[FE 1.0] Don't expand type enhancement

Actually shallow type enhancement is primary, it's more specific

^KT-50734 Fixed

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendForeignAnnotationsCompiledJavaTestGenerated.java

@@ -98,6 +98,12 @@ public class FirOldFrontendForeignAnnotationsCompiledJavaTestGenerated extends A
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt48316_multiModuleAnnotationDefault.kt");
         }
 
+        @Test
+        @TestMetadata("kt50734.kt")
+        public void testKt50734() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.kt");
+        }
+
         @Test
         @TestMetadata("lombokSimple.kt")
         public void testLombokSimple() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendForeignAnnotationsCompiledJavaWithPsiClassReadingTestGenerated.java

@@ -98,6 +98,12 @@ public class FirOldFrontendForeignAnnotationsCompiledJavaWithPsiClassReadingTest
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt48316_multiModuleAnnotationDefault.kt");
         }
 
+        @Test
+        @TestMetadata("kt50734.kt")
+        public void testKt50734() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.kt");
+        }
+
         @Test
         @TestMetadata("lombokSimple.kt")
         public void testLombokSimple() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendForeignAnnotationsSourceJavaTestGenerated.java

@@ -98,6 +98,12 @@ public class FirOldFrontendForeignAnnotationsSourceJavaTestGenerated extends Abs
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt48316_multiModuleAnnotationDefault.kt");
         }
 
+        @Test
+        @TestMetadata("kt50734.kt")
+        public void testKt50734() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.kt");
+        }
+
         @Test
         @TestMetadata("lombokSimple.kt")
         public void testLombokSimple() throws Exception {

compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.fir.kt

@@ -0,0 +1,40 @@
+// FILE: Supplier.java
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.annotations.Nullable;
+
+// Shown from RxJava for reference
+@FunctionalInterface
+public interface Supplier<@NonNull T> {
+    T get() throws Throwable;
+}
+
+// FILE: Maybe.java
+public abstract class Maybe<T> {
+    public final void subscribe() {}
+}
+
+// FILE: FromSupplier.java
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.annotations.Nullable;
+
+public class FromSupplier {
+    static <@NonNull T> Maybe<T> fromSupplier3(Supplier<? extends @Nullable T> supplier) {
+        return null;
+    }
+    static <@NonNull T> Maybe<T> fromSupplier5(@NonNull Supplier<? extends @Nullable T> supplier) {
+        return null;
+    }
+}
+
+// FILE: main.kt
+fun main() {
+    // No Warning
+    // In this case, we have nullable type enhancement
+    FromSupplier.fromSupplier3<Boolean> { null }
+        .subscribe()
+
+    // In this case, we have not-null type enhancement
+    // Warning: Type Mismatch: Required Boolean? found Nothing
+    FromSupplier.fromSupplier5<Boolean> { null }
+        .subscribe()
+}

compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.kt

@@ -0,0 +1,41 @@
+
+// FILE: Supplier.java
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.annotations.Nullable;
+
+// Shown from RxJava for reference
+@FunctionalInterface
+public interface Supplier<@NonNull T> {
+    T get() throws Throwable;
+}
+
+// FILE: Maybe.java
+public abstract class Maybe<T> {
+    public final void subscribe() {}
+}
+
+// FILE: FromSupplier.java
+import io.reactivex.rxjava3.annotations.NonNull;
+import io.reactivex.rxjava3.annotations.Nullable;
+
+public class FromSupplier {
+    static <@NonNull T> Maybe<T> fromSupplier3(Supplier<? extends @Nullable T> supplier) {
+        return null;
+    }
+    static <@NonNull T> Maybe<T> fromSupplier5(@NonNull Supplier<? extends @Nullable T> supplier) {
+        return null;
+    }
+}
+
+// FILE: main.kt
+fun main() {
+    // No Warning
+    // In this case, we have nullable type enhancement
+    FromSupplier.fromSupplier3<Boolean> { <!NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>null<!> }
+        .subscribe()
+
+    // In this case, we have not-null type enhancement
+    // Warning: Type Mismatch: Required Boolean? found Nothing
+    FromSupplier.fromSupplier5<Boolean> { <!NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS!>null<!> }
+        .subscribe()
+}

compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.txt

@@ -0,0 +1,29 @@
+package
+
+public fun main(): kotlin.Unit
+
+public open class FromSupplier {
+    public constructor FromSupplier()
+    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
+
+    // Static members
+    public/*package*/ open fun </*0*/ @io.reactivex.rxjava3.annotations.NonNull T : kotlin.Any!> fromSupplier3(/*0*/ supplier: Supplier<out @io.reactivex.rxjava3.annotations.Nullable T!>!): Maybe<T!>!
+    public/*package*/ open fun </*0*/ @io.reactivex.rxjava3.annotations.NonNull T : kotlin.Any!> fromSupplier5(/*0*/ @io.reactivex.rxjava3.annotations.NonNull supplier: @io.reactivex.rxjava3.annotations.NonNull Supplier<out @io.reactivex.rxjava3.annotations.Nullable T!>!): Maybe<T!>!
+}
+
+public abstract class Maybe</*0*/ T : kotlin.Any!> {
+    public constructor Maybe</*0*/ T : kotlin.Any!>()
+    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 final fun subscribe(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+@FunctionalInterface /* annotation class not found */ public interface Supplier</*0*/ @io.reactivex.rxjava3.annotations.NonNull T : kotlin.Any!> {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun get(): T!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

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

@@ -98,6 +98,12 @@ public class ForeignAnnotationsCompiledJavaTestGenerated extends AbstractForeign
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt48316_multiModuleAnnotationDefault.kt");
         }
 
+        @Test
+        @TestMetadata("kt50734.kt")
+        public void testKt50734() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.kt");
+        }
+
         @Test
         @TestMetadata("lombokSimple.kt")
         public void testLombokSimple() throws Exception {

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

@@ -98,6 +98,12 @@ public class ForeignAnnotationsCompiledJavaWithPsiClassReadingTestGenerated exte
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt48316_multiModuleAnnotationDefault.kt");
         }
 
+        @Test
+        @TestMetadata("kt50734.kt")
+        public void testKt50734() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.kt");
+        }
+
         @Test
         @TestMetadata("lombokSimple.kt")
         public void testLombokSimple() throws Exception {

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

@@ -98,6 +98,12 @@ public class ForeignAnnotationsSourceJavaTestGenerated extends AbstractForeignAn
             runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt48316_multiModuleAnnotationDefault.kt");
         }
 
+        @Test
+        @TestMetadata("kt50734.kt")
+        public void testKt50734() throws Exception {
+            runTest("compiler/testData/diagnostics/foreignAnnotationsTests/tests/kt50734.kt");
+        }
+
         @Test
         @TestMetadata("lombokSimple.kt")
         public void testLombokSimple() throws Exception {

core/descriptors/src/org/jetbrains/kotlin/types/TypeSubstitutor.java

@@ -193,7 +193,7 @@ public class TypeSubstitutor implements TypeSubstitutorMarker {
             KotlinType substitutedEnhancement = substitute(enhancement, originalProjection.getProjectionKind());
             KotlinType resultingType = TypeWithEnhancementKt.wrapEnhancement(
                     substitution.getType().unwrap(),
-                    substitutedEnhancement instanceof TypeWithEnhancement ? ((TypeWithEnhancement) substitutedEnhancement).getEnhancement() : substitutedEnhancement
+                    substitutedEnhancement
             );
 
             return new TypeProjectionImpl(substitution.getProjectionKind(), resultingType);