[NI] Infer type variable to Nothing if all upper constraints are from upper bounds

#KT-32196 Fixed

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestGenerated.java

@@ -9893,6 +9893,11 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
             runTest("compiler/testData/diagnostics/tests/inference/kt3184.kt");
         }
 
+        @TestMetadata("kt32196.kt")
+        public void testKt32196() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/inference/kt32196.kt");
+        }
+
         @TestMetadata("kt32415.kt")
         public void testKt32415() throws Exception {
             runTest("compiler/testData/diagnostics/tests/inference/kt32415.kt");

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/ResultTypeResolver.kt

@@ -18,10 +18,7 @@ package org.jetbrains.kotlin.resolve.calls.inference.components
 
 import org.jetbrains.kotlin.resolve.calls.NewCommonSuperTypeCalculator
 import org.jetbrains.kotlin.resolve.calls.inference.components.TypeVariableDirectionCalculator.ResolveDirection
-import org.jetbrains.kotlin.resolve.calls.inference.model.Constraint
-import org.jetbrains.kotlin.resolve.calls.inference.model.ConstraintKind
-import org.jetbrains.kotlin.resolve.calls.inference.model.VariableWithConstraints
-import org.jetbrains.kotlin.resolve.calls.inference.model.checkConstraint
+import org.jetbrains.kotlin.resolve.calls.inference.model.*
 import org.jetbrains.kotlin.types.AbstractTypeApproximator
 import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
 import org.jetbrains.kotlin.types.model.KotlinTypeMarker
@@ -82,7 +79,15 @@ class ResultTypeResolver(
             if (!checkConstraint(this, constraint.type, constraint.kind, resultType)) return false
         }
 
-        if (!trivialConstraintTypeInferenceOracle.isSuitableResultedType(resultType)) return false
+        /*
+         * If all upper constraints came from declared upper bounds we should accept Nothing
+         *   as suitable type as OI does
+         */
+        if (
+            variableWithConstraints.constraints.any {
+                it.kind == ConstraintKind.UPPER && it.position.from !is DeclaredUpperBoundConstraintPosition
+            } && !trivialConstraintTypeInferenceOracle.isSuitableResultedType(resultType)
+        ) return false
 
         return true
     }

compiler/testData/diagnostics/tests/inference/kt32196.fir.kt

@@ -0,0 +1,9 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+class Inv<T>
+
+fun <R : Any> Inv<Int>.mapNotNull(transform: (Int) -> R?): Inv<R> = null!!
+
+fun test(inv: Inv<Int>) {
+    inv.mapNotNull { null }
+}

compiler/testData/diagnostics/tests/inference/kt32196.kt

@@ -0,0 +1,9 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+class Inv<T>
+
+fun <R : Any> Inv<Int>.mapNotNull(transform: (Int) -> R?): Inv<R> = null!!
+
+fun test(inv: Inv<Int>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("Inv<kotlin.Nothing>")!>inv.mapNotNull { null }<!>
+}

compiler/testData/diagnostics/tests/inference/kt32196.txt

@@ -0,0 +1,11 @@
+package
+
+public fun test(/*0*/ inv: Inv<kotlin.Int>): kotlin.Unit
+public fun </*0*/ R : kotlin.Any> Inv<kotlin.Int>.mapNotNull(/*0*/ transform: (kotlin.Int) -> R?): Inv<R>
+
+public final class Inv</*0*/ T> {
+    public constructor Inv</*0*/ T>()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -9900,6 +9900,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/inference/kt3184.kt");
             }
 
+            @TestMetadata("kt32196.kt")
+            public void testKt32196() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/kt32196.kt");
+            }
+
             @TestMetadata("kt32415.kt")
             public void testKt32415() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/kt32415.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -9895,6 +9895,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inference/kt3184.kt");
             }
 
+            @TestMetadata("kt32196.kt")
+            public void testKt32196() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/kt32196.kt");
+            }
+
             @TestMetadata("kt32415.kt")
             public void testKt32415() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/kt32415.kt");