"Call on collection type may be reduced": fix false positive with mapNotNull, generic lambda block and new inference

#KT-32801 Fixed

idea/src/org/jetbrains/kotlin/idea/inspections/collections/UselessCallOnCollectionInspection.kt

@@ -19,6 +19,7 @@ import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.calls.callUtil.getType
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
 import org.jetbrains.kotlin.types.KotlinType
+import org.jetbrains.kotlin.resolve.calls.inference.model.TypeVariableTypeConstructor
 import org.jetbrains.kotlin.types.TypeUtils
 import org.jetbrains.kotlin.types.isFlexible
 import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
@@ -53,7 +54,9 @@ class UselessCallOnCollectionInspection : AbstractUselessCallInspection() {
             if (TypeUtils.isNullableType(receiverTypeArgument)) return
             if (calleeExpression.text != "filterNotNull") {
                 // Also check last argument functional type to have not-null result
-                if (!resolvedCall.hasLastFunctionalParameterWithResult(context) { !TypeUtils.isNullableType(it) }) return
+                if (!resolvedCall.hasLastFunctionalParameterWithResult(context) {
+                        !TypeUtils.isNullableType(it) && it.constructor !is TypeVariableTypeConstructor
+                    }) return
             }
         }
 

idea/testData/inspectionsLocal/collections/uselessCallOnCollection/MapNotNullWithGenericLambda.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+// COMPILER_ARGUMENTS: -XXLanguage:+NewInference
+// WITH_RUNTIME
+
+fun <R> mylet(block: () -> R): R = block()
+
+val x = listOf(1, 2, 3).<caret>mapNotNull {
+    mylet {
+        null
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -1990,6 +1990,11 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
                 runTest("idea/testData/inspectionsLocal/collections/uselessCallOnCollection/MapNotNullTo.kt");
             }
 
+            @TestMetadata("MapNotNullWithGenericLambda.kt")
+            public void testMapNotNullWithGenericLambda() throws Exception {
+                runTest("idea/testData/inspectionsLocal/collections/uselessCallOnCollection/MapNotNullWithGenericLambda.kt");
+            }
+
             @TestMetadata("MapNotNullWithLambda.kt")
             public void testMapNotNullWithLambda() throws Exception {
                 runTest("idea/testData/inspectionsLocal/collections/uselessCallOnCollection/MapNotNullWithLambda.kt");