[NI] Fix extracting type variables for flexible types in in captured types

Bug was introduced in b99efb because of lack of tests.
All code in `AbstractTypeCheckerContextForConstraintSystem.extractTypeVariableForSubtype`
  related to IN projection looks suspicious and needs further investigation

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

@@ -9541,6 +9541,11 @@ public class FirDiagnosticsSmokeTestGenerated extends AbstractFirDiagnosticsSmok
             runTest("compiler/testData/diagnostics/tests/inference/cannotCompleteResolveWithFunctionLiterals.kt");
         }
 
+        @TestMetadata("capturedInProjectedFlexibleType.kt")
+        public void testCapturedInProjectedFlexibleType() throws Exception {
+            runTest("compiler/testData/diagnostics/tests/inference/capturedInProjectedFlexibleType.kt");
+        }
+
         @TestMetadata("coerceFunctionLiteralToSuspend.kt")
         public void testCoerceFunctionLiteralToSuspend() throws Exception {
             runTest("compiler/testData/diagnostics/tests/inference/coerceFunctionLiteralToSuspend.kt");

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

@@ -90,7 +90,7 @@ abstract class AbstractTypeCheckerContextForConstraintSystem : AbstractTypeCheck
         val projection = typeMarker.typeConstructorProjection()
         if (projection.isStarProjection()) return null
         if (projection.getVariance() == TypeVariance.IN) {
-            val type = projection.getType().let { it.asSimpleType() ?: it.asFlexibleType()?.lowerBound() } ?: return null
+            val type = projection.getType().asSimpleType() ?: return null
             if (isMyTypeVariable(type)) {
                 simplifyLowerConstraint(type, superType)
                 if (isMyTypeVariable(superType.asSimpleType() ?: return null)) {

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

@@ -0,0 +1,16 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+// FILE: A.java
+
+public class A<T> {
+    public A<? super T> getSuperA() { return null; }
+}
+
+// FILE: main.kt
+
+fun <T : Any> foo(x: T?, func: (T) -> T?) {}
+
+fun test(a: A<*>) {
+    foo(a) { it.superA }
+}

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

@@ -0,0 +1,12 @@
+package
+
+public fun </*0*/ T : kotlin.Any> foo(/*0*/ x: T?, /*1*/ func: (T) -> T?): kotlin.Unit
+public fun test(/*0*/ a: A<*>): kotlin.Unit
+
+public open class A</*0*/ T : kotlin.Any!> {
+    public constructor A</*0*/ T : kotlin.Any!>()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open fun getSuperA(): A<in T!>!
+    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

@@ -9548,6 +9548,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/inference/cannotCompleteResolveWithFunctionLiterals.kt");
             }
 
+            @TestMetadata("capturedInProjectedFlexibleType.kt")
+            public void testCapturedInProjectedFlexibleType() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/capturedInProjectedFlexibleType.kt");
+            }
+
             @TestMetadata("coerceFunctionLiteralToSuspend.kt")
             public void testCoerceFunctionLiteralToSuspend() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/coerceFunctionLiteralToSuspend.kt");

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

@@ -9543,6 +9543,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inference/cannotCompleteResolveWithFunctionLiterals.kt");
             }
 
+            @TestMetadata("capturedInProjectedFlexibleType.kt")
+            public void testCapturedInProjectedFlexibleType() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/capturedInProjectedFlexibleType.kt");
+            }
+
             @TestMetadata("coerceFunctionLiteralToSuspend.kt")
             public void testCoerceFunctionLiteralToSuspend() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/coerceFunctionLiteralToSuspend.kt");