[AA] KT-56617 Sync hashCode/equals of Java and regular class symbols

- Some completion tests failed because the `hashCode` of
  `KtFirNamedClassOrObjectSymbol` and `KtFirPsiJavaClassSymbol` was
  different for symbols which should be equal. Both symbols now use the
  `ClassId` hash code.
- `KtFirNamedClassOrObjectSymbol.equals` is now properly symmetric with
  `KtFirPsiJavaClassSymbol`.
- `KtFirPsiJavaClassSymbol` now has a definite class ID, which
  simplifies its implementation a little. `KtFirPsiJavaClassSymbol`
  doesn't support local Java classes by design.

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirVisibilityChecker.kt

@@ -82,13 +82,6 @@ internal class KtFirVisibilityChecker(
      * Returns `null` if visibility cannot be decided by the heuristic.
      */
     private fun KtFirPsiJavaClassSymbol.isVisibleByPsi(useSiteFile: KtFirFileSymbol): Boolean? {
-        val classId = classIdIfNonLocal
-        if (classId == null) {
-            // Local classes are only visible in their containing method. Since we're checking the visibility for a Kotlin file, a local
-            // class from Java can never be accessible.
-            return false
-        }
-
         when (visibility) {
             Visibilities.Private ->
                 // Private classes from Java cannot be accessed from Kotlin.
@@ -101,7 +94,7 @@ internal class KtFirVisibilityChecker(
                 }
 
             JavaVisibilities.PackageVisibility -> {
-                val isSamePackage = classId.packageFqName == useSiteFile.firSymbol.fir.packageFqName
+                val isSamePackage = classIdIfNonLocal.packageFqName == useSiteFile.firSymbol.fir.packageFqName
                 if (!isSamePackage) return false
 
                 return when (val outerClass = this.outerClass) {

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/symbols/KtFirNamedClassOrObjectSymbol.kt

@@ -10,7 +10,6 @@ import org.jetbrains.kotlin.analysis.api.KtAnalysisApiInternals
 import org.jetbrains.kotlin.analysis.api.KtAnalysisSession
 import org.jetbrains.kotlin.analysis.api.base.KtContextReceiver
 import org.jetbrains.kotlin.analysis.api.fir.KtFirAnalysisSession
-import org.jetbrains.kotlin.analysis.api.fir.KtSymbolByFirBuilder
 import org.jetbrains.kotlin.analysis.api.fir.annotations.KtFirAnnotationListForDeclaration
 import org.jetbrains.kotlin.analysis.api.fir.findPsi
 import org.jetbrains.kotlin.analysis.api.fir.utils.cached
@@ -105,6 +104,22 @@ internal class KtFirNamedClassOrObjectSymbol(
         createNamedClassOrObjectSymbolPointer()
     }
 
-    override fun equals(other: Any?): Boolean = symbolEquals(other)
-    override fun hashCode(): Int = symbolHashCode()
+    /**
+     * [KtFirNamedClassOrObjectSymbol] must be able to equal [KtFirPsiJavaClassSymbol].
+     */
+    override fun equals(other: Any?): Boolean {
+        if (other === this) return true
+
+        return when (other) {
+            is KtFirNamedClassOrObjectSymbol -> symbolEquals(other)
+            is KtFirPsiJavaClassSymbol -> other == this
+            else -> false
+        }
+    }
+
+    /**
+     * A non-local [KtFirNamedClassOrObjectSymbol] must have the same kind of hash code as [KtFirPsiJavaClassSymbol] so that they are
+     * interchangeable in collections.
+     */
+    override fun hashCode(): Int = classIdIfNonLocal?.hashCode() ?: symbolHashCode()
 }

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/symbols/KtFirPsiJavaClassSymbol.kt

@@ -46,12 +46,6 @@ internal class KtFirPsiJavaClassSymbol(
     override val psi: PsiClass,
     override val analysisSession: KtFirAnalysisSession,
 ) : KtNamedClassOrObjectSymbol(), KtFirPsiSymbol<PsiClass, FirRegularClassSymbol> {
-    init {
-        require(psi.qualifiedName != null) {
-            "${KtFirPsiJavaClassSymbol::class.simpleName} requires a PSI class with a qualified name."
-        }
-    }
-
     /**
      * [javaClass] is used to defer some properties to the compiler's view of a Java class.
      */
@@ -59,20 +53,17 @@ internal class KtFirPsiJavaClassSymbol(
 
     override val name: Name = withValidityAssertion { javaClass.name }
 
-    override val classIdIfNonLocal: ClassId? by cached { psi.classIdIfNonLocal }
-
-    private val qualifiedName: String
-        get() = withValidityAssertion { psi.qualifiedName!! }
+    override val classIdIfNonLocal: ClassId = withValidityAssertion {
+        psi.classIdIfNonLocal ?: error("${KtFirPsiJavaClassSymbol::class.simpleName} requires a non-local PSI class.")
+    }
 
     override val origin: KtSymbolOrigin
         get() = withValidityAssertion { KtSymbolOrigin.JAVA }
 
     override val symbolKind: KtSymbolKind
         get() = withValidityAssertion {
-            val classId = classIdIfNonLocal
             when {
-                classId == null -> KtSymbolKind.LOCAL
-                classId.outerClassId != null -> KtSymbolKind.CLASS_MEMBER
+                classIdIfNonLocal.outerClassId != null -> KtSymbolKind.CLASS_MEMBER
                 else -> KtSymbolKind.TOP_LEVEL
             }
         }
@@ -88,7 +79,7 @@ internal class KtFirPsiJavaClassSymbol(
         get() = withValidityAssertion { javaClass.visibility }
 
     override val isInner: Boolean
-        get() = withValidityAssertion { classIdIfNonLocal?.outerClassId != null && !javaClass.isStatic }
+        get() = withValidityAssertion { classIdIfNonLocal.outerClassId != null && !javaClass.isStatic }
 
     val outerClass: KtFirPsiJavaClassSymbol?
         get() = withValidityAssertion {
@@ -128,9 +119,11 @@ internal class KtFirPsiJavaClassSymbol(
     }
 
     /**
-     * Since [PsiEquivalenceUtil] doesn't have a hash code function, we use the class's fully qualified name as a conservative hash code.
+     * Since [PsiEquivalenceUtil] doesn't have a hash code function, we use the class ID as a conservative hash code.
+     *
+     * Also see [KtFirNamedClassOrObjectSymbol.hashCode], which must generate the same hash code for non-local classes.
      */
-    override fun hashCode(): Int = qualifiedName.hashCode()
+    override fun hashCode(): Int = classIdIfNonLocal.hashCode()
 
     ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
     // Slow Operations (requiring access to the underlying FIR class symbol)