Do preparation of enhancement as well (for types with enhancement), during subtype checks

^KT-47899 Fixed

compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/warnMode/kt47899.kt

@@ -0,0 +1,15 @@
+// JSPECIFY_STATE: warn
+
+// FILE: Foo.java
+import org.jspecify.nullness.Nullable;
+
+public class Foo {
+    public static <T> void gauge(@Nullable T stateObject) {}
+}
+
+// FILE: main.kt
+fun <T> test(metric: T) {
+    if (metric is String) {
+        Foo.gauge(<!DEBUG_INFO_SMARTCAST!>metric<!>)
+    }
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/ForeignAnnotationsCompiledJavaTestGenerated.java

@@ -808,6 +808,12 @@ public class ForeignAnnotationsCompiledJavaTestGenerated extends AbstractForeign
                     runTest("compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/warnMode/IgnoreAnnotations.fir.kt");
                 }
 
+                @Test
+                @TestMetadata("kt47899.kt")
+                public void testKt47899() throws Exception {
+                    runTest("compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/warnMode/kt47899.kt");
+                }
+
                 @Test
                 @TestMetadata("NonPlatformTypeParameter.kt")
                 public void testNonPlatformTypeParameter() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/ForeignAnnotationsCompiledJavaWithPsiClassReadingTestGenerated.java

@@ -808,6 +808,12 @@ public class ForeignAnnotationsCompiledJavaWithPsiClassReadingTestGenerated exte
                     runTest("compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/warnMode/IgnoreAnnotations.fir.kt");
                 }
 
+                @Test
+                @TestMetadata("kt47899.kt")
+                public void testKt47899() throws Exception {
+                    runTest("compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/warnMode/kt47899.kt");
+                }
+
                 @Test
                 @TestMetadata("NonPlatformTypeParameter.kt")
                 public void testNonPlatformTypeParameter() throws Exception {

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/ForeignAnnotationsSourceJavaTestGenerated.java

@@ -808,6 +808,12 @@ public class ForeignAnnotationsSourceJavaTestGenerated extends AbstractForeignAn
                     runTest("compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/warnMode/IgnoreAnnotations.fir.kt");
                 }
 
+                @Test
+                @TestMetadata("kt47899.kt")
+                public void testKt47899() throws Exception {
+                    runTest("compiler/testData/diagnostics/foreignAnnotationsTests/java8Tests/jspecify/warnMode/kt47899.kt");
+                }
+
                 @Test
                 @TestMetadata("NonPlatformTypeParameter.kt")
                 public void testNonPlatformTypeParameter() throws Exception {

core/descriptors/src/org/jetbrains/kotlin/types/TypeWithEnhancement.kt

@@ -144,6 +144,9 @@ fun KotlinType.unwrapEnhancementDeeply() = getEnhancementDeeply() ?: this
 
 fun KotlinType.unwrapEnhancement(): KotlinType = getEnhancement() ?: this
 
+fun UnwrappedType.inheritEnhancement(origin: KotlinType, transform: (KotlinType) -> KotlinType): UnwrappedType =
+    wrapEnhancement(origin.getEnhancement()?.let(transform))
+
 fun UnwrappedType.inheritEnhancement(origin: KotlinType): UnwrappedType = wrapEnhancement(origin.getEnhancement())
 
 fun UnwrappedType.wrapEnhancement(enhancement: KotlinType?): UnwrappedType {

core/descriptors/src/org/jetbrains/kotlin/types/checker/KotlinTypePreparator.kt

@@ -68,7 +68,7 @@ abstract class KotlinTypePreparator : AbstractTypePreparator {
                     unwrappedType
                 }
             }
-        }.inheritEnhancement(unwrappedType)
+        }.inheritEnhancement(unwrappedType, ::prepareType)
     }
 
     object Default : KotlinTypePreparator()