[FIR] Support when exhaustiveness for java enum

The problem appear because for java enum its entries was represented by
FirJavaField. To fix this FirEnumEntry was used

#KT-39621 Fixed

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/DefaultEnum.fir.txt

@@ -11,8 +11,7 @@ public/*package*/ open class A : R|kotlin/Any| {
 
 }
 public final enum class Mixed : R|kotlin/Enum<ft<Mixed, Mixed?>!>| {
-    public final static field NOT_ENTRY_EITHER: R|Mixed|
-
+    public final static enum entry NOT_ENTRY_EITHER: R|Mixed|
     public final static fun values(): R|kotlin/Array<Mixed>| {
     }
 
@@ -21,10 +20,8 @@ public final enum class Mixed : R|kotlin/Enum<ft<Mixed, Mixed?>!>| {
 
 }
 public final enum class Signs : R|kotlin/Enum<ft<Signs, Signs?>!>| {
-    public final static field HELLO: R|Signs|
-
-    public final static field WORLD: R|Signs|
-
+    public final static enum entry HELLO: R|Signs|
+    public final static enum entry WORLD: R|Signs|
     public final static field X: R|ft<Signs, Signs?>!|
 
     public final static fun values(): R|kotlin/Array<Signs>| {

compiler/fir/analysis-tests/testData/resolve/exhaustiveness_enumJava.kt

@@ -0,0 +1,60 @@
+// FILE: JavaEnum.java
+public enum JavaEnum {
+    A, B, C;
+
+    public int i = 0;
+}
+
+// FILE: main.kt
+fun test_1(e: JavaEnum) {
+    val a = when (e) {
+        JavaEnum.A -> 1
+        JavaEnum.B -> 2
+    }.<!UNRESOLVED_REFERENCE!>plus<!>(0)
+
+    val b = when (e) {
+        JavaEnum.A -> 1
+        JavaEnum.B -> 2
+        is String -> 3
+    }.<!UNRESOLVED_REFERENCE!>plus<!>(0)
+
+    val c = when (e) {
+        JavaEnum.A -> 1
+        JavaEnum.B -> 2
+        JavaEnum.C -> 3
+    }.plus(0)
+
+    val d = when (e) {
+        JavaEnum.A -> 1
+        else -> 2
+    }.plus(0)
+}
+
+fun test_2(e: JavaEnum?) {
+    val a = when (e) {
+        JavaEnum.A -> 1
+        JavaEnum.B -> 2
+        JavaEnum.C -> 3
+    }.<!UNRESOLVED_REFERENCE!>plus<!>(0)
+
+    val a = when (e) {
+        JavaEnum.A -> 1
+        JavaEnum.B -> 2
+        JavaEnum.C -> 3
+        null -> 4
+    }.plus(0)
+
+    val a = when (e) {
+        JavaEnum.A -> 1
+        JavaEnum.B -> 2
+        JavaEnum.C -> 3
+        else -> 4
+    }.plus(0)
+}
+
+fun test_3(e: JavaEnum) {
+    val a = when (e) {
+        JavaEnum.A, JavaEnum.B -> 1
+        JavaEnum.C -> 2
+    }.plus(0)
+}

