedCast
 import org.jetbrains.kotlin.utils.addToStdlib.cast
 import org.jetbrains.kotlin.utils.sure
 import org.jetbrains.uast.*
@@ -360,6 +361,20 @@ class KotlinUastApiTest : AbstractKotlinUastTest() {
         barMethod.assertResolveCall("contains(2 as Int)", "longRangeContains")
         barMethod.assertResolveCall("IntRange(1, 2)")
     }
+
+    @Test
+    fun testUtilsStreamLambda() {
+        doTest("Lambdas") { _, file ->
+            val lambda = file.findElementByTextFromPsi<ULambdaExpression>("{ it.isEmpty() }")
+            assertEquals(
+                "kotlin.jvm.functions.Function1<? super java.lang.String,? extends java.lang.Boolean>",
+                lambda.getExpressionType()?.canonicalText
+            )
+            val uCallExpression = lambda.uastParent.assertedCast<UCallExpression> { "UCallExpression expected" }
+            assertTrue(uCallExpression.valueArguments.contains(lambda))
+        }
+    }
+
 }
 
 fun <T, R> Iterable<T>.assertedFind(value: R, transform: (T) -> R): T =

plugins/uast-kotlin/tests/KotlinUastApiTest.kt.172

@@ -7,6 +7,7 @@ import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 import org.jetbrains.kotlin.test.testFramework.KtUsefulTestCase
+import org.jetbrains.kotlin.utils.addToStdlib.assertedCast
 import org.jetbrains.kotlin.utils.addToStdlib.cast
 import org.jetbrains.kotlin.utils.sure
 import org.jetbrains.uast.*
@@ -214,4 +215,16 @@ class KotlinUastApiTest : AbstractKotlinUastTest() {
         barMethod.assertResolveCall("joinToString()")
         barMethod.assertResolveCall("last()")
     }
+
+    @Test
+    fun testUtilsStreamLambda() {
+        doTest("Lambdas") { _, file ->
+            val lambda = file.findElementByTextFromPsi<ULambdaExpression>("{ it.isEmpty() }")
+            assertEquals(
+                "kotlin.jvm.functions.Function1<? super java.lang.String,? extends java.lang.Boolean>",
+                lambda.getExpressionType()?.canonicalText
+            )
+            val uCallExpression = lambda.uastParent.assertedCast<UCallExpression> { "UCallExpression expected" }
+            assertTrue(uCallExpression.valueArguments.contains(lambda))
+        }
 }

plugins/uast-kotlin/tests/KotlinUastApiTest.kt.173

@@ -8,6 +8,7 @@ import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
 import org.jetbrains.kotlin.psi.psiUtil.parentsWithSelf
 import org.jetbrains.kotlin.test.testFramework.KtUsefulTestCase
+import org.jetbrains.kotlin.utils.addToStdlib.assertedCast
 import org.jetbrains.kotlin.utils.addToStdlib.cast
 import org.jetbrains.kotlin.utils.sure
 import org.jetbrains.uast.*
@@ -324,6 +325,20 @@ class KotlinUastApiTest : AbstractKotlinUastTest() {
         barMethod.assertResolveCall("joinToString()")
         barMethod.assertResolveCall("last()")
     }
+
+    @Test
+    fun testUtilsStreamLambda() {
+        doTest("Lambdas") { _, file ->
+            val lambda = file.findElementByTextFromPsi<ULambdaExpression>("{ it.isEmpty() }")
+            assertEquals(
+                "kotlin.jvm.functions.Function1<? super java.lang.String,? extends java.lang.Boolean>",
+                lambda.getExpressionType()?.canonicalText
+            )
+            val uCallExpression = lambda.uastParent.assertedCast<UCallExpression> { "UCallExpression expected" }
+            assertTrue(uCallExpression.valueArguments.contains(lambda))
+        }
+    }
+
 }
 
 fun <T, R> Iterable<T>.assertedFind(value: R, transform: (T) -> R): T = find { transform(it) == value } ?: throw AssertionError("'$value' not found, only ${this.joinToString { transform(it).toString() }}")