Don't show type hints for SAM constructors

#KT-22050 Fixed

idea/src/org/jetbrains/kotlin/idea/parameterInfo/TypeHints.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.descriptors.ConstructorDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.core.formatter.KotlinCodeStyleSettings
 import org.jetbrains.kotlin.idea.intentions.SpecifyTypeExplicitlyIntention
+import org.jetbrains.kotlin.load.java.sam.SamConstructorDescriptor
 import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.endOffset
@@ -82,9 +83,12 @@ private fun isUnclearType(type: KotlinType, element: KtCallableDeclaration): Boo
         if (initializer is KtCallExpression) {
             val bindingContext = element.analyze()
             val resolvedCall = initializer.getResolvedCall(bindingContext)
-            val constructorDescriptor = resolvedCall?.candidateDescriptor as? ConstructorDescriptor
+            val resolvedDescriptor = resolvedCall?.candidateDescriptor
-            if (constructorDescriptor != null &&
+            if (resolvedDescriptor is SamConstructorDescriptor) {
-                (constructorDescriptor.constructedClass.declaredTypeParameters.isEmpty() || initializer.typeArgumentList != null)) {
+                return false
+            }
+            if (resolvedDescriptor is ConstructorDescriptor &&
+                (resolvedDescriptor.constructedClass.declaredTypeParameters.isEmpty() || initializer.typeArgumentList != null)) {
                 return false
             }
         }

idea/tests/org/jetbrains/kotlin/idea/parameterInfo/InlayTypeHintsTest.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2010-2017 JetBrains s.r.o.
+ * Copyright 2000-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
- *
+ * that can be found in the license/LICENSE.txt file.
- * 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.parameterInfo
@@ -116,4 +105,9 @@ class InlayTypeHintsTest : KotlinLightCodeInsightFixtureTestCase() {
                 return Triple(<hint text="first:" />"A", <hint text="second:" />"B", <hint text="third:" />"C")
             }""")
     }
+
+    fun testSAMConstructor() {
+        HintType.PROPERTY_HINT.option.set(true)
+        check("""val x = Runnable { }""")
+    }
 }