compiler/fir/analysis-tests/testData/resolve/exhaustiveness_enumJava.txt

@@ -0,0 +1,100 @@
+FILE: main.kt
+    public final fun test_1(e: R|JavaEnum|): R|kotlin/Unit| {
+        lval a: <ERROR TYPE REF: Unresolved name: plus> = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.B|) ->  {
+                Int(2)
+            }
+        }
+        .<Unresolved name: plus>#(Int(0))
+        lval b: <ERROR TYPE REF: Unresolved name: plus> = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.B|) ->  {
+                Int(2)
+            }
+            ($subj$ is R|kotlin/String|) ->  {
+                Int(3)
+            }
+        }
+        .<Unresolved name: plus>#(Int(0))
+        lval c: R|kotlin/Int| = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.B|) ->  {
+                Int(2)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.C|) ->  {
+                Int(3)
+            }
+        }
+        .R|kotlin/Int.plus|(Int(0))
+        lval d: R|kotlin/Int| = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) ->  {
+                Int(1)
+            }
+            else ->  {
+                Int(2)
+            }
+        }
+        .R|kotlin/Int.plus|(Int(0))
+    }
+    public final fun test_2(e: R|JavaEnum?|): R|kotlin/Unit| {
+        lval a: <ERROR TYPE REF: Unresolved name: plus> = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.B|) ->  {
+                Int(2)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.C|) ->  {
+                Int(3)
+            }
+        }
+        .<Unresolved name: plus>#(Int(0))
+        lval a: R|kotlin/Int| = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.B|) ->  {
+                Int(2)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.C|) ->  {
+                Int(3)
+            }
+            ==($subj$, Null(null)) ->  {
+                Int(4)
+            }
+        }
+        .R|kotlin/Int.plus|(Int(0))
+        lval a: R|kotlin/Int| = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.B|) ->  {
+                Int(2)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.C|) ->  {
+                Int(3)
+            }
+            else ->  {
+                Int(4)
+            }
+        }
+        .R|kotlin/Int.plus|(Int(0))
+    }
+    public final fun test_3(e: R|JavaEnum|): R|kotlin/Unit| {
+        lval a: R|kotlin/Int| = when (R|<local>/e|) {
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.A|) || ==($subj$, Q|JavaEnum|.R|/JavaEnum.B|) ->  {
+                Int(1)
+            }
+            ==($subj$, Q|JavaEnum|.R|/JavaEnum.C|) ->  {
+                Int(2)
+            }
+        }
+        .R|kotlin/Int.plus|(Int(0))
+    }

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirDiagnosticsTestGenerated.java

@@ -133,6 +133,11 @@ public class FirDiagnosticsTestGenerated extends AbstractFirDiagnosticsTest {
         runTest("compiler/fir/analysis-tests/testData/resolve/exhaustiveness_enum.kt");
     }
 
+    @TestMetadata("exhaustiveness_enumJava.kt")
+    public void testExhaustiveness_enumJava() throws Exception {
+        runTest("compiler/fir/analysis-tests/testData/resolve/exhaustiveness_enumJava.kt");
+    }
+
     @TestMetadata("exhaustiveness_sealedClass.kt")
     public void testExhaustiveness_sealedClass() throws Exception {
         runTest("compiler/fir/analysis-tests/testData/resolve/exhaustiveness_sealedClass.kt");

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirDiagnosticsWithLightTreeTestGenerated.java

@@ -133,6 +133,11 @@ public class FirDiagnosticsWithLightTreeTestGenerated extends AbstractFirDiagnos
         runTest("compiler/fir/analysis-tests/testData/resolve/exhaustiveness_enum.kt");
     }
 
+    @TestMetadata("exhaustiveness_enumJava.kt")
+    public void testExhaustiveness_enumJava() throws Exception {
+        runTest("compiler/fir/analysis-tests/testData/resolve/exhaustiveness_enumJava.kt");
+    }
+
     @TestMetadata("exhaustiveness_sealedClass.kt")
     public void testExhaustiveness_sealedClass() throws Exception {
         runTest("compiler/fir/analysis-tests/testData/resolve/exhaustiveness_sealedClass.kt");

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/java/JavaClassRendering.kt

@@ -9,12 +9,14 @@ import org.jetbrains.kotlin.fir.FirRenderer
 import org.jetbrains.kotlin.fir.FirSession
 import org.jetbrains.kotlin.fir.declarations.FirCallableMemberDeclaration
 import org.jetbrains.kotlin.fir.declarations.FirDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirEnumEntry
 import org.jetbrains.kotlin.fir.java.declarations.FirJavaClass
 import org.jetbrains.kotlin.fir.java.declarations.FirJavaConstructor
 import org.jetbrains.kotlin.fir.java.declarations.FirJavaField
 import org.jetbrains.kotlin.fir.java.declarations.FirJavaMethod
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
 import org.jetbrains.kotlin.fir.resolve.buildUseSiteMemberScope
+import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
 
 fun renderJavaClass(renderer: FirRenderer, javaClass: FirJavaClass, session: FirSession) {
     val memberScope = javaClass.buildUseSiteMemberScope(session, ScopeSession())
@@ -28,6 +30,16 @@ fun renderJavaClass(renderer: FirRenderer, javaClass: FirJavaClass, session: Fir
         renderer.renderSupertypes(javaClass)
         renderer.renderInBraces {
             val renderedDeclarations = mutableListOf<FirDeclaration>()
+
+            fun renderAndCache(symbol: FirCallableSymbol<*>) {
+                val enhanced = symbol.fir
+                if (enhanced !in renderedDeclarations) {
+                    enhanced.accept(renderer, null)
+                    renderer.newLine()
+                    renderedDeclarations += enhanced
+                }
+            }
+
             for (declaration in javaClass.declarations) {
                 if (declaration in renderedDeclarations) continue
 
