FIR: Add ConeVisibilityError to distinguish between candidates that are

invisible versus hidden due to deprecation.

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/coneDiagnosticToFirDiagnostic.kt

@@ -45,6 +45,7 @@ private fun ConeDiagnostic.toFirDiagnostic(
     is ConeFunctionExpectedError -> FirErrors.FUNCTION_EXPECTED.createOn(source, this.expression, this.type)
     is ConeResolutionToClassifierError -> FirErrors.RESOLUTION_TO_CLASSIFIER.createOn(source, this.candidateSymbol)
     is ConeHiddenCandidateError -> FirErrors.INVISIBLE_REFERENCE.createOn(source, this.candidateSymbol)
+    is ConeVisibilityError -> FirErrors.INVISIBLE_REFERENCE.createOn(source, this.candidateSymbol)
     is ConeInapplicableWrongReceiver -> FirErrors.UNRESOLVED_REFERENCE_WRONG_RECEIVER.createOn(source, this.candidateSymbols)
     is ConeNoCompanionObject -> FirErrors.NO_COMPANION_OBJECT.createOn(source, this.candidateSymbol)
     is ConeAmbiguityError -> when {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/FirCallResolver.kt

@@ -704,6 +704,7 @@ class FirCallResolver(
                 val candidate = candidates.single()
                 val diagnostic = when (applicability) {
                     CandidateApplicability.HIDDEN -> ConeHiddenCandidateError(candidate.symbol)
+                    CandidateApplicability.VISIBILITY_ERROR -> ConeVisibilityError(candidate.symbol)
                     CandidateApplicability.INAPPLICABLE_WRONG_RECEIVER -> ConeInapplicableWrongReceiver(listOf(candidate.symbol))
                     CandidateApplicability.NO_COMPANION_OBJECT -> ConeNoCompanionObject(candidate.symbol as FirRegularClassSymbol)
                     else -> ConeInapplicableCandidateError(applicability, candidate)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolutionDiagnostic.kt

@@ -63,6 +63,8 @@ object InapplicableCandidate : ResolutionDiagnostic(INAPPLICABLE)
 
 object HiddenCandidate : ResolutionDiagnostic(HIDDEN)
 
+object VisibilityError : ResolutionDiagnostic(VISIBILITY_ERROR)
+
 object ResolvedWithLowPriority : ResolutionDiagnostic(RESOLVED_LOW_PRIORITY)
 
 class InapplicableWrongReceiver(

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ResolutionStages.kt

@@ -237,7 +237,7 @@ internal object CheckVisibility : CheckerStage() {
 
             if (classSymbol is FirRegularClassSymbol) {
                 if (classSymbol.fir.classKind.isSingleton) {
-                    sink.yieldDiagnostic(HiddenCandidate)
+                    sink.yieldDiagnostic(VisibilityError)
                 }
                 checkVisibility(classSymbol.fir, sink, candidate, visibilityChecker)
             }
@@ -251,7 +251,7 @@ internal object CheckVisibility : CheckerStage() {
         visibilityChecker: FirVisibilityChecker
     ): Boolean {
         if (!visibilityChecker.isVisible(declaration, candidate)) {
-            sink.yieldDiagnostic(HiddenCandidate)
+            sink.yieldDiagnostic(VisibilityError)
             return false
         }
         return true

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/diagnostics/FirDiagnostics.kt

@@ -72,6 +72,12 @@ class ConeResolutionToClassifierError(override val candidateSymbol: FirRegularCl
 
 class ConeHiddenCandidateError(
     override val candidateSymbol: FirBasedSymbol<*>
+) : ConeDiagnosticWithSingleCandidate {
+    override val reason: String get() = "HIDDEN: ${describeSymbol(candidateSymbol)} is deprecated with DeprecationLevel.HIDDEN"
+}
+
+class ConeVisibilityError(
+    override val candidateSymbol: FirBasedSymbol<*>
 ) : ConeDiagnosticWithSingleCandidate {
     override val reason: String get() = "HIDDEN: ${describeSymbol(candidateSymbol)} is invisible"
 }

compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/tower/CandidateApplicability.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.resolve.calls.tower
 enum class CandidateApplicability {
     RESOLVED_TO_SAM_WITH_VARARG, // migration warning up to 1.5 (when resolve to function with SAM conversion and array without spread as vararg)
     HIDDEN, // removed from resolve
+    VISIBILITY_ERROR, // problems with visibility
     UNSUPPORTED, // unsupported feature
     INAPPLICABLE_WRONG_RECEIVER, // receiver not matched
     INAPPLICABLE_ARGUMENTS_MAPPING_ERROR, // arguments not mapped to parameters (i.e. different size of arguments and parameters)
@@ -15,7 +16,7 @@ enum class CandidateApplicability {
     INAPPLICABLE_MODIFIER, // no expected modifier (eg infix call on non-infix function)
     NO_COMPANION_OBJECT, // Classifier does not have a companion object
     IMPOSSIBLE_TO_GENERATE, // access to outer class from nested
-    RUNTIME_ERROR, // problems with visibility
+    RUNTIME_ERROR, // TODO: FE 1.0 uses this as catch-all for all other errors. Consider re-assigning those diagnostics.
     UNSAFE_CALL, // receiver or argument nullability doesn't match
     UNSTABLE_SMARTCAST, // unstable smart cast
     CONVENTION_ERROR, // missing infix, operator etc