@@ -38,30 +50,10 @@ fun renderJavaClass(renderer: FirRenderer, javaClass: FirJavaClass, session: Fir
                         memberScope
 
                 when (declaration) {
-                    is FirJavaConstructor -> scopeToUse!!.processDeclaredConstructors { symbol ->
-                        val enhanced = symbol.fir
-                        if (enhanced !in renderedDeclarations) {
-                            enhanced.accept(renderer, null)
-                            renderer.newLine()
-                            renderedDeclarations += enhanced
-                        }
-                    }
-                    is FirJavaMethod -> scopeToUse!!.processFunctionsByName(declaration.name) { symbol ->
-                        val enhanced = symbol.fir
-                        if (enhanced !in renderedDeclarations) {
-                            enhanced.accept(renderer, null)
-                            renderer.newLine()
-                            renderedDeclarations += enhanced
-                        }
-                    }
-                    is FirJavaField -> scopeToUse!!.processPropertiesByName(declaration.name) { symbol ->
-                        val enhanced = symbol.fir
-                        if (enhanced !in renderedDeclarations) {
-                            enhanced.accept(renderer, null)
-                            renderer.newLine()
-                            renderedDeclarations += enhanced
-                        }
-                    }
+                    is FirJavaConstructor -> scopeToUse!!.processDeclaredConstructors(::renderAndCache)
+                    is FirJavaMethod -> scopeToUse!!.processFunctionsByName(declaration.name, ::renderAndCache)
+                    is FirJavaField -> scopeToUse!!.processPropertiesByName(declaration.name, ::renderAndCache)
+                    is FirEnumEntry -> scopeToUse!!.processPropertiesByName(declaration.name, ::renderAndCache)
                     else -> {
                         declaration.accept(renderer, null)
                         renderer.newLine()

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt

@@ -11,16 +11,10 @@ import com.intellij.psi.PsiElement
 import com.intellij.psi.search.GlobalSearchScope
 import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.descriptors.Visibility
-import org.jetbrains.kotlin.fir.FirSession
-import org.jetbrains.kotlin.fir.declarations.FirDeclarationOrigin
-import org.jetbrains.kotlin.fir.declarations.FirRegularClass
-import org.jetbrains.kotlin.fir.declarations.FirTypeParameter
-import org.jetbrains.kotlin.fir.declarations.addDefaultBoundIfNecessary
-import org.jetbrains.kotlin.fir.declarations.builder.FirTypeParameterBuilder
-import org.jetbrains.kotlin.fir.declarations.builder.buildConstructedClassTypeParameterRef
-import org.jetbrains.kotlin.fir.declarations.builder.buildOuterClassTypeParameterRef
-import org.jetbrains.kotlin.fir.generateValueOfFunction
-import org.jetbrains.kotlin.fir.generateValuesFunction
+import org.jetbrains.kotlin.fir.*
+import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.builder.*
+import org.jetbrains.kotlin.fir.declarations.impl.FirDeclarationStatusImpl
 import org.jetbrains.kotlin.fir.java.declarations.*
 import org.jetbrains.kotlin.fir.resolve.constructType
 import org.jetbrains.kotlin.fir.resolve.providers.AbstractFirSymbolProvider
@@ -30,7 +24,6 @@ import org.jetbrains.kotlin.fir.scopes.impl.lazyNestedClassifierScope
 import org.jetbrains.kotlin.fir.scopes.impl.nestedClassifierScope
 import org.jetbrains.kotlin.fir.symbols.CallableId
 import org.jetbrains.kotlin.fir.symbols.impl.*
-import org.jetbrains.kotlin.fir.toFirPsiSourceElement
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.impl.ConeTypeParameterTypeImpl
 import org.jetbrains.kotlin.load.java.JavaClassFinder
@@ -191,22 +184,39 @@ class JavaSymbolProvider(
                     for (javaField in javaClass.fields) {
                         val fieldName = javaField.name
                         val fieldId = CallableId(classId.packageFqName, classId.relativeClassName, fieldName)
-                        val fieldSymbol = FirFieldSymbol(fieldId)
                         val returnType = javaField.type
-                        val firJavaField = buildJavaField {
-                            source = (javaField as? JavaElementImpl<*>)?.psi?.toFirPsiSourceElement()
-                            session = this@JavaSymbolProvider.session
-                            symbol = fieldSymbol
-                            name = fieldName
-                            visibility = javaField.visibility
-                            modality = javaField.modality
-                            returnTypeRef = returnType.toFirJavaTypeRef(this@JavaSymbolProvider.session, javaTypeParameterStack)
-                            isVar = !javaField.isFinal
-                            isStatic = javaField.isStatic
-                            isEnumEntry = javaField.isEnumEntry
-                            addAnnotationsFrom(this@JavaSymbolProvider.session, javaField, javaTypeParameterStack)
+                        val firJavaDeclaration = when {
+                            javaField.isEnumEntry -> buildEnumEntry {
+                                source = (javaField as? JavaElementImpl<*>)?.psi?.toFirPsiSourceElement()
+                                session = this@JavaSymbolProvider.session
+                                symbol = FirVariableSymbol(fieldId)
+                                name = fieldName
+                                status = FirDeclarationStatusImpl(javaField.visibility, javaField.modality).apply {
+                                    isStatic = javaField.isStatic
+                                    isExpect = false
+                                    isActual = false
+                                    isOverride = false
+                                }
+                                returnTypeRef = returnType.toFirJavaTypeRef(this@JavaSymbolProvider.session, javaTypeParameterStack)
+                                resolvePhase = FirResolvePhase.ANALYZED_DEPENDENCIES
+                                origin = FirDeclarationOrigin.Java
+                                addAnnotationsFrom(this@JavaSymbolProvider.session, javaField, javaTypeParameterStack)
+                            }
+                            else -> buildJavaField {
+                                source = (javaField as? JavaElementImpl<*>)?.psi?.toFirPsiSourceElement()
+                                session = this@JavaSymbolProvider.session
+                                symbol = FirFieldSymbol(fieldId)
+                                name = fieldName
+                                visibility = javaField.visibility
+                                modality = javaField.modality
+                                returnTypeRef = returnType.toFirJavaTypeRef(this@JavaSymbolProvider.session, javaTypeParameterStack)
+                                isVar = !javaField.isFinal
+                                isStatic = javaField.isStatic
+                                isEnumEntry = javaField.isEnumEntry
+                                addAnnotationsFrom(this@JavaSymbolProvider.session, javaField, javaTypeParameterStack)
+                            }
                         }
-                        declarations += firJavaField
+                        declarations += firJavaDeclaration
                     }
                     for (javaMethod in javaClass.methods) {
                         val methodName = javaMethod.name

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/enhancement/SignatureEnhancement.kt

@@ -69,21 +69,22 @@ class FirSignatureEnhancement(
         name: Name
     ): FirVariableSymbol<*> {
         when (val firElement = original.fir) {
-            is FirField -> {
+            is FirEnumEntry -> {
                 if (firElement.returnTypeRef !is FirJavaTypeRef) return original
                 val memberContext = context.copyWithNewDefaultTypeQualifiers(typeQualifierResolver, jsr305State, firElement.annotations)
-                val isEnumEntry = (firElement as? FirJavaField)?.isEnumEntry ?: false
-
-                val predefinedInfo = if (isEnumEntry) {
+                val predefinedInfo =
                     PredefinedFunctionEnhancementInfo(
                         TypeEnhancementInfo(0 to JavaTypeQualifiers(NullabilityQualifier.NOT_NULL, null, false)),
                         emptyList()
                     )
-                } else {
-                    null
-                }
 
                 val newReturnTypeRef = enhanceReturnType(firElement, emptyList(), memberContext, predefinedInfo)
+                return firElement.symbol.apply { this.fir.replaceReturnTypeRef(newReturnTypeRef) }
+            }
+            is FirField -> {
+                if (firElement.returnTypeRef !is FirJavaTypeRef) return original
+                val memberContext = context.copyWithNewDefaultTypeQualifiers(typeQualifierResolver, jsr305State, firElement.annotations)
+                val newReturnTypeRef = enhanceReturnType(firElement, emptyList(), memberContext, null)
 
                 val symbol = FirFieldSymbol(original.callableId)
                 buildJavaField {

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirRenderer.kt

@@ -342,7 +342,6 @@ class FirRenderer(builder: StringBuilder, private val mode: RenderMode = RenderM
     }
 
     override fun visitEnumEntry(enumEntry: FirEnumEntry) {
-        enumEntry.annotations.renderAnnotations()
         visitCallableDeclaration(enumEntry)
         enumEntry.initializer?.let {
             print(" = ")